فهرست مطالب

پژوهش های علوم دامی - سال بیست و نهم شماره 1 (بهار 1398)
  • سال بیست و نهم شماره 1 (بهار 1398)
  • تاریخ انتشار: 1398/03/01
  • تعداد عناوین: 12
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  • حسین امیرزاده شمالی، سید عباس رافت*، جلیل شجاع، صادق علیجانی، لیلا ایرانزاده صفحات 1-14
    زمینه مطالعاتی
    هم خونی یکی از فاکتور های مهمی است که می تواند شیر تولیدی و سود اقتصادی را در گله های گاو شیری کاهش دهد.
    هدف
    هدف تحقیق این است که اثر همخونی بر روی صفات تولیدی گاو نژاد سرابی که از نژاد های در معرض نابودی است دانسته شود.
    روش کار
    در این تحقیق از داده های 1250 راس گاو نژاد سرابی که طی  سال های 1370 تا 1390 در مرکز پشتیبانی گاو بومی سرابی ثبت شده بود استفاده گردید. بر این اساس ضریب هم خونی در سال های مختلف محاسبه گردید و اثر  هم خونی به حالت  گسسته بر تولید شیر، چربی، پروتئین، درصد چربی، درصد پروتئین و وزن تولد بررسی شد. رکورد های تحت بررسی شامل 4208 رکورد تولید شیر، چربی، پروتئین، درصد چربی، درصد پروتیین و 961 رکورد وزن تولد بود.
    نتایج
    ضریب هم خونی در این گله بین 28/-0 برآورد شد. از کل گله، 19% حیوانات هم خون بودند. میانگین ضریب هم خونی در کل جمعیت 0109/0 و در بین افراد هم خون 0574/0  برآورد گردید.   نتایج بدست آمده نشان داد که عامل هم خونی به همراه سال-فصل زایش و شکم زایش به لحاظ آماری اثر معنی داری بر صفات  تحت بررسی داشت (01/0 >P). ضرایب تابعیت هم خونی در دو حالت پیوسته و گسسته اندازه گیری شد. در حالت پیوسته بر صفات تولید شیر، درصد چربی و درصد پروتئین به ازای افزایش یک درصد هم خونی به ترتیب 69/2- کیلوگرم، 59/1+% ، 18/1+% بدست آمد؛ و در حالت  متغیر گسسته  به ترتیب 129/0- کیلوگرم، 093/0+% و 072/0+% بود. میزان ضریب تابعیت هم خونی بر صفت وزن تولد در حالت متغیر گسسته برابر 564/0- کیلوگرم بود.
    نتیجه گیری نهایی
    برای حفظ ذخایر ژنتیکی کشور که گاو نژاد سرابی یکی از مهمترین آنها است، لازم است مدیریت تلاقی ها در جمعیت گاو سرابی بدقت تحت نظر قرار گیرد. با عنایت به تلاقی نژاد سرابی با نژاد هلشتاین و کاهش تدریجی تعداد گاو نژاد سرابی لازم است پدیده هم خونی و نحوه تلاقی ها بخوبی رصد شود تا از انقراض این نژاد جلوگیری بعمل آید.
    کلیدواژگان: پس روی همخونی، تولید شیر، وزن تولد، گاو سرابی
  • زهرا هاشمی، طاهره محمد آبادی*، مرتضی چاجی، صالح طباطبایی صفحات 15-33
    زمینه مطالعاتی
     مغز میوه بلوط به عنوان منبع انرژی در تغذیه دام نشخوار کننده استفاده می شود و تانن آن فعالیت میکروارگانیسم های شکمبه را تحت تاثیر قرار می دهد.
    هدف
    این آزمایش به منظور بررسی اثر مغز میوه بلوط بر جمعیت و فعالیت هضمی باکتری ها، قارچ ها و جمعیت پروتوزوآی شکمبه بز نجدی و گوسفند عربی انجام گرفت.
    روش کار
    بدین منظور 6 راس بز نجدی و 6 راس گوسفند عربی (با میانگین وزن 2 ± 35) برای 28 روز با جیره های آزمایشی حاوی مغز میوه بلوط و بدون مغز میوه بلوط (شاهد) تغذیه شدند.
    نتایج
    ناپدید شدن ماده خشک، الیاف نامحلول در شوینده خنثی و الیاف نامحلول در شوینده اسیدی توسط باکتری های شکمبه بز تیمار شاهد در زمان های 24، 48 و72 ساعت بیشتر از تیمار بلوط بود (05/0>P). ناپدید شدن ماده خشک، الیاف نامحلول در شوینده خنثی و الیاف نامحلول در شوینده اسیدی توسط قارچ های شکمبه بز و گوسفند بین تیمار شاهد و بلوط در زمان های 3 و 6 روز تفاوت معنی داری داشت (05/0>P). پتانسیل تولید گاز کاه گندم، پارتشینینگ فاکتور، تولید توده میکروبی، راندمان توده میکروبی و ماده آلی واقعا هضم شده توسط باکتری ها و قارچ های شکمبه گوسفند و بز در تیمار شاهد و تیمار بلوط اختلافی نداشتند (05/0P>). ماده آلی واقعا هضم شده در تیمار شاهد بالاتر از تیمار بلوط بود (05/0P<). میزان پارتشینینگ فاکتور توسط قارچ های شکمبه گوسفند در جیره حاوی بلوط بالاتر از بز شد و ماده آلی واقعا هضم شده توسط قارچ های شکمبه بز در جیره شاهد بالاتر از گوسفند بود (05/0P<). جمعیت کل پروتوزوآ و گونه هولوتریش تیمار بلوط در گوسفند و بز کاهش یافت (05/0P<). جمعیت باکتری ها و قارچ های شکمبه تیمار شاهد بز نسبت به تیمار شاهد گوسفند بیشتر بود.
    نتیجه گیری نهایی
    استفاده از 63 درصد مغز میوه بلوط منجر به کاهش جمعیت، ناپدید شدن مواد مغذی، فراسنجه های تخمیری باکتری ها و قارچها و کاهش جمعیت پروتوزوآی شکمبه در گوسفند عربی و بز نجدی شد همچنین نتایج، تحمل بیشتر بزها نسبت به تانن های جیره در مقایسه با گوسفند را نشان داد.
    کلیدواژگان: محیط کشت، مغز میوه بلوط، میکروارگانیسم ها، ناپدیدشدن
  • آرش حسن زاده سیدی*، حسین جانمحمدی، سید علی میرقلنج، مجید علیایی صفحات 35-47
    زمینه مطالعاتی
    تغذیه سطوح مورد نیاز اسید آمینه والین نقش موثری بر عملکرد جوجه های گوشتی دارد.
    هدف
    این آزمایش به منظور تعیین احتیاجات اسید آمینه والین قابل هضم و اثرات آن بر صفات عملکردی جوجه خروس های گوشتی سویه راس 308 انجام گرفت.
    روش کار
    تعیین احتیاجات اسید آمینه والین براساس شاخص های عملکردی جوجه خروس های گوشتی در قالب طرح کاملا تصادفی با450 قطعه جوجه یک روزه سویه راس 308 از سن 8 تا 21 روزگی در 6 تیمار و 5 تکرار (15 پرنده در هر تکرار) انجام گردید. جیره غذایی پایه حاوی ذرت و کنجاله سویا برای مقادیر کافی تمام مواد مغذی به جز اسید آمینه والین تنظیم گردید. سطوح افزایشی اسید آمینه والین به جیره غذایی پایه جهت ایجاد 6 سطح اسید آمینه والین قابل هضم، در دامنه 74/0 تا 99/0 درصد تامین گردید. افزایش وزن بدن، مصرف خوراک، ضریب تبدیل غذایی، راندمان غذایی و میزان مصرف اسید آمینه والین قابل هضم طی دوره آزمایشی اندازه گیری شد.
    نتایج
    مدل خطوط شکسته غیرخطی برای برآورد احتیاجات والین قابل هضم جوجه های گوشتی سویه راس 308 به خوبی روی داده های افزایش وزن، خوراک مصرفی و ضریب تبدیل غذایی برازش داده شد و میزان والین قابل هضم مورد نیاز برای این سه صفت به ترتیب 85/0، 95/0 و 84/0 درصد جیره غذایی برآورد گردید. میانگین مقادیر شاخص های افزایش وزن بدن، مصرف خوراک، ضریب تبدیل غذایی، راندمان غذایی و میزان مصرف اسید آمینه والین قابل هضم به طور معنی داری تحت تاثیر اسید آمینه والین قرار گرفت (01/0>p). بطوریکه کمترین مقادیر ضریب تبدیل غذایی و بالاترین راندمان غذایی مربوط به سطح 89/0 درصد اسید آمینه والین بود.
    نتیجه گیری نهایی
    با توجه به نتایج، میزان احتیاجات اسیدآمینه والین برای حداکثر عملکرد جوجه های گوشتی بین 84/0 تا 95/0 متغییر می باشد و اختلاف چشمگیری بین احتیاجات والین برآورد شده سویه راس 308در دوره رشد با سایر منابع مشاهده شد.
    کلیدواژگان: اسید آمینه والین، مدل خط شکسته غیرخطی، جوجه خروس گوشتی، سویه راس 308
  • محمد شمس الهی، حسین دقیق کیا*، غلامعلی مقدم، اکبر تقی زاده صفحات 49-60
    زمینه مطالعاتی
    لسیتین سویا می تواند بعنوان رقیق کننده در فرآیند انجماد اسپرم مورد استفاده قرار گیرد.
    هدف
    هدف از این مطالعه بررسی اثر سطوح مختلف لسیتین سویا بعنوان رقیق کننده بر روی کیفیت اسپرم قوچ بعد از فرآیند انجماد-یخ گشایی می باشد.
    روش کار
    در این تحقیق نمونه های منی با استفاده از واژن مصنوعی از پنج راس قوچ نژاد قزل به صورت هفته ای دوبار جمع آوری شد. برای حذف اثرات فردی، نمونه ها پس از ارزیابی اولیه با هم مخلوط شدند. سطوح مختلف لسیتین سویا بعنوان رقیق کننده (1، 5/1 و 2 درصد) به بافر تریس اضافه گردید. بعد از فرآوری و انجماد، نمونه ها تا زمان ارزیابی در ازت مایع نگهداری شدند. بعد از ذوب، تحرک اسپرم و پارامترهای حرکتی، زنده مانی، یکپارچگی غشاء پلاسمایی و آکروزومی، اسپرم های غیر طبیعی و مقدار لیپید پراکسیداسیون (MDA) مورد ارزیابی قرار گرفتند.
    نتایج
    نتایج نشان داد که تحرک کل و برخی پارامترهای حرکتی اسپرم (VSL، VCL، VAP و ALH) بطور معنی داری در گروه تیماری 5/1 درصد لسیتین سویا بیشتر بود (05/0P<). بین تیمارها به لحاظ زنده مانی، درصد اسپرم های غیر طبیعی، یکپارچگی غشاء پلاسمایی و پراکسیداسیون لیپیدها تفاوت معنی داری مشاهده نشد. یکپارچگی غشاء آکروزوم در گروه تیماری 5/1 درصد لسیتین سویا نسبت به سایر تیمارها بیشتر بود (05/0P<).
    نتیجه گیری کلی
    بطور خلاصه سطح 5/1 درصد لسیتین سویا نسبت به سایر سطوح عملکرد بهتری بر کیفیت اسپرم بعد از فرآیند انجماد-یخ گشایی داشت.
    کلیدواژگان: آکروزوم، اسپرم، انجماد-یخ گشایی، قوچ، لسیتین سویا
  • فاطمه ثانی، محمد قهرمان زاده، رویا ثانی، قادر دشتی * صفحات 61-76
    زمینه مطالعاتی
     امروزه بهبود بهره وری به عنوان بهترین و کارآمدترین روش دستیابی به رشد اقتصادی با توجه به کمیابی منابع تولیدی مطرح است. مدیریت بهره وری مستلزم شناخت اجزاء و تحلیل تغییرات آن در پروسه توسعه است.
