نشریه پژوهش های علوم دامی
سال بیست و دوم شماره 1 (بهار 1391)

In order to investigate the effect of genetic markers in genetic improvement of domestic fowl, seven breeding programs were simulated. In first breeding program called base program, phenotypic information of traits was only used. In this program, aggregative genotype equation consisted of body weight at 8 weeks of age, egg weight and egg number and selection index consisted of traits in aggregative genotype together with two other tarits including body weight at 12 weeks of age and age at sexual maturity. In other programs called marker assisted programs, QTL information that described 5, 10, 20, 30, 40 and 50% of genetic variation of egg number were also included in selection index. Based on obtained results, in program that QTL described 5% of genetic variance, economic response was improved by 3.37% compared to base program. Economic response in program that QTL described 50% of genetic variance was also improved by 14.28% compared to base program. Rate of Inbreeding was decreased from 0.69% in base program to 0.50% in program that QTL described 50% of genetic variance in each generation. The result of present study showed that QTL information, even with 5% description of genetic variance, can effectively improve economic traits in native fowl.

In this experiment, the effect of different dietary vitamin premix levels was evaluated between 29 and 42 day of age on broiler chicken performance, and carcass characteristics in floor system. A total of 504 day-old male broiler chicks (Ross 308) were allocated to 7 treatment groups, with 4 replicates per treatment group and 18 birds per replicate pen. This experiment was a completely randomized design and the dietary treatments were: T1) the basal diet with no vitamin premix during at 29-42 days; T2) the basal diet 33.33% vitamin premix during 29-42 days; T4) the basal diet 66.66% vitamin premix during at 29-42 days and T6) 100% vitamin premix during at 29-42 days and treatments 3, 5 and 7 to 35 days, respectively, similar treatments 2, 4 and 6 and at age 36 days after treatment as a dietary were not vitamin premix. Feed intake and weight gain were measured at 35 and 42 days of ages and feed conversion ratio was calculated. Also, at 35 and 42 days of age, after slaughtered and measured carcass weight and percentage of thigh, breast, abdominal fat liver and heart. Results showed that different levels of vitamin premix did not impair performance and carcass characteristics during the final period of broilers (P>0.05). In conclusion, it is possible to withdraw vitamin premix from finisher diets.

The aim of the present study was to investigate the effects of replacing dietary barely with different levels of sorghum on lamb performances. Sixteen Ghezel×Arkhar-Merino crossbred male lambs with live weights 46 ± 5.8 (mean ± SD) were used in the experiment. All dietary treatments had alfalfa hay (20% total DM), and remain part of diets (80% total DM) were contain different levels of barley and sorghum grain with different level of substitution. Lambs were randomly assigned to one of the four dietary treatments in a completely randomized design assignment, in which sorghum grain was used in the levels of 0, 60, 70 and 80 percent of total ration. Experimental diets were containing 0, 0.588, 0.686, and 0.784 percent of total tannin; respectively. The results of present experiment showed that different levels of dietary sorghum had significant effect on average weight gain of lambs (p<0.05) however it had no significant effect on dry mater intake and feed conversion ratio of lambs. Also dietary treatments couldnt affect total VFA, N-NH3 and pH of ruminal fluid and feces. Carcass characteristics such as hot and cold carcass weight, tail fat and dissectable fat weight affected by treatments (p<0.05). Using moderate level of sorghum grain along with barley grain in finishing lambs diet in a manner in which, dietary total taninn dont exceed 0.6 percent, showed the best results from stand point of performance and weight gain.

Thirty Holstein calves (15 males and 15 females) were used to evaluate the effects of feeding steam-rolled barley grain on feed intake, weight gain, feed efficiency, rumen metabolites and weaning age. Average birth weight of calves was 40.1_+ 0.8 kg. The experimental diets were as: 1- starter containing ground barley, 2- starter containing dry rolled barley and 3- starter containing steam-rolled barley. All experimental diets were formulated to be iso energetic and iso nitrogenous, and offered from the first day of experiment (3 days age). During the experiment, calves were fed raw milk based on 10% of their birth body weight and they were taken out two weeks after weaning. Experimental data were analyzed based upon a completely randomized design in which there were 3 treatments and 10 replicates per each treatment. The results of this study showed that there was not statistically significant differences among experimental diets regarding average daily feed intake, average daily gain, and average feed efficiency in pre and post weaning period. Calves fed diet 3 at wk 6, two wk after weaning and in whole period of experiment had significantly (P<0.05) greater rumen propionate concentrations than those fed diets 1 and 2. Calves fed diets 1 and 2 at two wk after weaning and whole period of experiment had significantly (P<0.05) greater rumen butyrate concentrations than those fed diet 3. The results of this study showed feeding steam-rolled barley grain to calves from the first week after birth although affect some VFAs concentration, but did not affect performance and weaning age of Holstein calves.

