مجله علوم دامی ایران
سال چهل و دوم شماره 2 (تابستان 1390)

This study was carried out to determine the effects of different levels of protein and probiotic (Protexin) on performance, and immune response in Ross (308) broiler exposed to heat stress. Five hundred and forty one-day old broilers were employed in a compeletly randomized design (3×3 factorial arrangement) of 3 replicates for each treatment. The diets were formulated according to NRC (1994) recommendation with protein levels (90, 100 and 110% of NRC recommendations) along with probiotic (0, 200 and 400 ppm, containing 2×109 cfu/g of spores). The birds were exposed to heat stress (34±3?C) for 8 hours/day (10:00 to 18:00). The results indicated that, the body weight gain in broilers fed NRC plus %110 NRC protein was significantly higher than that in those fed %90 NRC protein (P<0.05). Feed conversion ratio in chicks fed diets containing 100 and %110 NRC protein were significantly improved in comparison with %90 NRC protein diet, within 0-42 days (P<0.05). The addition of 200 ppm probiotic to diets significantly increased body weight gain compared to control during the 0-42 days of age (P<0.05). The treatment containing %110 NRC protein +200 ppm Probiotic, significantly decreased feed conversion ratio as compared with treatments of %90 NRC+probiotic (0 and 400 ppm) in 0-42 day periods (P<0.05). Feeding of %110 NRC versus %90 NRC, along with a feeding of 200 ppm probiotic as against control (0 ppm probiotic), significantly increaseed total protein concentration in broiler's blood serum at its 42 days of age (P<0.05). Serum cholesterol concentration, was significantly lower in broilers fed 200 and 400 ppm probiotic, in comparison with those receiving no probiotic containing diet (P<0.05). Supplementing diet with 200 and 400 ppm probiotic significantly increased WBC count while decreasing H/L as compared with control group (P<0.05). In total, this research indicated that increase in protien level upto %110 of NRC (1994) in diets along with an addition of 200 ppm probiotic would improved the broiler's performance plus their immune response to heat stress, and which could be employed as a measure for diminishing the effects of heat stress.

Effect of two fattening systems were studied on feedlot performance and carcass characteristics of using of 66 Fars native male kids in different ages. Six kids were slaughtered at the first day of experiment and sixty kids were divided into two groups. The first group were kept in feedlot in individual pens and the second group grazed on rangeland, and after 3 months, were kept in feedlot in individual pens. The fattening period for first and second groups were 9 and 6 months respectively. Eight kids from each system were slaughtered randomly at the 6, 9 and 12 months of age, for recording carcass characteristics. Live body weights in each age class were different (P<0.01) between two systems. Daily weight gains changes in periods of 3 to 6, and 6 to 9 months of age in two systems and were different (P<0.01), but for period of 9 to 12 months of age were not different (P>0.05). Feed conversion ratios in period 6 to 9 months of age were different (P<0.01) between two systems, but was not differed in period 9 to 12 months of age (P>0.05). Cold dressing percentages at 6 and 9 months of age were different (P<0.05) between two systems. Valuable carcass cuts (leg, shoulder and loin) percentages in each age were the same between two systems (P>0.05). Carcass lean and bone percentages in each age were the same between two systems (P>0.05). Carcass fat deposited percentages at 6 months of age were different (P<0.05), but were not different at 9 and 12 months of age between two systems (P>0.05). Live body weights, daily weight gains, feed conversion ratios, dressing percentages, Carcass lean, fat deposited and bone percentages in each age were different (P<0.01) between two systems. Average live body weight of kids at 6 months of age after 3 months of range grazing (system 2) were 18.54 kg and average live body weight of kids at 6 months of age after 3 months of fattening (system 1) was 25.5 kg. Live body weight of grazing kids decreased at the beginning of grazing on range and after that had low gain on range, and also had low gain in feedlot. Therefore, feedlot in system 1 had better efficiency. With increaseing the age, feedlot efficiency decreased in two systems and internal fat and carcass fat deposited percentages increased along with carcass quality decreasing. Fattening of kids just after weaning (system 1) in a period of three months is suggested.

The Cornell Net Carbohydrate and Protein System (CNCPS) model has recently been increasingly employed in preparation of balanced feed ration of dairy cattle in Iran. However, a lack of appropriate characterization of the feeds has restricted the model's application. This study was conducted to evaluate the protein contents of some feedstuffs (wheat bran, sugar beet pulp, soybean meal, cottonseed meal, cottonseed whole, corn gluten meal, poultry offal meal, blood meal, canola meal and bagasse) commonly used in the cattle ration in Iran with characteristics needed as inputs for CNCPS. Based on data obtained from this work, the level of neutral detergent fibre, ether extract, crude protein, soluble protein, non protein nitrogen, soluble true protein, neutral detergent insoluble protein and acid detergent insoluble protein contents were numerically different from the records of CNCPS, the difference for which may be due to climate, agricultural practices, and storage conditions. Hence, the use of date obtained for the available feeds in place of CNCPS' tabular values is strongly recommended in formulating balanced rations. This would expectedly result in more efficient use and less waste of nutrients.