    هدف
    مطالعه حاضر با هدف اندازه گیری و تجزیه روند تغییرات بهره وری گاوداری های شیری صنعتی صورت گرفت.
    روش کار
    این مطالعه با استفاده از روش تحلیل پوششی داده ها و شاخص هیکس مورستین به محاسبه و تجزیه بهره وری کل عوامل تولید می پردازد. آمار و اطلاعات مورد استفاده تحقیق از نتایج طرح آمارگیری نمونه ای گاوداری های صنعتی استان های کشور طی سال های 92-1369 جمع آوری گردید.
    نتایج
    نتایج نشان داد که در طی دوره 75-1369 شاخص رشد قیمت ستاده به رشد قیمت نهاده (TT) نسبت به سال پایه (1369) حدود 86 درصد افزایش یافته که این دوره با کاهش شاخص بهره وری کل عوامل تولید ((TFP به میزان 15 درصد همراه بوده است. بررسی شاخص TFP نیز حاکی از آن است که شاخص مذکور ابتدا سیر نزولی و سپس سیر صعودی داشته است و علیرغم نوسانات موجود در طی دوره زمانی 92-1369، به طور متوسط نسبت به سال پایه حدود 15 درصد افزایش یافته است. کارایی بهره وری کل عوامل تولید (TFPE) از سال 1369 تا سال 1392 روند کاهشی داشته و از 521/0 در سال 1369 به 248/0 در سال 1392 کاهش یافته است. همچنین ارزیابی و تحلیل منابع تغییرات TFP نشان داد که در دهه ی 1370 مهم ترین جزء تغییرات TFP، کارایی مقیاس پسماند ستاده گرا (ROSE) و در طی نیمه دوم دوره مطالعه، تغییرات تکنولوژی به عنوان یکی از اصلی ترین عناصر تغییرات TFP گاوداری های شیری صنعتی کشور محسوب می شود.
    نتیجه گیری نهایی
    همین امر نشان می دهد که برای افزایش بهره وری، بایستی توجه به ترویج تکنولوژی مد نظر قرار گیرد تا بتواند در فرآیند تولید ثمربخش باشد. در مجموع توسعه و ترویج نمادهای تکنولوژی از جمله گاوهای اصلاح نژاد شده، خدمات تلقیح مصنوعی و انتقال جنین و همچنین افزایش مقیاس تولید از طریق اعمال سیاست های تشویقی و حمایت از واحدهای تولیدی بزرگ می تواند به ارتقاء بهره وری عوامل تولیدی منجر شود.
    کلیدواژگان: بهره وری کل عوامل تولید، شاخص هیکس مورستین، کارایی بهره وری، کارایی مقیاس پسماند، گاوداری شیری
  • امین الله پورملکشاهی، علی خطیب جو*، فرشید فتاح نیا، هوشنگ جعفری صفحات 77-87
    زمینه مطالعاتی
     افزودن سیر و ال-کارنتین می تواند سبب بهبود عملکرد جوجه های گوشتی شود.
    هدف
    به منظور ارزیابی تاثیر ال-کارنیتین و پودر سیر بر عملکرد، فراسنجه های چربی خونی و خصوصیات لاشه جوجه های گوشتی این آزمایش طراحی شد. روش کار: آزمایش با استفاده از 480 قطعه جوجه گوشتی سویه آرین، در قالب فاکتوریل (5×2) بر پایه طرح کاملا تصادفی با 5 تیمار، 4 تکرار و 12 قطعه جوجه در هر تکرار و دو دوره کوتاه (3 هفته اول دوره پرورش) و بلند مدت (کل دوره پرورش) انجام شد. تیمارهای آزمایشی شامل جیره شاهد (بدون افزودنی)، جیره حاوی 02/0 درصد آنتی بیوتیک فلاوومایسین (کنترل مثبت)، جیره حاوی 5/1 درصد پودر سیر، جیره حاوی 025/0 درصد ال-کارنیتین و  جیره حاوی 025/0 درصد ال-کارنیتین و 5/1 درصد پودر سیر در دوره آزمایشی بودند.
    نتایج
    نتایج نشان داد که وزن زنده، افزایش وزن، میزان خوراک مصرفی و ضریب تبدیل جوجه های گوشتی تحت تاثیر جیره های آزمایشی و مدت زمان مصرف آن ها قرار نگرفت (05/0<P). افزودن پودر سیر یا ال-کارنیتین به جیره جوجه های گوشتی در کوتاه مدت سبب کاهش چربی حفره بطنی شد اما تغذیه بلند مدت افزودنی ها سبب افزایش درصد سینه جوجه های گوشتی شد (05/0>P). مدت زمان مصرف و جیره های آزمایشی بر تری گلیسرید، کلسترول، کلسترول-HDL، کلسترول-LDL سرم و اسید لاکتیک گوشت سینه تاثیر معنی داری نداشتند (05/0<P).
    نتیجه گیری نهایی
    به طور کلی کاربرد مکمل های ال-کارنیتین  به مقدار 025/0 درصد و پودر سیر به میزان 5/1 درصد در جیره جوجه های گوشتی به صورت مصرف کوتاه یا بلند مدت به دلیل افزایش هزینه ها در مقابل اثرات مثبت آنها قابل توصیه نمی باشد.
    کلیدواژگان: ال- کارنیتین، جوجه گوشتی، خصوصیات لاشه، سیر، عملکرد
  • فاطمه خسروی، محمد حسن فتحی نسری*، سید علیرضا وکیلی، همایون فرهنگ فر صفحات 89-105
    زمینه مطالعاتی
    افزودن برخی ترکیبات به جیره نشخوارکنندگان می تواند تولید متان را در شکمبه کاهش دهد.
    هدف
    هدف از انجام این آزمایش بررسی اثر فرآورده های انار (روغن خالص انار و پودر پوست انار) بر تولید گاز متان شکمبه ای تحت شرایط برون تنی بود.
    روش کار
    سوبسترای خوراکی پایه حاوی مخلوطی از یونجه خشک و کنسانتره بود که با نسبت 60 به 40 با هم مخلوط شدند. در آزمایش اول روغن انار به میزان 2، 4 و 6 درصد ماده خشک سوبسترا و در آزمایش دوم پودر پوست انار به میزان 5/2، 5 و 7 درصد ماده خشک سوبسترا به محیط کشت اضافه شد. تخمیر آزمایشگاهی با استفاده از مایع شکمبه و محیط کشت بی هوازی (منک و استینگاس 1988) در بطری های با حجم 120 میلی لیتر انجام گردید. محیط کشت بی هوازی (30 میلی لیتر) و ماده تلقیحی (10 میلی لیتر) درون هر بطری 120 میلی لیتری حاوی 200 میلی گرم سوبسترای خوراکی پایه ریخته شد. میزان تولید گاز در ساعت های 2، 4، 6، 8، 12، 16، 24، 48، 72 و 96 و میزان گاز دی اکسید کربن و متان پس از 24 ساعت انکوباسیون تعیین گردید و داده ها با نرم افزار آماری SAS و با رویه GLM در قالب طرح کامل تصادفی آنالیز شد.
    نتایج
    نتایج آزمایش اول نشان داد استفاده از روغن انار میزان تولید گاز شکمبه ای را در ساعت های مختلف  تحت تاثیر قرار نداد و فراسنجه های هضم، انرژی قابل متابولیسم و قابلیت هضم ماده آلی نیز تحت تاثیر تیمارهای مختلف قرار نگرفت.  استفاده از 6 درصد روغن انار میزان تولید متان را بطور معنی داری کاهش داد (05/0P<) در حالی که مقادیر کمتر آن تاثیر معنی داری بر تولید گاز متان نداشت. در آزمایش دوم استفاده از پودر پوست انار به میزان 5 و 5/7 درصد ماده خشک مقدار گاز تولیدی شکمبه را  در ساعت های 48، 72 و 96 انکوباسیون بطور معنی داری کاهش داد. همچنین درصد گاز متان تیمارهای حاوی پوست انار در مقایسه با تیمار شاهد بطور معنی داری کاهش یافت (05/0P<) اما تولید متان بین تیمارهای حاوی غلظت های مختلف پوست انار تفاوتی نداشت.
    نتیجه گیری نهایی
    با توجه به نتایج حاصله افزودن فرآورده های فرعی انار می تواند تولید گاز متان و اتلاف انرژی را تا حد زیادی در شکمبه کاهش دهد.
    کلیدواژگان: روغن انار، پودر پوست انار، گازهای شکمبه ای، تولید گاز متان
  • محمد امیری، لیلا هاشمی، فرهاد صمدیان، مصطفی قادری زفره‎ای * صفحات 107-123
    زمینه مطالعاتی
     متیلاسیون DNA اساسا در دی‏نوکلئوتیدهای CpG اتفاق می افتد و در تنظیم بیان ژنی درگیر می‏باشد. در پستانداران، مشخص شده است که بیش‎متیلاسون در جزایر CpG با پیری و بیماری‎های مختلف در دام مرتبط است. میزان نیمرخ متیلاسیون ژن‌ها می‌تواند به متخصص اصلاح نژاد کمک کند که برای مدیریت بیماریی که این ژن‌ها در آن درگیر هستند از روش‌های ژنتیک یا وراژنتیک استفاده کند.
    هدف
    کنکاش غیر مستقیم متیلاسیون DNA در سطح ژن‌های کاندیدای موثر در ورم پستان گاوشیری]ژن‌های اینترلوکین‌ 1 تا 13 (به جز اینترلوکین 8 و 9)، ژن‌ TNF و ژن اینترفرون گاما (در کل 13 ژن کاندید)[و پروتئین حاصل از این ژن‌ها هدف اصلی پژوهش حاضر است. امید بر آن که بتوان ژن‌های درگیر در این بیماری را از نظر میزان متیلاسیون گروه‌بندی کرد و به اهمیت پدیده ژنتیکی متیلاسیون ژن‌ها در مدیریت بیماری ورم پستان در گاو شیری پی برد.
    روش کار
    ویژگی‌‌هایی مثل مکان ژن، تعداد اگزون، طول کلی اکسون پیرایش یافته و حاشیه‎نویسی شده، درصد گوانین، تعداد گوانین، درصد سیتوزین، تعداد سیتوزین و طول ژن‌ها استخراج شدند. برای استخراج ویژگی‌های وراژنتیک ژن‌های مورد بررسی در این پژوهش، از ترکیبی از انواع نرم افزارهای برخط DBCAT ، SMS و Geneinfinity و یک نرم افزار متکی به ++ C استفاده شد. بعد از استخراج ویژگی‏های ژنی، مشاهده گردید که ژن‌های مورد بررسی از نظر اندازه، تعداد آکسون و درصد GC تفاوت زیادی با هم‌ دارند. با توجه به نوع الگوریتم استفاده شده برای شناسایی جزایر CpG، تعداد و طول جزایر CpG یافت شده متفاوت بود. CpGهای پیش‏بینی شده به عنوان معیاری غیر مستقیم برای بررسی میزان متیلاسیون در سطح DNA ژن‌ها به کار رفت.
    نتایج
    نتایج نشان داد که به طور میانگین کمتر از 50 درصد جزایر CpG در ناحیه راه‌انداز ژن‌ها قرار داشتند و جزایر CpG متیله شده بیشتر در نواحی بین ژنی توزیع شده بودند. بیشترین میزان متیلاسیون در اینترلوکین‌های 1، 2 و ژن TNF مشاهده شد که از مهم‏ترین ژن‌های سرکوب ورم پستان به شمار می‌روند. درجه متیلاسیون در پروتئین‌های حاصل از ژن‌های مورد بررسی، با نتایج متیلاسیون رخ داده در سطح دی‏ان‏ایی (DNA) این ژن‌ها همخوانی و مطابقت نداشت. پروتئین حاصله از اینترلوکین‌ 11 در قسمت‌های زیادی از ساختار اولیه خود دچار متیلاسیون می‌شود. در سطح DNA نیز این ژن، بیشترین تعداد CpG را در قسمت راه‌انداز خود داشت.
