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پژوهشهای علوم دامی ایران - سال نهم شماره 3 (پاییز 1396)
  • سال نهم شماره 3 (پاییز 1396)
  • تاریخ انتشار: 1396/10/30
  • تعداد عناوین: 10
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  • علمی پژوهشی - تغذیه نشخوارکنندگان
  • عباسعلی ناصریان*، رضا ولی زاده، محمد رضا نصیری صفحات 269-283
    تعداد بیست و هشت راس بره ماده بلوچی با میانگین سن 3/2 ± 9/14 هفته و وزن 6/4 ± 3/26 کیلوگرم از جیره های با یا بدون پیه، بر پایه دانه ذرت یا جو، در قالب طرح کاملا تصادفی به روش فاکتوریل 2×2 به مدت 9 هفته تغذیه شدند. مصرف جیره های آزمایشی اثری بر میانگین خوراک مصرفی بره ها نداشت، اگرچه افزایش وزن روزانه و بازدهی خوراک در هفته های 4 تا 8، تحت تاثیر اثر تداخل چربی × غله قرار گرفت و در تیمار لیپوژنیک-ذرت بالاترین مقدار بود. افزودن پیه به جیره، به ترتیب سبب افزایش و کاهش غلظت کلسترول و گلوکز سرم بره ها در طول دوره آزمایش شد. درحالی که، غلظت انسولین و نسبت گلوکز: انسولین، تحت تاثیر اثر غله قرار گرفته، در تیمارهای جو در مقایسه با ذرت، به ترتیب افزایش و کاهش یافت. در بره های تغذیه شده با جیره های لیپوژنیک در مقایسه با جیره های گلوکوژنیک، غلظت پایه گلوکز کاهش و غلظت پایه کلسترول و آسپارتات آمینوترانسفراز افزایش یافت. ازطرفی، غلظت پایه اسیدهای چرب استریفیه نشده سرم و شاخص کمی حساسیت انسولینی تحت تاثیر اثر تداخل چربی × غله قرار گرفته و شاخص حساسیت انسولینی به طور معنی دار با بازدهی خوراک همبستگی مثبت نشان داد. به نظر می رسد غلظت چربی و کمیت و ماهیت منبع نشاسته ای جیره، عواملی هستند که می توانند بر فراسنجه های حساسیت انسولینی نشخوارکنندگان اثرگذار باشند. همچنین، به نظر می رسد جیره هایی که نسبت مطلوبی از چربی و نشاسته را فراهم کنند، بتوانند سبب بهبود بازدهی و وضعیت انرژی حیوان شوند.
    کلیدواژگان: بازدهی خوراک، پیه، جو، حساسیت انسولینی، ذرت
  • جمال سیف دواتی *، زهرا اسلامی، حسین عبدی بنمار، فرزاد میرزائی آقچه قشلاق، رضا سید شریفی صفحات 284-299
    هدف آزمایش حاضر برآورد کمی اثر تانن و ترکیبات فنولی غلاف نخود سبز (.Pisum sativum L) بر قابلیت هضم شکمبه ای با روش های آزمایشگاهی بود. در این بررسی از ترکیب پلی اتیلن گلیکول (PEG) عامل غیر فعال و کمپلکس کننده تانن و ترکیبات فنولی به صورت افزودنی در سطوح توصیه شده استفاده شد. داده های حاصل در قالب طرح کاملا تصادفی تجزیه و تحلیل شدند. ترکیبات شیمیایی غلاف نخود سبز شامل ماده خشک، پروتئین خام، چربی خام، ماده آلی، خاکستر خام، الیاف نا محلول در شوینده خنثی NDF)) و الیاف نا محلول در شوینده اسیدی ((ADF به ترتیب 53/87، 03/10، 5/2، 49/79، 046/8، 31/40 و 69/23 درصد اندازه گیری شدند. فنل کل همراه با تانن، فنل کل بدون تانن، تانن کل و تانن متراکم به ترتیب 502/0 ،196/0، 306/0 و 044/0 بر حسب گرم در کیلو گرم ماده خشک به دست آمد. قابلیت هضم ماده خشک، ماده آلی، ماده آلی در ماده خشک (درصد) و انرژی قابل متابولیسم (مگاژول بر کیلو گرم) در غلاف نخود سبز به ترتیب 06/81، 46/80، 98/73 و 61/11 بود. پس از انکوباسیون نمونه خشک غلاف نخود سبز مقادیر تولید گاز در زمان های 2، 4، 8، 12، 24، 48، 72 و 96 ساعت، میزان گاز بخش نا محلول اما قابل تخمیر گروه کنترل (16/75 میلی لیتر) در مقایسه با سایر تیمارها مشابه بوده و بین آنها تفاوت معنی دار نبود. همچنین ثابت نرخ تولید گاز در گروه کنترل (086/0) برابر و بدون اختلاف معنی دار با تیمار حاوی 200 میلی گرم PEG و تیمارهای حاوی 400 میلی گرم PEG (082/0) و600 میلی گرم PEG (079/0) بود. گاز تولیدی از بخش نا محلول اما قابل تخمیر (b) در غلاف نخود سبز با سطوح افزایشی PEG مشابه با گروه کنترل (85/73 میلی لیتر) بود. در اثر عمل آوری و مکمل سازی این خوراک با پلی اتیلن گلیکول در مقدار گاز حاصل از بخش محلول، بخش نا محلول و مجموع تولید گاز از بخش محلول و نا محلول در غلاف نخود سبز تفاوت معنی دار مشاهده نشد (p>0/05). با توجه به مقدار پروتئین خام غلاف نخود که حدود 50 درصد پروتئین خام دانه نخود می باشد و مقادیر ترکیبات دیواره سلولی و پتانسیل تولید گاز آن در این تحقیق غلاف نخود سبز را می توان به عنوان منبع فیبر غیر علوفه ای و مواد خوراکی ارزان قیمت جایگزین بخشی از مواد خوراکی اصلی در جیره دام ها نمود.