Genetic diversity of Red Jabal Barez red goat population was studied based on eight microsatellite markers consist BM1312, MAF64, ILSTS034, ILSTS059, OraFCB20, IL2RA, LSCV24 and LSCV11. Blood sample extracted of 100 Red Jabal Barez goats were randomly collected from 10 farms and DNA was isolated using the Diatom DNA PREP kit. The PCR reactions were successfully done and all loci showed suitable polymorphism with 7.62 alleles, on average. Five loci of LSCV11, ILSTS034, ILSTS059, OraFCB20, IL2RA were at Hardy-Weinberg disequilibrium (P<0.05). In this population, hetrozygosity varied from 0.7616 at IL2RA to 0.8743 at OraFCB20 locus and the same loci had the lowest and the highest diversity based on Shannon index and polymorphic information content (PIC), respectively. Number of observed and effective alleles and expected hetrozygosity were also calculated for each locus. Average hetrozygosity was estimated as 0.81 for this population. It can be concluded that Red Jabalbarez goat benefits from approximately high genetic variation. Therefore we can well use this potential in conservative and breeding programs for this population.

The objective of this study was to evaluate the effects of sources of four starch on milk production and composition, nutrients digestibility and blood metabolites of lactating Holstein cows. Eight multiparous Holstein cows (683±31 kg of body weight; 83±9 DIM) were used in a replicated 4×4 Latin square design with 21-d periods. The exprimental diets contained wheat, barley, corn, or potato as the primary source of starch and contained 25.4, 31, 22, and 23 percent of diet DM respectively. Dry matter intake was similar among treatments. Raw, fat, and energy corrected milk production was lower (P<0.05) in cows fed the potato-based diet compared with other diets. Cows fed the corn-based diet had higher (P<0.05) milk fat content, but milk protein content was unaffected by the source of dietary starch. Milk production and lactuting net energy efficiency, milk nitrogen and feed nitrogen efficiency was lowes in cows received potato based diet (P<0.05). Total tract apparent digestibility of dry and organic matter, crude protein and ether extract were higher (P<0.05) in cows fed the wheat or corn-based diets compared with those fed barley or potato-based diets. Plasma glucose, total cholesterol, HLD-cholesterol and LDL-cholesterol concentrations were similar among experimental diets, but triglycerides concentration was higher (P<0.05) in cows fed potato-based diet compared with other diets. These results showed that corn and wheat based diets improved the nutrient digestihilty, feed energy and nitrogen efficiency, and milk production compare to potato based diet.

In this research the effect of feeding wheat/ barley based diets supplemented with three commercial enzymes containing xylanase and? -glucanase activities and including matrix value their on performance and gastrointestinal tract size of broiler chicks was investigated. A total of 260-day-old male broiler chicks (Ross 308) were allocated to 5 treatment groups, with 4 replicates per treatment and 13 birds per replicate in a RCB design. Results showed that only addition of enzymes B and C to wheat/ barley based diet increased average daily feed intake significantly (P<0.05). Addition of all enzymes to wheat/barley based diets significantly (P<0.05) improved body weight gain and feed conversion ratio (FCR) of birds in comparison with feeding unsupplemented wheat/barley based diets. At day 43, the pancreas relative weight was significantly decreased by addition of all enzymes to wheat/barley based diet (P<0.05), but, that of liver and relative length and weight of duodenum, jejunum, ileum and cecum was not significantly affected by enzyme supplementation (P>0.05). However, relative weight of abdominal fat was significantly (P<0.05) increased only with addition of A and B enzymes. The result of current study showed that, addition of all three enzymes improve FCR similarly in diets and regarding final body weight, enzyme C had the best performance. Form the economical point of view the based on total rearing period the treatments of enzymes A and B were better than other treatments.