The purpose of this study was to evaluate effects of yeast culture on rumen fermentation parameters, rumen protozoa biodiversity and generic distribution in Ghizel sheep. Sixteen rams (33.8±6.5) were used in a completely randomized design and treatments contained 0, 2.5, 5 and 7.5 g YSC (yeast Saccharomyces cerevisiae)/head/day. Rumen fluid samples were collected from all rams pre feeding and 2 h after morning feeding. Protozoa were counted using a Neubauer Improved Bright-Line counting cell. Ruminal pH, Methylen Blue Retention Time and Sedimentation and Floating Time also were evaluated. Data were analyzed in a completely randomized design with 4 replacements by SAS software and treatment means were compared by the Duncan test. Ruminal pH of YSC treated sheep were higher than control sheep (P<0.05), also sheep that received YSC, had lower (P<0.05) MBRT and SFT than control group. According to obtained data, total count of protozoa population in both sampling time showed an upward trend by increasing of YSC level. Also generic distribution of protozoa were affected by yeast addition in both sampling time (P<0.05). Entodinium genus was the most popular ciliate protozoa which identified and counted in the ruminal fluid. Number of total protozoa was higher in the 7.5 g YSC treatment. It was concluded that YSC was affected ruminal fermentation mechanism, so YSC had potential for ruminal ecosystem manipulating.

In order to determine the economic optimal level of crude protein and lysine (Lys) in broilers diet, an experiment was performed based on compeletly randomized design in a 5×2 factorial experiment, with 5 levels of crude protein (Cobb recommendation and ± 1 or ±2 percent point higher or lower than Cobb recommendation) and 2 levels of dietary lysine (5.8 or 4.8 percent of dietary protein level). Birds had ad libitum access to diets in starter (0-10 days of age), grower (10-28d), finisher 1 (28-42d) and finisher 2 (42-49d) periods. Feed intake and average weight gain were measured at the end of each period. Minimum feed cost per kilogram live weight and maximum profit was used for economical analysis of data. Different level of crude protein and Lys had significant (P<0.01) effects on feed intake, average weight gain (except of finisher 2 periods). Different level of protein had significant (P<0.01) effect on feed conversion ratio, while levels of Lys had not significant effect on feed conversion ratio. The interaction between different level of protein and Lys was significant on feed intake at starter period (P<0.05), weight gain in grower (P<0.05) and entire rearing period (P<0.01) and feed conversion ratio (P<0.05) in grower period. Economical analysis showed the accuracy and sensitivity of the maximum benefit. For maximising benefit, increasing the level of dietary protein more than two percent higher from Cobb recommendation was economically justifiable. Also, results showed that increasing dietary Lys up to Cobb recommendation is economically profitable, especially in low protein diets, but if protein content in diets be more than Cobb recommendation, use of NRC Lys recommendation can be beneficial.

The present study aimed at the investigation of dietary supplementation of different levels of specific egg yolk antibody (IgY) powder on intestinal mucosal immunity and serum protein electrophoretic patterns of E. coli O78:K80-challenged broiler chicks. For lyophilized antibody preparation, forty 36-week-old White Leghorn hens were hyperimmunized with E. coli O78:K80 bacteria for a 12-week-period and IgY was isolated from the eggs by the water-dilution method. Seven-day-age broiler chicks were challenged orally with 0.5 mL of E. coli O78:K80 suspension (except for the negative control). The challenge was continued for additional 7 days from day 14 to 21 with 1.0 mL of a late log phase culture (109 cfu/mL) until the level of E. coli in droppings reached to 105 cfu/g. A total of 280 broiler chicks were randomly assigned to 5 dietary treatments with 4 replicates of 14 chicks each. The four challenged-groups received a basal diet supplemented with 0 (as positive control), 0.1, 0.2, or 0.4% (wt/wt) IgY. The unchallenged-group, as negative control, fed the same unsupplemented diet. Oral infection caused increase in ileal E. coli enumeration, and induced systemic and mucosal inflammatory reactions. After three weeks of feeding, the levels of 0.2 and 0.4% IgY had the most suppressive effects (P<0.01) on the ileal E. coli enumeration and intestinal secretory IgA concentration. However, with at least 0.2% IgY, serum IgA concentration and the albumins to globulins ratio were slightly decreased (P=0.36) and increased (P=0.20), respectively. It was concluded that feeding high level of specific antibody powder, in addition to decreasing inflammatory factors, may increase the ratio of serum albumin. Therefore, the serum proteins can be directed toward metabolic pathways instead of being imposed on inflammatory pathways.