    کلیدواژگان: تانن، ترکیب شیمیایی، تولید گاز، غلاف نخود سبز، فیبر غیرعلوفه ای
  • ایمان مهرامیری، مرتضی چاجی*، صالح طباطبایی وکیلی، طاهره محمدآبادی، محسن ساری صفحات 300-313
    آزمایش حاضر به منظور بررسی اثرات جایگزینی کاه ماش با کاه گندم و سیلاژ ذرت بر قابلیت هضم، عملکرد و جمعیت پروتوزوآی شکمبه در بره های نر عربی انجام گرفت. در مرحله اول پس از تعیین سطح مناسب جایگزینی کاه ماش با کاه گندم و سیلاژ ذرت با استفاده از روش هضم دو مرحله ای، بره ها با جیره های آزمایشی برگزیده از مرحله اول شامل جیره فاقد کاه ماش (شاهد)، 100 درصد جایگزینی کاه ماش به جای کاه گندم (جیره 1)، 25 درصد جایگزینی کاه ماش به جای سیلاژ ذرت (جیره 2) و 50 درصد جایگزینی کاه ماش به جای سیلاژ ذرت (جیره 3) در قالب طرح کاملا تصادفی برای تعیین قابلیت هضم، تخمیر و عملکرد پروار تغذیه شدند. برای تعیین قابلیت هضم، حیوانات در یک وعده صبح با جیره های مورد آزمایش تغذیه شدند و جهت محاسبه قابلیت هضم، مقدار خوراک داده شده، باقی مانده و مدفوع روزانه جمع آوری و وزن آنها ثبت شد. جهت اندازه گیری فراسنجه های خونی و تخمیری شکمبه و شمارش جمعیت پروتوزوآیی شکمبه در روزهای پایانی آزمایش، از دام ها خون و مایع شکمبه گرفته شد. در مرحله دوم، جهت برآورد ضریب تبدیل و افزایش وزن روزانه از بره های نر با میانگین وزن 24 کیلوگرم و سن 5 ماه استفاده شد. طول دوره آزمایش 60 روز شامل 15 روز عادت پذیری و 45 روز نمونه گیری و وزن کشی بود. نتایج تعیین سطح مناسب نشان داد که از نظر قابلیت هضم اختلافی بین جیره های آزمایشی وجود نداشت. نتایج حاصل از آزمایش دوم نشان داد که از نظر مقدار خوراک مصرفی در کل دوره بین جیره ها اختلاف وجود داشت و در جیرهای حاوی کاه ماش (جیره 1 و 3 به استثناء 2) بیشتر از شاهد بود. بیشترین قابلیت هضم مواد مغذی مربوط به جیره یک بود. در مورد فراسنجه های خونی و شکمبه ای مورد ارزیابی، اختلاف معنی داری بین جیره ها مشاهده نشد. از نظر میانگین افزایش وزن روزانه و ضریب تبدیل خوراک، اختلاف معنی داری بین جیره های آزمایشی مشاهده نشد. بنابراین، با توجه به عدم اختلاف در عملکرد هضم و پروار بره ها در آزمایش حاضر و حتی نتایج بهتر در برخی موارد نظیر مصرف خوراک کل دوره، افزایش وزن روزانه تا 15 و 30 روزگی و ضریب تبدیل تا 15 روزگی، استفاده از کاه ماش به دلیل ارزان تر بودن و فراوانی آن در فصل هایی خاص از سال به صورت جایگزینی برای کاه گندم یا سیلاژ ذرت کم دانه در تغذیه بره های پرواری توصیه می شود.
    کلیدواژگان: افزایش وزن روزانه، پروتوزوآی شکمبه، ضریب تبدیل خوراک، قابلیت هضم، نیتروژن آمونیاکی
  • حسن علی عربی*، محمد مهدی طباطبایی، پویا زمانی، سپیده افروزی، خلیل زابلی صفحات 314-327
    جهت بررسی اثر بلوک اوره- ملاس غنی شده با موننسین بر عملکرد، قابلیت هضم و برخی فراسنجه های خون و شکمبه در بره های نر، آزمایشی به صورت فاکتوریل در قالب طرح کاملا تصادفی انجام شد. بلوک اوره- ملاس، از کنجاله پنبه دانه (21٪)، سبوس گندم (7/19٪)، اوره (5/2٪)، ملاس (3/43٪)، کلسیت (4/3٪)، مکمل معدنی (2/4٪) و نمک (9/5٪) ساخته شد. در آزمایش اول، 24 راس بره 8-7 ماهه به صورت تصادفی در 4 تیمار آزمایشی شامل 1) جیره مخلوط علوفه و کنسانتره (جیره پایه)، 2) جیره پایه به علاوه 30 قسمت در میلیون موننسین، 3) جیره پایه (85% جیره) و بلوک بدون موننسین (15% جیره) و 4) جیره پایه (85٪) و بلوک غنی شده با موننسین (15٪ جیره) تقسیم شدند. در طول دوره آزمایش، ماده خشک مصرفی و تغییرات وزن زنده اندازه گیری شدند. نمونه های خون و مایع شکمبه به ترتیب در روزهای 68 و 69 آزمایش، 3 ساعت پس از خوراک دهی صبح تهیه شدند. سپس، قابلیت هضم و ابقاء نیتروژن بر روی دام ها بررسی شد. نتایج نشان داد اثرات اصلی موننسین و بلوک سبب افزایش ماده خشک مصرفی، افزایش وزن روزانه، قابلیت هضم پروتئین خام جیره، غلظت کل اسیدهای چرب فرار شکمبه و گلوکز خون شد (05/0P
    کلیدواژگان: ابقاء نیتروژن، بره مهربان، بلوک اوره، ملاس، قابلیت هضم، موننسین
  • علمی پژوهشی - تغذیه طیور
  • نسیم بیدار، احمد حسن آبادی *، حسن نصیری مقدم، مهدی وریدی، محمد محسن زاده صفحات 328-339
    در این آزمایش اثر افزودن سطوح مختلف اسانس اسطوخودوس Lavandula angustifolia)) به جیره بر عملکرد، فراسنجه های خونی و قابلیت هضم ایلئومی مواد مغذی در جوجه های گوشتی مطالعه گردید. برنامه تغذیه شامل جیره آغازین از 1 تا 10 روزگی، جیره رشد از 11 تا 24 روزگی و جیره پایانی از 25 تا 42 روزگی بود. پنج تیمار آزمایشی عبارت بودند از: تیمار شاهد، افزودن ویرجینیامایسین 10% به جیره) 50 میلی گرم در کیلوگرم( و سه سطح اسانس اسطوخودوس (350، 525 و700 میلی گرم در کیلوگرم). جوجه های تیمار حاوی ویرجینیامایسین در سن 42 روزگی بیشترین مصرف خوراک را داشتند و پس از آن جوجه های تغذیه شده با جیره های حاوی 525 و700 میلی گرم در کیلوگرم اسانس اسطوخودوس قرار داشتند. بیشترین افزایش وزن در کل دوره مربوط به جیره حاوی ویرجینیامایسین و کمترین افزایش وزن مربوط به جیره شاهد بود. در سن 28 روزگی کمترین میزان کلسترول خون در تیمار حاوی350 میلی گرم در کیلوگرم اسانس مشاهده شد که با تیمار آنتی بیوتیک اختلاف معنی داری داشت. همچنین جیره های حاوی اسانس اسطوخودوس باعث کاهش لیپوپروتئین با چگالی بالا سرم نسبت به جیره های حاوی ویرجینیامایسین و شاهد شدند. اثرات معنی داری بر ضریب تبدیل غذایی، تری گلیسرید، لیپوپروتئین با چگالی پایین، لیپوپروتئین با چگالی خیلی پایین سرم و قابلیت هضم مواد مغذی مشاهده نگردید. بر طبق نتایج این آزمایش اسانس اسطوخودوس باعث بهبود نتایج عملکردی در حد آنتی بیوتیک نگردید، اما استفاده از آن می تواند اثرات مثبتی بر مصرف خوراک، افزایش وزن و کاهش کلسترول داشته باشد، هر چند تحقیقات بیشتری در این زمینه مورد نیاز است.