    نتیجه‏ گیری نهایی:
    ژن اینترلوکین‌ 11 می‌تواند از کاندید‌های مناسب برای انجام آزمایش‌های دمتیلاسیون، تهیه داروهای زیستی و بررسی اثر آن بر سرکوب عفونت ورم پستان باشد.
  • سید اصغر زاهد، امیر گنج خانلو، علی حسن پور * صفحات 125-136
    زمینه مطالعاتی
    بیماری لپتوسپیروزیس یک بیماری زئونوز است که عامل ایجاد کننده آن باکتری گرم منفی و هوازی لپتوسپیرا انتروگانس و سرووارهای گوناگون آن می‌باشد. این بیماری می‌تواند در دام ایجاد سقط جنین، ناباروری، کاهش تولید شیر، تورم بیضه‌ها، کاهش تولید اسپرم و متعاقب آن ایجاد هزینه‌های درمانی زیاد را در بر داشته باشد.
    هدف
    هدف از این بررسی میزان شیوع سرووارهای مهم لپتوسپیرا در جنس نر و ماده دام‌های (گاو، اسب، گوسفند و بز) شهرستان طارم در سنین متفاوت بود.
    روش کار
    200 نمونه خون (80 راس گاو، 10 راس اسب، 90 راس گوسفند، 20 راس بز) از ورید وداج دام‌های مناطق مختلف شهرستان طارم به صورت تصادفی جمع آوری شد و با روش میکروآگلوتیناسیون (MAT) مورد آزمایش قرار گرفتند.
    نتایج
    در 48 نمونه (24 درصد) شامل 23 راس گاو، 7 راس بز، 15 راس گوسفند و 3 راس اسب از بین 200 نمونه اخذ شده، آلودگی به لپتوسپیرا اینتروگانس مشخص شد که در این بین بیشترین درصد مربوط به لپتوسپیرا گریپوتیفوزا با 59/39 درصد (19 راس دام) شامل 10 راس گاو، 7 راس گوسفند و 2 راس اسب بود. میزان آلودگی در مناطق مختلف این شهرستان متفاوت بود، ولی اختلاف معنی‌داری از نظر موقعیت مکانی در آنها دیده نشد (05/0P>). میزان آلودگی در جنس ماده (56/21 درصد) به طور ‌معنی‌داری از جنس نر بیشتر بود (05/0P<). ارتباط بین سن و آلودگی سرمی به لپتوسپیرا در گاو معنی‌دار (05/0P<)، ولی در گوسفند، بز و اسب معنی‌دار نبود.
    نتیجه گیری نهایی
    آلودگی سرمی به سویه‌های مختلف لپتوسپیرا در بین دام‌های (گاو، اسب، گوسفند و بز) شهرستان طارم وجود دارد که می‌تواند موجب انتقال بیماری به سایر دام‌های سالم و انسان شود. موقعیت مکانی، جنس و سن تاثیر معنی داری در شیوع این آلودگی ندارد. لذا با توجه به عدم واکسیناسیون دام‌ها در منطقه باید واکسیناسیون و توصیه‌های بهداشتی و ضروری در جهت پیشگیری از رخداد بیماری در این منطقه به طور کامل مورد توجه قرار گیرد.
    کلیدواژگان: لپتوسپیرا، جمعت دامی، شهرستان طارم
  • حمید امانلو، علی نیکخواه، علی مصطفی تهرانی، حمیدرضا میرزایی الموتی، محمد حسین نعمتی، بیتا ناصری، معصومه حسینی، سید سعید موسوی * صفحات 137-151
    زمینه مطالعاتی
    پرواربندان بره به‌علت عدم اطلاع از روش مناسب پروار، سود کمتری دریافت می‌کنند همان طور که در پرورش جوجه های گوشتی مرسوم است جیره پیش دان حاوی پروتئین وانرژی زیاد به جوجه های تازه تفریخ شده اختصاص می‌یابد و هرساله از تعداد فاصله بین روز تفریخ و کشتار کاسته می‌شود، لذا همین روش می‌تواند در بره های تازه متولد شده با دریافت خوراک خزشی مورد آزمون قرارگیرد.
    هدف
    انتخاب روش مناسب پروار و رساندن بره‌ها به وزن کشتار در حداقل زمان ممکن، کاهش هزینه پرورش دام و خروج دام اضافی از مرتع بود.
    روشکار
    51 راس بره نر افشاری از بدو تولد در قالب طرح کاملا تصادفی نا متعادل به 4 تیمار شامل تیمار اول: شیرمادر+ یونجه+ مرتع (شاهد مرسوم بدون پروار بصورت پرورش نیمه متمرکز یا CONT-UF)، تیمار دوم: شیر مادر+ یونجه+ مرتع سپس دریافت جیره پرواری (شاهد مرسوم پرواربندی شده بصورت پرورش نیمه متمرکز یا CONT-F)، تیمار سوم: شیر مادر+ تغذیه خزشی (حاوی پروتئین قابل‌متابولیسم زیاد بصورت پرورش متمرکز یا HMP) و تیمار چهارم: شیر مادر+ تغذیه خزشی (حاوی پروتئین قابل‌متابولیسم کم اما دارای لیزین و متیونین محافظت شده شکمبه ای بصورت پرورش متمرکز یا LMP+LMRP) اختصاص یافتند.
    نتایج
    اثر تغذیه خزشی بر افزایش وزن روزانه بره‌ها معنی دار بود (0001/0=P). مقدار ماده خشک مصرفی بین تیمارهای آزمایشی معنی‌دار و بیشترین آن مربوط به تیمار CONT-F بود (0001/0=P). ضریب تبدیل غذایی در تیمار های شاهد به‌طور معنی‌دار افزایش و بیش ترین ضریب تبدیل غذایی در تیمار CONT-F بود(0001/0=P). بازده لاشه در تیمار CONT-UF کاهش معنی دار یافت(0001/0=P). بیشترین سود در تیمار LMP+LMRP وجود داشت و زیان در تیمار CONT-F مشاهده شد (0001/0=P).
    نتیجه گیری نهایی
    بر اساس محاسبات اقتصادی، تیمار LMP+LMRP روش بهتری برای پروار بندی بره تشخیص داده شد.
    کلیدواژگان: بره، پروار، خزشی، لیزین، متیونین
  • الناز پیرعدل، رسول پیرمحمدی، حامد خلیل وندی صفحات 153-173
    زمینه مطالعاتی
    عمل آوری غیرحرارتی دانه جو می تواند سبب کاهش خطرات احتمالی اسیدوز شود.
    هدف
    پژوهش حاضر، به منظور بررسی روند تجزیه پذیری نشاسته و پروتئین خام ارقام مختلف دانه جو پرتوتابی شده با گاما و نحوه توزیع پروتئین در سیستم کربوهیدرات و پروتئین خالص کرنل و سیستم پروتئین متابولیسمی انجام شد.
    روش کار
    کنتیک و زیست سنجه های تجزیه پذیری شکمبه ای نشاسته و پروتئین خام ارقام جو ماکویی، بهمن آبی و سهند پس از پرتودهی با اشعه گاما در دوزهای 50 ، 100 و 150 کیلوگری به روش کیسه های نایلونی با استفاده از سه راس گوساله های نر نژاد هلشتاین مجهز به فیستولای شکمبه ای در ساعات 0، 2، 4، 6، 8، 12، 24 و 48 ساعت و در قالب طرح بلوک های کامل تصادفی در دو انکوباسیون مجزا تعیین شد.
    نتایج
    تجزیه واریانس نشان دهنده ی تاثیر کاهنده و معنی دار پرتوتابی در سطوح مختلف بر میزان تجزیه پذیری موثر نشاسته و پروتئین در شکمبه و وجود اختلاف معنی داری (05/0P<) بین ارقام مختلف بود. در بین ارقام مختلف مورد مطالعه، زیست سنجه های مختلف تجزیه پذیری ماده خشک، پروتئین و نشاسته رقم جوی سهند بیش از سایر ارقام تحت تاثیر عمل آوری قرار گرفت. عمل آوری ارقام مختلف دانه جو با پرتوهای گاما سبب کاهش بخش سریع تجزیه و افزایش بخش کند تجزیه شد(05/0P<). تفاوت در پاسخ ارقام مختلف جو به پرتوتابی با امواج گاما مشاهده شد به طوری که بهترین پاسخ در تاثیرگذاری بر فراسنجه های ارزش غذایی در راستای بهبود تخمیر شکمبه ای، تجزیه پذیری پروتئین، نشاسته و افزایش مقادیر نشاسته و پروتئین ورودی به روده باریک را می توان پرتوتابی در دز 50 کیلوگری دانست.
    نتیجه گیری کلی
    پرتوتابی گاما می تواند مانند سایر روش های متداول عمل آوری برای کاهش تجزیه پذیری ماده خشک، نشاسته و پروتئین شکمبه ای و افزایش نشاسته و پروتئین عبوری قابل هضم در راستای بهبود تخمیر شکمبه مورد استفاده قرار گیرد.
    کلیدواژگان: گاما، نشاسته، دانه جو، تجزیه پذیی، عمل آوری
  • بنفشه فردوست، مرضیه ابراهیمی *، غلامعلی مقدم، مجید علیایی، مسعود ادیب مرادی، صادق علیجانی صفحات 175-188
    زمینه مطالعاتی
     متیونین به عنوان اولین اسید آمینه محدود‌کننده در طیور برای ساخت پروتئین و رشد ضروری است. در چندین مطالعه اثر تزریق درون‌تخم‌مرغی دی‌ال-‌متیونین بررسی شده است، اما در مورد تزریق درون‌تخم‌مرغی ال-‌متیونین گزارشی وجود ندارد.
    هدف
    بنابراین هدف از این پژوهش بررسی اثر تغذیه درون‌تخم‌مرغی ال-متیونین بر وزن، صفات لاشه، ریخت‌شناسی روده‌کوچک و فراسنجه‌های خونی در جوجه‌های گوشتی یک روزه بود.
    روش کار
    به منظور دستیابی به هدف این مطالعه، 240 تخم‌مرغ مادر گوشتی (راس 308) بر اساس طرح کاملا تصادفی با 8 تیمار آزمایشی و 30 تخم‌مرغ در هر تیمار استفاده شد. تیمارهای آزمایشی شامل 6 سطح ال-متیونین (19/0، 38/0، 57/0، 76/0، 95/0 و 14/1 درصد ال- متیونین)، شم شاهد (تزریق آب مقطر) و شاهد (گروه بدون تزریق) بودند که در روز 14 دوره جوجه‌کشی به درون مایع‌آمنیوتیک تزریق شدند. بعد از تفریخ، جوجه‌ها وزن کشی شدند، نمونه‌های خون جمع‌آوری شده و جوجه‌ها کشتار شدند تا صفات لاشه و ریخت‌شناسی روده‌کوچک بررسی شوند. سپس سرم نمونه‌های خونی جمع‌آوری شد و برای اندازه گیری غلظت متابولیت‌های خونی استفاده شد.
    نتایج
    نتایج این پژوهش نشان داد تغذیه درون‌تخم‌مرغی ال-متیونین بازده لاشه و وزن ران، سینه، سنگدان و تیموس را افزایش داد (05/0 P<)، اما اثری بر جوجه‌درآوری نداشت (05/0 P>). همچنین، اثرهای کاهشی تیمارهای ال- میتونین بر گلوکز، تری گلیسرید و نیتروژن اوره‌ای خون مشاهده شد (05/0 P<). علاوه‌بر‌این، تزریق درون‌تخم‌مرغی ال-متیونین موجب بهبود طول و وزن روده‌کوچک و فراسنجه‌های ریخت‌شناسی ژژنوم و دوازدهه شد (طول پرز، نسبت طول پرز به عمق کریپت، قطر کریپت و عمق کریپت)، (05/0 P<).