In this research 400 Ross 308 breeder fertile eggs were weighed At day 16 of incubation and evenly distributed into 4 treatments with 4 replicates per treatment and 25 eggs per replicate in a CRD design. On day 18 of incubation, 1 ml of an in ovo feed solution including: I) Carbohydrate (CHO), II) Amino acid (AA), and III) Butyric acid solution in 0.5% saline was injected into amniotic fluid of eggs. The control group remained non-injected. After injection eggs were transferred to hatcher. Upon hatch, chicks were weighed, sexed and transferred to the experimental house and reared to 42 days. At day two the midpoint of the jejunum was sampled for intestinal morphometric examination. The hatchability didnt differ significantly between treatments. Body weight and body weight to egg weight ratio of all in ovo injected hatchlings was greater than in controls (P<0.01). Chicks in ovo fed AA had greatest improvements in body weight gain during 1-21 and 1-42 d period relative to non-injected controls (P<0.05), but without any differences with other injected groups. On day 2 post-hatch villi height in butyric acid injected groups was increased significantly relative to control group (P<0.05). The surface area of an average villus was increased for the CHO, AA and butyric acid in ovo injected groups in comparisson with those of the control group (P<0.05). Effects of in ovo administration of AA, CHO and butyric acid on FCR was not significant. Our results showed that in ovo injection of AA, CHO and butyric acid during last period of incubation can improve post- hatch performance and enteric development.

This experiment was conducted to determine the effects of either twice or thrice a day feeding regimens on performance and as well on plasma hormone and metabolite levels of broiler breeder hens during 24 to 38 wk of their productive age. Breeder pullets were provided form a commercial flock, and distributed in experimental units, in a compeletly randomized design with three feeding regimens (treatments) included 1, 2 or 3 feeding times per day with 4 replicates. Birds fed once a day, received all their total feed at 06:15 h, whereas birds fed twice a day, received 50% of their total feed allowance at 06:15 h and the other 50% at 12:15 h, and while birds fed thrice a day, received 33% of their total feed at 06:15 h, 33% at 12:15 h and the last portion at 18:15 h. Total daily feed did not differ among treatments. Blood samples were taken at the peak of production (32 wk of age) and at the end of trial (38 wk of age). For the 13 wk production period, total hen-day egg production through 38 wk of age in the hens that were provided feed twice and thrice a day was greater (67.1 and 67.2 vs 62.2 eggs/hen, P<0.01) than in hens fed once a day. Also, broiler breeder hens fed 2 or 3 times per day laid heavier eggs (P<0.01) compared with once a day fed birds. Twice and thrice a day fed birds carried significantly lower plasma T3, glucose and cholesterol concentration and higher 17? -estradiol level than did once a day fed birds (P<0.05). In conclusion, the twice and thrice a day feeding regimens improve the reproductive performance of broiler breeder hens during the early egg-laying cycle.

Test day records of first lactation Holstein cows from 1996 to 2008 were obtained from Animal Breeding Center of Iran and used in this research. Data consisted of 872125 test-day milk records of 95816 cows from 59 herds. (Co)Variance components and genetic parameters were estimated using random regression model via Gibbs sampling method. Two order Legendre polynomials and third coefficient of Wilmink function were used to describe the lactation curve in genetic and permanent environment levels. The heterogeneity of the residual variance in days 5 to 365 of lactation was modeled using a number of thirty six 10-day intervals. Residual variance was high at the beginning but it was steady and decreased slowly to the end of the lactation. Permanent environmental variance was high at the extremes. The total variance and heritability were affected by the pattern of PE variance. The lowest and highest genetic variances occurred at the beginning and at the end of lactation, respectively. Heritability estimates for daily yields were low in the early lactation and generally ranged from 0.077 to 0.252 for days 5 and 305, respectively. High residual and permanent variances and lower genetic variance were lead to low heritability at the first part of lactation. Genetic correlations were positive and higher than phenotypic ones for all the days in lactation. The lowest genetic correlation was 0.35, between the extremes. Genetic correlations between daily yields decreased with increase in interval between tests. The estimated parameters in this study can be used to predict breeding values for Holstein dairy cattle of Iran.

Heat shock proteins (Hsps), are highly important due to their association with such economically important traits in animals as resistance to temperature shock and mastitis. In the current study, to get a comprehensive information on molecular structure and evolution of the Hsp70s, and the available Hsp70 sequences of the cattle and other animals taken from NCBI and aligned together. Then, nucleotide substitution rate of the sequences and molecular evolution of the gene family were calculated by maximum likelihood and neighbor-joining method, respectively, and phylogenetic tree was constructed. Bioinformatic researches results identified that Hsp70 gene family are distributed across the genome and express various transcripts necessary for functions of the related traits. On the other hand, base substitution rate of the pyrimidines to pyrimidines or purines is much more than that of in purines to pyrimidines or purines in this genes family. The dN/ds ratio of the Hsp70 sequences indicated purifying selection and stability of the structures of the genes family during evolution. Phylogenetic analysis showed that Hsp70 proteins, based on mainly are divided to two clades their evolutionary relationships. Hsp70 12a and b are sisters in one clade and sequences of the other Hsp70 proteins are in second clad and divided to many branches.