    کلیدواژگان: اسطوخودوس، جوجه های گوشتی، عملکرد، فراسنجه های خونی، قابلیت هضم
  • علی نوبخت*، محسن جلیلی صفحات 340-356
    این آزمایش جهت بررسی اثرات استفاده از نوع چربی و سطح انرژی جیره بر عملکرد و لیپیدهای خون جوجه های گوشتی انجام گرفت. آزمایش با 432 قطعه جوجه گوشتی سویه تجاری راس 308 با آرایش فاکتوریل 2×2×2 شامل دو نوع چربی (پیه گاوی و روغن کلزا)، دو سطح چربی (3 و 6 درصد) و دو سطح انرژی قابل متابولیسم (2900 و 3100 کیلوکالری بر کیلوگرم جیره)، با 8 تیمار، 4 تکرار و 12 قطعه جوجه گوشتی از سن 11 تا 42 روزگی جوجه ها در دو دوره آزمایشی رشد (11 تا 24 روزگی) و پایانی (25 تا 42 روزگی) در قالب طرح کاملا تصادفی انجام گردید. کل دوره آزمایش، استفاده از روغن کلزا در مقایسه با پیه گاوی موجب کاهش مقدار خوراک مصرفی روزانه، بهبود ضریب تبدیل خوراک و افزایش وزن نهایی و شاخص تولید شد (05/0>P).‍‍‍ سطح چربی اثرات معنی داری بر عملکرد نداشت (05/0> P). جیره با 3100 کیلوکالری انرژی افزایش وزن و شاخص تولید بیشتر را موجب گردیده و باعث بهبود ضریب تبدیل خوراک شد (05/0>P).‍‍‍ در اثرات متقابل نوع چربی و سطح آنها، 6 درصد پیه گاوی ضریب تبدیل خوراک را افزایش داد (05/0>P).‍‍‍ در خصوص اثر نوع چربی با سطح انرژی جیره حاوی روغن کلزا و 3100 کیلوکالری بر کیلوگرم انرژی قابل متابولیسم بهترین ضریب تبدیل خوراک را داشت (05/0>P).‍‍‍ اثرات متقابل سطح انرژی و سطح چربی بر عملکرد معنی دار نبود (05/0> P). در رابطه با اثرات متقابل نوع چربی، سطح چربی و سطح انرژی جیره بر عملکرد، استفاده از 3 و 6 درصد روغن کلزا با 3100 کیلوکالری بر کیلوگرم انرژی قابل متابولیسم موجب افزایش مقدار خوراک مصرفی، افزایش وزن روزانه، بهبود ضریب تبدیل خوراک و افزایش وزن نهایی جوجه ها شد (05/0>P).‍‍‍ ترکیب لاشه جوجه ها تحت تاثیر منبع چربی و سطوح آنها و سطح انرژی قرار نگرفت (05/0> P). جیره حاوی پیه گاوی غلظت HDLخون را افزایش داد (05/0>P).‍‍‍ جیره با 3100 کیلوکالری بر کیلوگرم انرژی قابل متابولیسم موجب کاهش غلظت کلسترول، HDL وLDL خون جوجه ها شد (05/0>P).‍‍‍ در اثرات متقابل نوع چربی و سطح آن، استفاده از 6 درصد پیه گاوی موجب افزایش غلظت HDL خون شد (05/0>P).‍‍‍ در اثرات متقابل نوع چربی و سطح انرژی، استفاده از پیه گاوی با جیره حاوی 2900 کیلوکالری بر کیلوگرم انرژی قابل متابولیسم موجب افزایش سطوح کلسترول و HDL خون جوجه ها شد (05/0>P).‍‍‍ در اثرات متقابل سطح چربی و سطح انرژی، استفاده از 6 درصد روغن کلزا و 3100 کیلوکالری انرژی قابل متابولیسم موجب کاهش معنی دار کلسترول، HDL وLDL خون جوجه ها شد (05/0>P).‍‍‍ در اثرات متقابل نوع چربی، سطح چربی و سطح انرژی، استفاده از 6 درصد روغن کلزا با 3100 کیلوکالری بر کیلوگرم انرژی قابل متابولیسم موجب کاهش غلظت کلسترول، HDL و LDL خون جوجه ها شد (05/0>P).‍‍‍ به طور کلی در جوجه های گوشتی استفاده از جیره با 3100 کیلوکالری بر کیلوگرم انرژی قابل متابولیسم و تا 6 درصد روغن کلزا نتایج بهتری در خصوص عملکرد و فراسنجه های خونی جوجه ها دارد ولی استفاده از پیه گاوی به خصوص سطح 6 درصدی آن اثرات سوئی در این موارد دارد.
    کلیدواژگان: انرژی، پیه گاوی، جوجه گوشتی، روغن کلزا، عملکرد
  • علمی پژوهشی- ژنتیک و اصلاح دام و طیور
  • مجتبی طهمورث پور *، نصیرالدین مقدر صفحات 357-362
    هدف از این مطالعه بررسی تاثیر خطای برآورد اثرات QTL با در نظر گرفتن وجود انحراف غالبیت بر پاسخ به انتخاب به کمک مارکرهای ژنتیکی بود. جمعیتی پایه برابر 1000 نفر غیرخویشاوند و غیرهمخون بر اساس وراثت پذیری های 1/0 و 3/0 که تحت تاثیر QTL با اثرات مختلف افزایشی و غابیت و اثر پلی ژنتیک باقی مانده قرار داشتند شبیه سازی گردید. اثرات QTL با خطای صفر، ده و بیست درصد در نظر گرفته شد و دو سطح غالبیت کامل و غیر کامل برای QTL فرض گردید. پاسخ به انتخاب برای انتخاب به کمک مارکر و انتخاب بدون استفاده از مارکر محاسبه گردید. پاسخ به انتخاب بر اساس انتخاب توده ای 20 درصد از افرادی که بیشترین شاخص انتخاب را داشته اند محاسبه گردید. نتایج نشان داد انتخاب به کمک مارکرهای ژنتیکی باعث افزایش پاسخ به انتخاب می شود اما وجود اثرات غالبیت در شرایطی که اثر QTL با خطا توام باشد باعث کاهش پاسخ به انتخاب می گردد و در شرایطی که خطای برآورد بالا باشد پاسخ به انتخاب به کمک مارکر کمتر از پاسخ انتخاب بدون استفاده از مارکر خواهد بود. نتایج این آزمایش نشان داد پارامترهای QTL قبل از استفاده در برنامه های اصلاحی کاربردی بایستی از دقت بالا برخوردار باشد.
    کلیدواژگان: انتخاب به کمک مارکر، انحراف غالبیت، جایگاه های ژن های کمی
  • رحیمه سپهری، صادق علیجانی، جلیل شجاع غیاث، محمدطاهر هرکی نژاد *، سید عباس رافت صفحات 363-375
    لپتین یک پروتئین 16کیلودالتونی است که در کنترل اشتها، تعادل انرژی و توزیع ذخیره چربی در بدن نقش دارد. هدف مطالعه حاضر، شناسایی آللهای احتمالی این ژن در ناحیه اگزون 3 بود. برای این منظور تعداد 133 راس بره از یک گله و در سن تقریبا یکسان در سه گروه افشاری خالص و نسل F2 و F5 آمیخته افشاری- برولامرینو مورد استفاده قرار گرفتند. پس از خون گیری و انجام اندازه گیری های فنوتیپی بر روی دام زنده، تعداد 85 راس از آن ها کشتار شدند. ، وزن لاشه بعد از کشتار و وزن ران، سردست، قلوه گاه، دنبه و ضایعات بعد از 24 ساعت ماندن لاشه در سردخانه، بدست آمد. محصولات PCR جهت شناسایی SNP (های) احتمالی، مستقیما توالی یابی و دو SNP شناسایی شدند. تعیین ژنوتیپ نمونه های توالی یابی نشده به روش RFLP و به کمک دو آنزیم برشی Hpa II و AIwN I انجام شد. در چندشکلی اول سه ژنوتیپ GG ،GA و AA مشاهده شد. این چندشکلی سبب تغییر اسیدآمینه آرژینین به گلوتامین در کدون شماره 142 می شود و بر میزان چربی پشت و ارتفاع جدوگاه تاثیر معنی داری داشت. چندشکلی بعدی در میان نمونه ها دارای دو ژنوتیپ GG و GA بود که تغییر اسیدامینه ای مشابه را در کدون شماره 196 ایجاد می کند و با اندازه طول بدن ارتباط (p=0.077) نشان داد. بر اساس نتایج بدست آمده، مطالعات گذشته و نیز در صورتی که ارتباط این تغییرات با صفات ذکرشده در سطحی وسیعتر مورد تایید قرار گیرد چند شکلی اول می تواند در برنامه انتخاب دام به کمک نشانگرها مورد استفاده قرار گیرند.