    نتیجه گیری نهایی
    بر اساس نتایج این پژوهش، تغذیه درون‌تخم‌مرغی 19/0 درصد ال-متیونین اثر بهبود دهنده بر جوجه درآوری، صفات لاشه، فراسنجه‌های خونی، اندام‌های سیستم ایمنی و ریخت‌شناسی روده‌کوچک داشت؛ بنابراین 19/0 درصد ال-متیونین سطح قابل توصیه برای تغذیه درون‌تخم‌مرغی است.
    کلیدواژگان: ال- متیونین، تغذیه درون تخم مرغی، جوجه گوشتی، فراسنجه های خونی، روده کوچک
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  • H Amirzadeh Shomali, SA Rafat *, J Shodja, S Alijani, L Iranzadeh Pages 1-14
    Introduction
    About 6 million heads of cows in Iran are native cattle, but their characteristics and production potential remains unknown. Inbreeding is one of the important factors which must be considered in the herd and can be of considerable economic loss to producers. In this research, we tried to investigate the occurrence of inbreeding and its effects on the production traits of Serabi native cattle in a breeding center related to agricultural ministry located in Sarab. The aim of this study was to evaluate inbreeding effects on milk yield, fat percentage, protein percentage, and birth weight of Sarabi dairy cattle. In this research, the effects of inbreeding and environmental factors on production traits and birth weight of Sarabi cows have been studied.
    Material and methods
    The data were collected from 1250 Sarabi cows during 1992- 2012 years by Sarabi Breed Center in East Azerbaijan province. In the present study, a pedigree file containing 1250 head (764 females and 486 males) of dairy cows was used, including data about the registration number of the livestock, date of birth, gender, father's registration number, and registration number of the mother, date of birth, parity, and production records. After the removal of animals with unknown and unregistered parents in the flock, the pedigree was arranged using pedigree software. Pedigree software was used to calculate the inbreeding coefficient for each animal. The principles of this software in the calculation of inbreeding coefficient is based on the formation of a kinship matrix among the individuals. The inbreeding coefficients of animals were considered as a discrete trait in 4 groups.
    Results and discussion
    In this herd, inbreeding coefficient was estimated between 0- 0.28. Average inbreeding coefficients of all cows and inbred cows are 0.0109 and 0.0574, respectively. Totally, 19% of all animals were inbred. In this study, inbreeding coefficient has been included in the model either as a continuous variable or as a classification variable. When inbreeding factor considered as continuous variable in the model, its effect on milk yield, fat and protein percentage, and birth weight was significant (P<0.01). When inbreeding considered as a continuous trait, 1% increase in inbreeding coefficient had an effect equal to -2.69 kg, 1.59%, and +18.1% on milk yield, fat, and protein percentage, respectively. Miglior et al. (1995a) reported a 1% increase in inbreeding coefficient in Holstein cows reduced calf weaning by 0.44 kg and reduced milk production by 25 kg. Mohammadkarim (2006) using a univariate model reported for 1% increase in inbreeding coefficient, changes in milk yield, fat yield, open days and length of first lactation equal to -14.02, -0.349 kg, + 0.4839 and + 0.148 days, respectively. Inbreeding has a negative effect on production traits and birth weight. Results showed that the effects of year-season of calving and parity on production traits and birth weight were significant (P<0.01). The regression coefficient of milk, fat and protein percentages and birth weight on inbreeding, when inbreeding considered as a discrete variable, were -0.129kg, +0.093%, +0.072% and -0.564 kg, respectively. In this study, when inbreeding traits considered as a continuous variable, did not show any linear or nonlinear relation with birth weight trait of Sarabi cows. It can be concluded that in order to maintain the genetic reserves of Sarabi cattle breed, it is necessary to carefully monitor the reproduction breedings in this native cattle population. In the case of endangered breeds, such as Sarabi breed, these breeds have beneficial properties, particularly in relation to resistance to diseases, and tolerance to stressful environments. These desirable traits can be transferred to future genetic composition cattle breeds. Preserving the genetic resources of the country's livestock and pay attention to similar breeds of Sarabi should be taken into consideration by decision makers at livestock breeding centers. In Holstein cows it has been found that high milk production is associated with a genetic susceptibility to disease (Khaleghi & Rafat 2018), so the desirable characteristics of the Sarabi breed should be studied in this regard of susceptibility to diseases. The existence of a complete family tree in computer registrations is the first step in controlling inbreeding. The existence of this pedigree will help breeders to avoid breeding between close-up animals, like a brother-sister and a father -daughter, which will increase the incidence of inbreeding in the population. For this purpose, it is recommended to use optimal mixing softwares that controls inbreeding. There are programs for managing the breeding to identify animals as soon as possible and calculate their relativeness in the herd. By this method, it is possible to prevent the occurrence of high inbreeding in the herd and produce calves with high profitability. The prospect of this research is to carry out further research on the issue of inbreeding and effective population size on local breeds of dairy cattle to prevent the replacement of these breeds with Holstein.
    Conclusion
    It is imperative to prevent the replacement of the foreigner breeds (Holstein generally) instead of Sarabi breed and its extinction as much as possible.
    Keywords: Inbreeding depression, Milk yield, Birth weight, Sarabi cows
  • Z Hashemi, T Mohammadabadi *, M Chaji, S Tabatabaei Pages 15-33
    Introduction
    Oak nut is containing 55% starch and can be used as an energy source in the ruminant nutrition. In addition to nutritional compounds, oak nut contains high amounts of active biological compounds, such as tannin, gallic acid, galloyl or hexahydroxy decanol derivatives. Tannins form complexes with a large number of nutrients such as carbohydrates, proteins, polysaccharides, bacterial cell membranes, digestive enzymes, and minerals, but decrease microbial digestion in the rumen. This experiment was conducted to determine the effect of oak nut on the population and digestive activity of bacteria, fungi, and protozoa counts in the rumen of Najdi goat and Arabi sheep.
    Material and methods
    For this purpose, six Najdi goats and six Arabi sheep (average weight 35 ± 2 kg) were fed with a diet containing oak nut (63 %) and a diet without oak nut for 28 days. Iso-energetic and iso-nitrogenous diets were formulated according to NRC, in diet 30:70 forage to concentrate (3 animals per treatment). Samples of rumen fluid were collected before the morning feeding. Then, digestive activity of rumen bacteria and fungi, fermentation parameters, and protozoa counts of animals which fed with experimental diets were determined. Growth and digestive activity of rumen bacteria and fungi were determined by measuring DM, NDF and ADF disappearance in specific culture for each incubation time (9 replicates for each treatment). Gas production and fermentation parameters by fungi and bacteria were determined. The protozoa count, genus, and species were identified on the basis of Yanez Ruiz et al (2004). Cumulative gas production data were fitted into the exponential equation: Y = b (1 − e−ct), where b = gas production from the fermentable fraction (mL), c= the gas production rate constant (mL/h), t = the incubation time (h), and Y = gas produced in time t. Partitioning factor (PF), microbial biomass, and truly digested organic matter were calculated by Olivera (1998). For determination of partitioning factor (PF) at the end of each incubation period, the content of vials was transferred into an Erlenmeyer flask, mixed with 20 mL neutral detergent fiber solution, boiled for 1 hour, filtered, dried (in oven at 60 °C for 48 h), and ashed. The data were subjected to analysis as a split plot design using the General Linear Model (GLM) procedure of SAS (version 9.1). The Duncan’s multiple range test was used to compare the mean differences at P<0.05.
    Results and discussion
    The disappearance of DM, NDF, and ADF by goat rumen bacteria at 24, 48 and 72 h were significantly higher in the control group than oak nut treatment (P<0.05). According to the results, there were no significant differences for the disappearance of DM, NDF, and ADF by the sheep and goat rumen fungi between the control group and oak nut treatment at 1, 3, and 6 days of incubation (P>0.05). The disappearance of DM, NDF, and ADF by the rumen fungi was not different between treatments at all times of incubation (P<0.05). The gas production potential of wheat straw, PF, microbial biomass production, the efficiency of microbial biomass, and truly digested organic matter by the rumen bacteria and fungi of sheep and goats did not have any significant differences in control treatment compared with oak nut treatment (P>0.05). Truly digested organic matter in the control treatment were higher than oak nut treatment (P<0.05). The PF by rumen fungi of sheep in diets containing oak nut was higher than goats, while the truly digested organic matter by the rumen fungi of goats was higher than the control diet in sheep (P<0.05). The total population of protozoa and Holotriches species was deceased in oak nut treatment (P<0.05). The population of goat rumen bacteria and fungi in control group was higher than that in control sheep group. The phenolic compounds (tannins) in diets containing oak nut decreased fibrolytic enzyme activity, inhibited carbohydrates fermentation, and consequently decreased fiber digestibility by rumen microorganism (Tavendale et al. 2005). Tannins can reduce microorganism adhesion to nutrients; inhibit microbial activity which has negative effects on fermentation and methane production. But, the increase of gas production rate by oak nut is due to higher soluble carbohydrate and lower NDF and ADF in diets containing oak nut, which increases the digestibility (Hadi et al. 2003). Phenols may disrupt protozoal membranes, inactivate protozoal enzymes, and deprive protozoa of substrates and metal ions, which are essential for protozoa cell metabolism (Calsamiglia et al. 2007).
    Conclusion
    Based on the results, using 63% oak nut caused a decrease in microbial population, a decrease in the disappearance of nutrients and fermentation parameters of bacteria and fungi and a decline in the rumen protozoa population of Arabi sheep and Najdi goat. Also, the results showed higher tolerance of goats to the diet's tannin.
    Keywords: Culture, disappearance, microorganisms, oak nut
  • A Hassanzadeh Seyedi *, H Janmohammadi, SA Mirghelenj, M Olyayee Pages 35-47
    Introduction
    The knowledge of the requirement of essential amino acids helps to optimize the different nutritional inputs at various stages of broiler production. Before production of synthetic amino acids, protein was included in diets at rates far above animal requirements as a safety margin against amino acid deficiencies. Today, most necessary amino acids can be obtained in the crystalline form. Addition of these amino acids firstly allows for reduced dietary crude protein inclusion rates and secondly supplies the animal with an amino acid balance that is closer to that requirement of the animal. Recent studies showed Valine (Val) to be the 4th limiting amino acid in vegetable based of broiler diets (Han et al 1992). It seems that the amount of the 4th limiting amino acid depends on the diet composition and animal species (Fernandez et al 1994). The NRC (1994) recommendation for total Val in the grower periods is 0.82 % of diet. Corzo et al. (2008) estimated dig Val requirement during 14 to 28 d (0.9% of diet) which were higher than NRC (1994) total Val recommendation of 0.82%. Little information is available on the response of Val usage on improving the tissue protein synthesis in broiler chickens. However, the appropriate programs of eugenics in recent decades will continue to increase poultry productions and therefore, it is necessary to constantly improve and update responses of animals to amino acids usage. The aim of this experiment will be determining the valine requirements and the effect of digestible Val on performance characteristics in commercial varieties of broiler chick (Ross 308).
    Material and methods
    To determine Val requirement for growth performance of male broiler chicks, a total of 450 chicks, was assigned to 6 treatments with 5 replicates (with 15 birds per each replicate) from 8 to 21 days of age using a completely randomized design. Corn-soybean meal based diet was formulated to provide all nutrients except for Val. Basal diet was formulated with 0.74% Val and 1.056% lysine (Lys) content. In other diets, Val content was increased by adding L-Val with simultaneous decreasing in L-Glutamic acid from the basal level to provide isonitrogenous feeds. Dietary Val was supplied in 6 levels from 0.74 to 0.99% during the experimental period. Body weight gain and feed intake were measured during the period (d 8 -21). Val intake, feed conversion ratio (FCR), and feed efficiency ratio (FER) were calculated from feed intake data and there was no dead bird in experimental period. All data were analyzed based on a completely randomized design by GLM procedure of SAS (9.1). Duncan’s multiple range tests was used to study the differences between treatment means. Estimations of Val requirements were done at 95% of the plateaus of nonlinear regressions. Broken line Regression analysis was used to estimate Val requirements, when nonlinear regressions responses were statistically significant (P<0.01).
