فصلنامه تحقیقات تولیدات دامی
سال یکم شماره 3 (پاییز 1391)

The purpose of this study was to evaluate the effect of zilpaterol hydrochloride in two days on-two days off feeding program on performance, carcass quality and blood metabolites of Japanese quails. One hundred twenty eight, 26 days old male quails were assigned to four experimental groups with four replicates of 8 birds each. Diets were based on corn and soybean meal in finisher period (24% cp and 2900 kcal/kg of diet). The birds were supplemented daily with 0, 0.2, 0.225, or 0.25 mg of zilpaterol/kg of live weight. On day 47, 2 birds from each replicate were randomly selected for bleeding. After three days of zilpaterol withdrawal period (on day 50), two birds were slaughtered for carcass quality evaluation. Data were analyzed using the GLM procedure of SAS software. Zilpaterol hydrochloride supplementation significantly improved feed conversation ratio compared to the control group (P<0.05), while its effect on feed intake and weight gain were not significant (P>0.05). Carcass quality, (relative weights of legs, breast, liver, and fat pad) was not affected by Zilpaterol hydrochloride. Zilpaterol hydrochloride supplementation increased plasma glucose concentration compared to the control group, but it had no effect on plasma cholesterol and triglyceride concentrations.

The effects of Protexin (probiotic) and formic acid were studied on performance in 200 Cobb broiler chicks in a completely randomized design with 4 treatments and 5 replications and 10 chicks per replicate. The chicks in first group as control were fed with basal diet. The chicks in the second, third and forth groups were fed with food, which contained 0.1 gr/kg Protexin, 0.8 percent formic acid and 0.1 gr/kg Protexin with 0.8 percent Formic acid in diet, respectively. To measurement of performance, broilers and remainder food in each replication were weight, weekly and feed conversion rate were calculated in each week. The results indicated that body weight gain not affected by experimental treatments (P>0.05). Protexin and Protexin + formic acid in grower period and Protexin in finisher period reduced feed intake (P<0.05). Treatment groups improved feed conversion rate in grower and finisher periods (P<0.05) but the forth group were not significantly different from second and third groups (P>0.05). Thymus and bursa of Fabricius weights were increased in treatment groups (P<0.05). It is concluded that Protexin and formic acid improved feed conversion rate and increased weights of thymus and bursa of Fabricius, synergism effect of Protexin and formic acid on performance did not observe.

An experiment was conducted to investigate the effects of vitamin E, C, choline chloride, organic selenium, and also feed restriction on broiler performance and immune response and ascites related metabolites. Nine hundred one-day old Arian broiler chicks were allocated to 6 experimental treatments in a completely randomized design with 5 replicates and 30 samples per replicate. The first three treatments were: 1-Control diet, 2- Basal diet+ 250 IU Vit E, 300 mg Vit C and 0.3 ppm organic selenium, 3- Basal diet+ 250 IU Vit E, 300 mg choline chloride and 0.3 ppm organic selenium, and treatments 4, 5 and 6 were similar to treatments 1 to 3 but with feeding program. Feed intake, body weight, mortality, feed conversion were measured weekly. Immune system response was assessed by injecting sheep red blood cell in day 28. The ratio of right ventricle to total ventricle considered as ascites index in day 42. Results showed that feed conversion ratio and ascites index were not different among treatments (P>0.05). The highest level of antibody against red blood cell was for treatment 6 (P<0.05). Therefore, the utilization of vitamin, choline, organic selenium and feeding program was effective on humoral immune response of broilers.

Eight Holstein dairy cows (4 primiparous and 4 multiparous) were used in a replicated 4×4 Latin square design with four 21-d periods to investigate effects of xylose-treated soybean meal (XSBM) as a source of ruminal undegradable protein in early lactation cows fed barley-based diets. Treatments were diets with XSBM ratios of (1) 0% (control), (2) 4.5%, (3) 9% and (4) 13.7%5, on a dry matter DM basis. Milk production, 4%FCM, milk energy, milk protein, lactose, solids-non-fat and total solids yield were increased by feeding XSBM. Milk fat, protein, lactose, solids-non-fat and total solids percent were not different among treatments. Intake of dry mater, crude protein and energy, blood glucose, albumin and total protein, rumen, fecal and urine pH and changes in body weight were not affected by treatments. Feed, crude protein and energy efficiency were improved by substitution XSBM for soybean meal but not by parity. Increasing dietary XSBM in the ration reduced blood urea N. Results of this study showed that increasing dietary XSBM ratio improved milk production in early lactation cows fed diets based on barley.