    کلیدواژگان: چند قلوزایی، کیفیت لاشه، گوسفند افشاری، هورمون لپتین، SNP
  • محمد کشاورزپور، محمد رضا بحرینی بهزادی*، مصطفی محقق دولت آبادی صفحات 376-386
    هدف از این پژوهش بررسی تنوع و ساختار ژنتیکی و همچنین بررسی کاهش عملکرد ناشی از همخونی صفات وزن بدن در سنین مختلف در گوسفندان لری بختیاری بود. از اطلاعات مربوط به 7693 راس دام (2478 راس بره نر و 5215 راس بره ماده ) متولد سال های 1368 تا 1389 حاصل از 274 راس قوچ و 2006 راس میش استفاده شد. برای محاسبه ضرایب همخونی از نرم افزار CFC، تحلیل های شجره از نرم افزار ENDOG و محاسبه تابعیت صفات از همخونی، از نرم افزار WOMBAT استفاده شد. برای توصیف تنوع ژنتیکی این جمعیت از فراسنجه های تحلیل احتمال منشا ژن استفاده گردید. تعداد حیوانات بنیان گذار، تعداد موثر حیوانات بنیان گذار، تعداد موثر اجداد، تعداد موثر ژنوم حیوانات بنیان گذار، تعداد موثر ژنوم حیوانات غیر بنیان گذار به ترتیب 506، 105، 90، 65 و 181 راس برآورد شد. میانگین فاصله نسل در این جمعیت 23/4 سال و اندازه موثر جمعیت 249 راس بود. متوسط هم تباری و متوسط ضریب همخونی به ترتیب 76/0 و 56/0 درصد برآورد شد. ضریب تابعیت وزن های تولد، شیرگیری، شش ماهگی، نه ماهگی و یک سالگی از همخونی به ترتیب 11-، 6/106-، 7/259-، 2/161- و 9/239- گرم محاسبه شد. نتایج حاصل از فراسنجه های تحلیل احتمال منشا ژن نشان دهنده کاهش تنوع ژنتیکی این جمعیت بود. میزان کاهش عملکرد ناشی از همخونی صفات وزن بدن در گوسفندان لری بختیاری مورد مطالعه نسبت به گزارش های سایر نژادها در ایران بیشتر بود که نشان دهنده جفتگیری های افراد خویشاوند در این گله می باشد. همچنین وجود کاهش عملکرد ناشی از همخونی صفات وزن بدن نیز کاهش تنوع ژنتیکی جمعیت مورد مطالعه را تایید کرد.
    کلیدواژگان: ساختار شجره، صفات رشد، گوسفند لری بختیاری، همخونی
  • علمی پژوهشی- فیزیولوژی
  • سمیرا رضویان، حسین دقیق کیا *، ابوذر نجفی، حسین واثقی دودران صفحات 387-399
    این مطالعه به منظور بررسی اثر آنتی اکسیدانی سطوح مختلف عصاره نسترن بر پارامترهای میکروسکوپی، بیوشیمیایی و فعالیت آنزیم های آنتی اکسیدانی اسپرم قوچ پس از فرآیند انجماد-یخ گشایی با استفاده از 5 راس قوچ قزل انجام شد. بعد از انجام پیش آزمایش های تعیین غلظت بهینه روی اسپرم تازه و اسپرم رقیق شده، سه غلظت عصاره گیاه نسترن (میکرولیتر بر میلی لیتر 200 ،150 ،100) انتخاب و به رقیق کننده با پایه تریس-زرده تخم مرغ افزوده شد. نمونه های منی هفته ای دو بار با استفاده از مهبل مصنوعی گرفته شدند. به منظور حذف اثرات فردی نمونه های منی با هم مخلوط شدند. نمونه ها پس از فرآوری و انجماد تا زمان ارزیابی در ازت مایع نگهداری شدند. پس از یخ گشایی پارامترهای تحرک اسپرم، زنده مانی، یکپارچگی غشاء، ناهنجاری های اسپرم، پراکسیداسیون غشای لیپیدی، فعالیت آنزیم های آنتی اکسیدانی گلوتاتیون پراکسیداز، سوپراکسید دیسموتاز و ظرفیت کل آنتی اکسیدانی ارزیابی شدند. نتایج حاکی از عدم وجود اختلاف معنی دار در میزان مالون دی آلدهید و مورفولوژی اسپرم تیمارهای مورد بررسی نسبت به گروه شاهد بود. درصد اسپرم های غیر طبیعی و مقدار پراکسیداسیون لیپید در گروه نسترن 100 در مقایسه با گروه شاهد کمترین بود (05/0P
    کلیدواژگان: آنتی اکسیدان، اسپرم قوچ، انجماد-یخ گشایی، رقیق کننده، عصاره نسترن
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  • Abasali Naserian *, Reza Valizadeh, Mohammad Reza Nassiry Pages 269-283
    Introduction Recently, dietary balance of glucogenic and lipogenic nutrients is known as an important factor on severity of the NEB and metabolic disorders in transition dairy ruminants. Insulin plays a central role in metabolism by stimulating utilization of glucose in peripheral tissues such as muscle and adipose tissue and by promoting accumulation of glycogen and lipid reserves. In this study the main hypothesis was that plasma insulin concentration would be influenced by dietary quantity and quality of starch and fat. In different studies in dairy cows, insulin was increased by diets with high starch content and was decreased by diets with high fat content, although increased insulin concentrations were found when supplementary fat increased energy intake. Blood concentrations of NEFA, BHBA, Glucose, insulin, cholesterol, AST and the quantity of RQUICKI were assigned to detect the insulin sensitivity in dairy cows. This experiment was aimed to study the dietary fat concentration and starch degradability effects on insulin resistance in ruminants in equal energy diet, using Baluchi sheep.
    Materials and methods Twenty and eight female Baluchi lamb with 14.9 ± 2.3 wk of age and 26.3 ± 4.6 kg of BW were assigned to 4 treatments in completely randomized design with 2×2 factorial arrangement and fed 4 rations; 1) without tallow-corn (glucogenic-corn), 2) without tallow-barley (glucogenic-barley), 3) tallow-corn (lipogenic-corn) and 4) tallow-barley (lipogenic-barley), for 9 weeks. Experimental TMR rations were formulated with 60% concentrate and 40% alfalfa according to the AFRC, 1993. Lambs had free access to clean water and feed through individual boxes. Daily feed intake, body weight gain and fasting blood sampling were detected weekly. Blood sampling were sampled by the 6ml tubes (Gel/Clot activator, GD060SGC, Zhejiang Gongdong Medical Technology Co., Ltd), then Serums were reserved in the -800C until blood metabolites detection. Statistical analysis was performed by SAS (9.1) software.
    Results and discussion Experimental diets was not affected on average feed intake of lambs, but body weight gain and feed efficiency in week 4 to 8, affected by fat × cereal interaction and they were highest in lipogenic-corn treatment and feed efficiency was correlated with serum glucose concentration (P
    Keywords: Barley, Corn, Feed efficiency, Insulin sensitivity, Tallow
  • Jamal Seifdavati *, Zahra Islami, Hossein Abdi Benamar, Farzad Mirzaei Aghjeh Qeshlagh, Reza Seyed Sharifi Pages 284-299
    Introduction Agricultural by-products are the main feed sources for feeding livestock under conditions of feed restriction. However, phenolic compounds and tannins may limit use of some of them. Optimum utilization of agricultural by-products, needs adequate information about the animals needs, and access to nutritious feed used by livestockin order to determine the nutritional value and palatability, as well as limiting factors in feed such as phenolic compounds. Byproduct after harvesting peas (green peas) that have been manually extracted and separated parts of the stems, leaves and seed pods devoid of green. The green beans for the purposes of human nutrition and food preparation and consumption of the fresh green can be separated. In this study, the empty pods of green pea plants were considered. The purpose of the study was to estimate the effects of green pea (Pisum sativum L.) pods tannins and phenolic compounds on in vitro ruminal, post-ruminal digestibility using laboratory methods.