    Results and Discussion
    Result of this study showed that digestible Val requirement for Ross 308 male broiler chicks is the well fitted based on weight gain, feed intake, and feed conversion ratio. Evaluated digestible Val content for these performance parameters were 0.85, 0.95 and 0.84 % of diet, respectively. The result of this experiment showed that all performance parameters were significantly affected by Val supplementation in the diet (P< 0.01). The broiler chickens fed with 0.89 % of digestible Val level had the highest feed efficiency ratio, but the lowest feed conversion ratio (P<0.01). In this experiment, the digestible Lys content of the basal diets was 1.056% and the best digestible level for weight gain and feed conversion ratio were 0.85 and 0.84%, respectively. According to this information, the level of Val as a digestible ratio to Lys for weight gain and feed conversion ratio was 80.49 and 79.54 for linear broken linear model, respectively. Several studies have addressed the valine needs for broilers in starter phase (Thornton et al 2006). Baker et al. (2002) and Corzo et al. (2008) conducted two studies about of evaluation of the Val requirements for broiler chicks, but, there are many remarkable differences between their study and the present experiment. Although several researches with many similarities have been performed on Val requirement, their results are remarkably different. It could be originated from diet types (purified or practical diet), Leucine levels of diets, crude protein content of basal diet, immunological stress, amino acids interactions, metabolizable energy content of basal diet, broiler strains, age, extended experimental period, sex of broiler and amount of feed intake (D'Mello 1974).
    Conclusions
    The results of the current study suggested that the level of 0.93% digestible Val is the best level for an optimum performance of body weight gain and the level of 0.91% digestible Val is the best level for an optimum feed conversion ratio in growing broilers from 8 to 21 days of age. Based on statistical model and evaluated performance parameters for requirements, clearly differences were observed between result of this experiment for Val requirement in grower period of Ross 308 broiler chicks and other data sources.
    Keywords: Broken linear model, Male broiler chick, Ross 308, Valine
  • M Shamsallahi, H Daghigh Kia *, Gh Moghaddam, A Taghizadeh Pages 49-60
    Introduction
    The use of cryopreserved semen in artificial insemination (AI) has numerous advantages for the animal husbandry, especially when used in breeding programs. Long-term storage of sperm in liquid nitrogen is a valuable technique for genetic resources preservation (Mazur et al., 2008). Animals are transported frequently and widely around the world, and it is necessary to create and maintain suitable conditions during animal transportation (Salamon and Maxwell, 2000). However, the costs, the risks of escape, and the potential for accidental death of animals are unavoidable. On the other hand, cryopreserved sperm can be transported in liquid nitrogen at a markedly lower cost and without the risk of escape or death of animals (Aires et al., 2003). Numerous investigations have been performed to improve the protocols for cryopreservation of sperm. The extenders used for semen cryopreservation protect the sperm against thermal shock, preserving both motility and fertility by promoting the stabilization of the plasma membrane, and providing energy substrates (Amirat et al., 2004). These attributes reduce the deleterious effects of changes in the pH and osmolarity, prevent the growth of bacteria, and protect the sperm cells from the damage caused by refrigeration, freezing, and thawing. For sperm cryopreservation, protocols using egg yolk have been successfully established and applied in various animal species (Aisen et al., 2002). However, the use of egg yolk in cryopreservation has been questioned, because of certain potential negative aspects. Egg yolk contains a wide variety of compounds that are both beneficial and also potentially harmful to sperm. Additionally, egg yolk introduces a risk of contamination by microbes that can subsequently produce endotoxins; and so, the egg yolk and sperm are subjected to quarantine inspection in the case of import or export. Therefore, a replacement for egg yolk with a well-defined chemical composition would be very advantageous. Lecithin, also known as phosphatidylcholine, is a component of egg yolk and is known to prevent cold shock during the freezing and thawing process in sperm cryopreservation. Soybean lecithin in particular has already been used as a replacement for egg yolk in sperm cryopreservation in various animals. Its non-animal origin and minimal sanitary risks make it preferable for this application. Soybean Lecithin can be used as an extender in the cryopreservation process (Akhter et al., 2012). The aim of this study was to evaluate the effects of Soybean Lecithin as extender on the ram semen quality after freeze-thawing.
    Material and methods
    Semen was collected from the indigenous Ghezel rams. Twenty five ejaculates were collected throughout the entire study, with semen being collected twice a week (every Sunday and Tuesday) from each ram, using the artificial vagina. Ejaculates were collected in graduated test tubes, placed in a thermo flask at 34°C, and transported to the laboratory for evaluation within 1h interval. The raw or fresh undiluted semen was then microscopically evaluated for volume, concentration, and sperm motility. The sperm concentration was determined with the aid of a neubauer lam. A Computer Assisted Sperm Analysis (CASA) system was used to evaluate the different sperm motility characteristics. All data were analyzed using the statistical procedure of SAS (version 9.2). The analysis of variance (ANOVA) was used to test for significant differences between treatments. Characterization of the Ghezel ram sperm viability (percentage live/dead) of the semen samples was determined using an eosin/nigrosin stain (50μl eosin/nigrosin and 5μl semen). The volume of the ram ejaculates ranged between 0.75 and 1.5mL. The sperm concentration recorded in this study ranged between 0.9 and 1.3 × 109 sperm/mL. The effect of different soybean lecithin levels on the Ghezel ram semen characteristics following cryopreservation was evaluated. After initial evaluation of the ejaculates, all ram ejaculates were pooled and semen sample was then divided into three portions; then, semen samples were diluted with soybean lecithin (1, 1.5 and 2 %) citrate extender and cooled over a period of 2h to 5°C. The semen samples were equilibrated for 2h and then loaded into 0.25mL semen straws. The straws were frozen in liquid nitrogen (LN2) vapor, then semen straws were plunged into the LN2 (-196°C). The semen straws were thawed 30 days later, in a water bath (37°C) for 30 seconds. The sperm characteristics included motility and motion parameters, viability, plasma membrane and acrosome integrity, sperm abnormality, and lipid peroxidation were evaluated. Motility and velocity were microscopically evaluated using the Sperm Class Analyzer® (CASA) system.
    Results and discussion
    This study demonstrated that soybean lecithin (1.5%) containing 7% glycerol can be used to cryopreserve Ghezel ram semen effectively, based on the sperm motility characteristics. The low sperm motility results recorded when semen was cryopreserved in soybean lecithin (2%). The results showed that total motility and some sperm motion parameters (VSL, VCL, VAP and ALH) were significantly higher in 1.5% lecithin soybean treatment group (P <0.05). In terms of survival, the percentage of abnormal sperm, plasma membrane integrity, and lipid peroxidation were not significant between treatments. Acrosome membrane integrity of 1.5% soybean lecithin treatment group was higher than other treatments (P< 0.05).
    Conclusions
    Briefly, 1.5% soybean lecithin treatment had better performance than other levels on the quality of the sperm after freeze-thawing.
    Keywords: Acrosome, Sperm, Freeze-thawing, Ram, Soybean lecithin
  • F Sani, M Ghahramanzadeh, R Sani, Gh Dashti * Pages 61-76
    Introduction
    Over the last decades, productivity growth analysis in agriculture has attracted attention of the economic researchers as well as policy makers in both developed and developing countries. Improving productivity is the best and effective way to achieve economic growth due to scarcity of production resources. Productivity management involves understanding the components and analyzing its changes in the development process. Improving total factor productivity (TFP) is seen as necessary for producers to remain competitive and profitable, particularly in markets where they face declining terms of trade. Without changes scale, TFP can be increasing in several ways, such as increasing output from the same level of inputs, constant the same level of output with a lower level of inputs, or changing the mix of inputs and or outputs.
    Material and methods
    The objective of this research was measuring and decomposing productivity and profitability change. This paper estimated TFP changes and decomposed these changes into technical change, technical efficiency change, and scale and mix efficiency change in industrial dairy farms by using Hicks-Moorsteen TFP indexes. This index was chosen among other indexes, because it is an index that bases on distance functions and data envelopment analysis (DEA) methodology for estimating distances is convenient. Secondly, it is closely related to the Malmquist index, which has been used for some time as the index number of choice in the productivity decomposition literature. For the purposes of comparison, this paper developed data envelopment analysis (DEA) methodology for computing and decomposing Hicks-Moorsteen index. Input and output quantity and price data were included for labor, capital, animal feed, fuel, and milk using records from the results of a sample survey of industrial dairy farms in the provinces of Iran during 1990-2013.
    Results and discussion
    The results indicate that the TT effect (the growth in output prices relative to the growth in input prices) on profitability has been moderated by compensating changes in total factor productivity (TFP). The TT was improved 86 percent from 1990 to 1996 and during this period a simultaneous reduction in total factor productivity (TFP) by 15 percent was observed. In other words, industrial dairy farms productivity has been responsive to changes in the industrial dairy farms TT. The TFP survey also indicated that the index was initially decreased and then increased, and despite the fluctuations over the period of 1990-2013, the average has increased by 15% compared with the base year of 1990. Productivity efficiency (TFPE) has been decreased from 1990 to 2013, and decreased from 0.521 in 1990 to 0.248 in 2013. In other words, the gap between the existing TFP and the maximum TFP has increased over the study period. Analyzing TFP change in the 1990s indicates that important components of TFP change have been changed in ROSE and in the second half of the study period, the main component industrial dairy farms TFP change is technical change. These findings support the view that research and development expenditure has led to expansions in the production possibilities set, that dairy farms adopt new technologies quickly and make relatively few mistakes in the production process, and that they rationally adjust the scale and scope of their operations in response to changes in prices and other production incentives. The results demonstrate that industrial dairy farms have high technology, scale, and output mix-efficient throughout the study period, but input mix efficiency has been steadily decreasing over the study period and that reaches less than 40 per cent in 2013.
    Conclusion
    In general, the development and promotion of technological symbols such as improved cows, artificial insemination, and embryo transfer, as well as increased production scale through the implementation of incentive policies and support of large manufacturing units can be considered to improve the productivity of production factors. Moreover, province level variations in scale and mix efficiency suggest that there exists a scope for improving productivity by taking a differential approach to the efficient use of agricultural resources and to increase scale and mix efficiency in production of the industrial dairy farms. Being able to identify the components of TFP change is critically important for public policy-making. Policies that can lead to these outcomes include reductions in the levels of output price support, removal of input subsidies, increases in tax rates and any other policies that cause deteriorations in the agricultural TT. These policies can have the effect on increasing productivity.
    Keywords: Dairy Farms, Hicks-Moorsteen Index, Productivity Efficiency, Residual Scale Efficiency, Total Factor Productivity
  • A Pouraminollahi, A Khatibjoo *, F Fatahnia, H Jafari Pages 77-87
    Introduction
    Use of antibiotic growth promoters (AGP) in broiler diets has been banned in the European Union and in many countries. Therefore, researches have focused on the development of alternative strategies. Various products and natural materials such as probiotics, prebiotics, organic acids, and plant extracts have been tested as effective alternatives to AGPs. L-Carnitine (β-hydroxy-γ-trimethyl amino butyrate) is a water soluble quaternary amine and exists naturally in microorganisms, plants, and animals (Dikel et al., 2010). L-Carnitine is synthesized exclusively in the liver of animals and plays a key role in energy metabolism of cells, mainly by transferring long-chain acyl groups from cytoplasm to mitochondrial matrix for β- oxidation (Dikel et al., 2010). It has been reported that the addition of L-carnitine to broiler breeder diet in early stages of growth improved their performance (Golzar-adabi et al. 2005). Inclusion of L-Carnitine to young animal diet improves use of fatty acids and their energy efficiency; therefore, it improves growth and feed conversion ratio (Zhang et al. 2010). In the folklore of many cultures, garlic (Allium sativum L.) has been widely used as a therapeutic agent. Garlic has rich organosulfur compounds and metabolites (allicin, diallyl sulfide, and diallyl trisulfide) (Kim et al., 2009). Allicin and its related compounds in garlic inhibit the HMG-CoA reductase enzyme, which plays a key role in the formation of liver cholesterol; then, allicin decreases cholesterol levels (Anthony et al. 2005). Duration of L-Carnitine and garlic supplementation in broiler chicken diet may have different effects on broiler chicken performance. Therefore, the aim of this study was to investigate the duration of supplementation of L-Carnitine and garlic powder on broiler chicken performance, serum biochemistry, carcass parameters, and meat quality.