This experiment was carried out in order to determine of nutritive value of canola straw and its effect on fattening performance of male Holstein cluves. Canola straw (okapy variety) was provided from the seed and plant improvement Institute, Karaj, Iran. Canola straw was processed by urea, molasses, ammonia, peroxide and was stored in plastic bags for 28 days. This experiment was conducted in a completely randomized design with 7 treatments and 3 replicates in each treatment. Treatments included: 1 - not processed canola straw (control), 2- processed with urea (5.3 % of DM), 3- processed with urea + molasses (5.3 % of DM urea + 2 % of DM molasses of DM), 4- processed with ammonia (5.3% of DM) 5- processed with sodium hydroxide (5 % of DM), 6- processed with peroxide + sodium hydroxide (5% of DM sodium hydroxide + 2 % of DM hydrogen peroxide), 7- processed with water (71 % of DM). The rates of degradation of the treatments were evaluated in an in situ experiment using three non-lactating Holstein cows with average body weight of 670±15 kg. Experimental treatments were incubated intraruminally for 0, 3, 6, 12, 24, 48, 72 and 96 hours. Degradability parameters were calculated for dry matter, organic matter and cell wall by Neway software. In the second section were used 16 calves with average initial weight 266±64 kg to test the effect of straw processed on fattening performance of male Holstein calveswith average initial weight 266±64 kg. This experiment was conducted in a completely randomized design with two experimental diets and 8 replicates for each diet. This noitces was done in 90 day. Feed intake was measured daily and body weight was measured monthly. The results of the first section showed that canola straw processed with urea and urea + molasses had the highest CP percentage. Processing of canola straw with urea + molasses, sodium hydroxide and sodium hydroxide + peroxide significantly decreased the cell wall content. Processing with urea + molasses made significant difference in (a) parameter of DM and OM (p <0.05). Effects of processing with sodium hydroxide, sodium hydroxide + peroxide, urea and water on parameter of (b) for DM and OM were significant (p <0.05). On the base of present results, processing of canola straw with sodium hydroxide and sodium hydroxide + peroxide was suggested. The results of second part showed that the final weight, daily gain and feed conversion ratio was not significantly different in the both of calves groups.The dry matter intake in calves that fed with unprocessed canola straw was significantly less than calves fed processed. Results of the digestibility was not significant different between the two groups.

Marker assistant selection is one of the best methods to improve the accuracy of prediction and response to selection. In studies related to weight gain and meat quality Calpastatin gene has been identified as a candidate gene. This gene is located on cattle chromosome 7 and is effective on formation, lysis of muscle texture and meat tenderness after slaughtering animals. In order to study polymorphism of Calpastatin gene in Holstein cattle 50 animals from Behin Taliseh corporation were randomly sampled. DNA extraction was carried out by modified salting out method. Polymerase chain reaction was performed to amplify a 622bp fragment of the L region of exon and entron 1 of this gene. Restriction reaction of PCR products was done using MspI enzyme. Then all the animals were genotyped base on digested fragment profile, respectively. Frequencies of MM, MN and NN genotypes were 46%, 54% and 0% for Holstein cattle and 0%, 45% and 55% for Buffalo. Frequencies of M and N alleles were 0.73 and 0.27, respectively for Holstein cattle and 0.225 and 0.775 for Buffalo. Results showed that this locus was not at Hardy–Weinberg equilibrium in the Holstein cattle (P<0.05) while Buffalo herd showed equilibrium.

The present study was conducted to evaluate the effects of growth promoters Avilamycin, Butyric acid and Nutracid Focus® on performance, carcass characteristics and intestinal morphology of broiler chickens. A total of 176 one-day old male broiler chicks (Ross 308) were randomly allocated to four treatments with 4 replicates and 11 birds each according a completely randomized design and fed a basal diet or diets supplemented with 0.01% Avilamycin, 0.25% Butyric acid and 0.1% Nutracid Focus throughout the experimental period respectively. At days 21 and 42 of age, three and four birds per treatment were selected respectively and killed for analysis of carcass characteristics and intestinal morphology. In analysis of variance, no significant differences were observed between the treatments for feed consumption, body weight gain and feed conversion ratio, and also relative weights of carcass, liver, heart and gizzard (P>0.05). Furthermore in orthogonal array test, the supplementation of organic acids in comparison with control group decreased the abdominal fat weight and increased the goblet cell numbers in jejunum (P<0.05). In addition, the villus length and villus length to crypt depth ratio in duodenum were higher than those for Avilamycin fed birds (P<0.05). It was concluded that dietary supplementation of organic acids instead of growth promoter antibiotics could have some advantages on abdominal fat weight and intestinal morphological parameters in broiler chickens.

PPARGC1A is a member of a family of transcription coactivators that plays a central role in the regulation of cellular energy metabolism. OPN is a phosphoprotein that is synthesized in a variety of tissues and cells and secreted into body fluids. In this study DNA was isolated from blood samples collected from 398 Holstein cows of Tehran and Esfahan provinces. DNA isolation was performed using the Salting out method. RFLP-PCR method was used for genotyping of SNP T>C at position 1892 and SNP A>C at position 3359 in PPARGC1A gene, also SNPC>T at position 8514 in OPN gene. Using of Pop Gene soft ware frequencies of TT, TC and CC genotypes at position 1892 were calculated as 12, 65 and 23%, respectively. Also, Shanon and Nei indices were for this position 0.68 and 0.49, respectively. Frequencies of AA, AC and CC genotypes at position 3359 were calculated as 38, 52 and 10%, respectively. Also, Shannon and Nei indices were 0.65 and 0.46, respectively. Frequencies of CC, CT and TT genotypes of OPN gene were calculated as 19, 57 and 24%, respectively. Also, Shannon and Nei indices were 0.69 and 0.49, respectively. Hardy-Weinberg equilibrium (HWE) was evaluated using χ square test. The genotypes in all loci deviated from HWE.