    Materials and Methods In order to to determine the chemical composition and in vitro ruminal degradability of green pea pod cell wall, nylon bag and test gas technique were applied. After preparation of green peas and isolating pods and drying, chemical composition analysis for dry matter, crude protein, ether extract, organic matter, ash, neutral detergent fibre (NDF) and acid detergent fibre (ADF) were done as AOAC. The total phenolic content was estimated by Folin Ciocalteu method. Feed tested due to tannins substance and study its effect on the fermentation and gas production were processed and stained with levels 200 (one the weight of a sample), 400 (twice the weight of the sample) and 600 (three times the weight of sample) mg polyethylene powder glycol (Merck, MW = 6000). Effect of polyethylene glycol on the pH, methane (ml per 200 mg feed), and the number of protozoa in the rumen fluid per milliliter at 24 h of incubation green pea pods were studied. The obtained data were analyzed in a completely randomized design.
    Results and Discussion The results of chemical composition analysis for dry matter, crude protein, ether extract, organic matter, ash, neutral detergent fibre (NDF) and acid detergent fibre (ADF) were 87.53, 10.03, 2.5, 79.49, 8.04, 40.31 and 23.69 percent, respectively. Determination of rumen digestibility done by Holden method in digestion bottle and digestibility of dry matter, organic matter, dry organic matter digestibility (DOMD) and metabolizable energy were 81.06, 80.46,73,98 and 11.61, respectively. Amount of gas production recorded for 2,4,8.12,24,48,72 and 96 times after incubation and fermentation parameters with gas production (ml/200mgDM), in vitro organic matter digestibility(%DM), metabolizable energy (MJ/kg DM), NEL(MJ/kg DM) and short chain fatty acids (mmol/200mgDM) calculated. By treating and supplementation of this feed by PEG significant difference was not observed for gas amount of soluble fraction, insoluble fraction, and the total gas production from soluble and insoluble fractions of green pea pods. In this study after 24 h of incubation pH differences among different treatments was not significant. Total protozoa counted in significant differences between treatments (P
    Keywords: Chemical composition, Digestibility, Gas production, Green pea pod, Tannin, Non-forage fiber
  • Iman Mehramiri, Morteza Chaji *, Saleh Tabatabai Vakili, Tahereh Mohammadabadi, Mohsen Sari Pages 300-313
    Introduction Animal nutrition, accounted as significant portion of the animal husbandry costs. Dry and semi-arid climate and lack of rainfall in Iran has caused difficulty in preparation of inexpensive feed for ruminant animals. Therefore, one way to overcome limitation of forage resources and the high cost of livestock feeds is use of agricultural by products such as mung bean straw or other unconventional sources of the feed. Irrigated cultivation of mung bean in Iran distributed in Azerbaijan, Khorasan, Isfahan, Fars, Khuzestan and northern provinces, and rainfed cultivation in the foothills of Gorgan. Most nutritional studies, conducted with the mung bean, but just few studies have been done on its straw. Therefore, the present experiment was conducted to finding the effects of mung bean straw on digestion and sheep fattening performance when it was replaced by wheat straw or low grain-corn silage in diet of Arabic lambs.
    Materials and Methods After determining the appropriate level of replacing mung bean straw with wheat straw and corn silage using the in vitro two steps digestion method, in the second step of study the lambs, fed selected diets from first step, included: diet without mung bean straw (control ration), 100% replacing of mung bean straw with wheat straw (diet 1), 25% and 50% replacing of mung bean straw by corn silage (diets 2 and 3, respectively) as a completely randomized design. For determination of nutrients digestibility, the amount of feed intake, ort and fecal excretion was recorded. In order to estimate blood and rumen fermentation parameters, and rumen protozoa population count at the end of the experiment, rumen fluid and blood was taken from the lambs after the morning feeding. The weight of lambs was recorded at initial, final of experiment, also every fifteen days. Feed conversion ratio and feed efficiency was calculated.
    Results and Discussion The result of first step, determining the appropriate level of digestibility, was showed that there is no difference between the experimental diets for nutrients digestibility. According to the in vitro results, amount of feed intake was different between rations and in diets containing mung bean straw (diets 1 and 3 exception 2) was more than the control, diet 1 had the highest nutrients digestibility. The experimental diets had no effect on blood and rumen parameters. There was no significant difference between the diets for the average daily gain and feed conversion ratio in whole period of study. About 30-40% of rumen microbial digestion of fiber, done by protozoa population, also 34% from cellulolytic activity of the rumen is belonging to the protozoa. The fiber degradability significantly decreases by defaunation of rumen, so it is possible that more digestibilities of NDF and ADF in the diet containing 100% replacement of mung bean straw by wheat straw (diet 1) was related to more rumen protozoa population of this diet. Also, lower amount of pH, even non significant, in control diet, no. 2 and 3, may be caused to decrease their digestibility, because proper growth of cellulolytic bacteria and protozoa take place in pH 6.7 and when pH falls under 6.2, the significant decreases in digestibility of fiber will be happened and fiber decreasing continued by falling of pH. In the other hand, rumen protozoa have the ability for stabilizing the rumen pH, which is probably due to the rapid digestion of starch and stored by ciliated protozoan. So, perhaps the more population of fiber digester strains such as Entodinium in diet 1 improves its digestibility.
    Conclusion Therefore, according to the results of present study, there were no difference in the finishing performance and nutrients digestibility of lambs, also these traits were even better in some cases such as feed intake (0-45 day), gain (0-15 and 0-30 day) and feed conversion ratio (0-15 day), so the use of mung bean straw because of its abundance and relatively cheapness at the particular season of the year, the replacement of it by wheat straw or low grain-corn silage in the feeding of lambs is recommended.
    Keywords: Ammonia nitrogen, Daily gain, Digestibility, Feed conversion ratio, Rumen protozoa
  • Hassan Aliarabi *, Mohammad Mahdi Tabatabaei, Puya Zamani, Sepideh Afrouzi, Khalil Zaboli Pages 314-327
    Introduction Feed supplements can improve nutritional value of ruminant’s diet. According to many studies, urea molasses-mineral block (UMMB) is a good source of easily available nitrogen and fermentable energy and its usage causes nitrogen and energy available for rumen microorganisms simultaneously and improves feed efficiency especially in low quality feeds. Increased dry matter intake is reported when UMMB was included in the diet of buffalo. It was observed that increasing digestibility of dry matter, crude protein, NDF and ADF in cows by using UMMB. Also better availability of fermentable energy for rumen microorganisms was seen. Monensin, as a feed additive through the manipulation of rumen fermentation, increases feed efficiency in ruminants. This substance selectively inhibits gram-positive bacteria, thereby impacting ruminant metabolism by increasing efficiency of energy metabolism, improving nitrogen metabolism, and reducing bloat and lactic acidosis risk. Monensin may provide an additional energetic benefit from enhanced forage digestibility. In order to evaluate the effect of UMMB enriched with monensin on performance, digestibility, and some blood and rumen parameters in male lambs, two experiments were conducted in a factorial arrangement as a completely randomized design.