This study was undertaken to estimate the genetic parameters and genetic and phenotypic trends of the dry days in the first three lactations of Holstein cows in Iran during 1985 to 2006. Calving records from 1114 dairy herds comprising 264297 calving events of Holstein cows were analyzed using univariate and bivariate linear animal models. Genetic trends were estimated by regressing yearly mean estimates of breeding values on calving year. Average dry days were from 73.3 to 82.7 days and increased over the parities. Heritability estimates for dry days varied from 0.02 to 0.09 and increased over the parities. Estimates of genetic correlations between dry days in different parities were medium and ranged from 0.26 to 0.34. Also, estimates of phenotypic correlations between dry days in different parities were low and varied from 0.07 to 0.10. The average annual phenotypic trends were estimated from fitting linear regression of annual mean dry days were negative for the first three parities of Iranian Holsteins (P<0.01). On the other hand, there were significant and decreasing genetic trends for dry days at parities 1, 2 and 3 over the years (P<0.01). The low estimates of heritability for dry days obtained in the current study could be assigned to the high phenotypic variance arising from large environmental variation. Therefore, this implies that improvement in dry days could be achieved by improving the non-genetic factors such as management and production environment.

This experiment was conducted to determine the chemical composition, digestibility and degradability of restaurant waste (RW) using in vivo, nylon bags and gas production techniques. Sixteen male Ghezel* Arkhar- Merino hybrid sheep (43 ± 0.5 kg average weight) were used in the in vivo digestibility method. Experimental diets were including 0, 40, 50 and 60 percent of RW along with alfalfa as basal diet. Two fistulated Ghezele*Arkhar-Merino hybrid sheep (40 ± 1.5 kg average weight) were used in the in situ method. Chemical composition of RW including dry matter (DM), ether extract (EE), crude protein (CP), crude fiber (CF), Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF) were 33.4, 14, 15, 1.8, 15.2 and 6.8 percent respectively. Average gas production and metabolisable energy content of RW calculated using in vitro gas production technique were 87.7 (ml/g DM) and 3.27 Mcal/kg DM respectively. Dry matter and crude protein degradability of restaurant waste were 49.2, 44.8 and 41.2 percent for DM and 71.1, 64.6 and 59.2 percent for CP respectively in the passage rates of 2, 5 and 8 percents per hour. These results indicated that the restaurant waste can be use in the ruminant rations.

The aim of this study was if stabilized Vs raw rice bran may affect blood and egg cholesterol in laying hens? A total of 200 High line strain laying hens were divided into 5 treatments (4 replicates, and 10 birds per replication) in a completely randomized experiment for 10 weeks. Treatments include: 0% rice bran (NC),10% raw rice bran (RRB10), 10% stabilized rice bran (SRB10), 15% raw rice bran (RRB15) and 15% stabilized rice bran (SRB15). Results showed that inclusion of rice bran in diet lowered both serum and egg yolk cholesterol significantly (P<0.05). The lowest serum and egg yolk cholesterol (95.34 ± 25.22 mg/dl and 11.10 ± 3.35 mg/g respectively) were obtained with SRB15 while the highest level was recorded for NC for serum cholesterol (162.58 ± 14.2 mg/dl) and egg yolk (16.25 ± 0.57 mg/g) cholesterol. A similar trend was observed with egg cholesterol in which highest level (307.61 ± 26.43 mg/egg) was observed with NC and the lowest level (149.55 ± 16.74 mg/egg) was obtained when diet contained 15% SRB. There was not significant differences between SRB15 and RRB15 and also between SRB10 and RRB10 for both serum and egg yolk cholesterol. FCR, Egg weight and Egg yolk weight were not significantly affected by treatments. According DSM index color number 8 for SRB15 and RRB15, number 7 for SRB10 and RRB10 and number 6 for NC are obtained. Conclusion was that rice bran may be used to reduce blood and egg cholesterol in laying hens.