    Materials and methods
    In order to consider the effects of L-carnitine and garlic powder on broiler chicken performance, blood metabolites and carcass characteristics, a total of 480 Arian one-day-old broiler chicks were allocated to 2×5 factorial arrangements in a completely randomized design with 5 dietary treatments, 4 replicates, and 12 birds in each replicate. Dietary treatments were 1) basal diet with no additive (BD), 2) BD plus 0.02% flavomycin antibiotic (positive control), 3) diet containing 1.5% garlic powder, 4) BD plus 0.025% L-Carnitine, and 5) diet containing 0.025% L-Carnitine plus 1.5% garlic powder in two periods (short term: first 3 weeks and long term: 6 weeks period). The birds were kept under conventional conditions for vaccination, temperature, ventilation, and lighting based on Arian catalogue recommendations. The birds fed experimental diets from 1 to 42 days of age and standard management practices of commercial broiler production were applied. The broiler diets were formulated based on standardized ileal digestible amino acids and other requirements were obtained from Arian catalogue recommendations. During the experiment, body weight and feed intake were recorded and finally feed conversion ratio and European production efficiency factor were calculated. From 2 birds of each pen, blood samples were collected at the end of experiment, then cholesterol, triglycerides, HDL-cholesterol, and LDL-cholesterol were detected. At 42 d, 2 broiler chickens per replicate were selected and sacrificed. Carcass, spleen, bursa of Fabricius, abdominal fat, thigh, and breast percentages were expressed as their percentages to live body weight. Thigh and breast meat pH and color were measured by pH meter (330i/SET WTW model) and electric colorimeter (1002 model- RGB Lutron), respectively. The lactate concentration of the breast meat was estimated by a spectrophotometer and calculated using the following formula (Zhang et al., 2009): Lactate concentration = 𝑂𝑝𝑡𝑖𝑐𝑎𝑙 𝐴𝑏𝑠𝑜𝑟𝑝𝑡𝑖𝑜𝑛 𝑓𝑜𝑟 𝑆𝑎𝑚𝑝𝑙𝑒𝑂𝑝𝑡𝑖𝑐𝑎𝑙 𝑎𝑏𝑠𝑜𝑟𝑝𝑡𝑖𝑜𝑛 𝑓𝑜𝑟 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑 ×22
    Results and discussion
    Results showed that supplementation length and dietary treatments did not affect broiler chickens body weight, feed intake, feed conversion ratio, meat pH, serum triglyceride, cholesterol, HDL-cholesterol, and LDL-cholesterol, and breast meat lactate concentrations (P>0.05). Dietary treatments and supplementation period significantly influenced breast, bursa, and abdominal fat percentage (P<0.05). L-Carnitine positively facilitates consumption of short and medium chain fatty acids by the mitochondria (Tan et al. 2008). Therefore, the diet containing L-Carnitine stimulates the oxidation of fatty acids to produce adenosine triphosphate and use of energy. In addition, positive effect of garlic powder on performance of broiler chicks can be attributed to the antioxidant and some growth-promoting effects of this herbal plant (Anthony 2005). Conclusion It was concluded that application of the dietary supplements (0.025% L-Carnitine plus 1.5% garlic powder) in a short or long period, are not advisable for broiler chicken diets, since they make the rations more expensive.
    Keywords: Broiler Chicken, Carcass Characteristics, Garlic Powder, L-Carnitine, Performance
  • F Khosravi, MH Fathi *, SA Vakili, H Farhangfar Pages 89-105
    Introduction
    Methane eructated from ruminants is considered to be one of the most important contributors to global warming, imposing an environmental burden that cannot be ignored. Meanwhile, it represents a loss of 2% to 15% of the gross energy intake (Johnson and Johnson 1995). Animal nutritionists have been studying manipulation of the rumen microbial ecosystem to reduce methane emission without the adverse effects on rumen function. There is a need to identify feed additives to modify ruminal fermentation characteristics and increase the efficiency of feed utilization, thereby inhibiting the ruminal methanogenesis. In recent years, essential oils (Benchaar 2007), plant secondary metabolites such as condensed tannins and saponins (Pen et al., 2006; Bhatta etal, 2009) and dietary lipids (Dohme et al., 2001) have arisen as attractive rumen modifiers to improve rumen microbial metabolism as well as inhibit methane production in ruminants. Particularly, Woodward et al. (2006) showed a positive effect of fish oil (FO) on reducing CH4 emissions in a short-term study, whereas no reduction was observed for a longer-term study. The positive effects of tannin-rich plant extracts on methane emission and methanogens population in vitro as well as in vivo have been examined (Patra et al., 2006; Patra and Saxena, 2010; Becker et al., 2014). The objective of this study was to evaluate the effect of pomegranate by-products (pomegranate oil and peel) on the in vitro rumen fermentation with respect to methane emissions.
    Materials and methods
    Basic substrate was contained of 600 g/kg forage and 400 g/kg concentrate. Pomegranate oil was administered in doses of 2, 4, and 6% of substrate DM in the first trial and in the second trial powder peel pomegranate was added in doses of 2.5, 5, and 7.5% of substrate DM. Syringes were inoculated with 40 ml of a rumen fluid–buffer mix (10 ml rumen fluid and 30 ml buffer) and were incubated at 39°C. The gas production was measured at different incubation times and total gas production, CO2, hydrogen, and methane production were determined after 24h of incubation. Data were analyzed by GLM procedure of SAS (2001) software.
    Results and discussion
    The results of the first experiment showed that the addition of pomegranate oil to substrate did not affect total gas production, digestibility parameters (b and c), metabolizable energy (ME) and organic materails dry (OMD). Methane production was decreased by addition of 6% of pomegranate oil (P< 0.05), but not by lower levels of oil. Lipids significantly decreased CH4 emission in the short-term study (−27%), but this effect was not observed after 11 wk of lipid supplementation. On the other hand, several in vitro trials have shown that FO reduced CH4 methanogenesis (Fievez et al. 2003; Patra and Yu 2013). Saturated medium chain fatty acids, C10-C14, also lead to methane reduction. At ruminal temperature, an increasing chain length of medium chain fatty acids seems to reduce their efficiency in inhibiting methanogens and methane formation due to lower solubility (Bucher et al. 2008; Patra 2012). Beauchemin et al. (2008) reviewed the practical application of lipids to reduce methanogenesis. Oil supplementation to diet decreased methane emission by 80% in vitro (Fievez et al. 2003) and about 25% in vivo (Machmu¨ller et al. 2000). The toxic effects of certain oils on rumen protozoa contributed to reduce methane production (Machmu¨ller et al., 1998). The addition of canola oil at 0%, 3.5% or 7% to the diets of sheep reduced the number of rumen protozoa by 88–97% (Machmu¨ller et al. 1998). The detrimental impact of unsaturated fatty acids has also been reported (Henderson1973). Machmulleur et al. (1998) observed coconut oil as more effective inhibitor followed by rapeseed, sunflower seed, and linseed oil. Coconut oil comprises medium chain fatty acids. Dong et al. (1997) compared canola oil to coconut oil and demonstrated coconut oil as more effective methane inhibitor. Coconut oil controlled rumen methanogens by changing the metabolic activity and composition (Machmu¨ller et al., 2003). The inclusion of sunflower oil to the diet of cattle resulted in 22% decrease of methane emissions (McGinn et al., 2004). In the second experiment, adding of 5 and 7.5% of pomegranate peel to substrate DM reduced (P <0.05) total gas production after 24, 72, and 96 h of incubation. Metabolizable energy, b fraction, and OMD digestibility reduced by pomegranate peel powder. Because these parameters dependent the total gas production. Methane production was reduced by adding pomegranate peel to diet, but no difference was observed between methane produced by diet contained different doses of pomegranate peel. However, a direct effect of condensed tannins on rumen methanogens cannot totally be excluded (Field et al. 1989). Furthermore, tannins decrease the degradation of nutrients in the rumen, which then may be degraded in the hindgut. This could have contributed to a lower methane emission, because hindgut fermentation differs from ruminal fermentation by resulting in a lower methane production per unit of fermented nutrients (Fievez, et al. 1999). A meta-analysis of in vivo experiments with tannins by Jayanegara et al. (2012) reported a relatively close relationship between dietary tannin concentration and CH4 production per unit of digestible OM. According to Goel and Makkar (2012), the antimethanogenic effect of tannins depends on the dietary concentration and is positively related to the number of hydroxyl groups in their structure. These authors concluded that hydrolyzable tannins tend to act by directly inhibiting rumen methanogens, whereas the effect of condensed tannins on CH4 production is more through inhibition of fiber digestion. They also pointed out that more animal research is needed with these compounds to establish their antimethanogenic effect. Hydrolysable tannins are hydrolyzed in the rumen and some could be toxic (Lowry et al., 1996; McSweeney et al. 2003).
    Concluson
    Addition of pomegranate oil and pomegranate peel powder to base substrate did not have a significant effect on digestibility in in vitro conditions, but reduce the production of methane gas as a harmful greenhouse gas in the atmosphere, that would loss significant portion of the energy of the feed. Therefore, the use of pomegranate oil and pomegranate peel in the present experiment as inexpensive edible compounds not only have no negative effects on feeding ruminants, but also a good alternative to ionophors and other antigens.
    Keywords: Methane production, Pomegranate oil, Pomegranate peel powder, Ruminal gas
  • M Ghaderi *, M Amiri, L Hashemi, F Samadian Pages 107-123
    Introduction
    Epigenetics is assumed as the most complex field of biological sciences. Generally, epigenetics includes mechanisms that not only affect gene expression, but also bring about functional changes in the next generation of mitotic cell division (autosomal inheritance) and meiotic cell division (generational inheritance), though DNA nucleotide structure is not changed (Barazandeh, 2016). DNA methylation refers to the enzymatic addition of a CH3 group to a cytosine residue in DNA strand, which occurs almost particularly at CpG dinucleotides (i.e., a cytosine located 5′ of a guanine) in animals. The enzymatic machinery responsible for DNA methylation includes a family of DNA methyltransferases (DNMTs), including the maintenance methyltransferase DNMT1 (responsible for copying pre-existing DNA methylation patterns to the new strand during mitosis) and the de novo methyltransferases DNMT3A/3B. DNA methylation is considered as epigenetics factor. In mammalian, DNA methylation is necessary for both embryonic development and stem cell differentiation and this phenomenon is basically occurring in CpG dinucleotide. CpG dinucleotide intends to make cluster over genome that is called CpG island. CpG islands are considered gene markers and represent an important feature of mammalian genomes. CpG islands vary greatly among mammalian genomes (Medvedeva, 2011). Some factors such as recombination rate and chromosome size might have influenced the evolution of CpG islands in the course of mammalian evolution. Whenever CpG island in gene's promoter is not methylated and suitable transcriptional factors are accessible, gene expression machine is activated and therefore gene is expressed. However, methylation of CpG islands in gene promoter with compact form of chromatin could lead to inhibition of gene expression (Shi et al., 2012). Hypermethlation of CpG islands could cause a range of diseases such as cancer. Epigenetic process could modify proteins after translation that actually refers to biochemical events inflicting on proteins. Some of these events include: methylation, phosphorylation, glycosylation, sulfation, sumoylation, and ubiquitinylation disulfide bonding. Nutrition is seen as one of the greatest environmental determinants of an individual’s health. Although nutrient quantity and quality could impart direct effects, the interaction of nutrition with genetic and epigenetic is often overlooked despite being shown to influence different biological variation in mammals (Murdoch et al., 2016). Understating and unrevealing complex traits, such as those that are nutrition-related, to determine the genetic and epigenetic contributions toward a phenotype would be a formidable job to get it done. Similar to other epigenetic endpoints, patterns of DNA methylation could be susceptible to alterations by exposing to environmental treatments, including contaminants (Head, 2014). These sort of alterations may persist in the absence of the initial treatments as cells divide, and can even be inherited over generations provided that they occur in the germ line. Although our knowledge concerning patterns of DNA methylation in animals is increasing, a big gap remains in the literature, especially when it does come to species outside of those generally used for biomedical researches. Unlike DNA, epigenetic markers could be directly influenced by the environment factors; therefore, epigenetic markers have been shown to be pivotal mediators of phenotypic responses to environmental signals. To understand how epigenetic modifications facilitate and affect gene expression, it is crucial to understand how and when the epigenome is established (Faulk and Dolinoy, 2011). While we do not fully understand how all of the complex epigenetic genome changes occur, yet some epigenetic information is sought to retain and transmit to the next generation.