    Materials and Methods Ingredients used to manufacture UMMB were cotton seed meal (21%), wheat bran (19.7%), urea (2.5%), molasses (43.3%), calcite (3.4%), mineral supplement (4.2%) and common salt (5.9%). In the first experiment, 24 male lambs with 7-8 month age were randomly divided into 4 groups including 1) concentrate mixture and forage, 2) concentrate mixture and forage 30 ppm monensin, 3) concentrate mixture and forage (85%) and UMMB without monensin (15%), and 4) concentrate mixture and forage (85%) and UMMB enriched with monensin (15%). During the experimental period (70 days), dry matter intake and body weight gain were measured daily and fourth nightly, respectively. Blood and rumen fluid samples were taken on days 68 and 69, respectively, 3 hours after the morning feeding. For the second experiment, 4 lambs from each treatment were randomly selected and transferred to metabolic cages to determine the effects of UMMB and monensin on nutrients digestibility and nitrogen retention. Data were analyzed as a 2×2 factorial experiment based on a completely randomized design using the GLM procedure of SAS (1999).
    Results and Discussion The results showed that UMMB increased dry matter intake, daily weight gain and decreased feed conversion ratio (PConclusion Overall results showed that UMMB improves efficiency of fermentable energy and nitrogen, dry matter and crude protein digestibility and nitrogen retention in lambs. So it can be concluded that UMMB may be used to improve performance of growing male lambs.
    Keywords: Digestibility, Mehraban lamb, Monensin, Nitrogen retention, Urea molasses block
  • Nasim Bidar, Ahmad Hassan Abadi *, Hassan Nasiri Moghaddam, Mehdi Varidi, Mohammad Mohsen Zadeh Pages 328-339
    Introduction The lavender essential oil is traditionally believed to be antibacterial, antifungal, carminative (smooth muscle relaxing), sedative, antidepressive and effective for burns and insect. Lavender oil (primarily L. angustifolia) has also been found to be active against many species of bacteria and fungi. However, a few reports are available on the effect of lavender essential oil on poultry performance. The objective of this study was to evaluate the effect of lavender essential oil on performance, blood metabolites and apparent nutrient digestibility in male broiler chicks.
    Materials and Methods A 42-day trial was conducted to evaluate the effect of adding different levels of lavender (Lavandula angustifolia) essential oil to diet on performance, blood parameters and ileal nutrient digestibility. The feeding program consisted of starter (1-10 d), grower (11-24 d) and finisher (25-42d) diets. There were 5 treatments group: control; virginiamycin 10% (50 ppm); and three levels of lavender essential oil (350, 525 and 700 ppm). Body weight, feed intake and feed conversion ratio were recorded at the end of starter, grower and finisher periods. On d 28, blood samples were gathered from wing vein of 1 chick in each experimental unit. Blood samples were centrifuged (15 min, 3000 rpm) to separate sera, and then cholesterol, TG, HDL, LDL and VLDL were determined. Then one chick from each pen was killed by ketamine injection and ileal digesta was collected.
    Results and Discussion At 42 days of age, Chickens receiving diet containing virginiamycin showed the highest feed intake. Birds fed diets containing 525 and 700 ppm lavender essential oil numerically had more feed intake than birds fed control diet, but this difference was not significant. Broilers fed diet containing virginiamycin showed the highest weight gain and the control diet showed lowest weight gain at the end of the experiment. The lowest level of serum cholesterol was observed in 350 ppm lavender essential oil treatment. Essential oil treatments also caused lower serum high density lipoprotein (HDL) than virginiamycin and control treatments. There were no significant differences among treatments for feed conversion ratio, blood triglyceride, low density lipoprotein (LDL), very low density lipoprotein (VLDL) and ileal digestibility of dry matter, ether extract, crud protein, ash and organic matter of diets. Positive effects of essential oils on feed intake have been reported previously. Improved growth performance could be attributed to the presence of essential oil in the diet, which encourages secretions of endogenous digestive enzymes, which then enhance nutrient digestion and gut passage rate in chickens. It seems that phytogenic feed additives improved apparent ileal digestibility of nutrients at 21, 35, and 42 d of age. In contrast, there are studies where the effects on animal performance were not significant. However, in our experiment lavender essential oil caused a numerical increase in digestibility and its effect was not significant, but the improved weight gain in this experiment may be due to lavender essential oil effect on villus surface area and gut microflora. Also dietary supplementation of a mix of essential oils at 300 g/t, significantly increased villus width and surface area, indicative of improved nutrient absorption and performance. The effects of lavender essential oil on the intestinal microflora were not evaluated in this study; however, others have shown that essential oil have the capacity, when fed to broilers, to reduce the growth of E. coli and C. perfringens and increase the numbers of Lactobacillus spp. Similarly, the inclusion of thyme, marjoram, and rosemary in broiler diets reduced the numbers of cecal C. perfringens by >1 log. The contributory factors causing these differences reported in other studies could be attributed to the differences in the inclusion levels of essential oil, sources of herbs used to form blend of essential oil, basal diet composition, or the microbial environment in which the birds were reared. It has been suggested that birds fed essential oil have reduced concentrations of serum cholesterol and that the hypocholesterolemic effect of essential oil is due to compounds in essential oil that have the ability to inhibit hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, a key regulatory enzyme in cholesterolsynthesis.
    Conclusion According to the results of this experiment, lavender essential oil had lower effects on performance than antibiotic, but adding lavender to diets could have beneficial effects on weight gain and serum cholesterol levels in broiler chickens. However, more evidence is needed to clarify whether lavender essential oil can match the effects of antibiotics as feed additives in poultry diets.
    Keywords: Blood parameters, Broilers, Digestibility, Lavender, Performance
  • Ali Nobakht *, Mohsin Jalili Pages 340-356
    Introduction The terms of fat and oil refer to triglycerides of several profiles of fatty acids. Fatty acids that are not bound to other organic components as glycerol are the so-called free fatty acids. Lipids constitute the main energetic source for animals and they have the highest caloric value among all the nutrients. Linoleic acid is the only fatty acid whose dietetic requirement has been demonstrated. Besides supplying energy, the addition of fat to animal diets improves the absorption of fat-soluble vitamins, increases diet palatability, and the efficiency of utilization of the consumed energy. Furthermore, it reduces the rate of food passage through the gastrointestinal tract, which allows a better absorption of all nutrients present in the diet. The energetic value of oils and fats depend on the following: the length of the carbonic chain, the number of double bonds, the presence or absence of ester bonds (triglycerides or free fatty acids), the specific arrangements of the saturated and unsaturated fatty acids on the glycerol backbone, the composition of the free fatty acid, the composition of the diet, the quantity and the type of the triglycerides supplemented in the diet, the intestinal flora, the sex and the age of the birds.
    Dietary energy is one of the major effective nutrient, representing high percent of total cost of the diets for broilers. Diet energy has important effects on the regulation of the amount feed intake and performance in broilers. Fats are the main sources of energy in broiler diets. Different research showed that the advantages of fats especially in low energy diets.
    Materials and Methods This experiment was conducted as a (2*2*2) factorial arrangement including 2 fat sources (tallow fat and canola oil), 2 levels of fat (3% and 6%), and two levels of diet metabolizable energy (2900 and 3100 Kcal.Kg) with 432 Ross-308 broilers in 8 treatments, 4 replicates and 12 chicks in each replicate in two experiment period (grower from 11 to 24 days and finisher from 25 to 42 days) in a completely randomized design. Chicks were fed from 1 to 10 days with a common starter diet that recommended by Ross company. During experiment periods all birds had free access to water and feed. Measuring of weight gain and feed intake were done at the end of experimental periods and feed conversion ratio was calculating by dividing the amount of feed intake to the amount of weight gain. Carcass traits were measured at the end experiment period by killing 2 birds from each replicate. Blood sampling was done at the end of experimental period.
    Results and Discussion At the end of experimental period, using canola oil in contrast to beef tallow reduced the amount of daily feed intake, whereas improved the feed conversion ratio, final weight and production index (P0.05). Diet with 3100 Kcal.Kg ME caused the amount of weight gain and production index increase and feed conversion improve (P0.05). Interaction between fat sources, fat level and energy level, using 3% and 6% of canola oil increased the amounts of daily feed intake, daily weight gain and final weight and feed conversion ratio improved (P0.05). Diet with beef tallow increased the amount of HDL in blood (PConclusion The overall results showed that in broilers, using diet with 3100 Kcal/Kg metabolizable energy and canola oil up to 6% have positive results in broilers, but using more than 3% tallow have negative effect on broiler performance.
    Keywords: Broilers, Beef tallow, Canola oil, Energy, Performance
  • Mojtaba Tahmoorespur *, Nasiredin Moghadar Pages 357-362
    Introduction During years genetic improvement of economically important traits, which are amongst polygenic traits, has been based on the estimation of breeding values i.e. the total heritable effects of genes, based on pedigree and phenotypic records. This approach had limitations such as being time consuming and demanding massive phenotypic information. Nowadays, high throughput genomic technologies are available that provide genotypes of dense markers across genome towards estimating breeding values more accurately. Accurate estimation of allelic and genotypic effects of markers in linkage with QTLs needs a lot of phenotypic observations which is not always available in practice. Therefore, the amount of error of estimated QTL effect could be high. Further, the distribution of the effects of genes controlling traits might be non-non-normal. In case of overlooking these facts, the predicted genetic progress can be erroneous. The objective of this study was to find the influence of the accuracy of QTL effect estimation, considering the dominance deviation, on marker assisted selection response.
    Materials and Methods A base population of 1000 unrelated, non-inbred individuals was simulated according to a trait with heritability of 0.1 and 0.3. The trait was affected by residual polygenic and QTL with additive effect associated with 0.0, 0.1 and 0.2 standard errors and complete or incomplete dominance effect. The genotypic effects of the three QTL genotypes were a, d and –a, respectively for dominant homozygotes, heterozygotes and recessive homozygotes. The QTL had two alleles and the dominance deviation was considered either equal to or half of the genotypic effect a. The population was in Hardy-Weinberg equilibrium. The polygenic variance was calculated as the difference between total additive genetic variance and QTL variance. Residual variance was equal to the difference between phenotypic variance and total additive genetic variance. Two selection was employed; one with polygenes and marker information, and the other one with polygenic variance without marker information. The difference between mean of selected group and the population mean was considered as response to selection. The selection response calculated by truncation selection based on the performance of top 20% with and without using QTL information over 500 repetitions.
    Results and Discussion The results showed higher response for marker assisted selection compared to conventional selection without marker information, but it also showed the presence of dominance effect for QTL effect associated with estimation errors leads to decrease in marker assisted selection response. The superiority of genetic progress with marker assisted selection is proportional to the QTL variance contributing to the total genetic variance. Increasing standard error of QTL effect to 10 and 20 percent, led to lower genetic response to selection. When the contribution of QTL variance in total genetic variance is higher, with high levels of standard error of QTL effect, the response to selection was even lower than response to selection without marker information. Complete dominance further decreased the genetic response compared to incomplete dominance. This is because the genetic variance is more influenced by the dominance variance in case of complete dominance.
    Conclusion This study showed that QTL information may be used in practical selection programs when estimated parameters are of high accuracy to be used in practical selection programs. Estimating QTL effects with error causes that selection response would be even lower than polygenic selection if the associated error rate is high. Estimated effects of genes controlling quantitative traits should have less error rate in order to be used in breeding programs.
    Keywords: Dominance deviation, Marker assisted selection, QTL
  • Rahimeh Sepehri, Sadegh Alijani, Jalil Shoja Ghias, Mohammad Taher Harkinezhad *, Saied Abbas Rafat Pages 363-375
    Introduction Leptin is a 16 kDa protein produced by adipocytes. This protein controls appetite, energy balance, efficiency of production and distribution of fat storage in the body and therefore plays an important role in regulating body weight and growth in mammals. LEP gene in sheep (NC_019461) located on 4th chromosomes and has 16275 bp in length and contains 3 exons and 2 introns. The resulting protein contains 193 amino acids (the length of coding region is 579 bp). So far in this gene, 17 single nucleotide polymorphisms in the coding region were reported that seven of them are synonyms and the rest are missense. The entire exon 3 is containing 357 bp in length that starts from nucleotide 13544 till nucleotide 13903. This exon comprise 119 (or 118) codons, seven missense and a synonymous SNPs from this area of the gene is reported till now. Different alleles of this gene may lead to different phenotypic effects.
    Material and Methods The aim of this study was to identify alleles of the gene in exon 3. For this purpose, 133 lambs from a flock at almost the same age in three groups of Afshari pure breed and B1 and B4 of Afshari × Booroola Merino male lambs were used. Afshari sheep is one of the heavy weight sheep in Iran, which is important breed in terms of meat production. It has notable twinning rate and birth weight, growth rate and weaning weight is remarkable compared with other breeds of sheep in this country. Given the potential of this breed suitable for the production of meat, it can play an important role in production of red meat in the area. To increase productivity of this breed, FecB gene from Booroola Merino sheep was introgressed to this breed of sheep in University of Zanjan in 2007. Following the introgression of the gene (FecB) to Afshari breed Afshari- Booroola Merino crosses as a new genetic combinations was developed. This study aimed to identify single nucleotide polymorphisms (SNP) in exon 3 of Leptin gene and its association with carcass treats in male Afshari and cross lambs. First, blood samples of all the animals were taken and phenotypic measurements on live animals were done and then 85 lambs were slaughtered. After slaughter, carcass weight was measured and after 24 hours maintaining in cold, weight of carcass, thigh, shoulder, lion muscle, back fat and waste (tail, back and visceral fat) were measured. Estimation of the carcass traits in non-slaughtered lambs, were accomplished using regression coefficients achieved before. DNA was extracted using phenol-chloroform procedure from all the samples. Then, using designed primers, the target DNA was amplified and PCR products of a number of samples were directly sequenced to identify potential SNP(s). The sequencing data were analyzed and two SNPs were detected in samples. Thereafter, all the samples were genotyped by RFLP using two restriction enzymes Hpa II and AIwNI. The association of genotypes with phenotypic and carcass traits were studied.
    Result and Discussion According to this study results, one of the polymorphism was identified in nucleotide position 13713. All three genotypes of this; GG, GA and AA were observed in studied samples. This missense polymorphism led to amino acid arginine/glutamine change at codon 142 and had a significant effect on the back fat thickness and withers height. The second polymorphism observed in the nucleotide (G> A13875) and two GG and GA genotypes were found in the samples. This polymorphism also had the same amino acid changes at codon 196 and associated with body length (with probability close to significant level). The frequency of GG genotype in both SNP was higher than other genotypes. This genotype is the genotype of the reference sequence in biological data bases. The alleles locating in 13713 bp in the studied population were not in Hardy-Weinberg equilibrium. But alleles of the 13875 location were in Hardy-Weinberg equilibrium. The allele frequency of each SNP was significantly different in genetic groups. In location of 13713, the most frequent mutation allele (A) and the lowest frequency of this allele was observed in genetic group B4 and Afshari group respectively. In location 13875, Afshari group had the highest frequency of the mutant allele and B1 had the lowest frequency.