    Materials and methods
    In this study, first of all, some articles and resources that describe candidate genes affecting mastitis were explored and some of the genes which were considered candidate genes in bovine mastitis were chosen. These genes included 14 interleukins (in exception of interleukin 8 and interleukin 9), interferon-gamma, and tumor necrosis factor (in total 13 genes). Their DNA sequences and other features of selected genes (for example exon numbering, gene length, guanine percentage and cytosine percentage) were obtained from NCBI database and saved as FASTA format. The C++ based software and Promoter 2.0 Prediction Server were used to extract characteristics of genes and detecting gene promoters, respectively. This software is generally used to predict transcription factor-biding sites of DNA sequences in vertebrata. In order to detect CpG islands, DBCAT, SMS, and Geneinfinity softwares were used. Also, primary structure of proteins derived from these genes was extracted from NCBI database and finally protein methylation was obtained by using PMeS software. Depending on the type of algorithm used to identify the CpG islands, the number and length of the CpG islands found to be different. Predicted CpGs were used as measurements to indirectly investigate the level of methylation over DNA level of genes.
    Results and discussion
    The investigated genes in terms of some features like total size based on number of nucleotides, number of exons, total annotated spliced exon length, and percent of GC content were quite different. The essence of gene heterogeneity from different features made grouping of these genes a cumbersome job. In this research, our overall objective was to locate the position and number of CpG in the promoter region of genes. Referencing of applied software to detect CpG islands, number and length of detected CpGs was different. Results shown that methylation was not evenly/ uniformly occurring in considered genes and in average, less than 50 % of CpG islands were in promoter region of genes and methylated CpG was located in intergenic regions. Also, the maximum amount of methylation was seen in interleukin 1, 2, and TNF gene, which are among the most important genes in circumventing mastitis. The degree of methylation in the proteins derived from the investigated genes showed fairly non-concurrence results with their DNA methylation. However, protein derived from interleukin 11 undergoes methylation in large portions of its original protein structure. It should be noted that different algorithm architectures may give different results (Barazandeh, 2016; Medvedeva, 2011). At the DNA level, this gene also had the highest CpG in its promoter. This may indicate the complexity of epigenetic process with this gene. Therefore, this gene could be considered as a suitable candidate for performing demethylation experiments and proving biological drugs to circumvent mastitis. An integrative view to gene structure, DNA methylation and methylation of proteins derived from the investigated genes in this research would provide the better idea pertaining to methylation function in circumventing the mastitis in dairy cattle.
    Conclusion
    Out of the three software tested, the results of the two SMS and Geneinfinity software were almost similar and probably use a similar algorithmic architecture. It should be noted that the algorithms used in this study were not developed to identify specific CpG islands on the bovine genome. The genes under study had undergone a methylation process at many levels of their proteins. The results of this study depend on different algorithmic parameters and changing these parameters were diverse. As matter of fact that mastitis heritability is low in general, such studies could reveal a better role for single and group genes in the epigenetics process.
    Keywords: CpG Island, Dairy cow, Mastitis, Protein methylation
  • A Ganloo, SA Zahed, A Hassanpour * Pages 125-136
    Introduction
    Leptospirosis is a zoonotic disease, which is caused by gram negative and aerobic leptospira interrogans and its different serovars. All the pathogenic leptospirae were formerly classified as members of the species Leptospira interrogans; the genus has recently been reorganized and pathogenic leptospirae are now identified in several species of Leptospira. Leptospirosis is significant occupational hazard in the animal husbandry in certain areas. The majority of infections remain asymptomatic (Constable et al 2017). However, leptospirosis as a cause of acute respiratory distress is becoming more frequently recognized. A wide variety of serological tests, which show varying degrees of serogroups and serovar specificity, have been described. Laboratory procedures are used in the diagnosis of leptospirosis but two tests have a role in veterinary diagnosis: the microscopic agglutination test (MAT) and ELISA. Cross-reactions caused by exposure to leptospiros of the same serogroup can occur in MAT, for example, infection by L. balcanica and L. medanensis can produce false positive L. hardjo reactions (Quinn et al 2002). The MAT has the disadvantages that it is tedious and time consuming, and the use of live culture imposes a risk of human infection. Another disadvantage is the failure of the MAT to differentiate between titres after vaccination and those after natural infection, since the titres may be of similar magnitude. Uveitis is the most frequently encountered clinical manifestation of leptospirosis in animal, which appears to be mediated by autoimmune mechanisms involving cross reactivity between ocular tissues and leptospiral membrane proteins; however, abortion and stillbirth are serious problems. Many serological studies in different countries were conducted on leptospirosis disease which has mostly showed the highest percentage of infection in animal (Hassanpour et al 2009). The aim of the study is to determine the serovars of leptospira in Tarom area.
    Material and methods
    During June to September 2015 for this study, 200 blood samples randomly collected from jugular vein of different animal (47 males and 153 females) of Tarom area (Abbar, Chavarzag County and Daram, Dastjerde Village). None of these animals had been vaccinated against Leptospira and there was no history of leptospirosis-related symptoms or signs of the disease at the time of sampling. we have collected 10 ml of blood from the jugular vein of each animal. After taking blood, the tubes were stored at room temperature for 1 - 2 h, so that the blood clots are completely formed, then they were stored at 4˚C in refrigerator. Next morning these tubes were removed from the refrigerator and their serum was extracted using sterile Pasteur pipettes, and serums were transferred to Micro tubes. If there were red blood cells in the extracted serum, the serum would be centrifuged at 3000 rpm for 10 min, and then the pure serums were transferred to Micro tubes. It should be noted that during the transfer, the related numbers were inserted on Micro tubes. The serum micro tubes were frozen at -20˚C, so that the least damage occurs until performing the test. A few hours before MAT test, the samples were removed from the freezer and gradually melted at room temperature and tested by microscopic agglutination test (MAT). The serum samples were tested for antibodies to 4 live serovars of leptospira Canicola, leptospira Grippothyphosa, leptospira Pomona, and leptospira Icterohaemorrhagiae using the microscopic agglutination test. On the basis of age, these animal were divided in 4 groups (<1year old, 1-2-year old, 2-3-year old and 3-4-year old). On the basis of species, these animal were divided in 4 groups (Cattle, Sheep, Goat, and Horse) and on the basis of sex, these animal were divided in 2 groups (male and female). The results were analyzed by chi-square to determine the difference between sexes and different groups of ages.
    Results and discussion
    In 48 samples (24 percent), including 23 cattles, 7 goats, 15 sheep and 3 horses among the 200 collected samples, infection with leptospira interrogans was detected. Leptospira Grippothyphosa has the highest percentage 39.59 (19 animal) including 10 cases of cattles, 7 sheep, and 2 horses, followed in descending order by Icterohaemorrhagiae (25%), Pomona (18.75%), and canicola (16.66%). Species of animal was significantly related to the prevalence of leptosprial antibodies. In serological tests for leptospirosis such as MAT, the results often indicate infection with more than one serovar. This may be the result of mixed serovar infection, but the existence of cross-reactivity in the MAT between the serovars is well known and can be excluded from this interpretation. The predominant Leptospira serovars giving rise serological reaction vary somewhat between countries. Haji Hajikolahi et al. (2005) reported that serovar Grippothyphosa is present in 33.33% of positive horses in Ahavaz area in Iran. In Urmia district, serovar Pomona is identified as causing about 16.2% of leptospiral infection (Abdollahpour et al 2016). The rate of infection in different genders were studied, in which the most affected gender was female animals (16.5 percent) included 16 cattle, 4 goats, 12 sheep, and 1 horse. There was a significant difference between male and female seroprevalence (P<0.05), which is in agreement with the report by Abdollahpour et al. (2013) concerning goats in Urmia; and hassanpour et al. (2009) concerning horses in Tabriz. There was no significant relationship between aging and the incidence of leptospiral infection in goats, sheep, and horses (P>0.05), but there was a significant difference between aging and the incidence of leptospiral infection in cattle (P<0.05). The most general titer was 1:100 and the rate of infection in different ages were studied, in which the most affected age was 4-3 years, 23 animals (11.5 percent) including 11 cattles, 3 goats, 7 sheep, and 2 horses; which is in agreement with the report by Abdollahpour et al. (2016) concerning Buffalos in Urmia. In serological tests for leptospirosis such as MAT, the results often indicate infection with more than one serovar, but in this study, all samples showed a positive reaction to only one type of serovar. This may be the result of mixed serovar infection, but the existence of cross reactivity in the MAT between the serovars is well known and can be excluded from this interpretation. Leptospiral antibodies appear within a few days of infection and persist for weeks or months and, in some cases, years. Unfortunately, antibody titres may fall to undetectable levels, while animals remain chronically infected. To overcome this problem, sensitive methods are needed to detect the organism in urine or the genital tract of chronic carriers. The results were analyzed by chi-square to determine the difference between sexes and different groups of age and species of animal was significantly related to the prevalence of leptosprial antibodies. Therefore, the demonstration of leptospirae in the genital tract and or urine only must be interpreted with full consideration of the serological results and culture or detection of leptospirae in blood or body fluids, as these findings may indicate that the animals are carriers.
    Conclusion
    These results confirmed that leptospiral infection may exist in the animal population in Tarom region and the presence of antibodies in the absence of infection indicates exposure to the organism and must be acknowledged. In addition, these results confirmed that the majority of leptospiral infections are asymptomatic. Accordingly, prevention of animal leptospirosis must rely on good hygiene practices, minimization of rodent contact, and vaccination of other species of production and companion animals. In addition, these results confirmed that the majority of leptospiral infections are asymptomatic.
    Keywords: Animal, Leptospira, serum infection, Tarom
  • SS Mousavi *, H Amanlou, A Nikkhah, AM Tehrani, HR Mirzaei Alamouti, MH Nemati, B Naseri, M Hoseini Pages 137-151
    Introduction
    Lamb fatteners receive less benefit due to unawareness regarding the suitable methods of fattenering. As it is conventional in broiler breeding, the diet of pre-starter contains high levels of protein and energy, which is specified to freshly hatched chicks and it decreases the number of days between hatching and slaughter day every year. Therefore, the same method can be tested in newborn lambs, meaning that the lamb receives the whole mother's milk and the initial diet, which is referred to creep feeds. The creep feed contains at least 15 percent crude protein and breeding lambs immediately after birth, with receiving a diet either rich in metabolizable protein or low metabolizable protein with a lysine amino acid and a rumen-protected methionine. This may be substituted with the conventional method of feeding lamb via whole mother's milk, alfalfa and Rangeland forage and then, fed in an intensive system under Iranian conditions. The present research was designed and conducted to economically compare the conventional method with creep feeding method in Afshari lambs, and to investigate the possibility of shortening the time from birth to slaughter. Production of meat with high quality and quantity without increasing the number of livestock and gaining an appropriate profit in the short term is one of the main goals of the fattening industry. The cost of livestock feeds supply is about 65-70% of the costs of raising and maintaining. If these costs are reduced in a period of fattening, in addition to producing meat with a good quantity and quality, more income will be also earned by the livestock owner (Farzad 1996; Talebi and Edriss 1999; Mousavi et al. 2005, 2011). Improving human living standards, reducing physical activity and changing food habits have led to a reduction in tail fat consumption and a rise in demand for meat. Also, if low-fat and low-fat sheep are produced, improving the nutritional efficiency will increase the economic efficiency of fattening units (Talebi 1998), so that the livestock fed in the lower ages will have better food efficiency (Hasanpour 1965; Mousavi et al. 2005, 2011). Choosing the appropriate fattening method will reduce the starting age, longevity and cost of rearing lamb and leaving livestock out of the pasture, which will lead to a rapid return of payments and improvement of investment in the sheep industry, reduced overgrazing and preventing soil erosion and flood damage. Due to the advancement of ruminant nutrition science in recent years, it is possible to start fattenning at a young age. Then, the use of creeping rations is associated with a change in the composition of the diet, especially metabolizable protein; as a result, growth, daily weight gain, and feed efficiency are increased and carcass compositions may have more meat. The goal of this study was to select an appropriate Fattening system that would provide greater economic returns through a higher percentage of meat, less feed, and reduced lamb's longevity. Choosing the appropriate procedure of feedlot and deliver the lambs to slaughter weight in the possible shortest time reduces the cost of livestock and There was an additional livestock departure from the pasture.