    Conclusion In general, in this study polymorphisms were found out in exon 3 of the leptin gene which has been found in previous studies and sheep SNP projects and have been reported previously in biological databases. Based on the results obtained and the variations observed in some previous studies, if the changes associated with these traits be confirmed in next studies, these polymorphisms could be used in marker-assisted selection in breeding programs.
    Keywords: Afshari sheep, Carcass quality, Leptin, Multiple births, SNP
  • Mohammad Keshavarzpour, Mohammad Reza Bahreini Behzadi *, Mostafa Muhaghegh Dolatabadi Pages 376-386
    Introduction Control and management of genetic diversity of breeds is necessary for their sustainable use in the future because a limited number of breeding animals will unavoidably lead to increased inbreeding and thus to a reduction in additive genetic variance, and maybe to inbreeding depression. Managing inbreeding is usually one of the major goals in conservation and selection programs of breeds. Some of descriptive parameters of population structure are the inbreeding coefficient, effective population size, effective number of founders, effective number of ancestors, effective number of founder genomes, effective number of non-founder genomes and average generation interval, which are indicative of genetic diversity levels in a population. In a breeding program, the inbreeding coefficient and the rate of annual inbreeding should be monitored because of their influence on production and on the estimation of genetic parameters. The Lori-Bakhtiari sheep is one of the most important native breeds of Iran. With more than 1.7 million head population are mostly kept on village or semi-migratory system in Chaharmahal and Bakhtiari province. This breed has the largest fat-tail size among all of sheep breeds in Iran. The objective of this study was to investigate genetic structure and genetic diversity of Lori–Bakhtiari sheep using pedigree analysis and the inbreeding depression of body weight traits was estimated.
    Materials and methods The pedigree information of 7693 Lori–Bakhtiari lambs (2478 male and 5215 female) from 274 rams and 2006 ewes collected from 1990 to 2011, were used. The data were collected at Shooli sheep breeding station in Shahrekord, Chaharmahal and Bakhtiari province. Estimation of inbreeding coefficients was done by CFC software and Endog (v4.8) software was used to compute other pedigree analyses including mean coancestry, effective population size, probability of gene origin parameters and average generation interval. Parameters based on the probability of gene origin were used to describe genetic variability. To investigate the effect of inbreeding on body weight traits, the data of birth weights, weaning weights, weights at six months of age, weights at nine months of age and weights at 12 months of age were used. Inbreeding depression was estimated as the regression of these performance records on the individual inbreeding coefficients by fitting an animal model. WOMBAT software was used for estimating the inbreeding depression of body weight traits.
    Results and Discussion Total number of founders, effective number of founders, effective number of ancestors, effective number of founder genomes and effective number of non-founder genomes were 506, 105, 90, 65, 181 heads, respectively. Average generation interval and effective population size were 4.23 years and 249 heads, respectively. The generation interval in the dam-progeny pathway was shorter than in sire-progeny pathway. Estimated average coancestry and inbreeding coefficient were 0.76 and 0.56, respectively. Animals with progeny were 29.7 % and those of without progeny 70.3 % of the total animals. Animals with both known parents and one unknown parent constituted 92 % of the population. Between all the registered animals, 28 % were inbred. The average inbreeding coefficient during the study period for inbred and all animals were 2 and 0.56 %, respectively. The most inbred animals, equivalent to 25% of the inbreeds, had inbreeding coefficients equal to or lower than 5 %. The regression coefficients for birth weight, weaning weight, weight at 6, 9 and 12 months of age on inbreeding were -11, -106.6, -259.7, -161.2 and -239.9 g, respectively.
    Conclusion Considering the parameters obtained from the probability of gene origin analysis, the contribution rate of founders and major ancestors have been unbalanced due to the selection of animals that led to decrease of genetic diversity. Estimated inbreeding depression of body weight traits for this breed was higher than other sheep breeds of Iran and showed high degree of close mating in this herd. Due to the deleterious effect of inbreeding on body weight traits it is suggested that this breeding station should use a better breeding plan to avoid mating of close relative animals. At this study, the presence of inbreeding depression for body weight traits also confirmed reduction of genetic diversity in this population. The results of this study also indicate that genetic variability within this population has to be monitored constantly in order to prevent or minimize loss of founder alleles due to genetic drift or selection. The authors suggested that pedigree analysis should be done periodically in this breeding station. Doing this analysis would also prevent or control kinship in this breeding population.
    Keywords: Inbreeding, Growth traits, Lori-Bakhtiari sheep, Pedigree structure
  • Samira Razavian, Hossein Daghigh Kia *, Abozar Najafi, Hossein Vaseghi Dodran Pages 387-399
    Introduction Semen cryopreservation has detrimental effects on sperm cell organelles, including cell membranes, mitochondria, and DNA due to the increased level of reactive oxygen species (ROS). Oxidation of polyunsaturated fatty acids in the sperm cell membranes is caused by high levels of ROS produced during the freezing-thawing process. This problematic condition causes decreased sperm motility, membrane integrity, increased metabolic changes and, ultimately, decreased fertility of the sperm. The addition of antioxidant compounds to the semen extender before semen cryopreservation can decrease ROS levels and their deleterious effects on spermatozoa. This study was conducted to assess the antioxidant effect of different levels of Rosa canina extract on microscopic and biochemical parameters and antioxidant enzyme activities of Ghezel ram semen after freezing-thawing process.
    Materials and Methods Semen samples were collected from five Ghezel rams. Ejaculates were collected twice a week. To eliminate individual effects, ejaculates containing sperm with >80% progressive motility, volume of 0.75-2 mL, sperm concentrations greater than 3×109 sperm/mL and sperm abnormalities of less than 10% were pooled. Different concentrations of Rosa canina extract (0, 100, 150, 200 μL/mL) were added into the tris-egg yolk based diluent. After processing and freezing, the samples were stored in liquid nitrogen until the time of evaluation. Sperm motility characteristics were analyzed using computer-assisted sperm analysis (CASA). Sperm motility parameters including total motility, progressive motility, average path velocity, straight-line velocity, curvilinear velocity, linearity, straightness, amplitude of lateral head displacements and beat/cross frequency of sperm, viability, membrane integrity, sperm abnormalities, lipid peroxidation, antioxidant enzymes of glutathione peroxidase, superoxide dismutase and total antioxidant capacity were evaluated after thawing. Statistical analyses were performed using SAS software. The data were analyzed using the GLM procedure. Tukey–Kramer test were used to determine the significance differences between the experimental treatments. Significant differences were reported at the level of 5 percent.
    Results and Discussion The results of lipid peroxidation (LPO) measurements show that adding 100 μl / ml Rosa canina extract to the diluent medium reduced the amount of malondialdehyde, which was not significant in comparison to the control group. This could be indicative of the beneficial effect of Rosa canina extract to reduce the process of lipid peroxidation of the sperm membrane. The results showed no significant difference in malondialdehyde and morphology of sperm in treatments containing Rosa canina extract compared to the control group. The addition of Rosa canina extract was not significantly effect in morphology and structure of sperms compared to the control group. However, the percentage of abnormal sperms decreased at levels of 100 and 150 μL/mL compared to the control group. The addition of 150 μL/mL of Rosa canina extract significantly improved the viability and plasma membrane integrity of sperms after freezing-thawing compared to the control and other treatment groups (P
    Keywords: Antioxidant, Diluent, Freeze-thawing, Ram sperm, Rosa canina extract