    Material and methods
    51 male lambs of Afshari were used in an unbalanced completely randomized design with 4 treatments included: treatment 1: Milk + alfalfa + pasture (conventional control without fattening as semi-intensive farming or CONT-UF ), treatment 2: Milk + alfalfa + pasture then get a fattening diet ( conventional control with fattening as semi-intensive farming or CONT-F ), treatment 3: milk + creep feeding ( included high protein metabolism as intensive farming or HMP), and treatment 4: milk + creep feeding (including low protein metabolism with lysine and methionine rumen protected as intensive farming or LMP +LMRP).
    Results and discussion
    The effect of creep feeding on average daily gain of lambs was significant (p=0.0001), (Table 2) Which was consistent with the results of others (Karim et al. 2001; Moriel and Arthington 2013; Yiakoulaki et al. 2007; Lardy and Maddock 2007). The reason for the increase in daily weight gain at an early age is due to the higher growth rate of the animal early in life, which is justified by growth curves that are consistent with the goal of experimenting with early onset of slaughter and slaughter at an early age. The low daily gain was due to the non-fattening control treatment, but it was fattened in the control treatment because fattening started at 5 months of age and the daily gain was lower at high ages. Reduced protein intake and amino acids intake and no effect on body weight changes were observed in creep diets, whereas in Abdelrahman and Hunaiti (2007), Purchas et al (1998) and Yousefian et al (2013) studies, weight gain was observed but in the experiment, Heydari et al (2014) reduced yield. Dry matter intake among the treatments was statistically significant and the highest rate was found in the fattening control (p=0.0001), (Table 2) Which is consistent with the results of other researchers (Eilami 1995; Eilami 2005; Kianzad 1993). The amount of dry matter consumed depends on the body weight of the animal as the age of the animal increases and consequently body weight increases feed intake in this experiment as slaughter age varies so the amount of consumption depends on the life of the animal and in creep treatments due to nutrient availability. As well as increased feed efficiency at an early age, the amount of dry matter consumed was low, whereas this was not the case for the control treatments because the dry matter consumed before the beginning of the feed was used to maintain low weight gain. FCR in the fattening and non-fattening controls increased significantly and recorded the highest amount in the fattened control (p=0.0001), (Table 2) This is in agreement with the results of other researchers (Eilami 1995; Eilami 2005; Kianzad 1993). The conversion factor is a function of the amount of feed consumed to increase body weight, which is an increase in the feed conversion ratio with increasing age of the animal due to the type of animal body stored so that as the age of the animal increases, the amount of fat stored in the protein increases and the cost of increasing each gram of fat tissue increases. Compared to the cost of increasing every gram of muscle tissue, this increases the conversion factor. Carcass effiency was reduced significantly in the non-fattening control (p=0.0001), (Table 3) While in the creep treatments, even at a young age, carcass yield had a higher number, indicating greater growth of organs, but no significant difference was observed between creep and fattening treatments. The greatest benefit was observed in LMP + LMRP treatment and loss was observed in CONT-F treatment (P = 0.0001), (Table 4) Since the fattened control treatment had a life span of 260 days and the other treatments reached the kill weight in the shortest time.
    Conclusion
    Baesd on the economic calculations, LMP+LMRP treatment was determined as a better method for finishing lambs.
    Keywords: Lamb, Feedlot, Creep, Lysine, Methionine
  • E Piradl, R Pirmohammadi, H Khalilvandi * Pages 153-173
    Introduction
    Barley is mainly used as a feed grain for livestock in Iran. Historically, barley has been traded at a significantly lower price than corn in the world market (FAOSTAT 2015). The endosperm of the barley kernel is surrounded by the pericarp, which is overlain by a fibrous hull, which is extremely resistant to microbial degradation in the rumen (Wang et al 2003). Some of the feed processing technique treats that remove or cracked the hull makes the starch more accessible to microbes, and increases the rate and extent of starch ruminal degradation. In these cases, processing is essential to maximize the utilization of barley grain by cattle, but extensive grain processing increases ruminal starch degradation, which often decreases feed intake in ruminants. On the other hand, in some cases, the feeding of barley-based high concentrate diets has been linked to an increased incidence of digestive disorders, resulting reduced feed intake, cattle going off-feed, laminitis, bloat, acidosis, rumenitis, and liver abscesses (Yang et al 2000). It is assumed that the rapid rate of fermentation of starch in barley grain contributes to these nutritional and health problems. Differences in chemical composition exist between barley cultivars. Individual barley varieties differ in terms of the composition of the protein matrix in the starchy endosperm of the grain and this characteristic might be expected to influence degradability in the rumen (Gholizadeh et al 2017). Optimum alteration of the site of starch digestion requires processing methods or conditions that increase starch flow to the duodenum without reducing its total tract digestibility. Additional glucose absorption at the duodenum may reduce the needs for gluconeogenesis and increase productivity of ruminants (Nocek and Tamminga 1991). According to Parrott et al (1969), they have reported improved nutritional efficiency due to grain processing in ruminants. Radiation is a physical process approach that has the potential to replace other methods of processing without affecting the protein structure without radioactive activity, and this process is likely to cause cross-linking and clumping of proteins (Mani and Chandra 2003). Shawrang and Sadeghi (2006, 2007 and 2008) argued that the protective mechanism of proteins from rumen degradation in highly processed feeds has been very wrapped, and chemical reactions such as the millard reaction that occurs during thermal processing may be responsible for the reduction of rumen degradability. These reactions have the effect of converting the protein into resistant compounds to rumen degradation. The ionizer rays affect the structure of the protein and cause it to tear apart. It has been argued that irradiation may form cross-linking and protein binding (Gaber 2005, Ebrahimi et al 2011). Previous studies have confirmed that differences in rate of degradation can occur between barley cultivars. Although, these differences may indicate that certain cultivars of barley are more desirable as feed grains than the others. There are a limited data available for Iranian barley grains and their response to processing to make solid recommendations in this regard. In order to improve the nutritional value of fast fermentation cereal grains in the rumen, gamma irradiation can be used as a suitable treatment method in this regard. It is also important to choose the best radiation duration and dosage in the irradiation method. The aim of this study was to determine the effects of gamma irradiation on ruminal dry matter, starch and crude protein degradability of different varieties of barley grain. Additionally, protein profile in metabolizable protein system was calculated.
    Materials and methods
    Barley varieties Makoei, Bahman Abi, and Sahand were irradiated with the use of the gamma ray of 60 cobalt and 50, 100, and 150 KGy doses at the center of radiation in Yazd. Kinetics and parameters of protein and starch degradability of nylon bag samples were evaluated using three male Holstein calves equipped with ruminal fistula at 0, 2, 4, 6, 8, 12, 24, and 48 hours based on a completely randomized block design. Incubations were repeated two times to ensure day to day variations. All barley samples were grounded to pass a 2 mm screen. Approximately 5 g (air dry) of samples were weighed in triplicate into 10 cm × 20 cm nylon bags (porosity = 50 μm). Dry matter was determined by oven-drying at 55 °C for 48 h. The crude protein and starch content were determined, accordingly. The protein profile based on the metabolic protein system was determined based on the relevant equations. The amounts of crude protein and starch in the samples before and after incubation were measured using the Kjeldahl system and acid digestion and anthrone, respectively. Parameters of degradability and effective degradability at different rumen crossing velocities were determined by nonlinear equations of McDonald and Erskoff and McDonald using (PROC NLIN) statistical software SAS 9/4. The AFRC equations were used to estimate the amounts of fast rumen protein, slow rumen protein, rumen effective protein, total rumen protein, and rumen nonmodifiable protein.
    Results and discussion
    Analysis of variance showed that gamma irradiation at different levels reduced starch and protein degradability in rumen among different cultivars (P<0.05). Among different studied cultivars, the Sahand varietie was affected more than other cultivars. Different responses of barley grain varieties to different levels of processing can be related to the content of nutrients in the fiber shell, the distribution of starch in different grain segments and the difference in the structure of starch granules. The results of this study showed that the cultivation of different barley grain varieties with gamma rays reduced the fast degradability (P<0.05). Based on the results, the differences in the response of different barleys to gamma rays showed that the best response was affect the nutritional parameters in order to improve rumen fermentation, protein degradation, starch and increase starch values can be irradiated at 50 kGy.
    Conclusions
    Gamma irradiation can be used as one of the commonly treatments to reduce the degradability of dry matter, starch and rumen protein, and increase starch and digestible escape protein and fermentation, it improves the rumen's ecosystem and reduced the risk of acidosis.
    Keywords: Barley, Degradability, Gamma, Processing, Starch
  • B Frdoust, M Ebrahimi *, Gh Moghaddam, M Olyaee, M Adib Moradi, S Alijani Pages 175-188
    Introduction
    Methionine, as the first limiting amino acid in poultry, is necessary for protein synthesis and growth. Several studies evaluated the impact of in ovo injection of DL- methionine, but there is no report regarding the in ovo injection of L- methionine.
    Aim
    Therefore, the purpose of this study was to investigate the effect of in ovo feeding of L- methionine on weight, carcass traits, small intestine morphology, and blood metabolites of day-old broiler chicks.
    Materials and method
    To achieve the aim of the study, 240 broiler breeder eggs (Ross 308) were used based on a completely randomized design with eight experimental treatments and 30 eggs per each treatment. Experimental treatments included: six levels of L- methionine (0.19, 0.38, 0.57, 0.76, 0.95, and 1.14% L- methionine), a sham control (injection of distilled water), and a control (non- injected group), which were injected into the amniotic fluid at 14 days of incubation. After hatching, chicks were weighed, blood samples were collected, and they were humanly euthanized to evaluate carcass traits and small intestine morphology. After that, serum of blood samples was collected and used for measuring metabolite concentrations.
    Results
    The results of the study indicated that in ovo feeding of L- methionine increased carcass efficiency and thigh, breast, gizzard, and thymus weight (P<0.05), but did not influence hatchability (P>0.05). In addition, reducing effects of L- methionine treatments on serum glucose, triglyceride, and blood urea nitrogen were observed (P<0.05). Moreover, in ovo injection of L- methionine improved length and weight of small intestine, and duodenum and jejunum morphology parameters (villous height, villous height/crypt depth ratio, crypt diameter, and crypt depth), (P <0.05).
    Conclusion
    According to the results of this study, in ovo feeding of 0.19% L- methionine had an improving effect on hatchability, carcass traits, blood metabolites, immune system organs, and morphology of small intestine; therefore, 0.19% L- methionine is an advisable level for in ovo feeding.
    Keywords: Blood metabolite, Broiler chick, In ovo feeding, L- methionine, Small intestine