فصلنامه تحقیقات تولیدات دامی
سال یکم شماره 4 (زمستان 1391)

In order to study the effect of green tea and fish oil on performance and antibody titer against Newcastle disease, 405 day-old broiler chickens were evaluated in a 3×3 factorial experiment using completely randomized design. Chicks were divided into 9 parts and each part was split into 3 groups. Each part was fed by diet containing 0% (T0), 0.75% (T0.75) or 1.5% (T1.5) dry powder of green tea and 0% (F0), 0.75% (F0.75) or 1.5% (F1.5) fish oil. Feed intake, gain weight and feed conversion ratio were estimated weekly. The vaccine of Newcastle was inoculated at 8 and 17d. To assay the antibody of Newcastle by HI test, blood samples were collected from five checks of each group from brachial vein at 25, 32 and 39 d. The results showed that there was no difference between treatments on the feed conversion ratio (P>0.05) and the lowest weight gain (30.43) and the highest feed intake (72.25) were observed by 1.5% fish oil and 1.5% green tea. At 39 d, the highest level of antibody (3) was obtained by 1.5 % fish oil (P<0.05). At 32 and 39d, the levels of antibody against Newcastle was lower in 1.5% green tea (2.09 and 2.18, respectively) than 0% green tea (2.64 and 2.84, respectively; P<0.05). Therefore, the addition of 1.5% fish oil and 1.5% green tea to diet of broiler chickens increased and decreased the humoral immunity responses against Newcastle disease, respectively.

An experiment was conducted in order to study the effect of different substitution levels of extruded (ESB) with soybean meal (SBM) and two dietary vitamin E levels on production index and economic traits of broilers. 264 Cobb 500 day-old chicks of either sex were distributed among 24 groups of 11 chicks per each experiment was exerted as a 4×2 factorial arrangement (4 substitution levels of ESB with SBM: 0, 25, 50 and 75 % and two dietary levels of vitamin E, 42 and 75 IU/Kg) with three replicates in a completely randomized design (CRD). The results showed that different substitution levels had no significant effect on production index at 28 and 42 days of age (P>0.05). However recommended levels of vitamin E significantly improved production index at 28 days of age (P<0.05). The interaction effect of different substitution level of ESB with SBM and vitamin E supplement on feed cost at 28 days and feed cost per live weight gain at 28 and 42 days was significant (P<0.05). As increases each of them increased costs. Monetary return at 42 days of age was significant (P<0.05) and increase of monetary return was showed. It can be said that different substitution levels of ESB with SBM plus higher level of dietary vitamin E had not any negative effect on economic status and production index of broilers.

Present study was conducted to investigate the effects of L-carnitine and dietary fat source (Vegetable oil, animal fat and mixture of Vegetable and animal fats (50:50%)) on performance and some blood parameters of broiler chickens. Two hundred and forty one-day-old male broilers (Ross 308) in 6 treatments with 4 replicates and 10 birds in each replicate were used in this experiment. Dietary treatments consisted of: 1) basal diet with 5% Vegetable oil (T1); 2) basal diet with 5% Vegetable oil + 300 mg/kg L-carnitine (T2); 3) basal diet with 5% animal fat (T3); 4) basal diet with 5% animal fat + 300 mg/kg L-carnitine (T4); 5) basal diet with a mixture of vegetable and animal fats (with the same amount of 2.5 percent) without L-carnitine (T5); 6) basal diet with a mixture of vegetable and animal fats (with the same amount of 2.5 percent) supplemented + 300 mg/kg L-carnitine. At the end of experiment (42 day) blood samples were taken from one bird of each replicate in different groups. The serum samples were analyzed for some blood parameters. The result showed that used diet with L-carnitine had a significant effect on body weight gain in growth and whole period (P<0.05). Adding L-carnitine and animal fat in diet had a significant effect on feed intake and feed conversion ratio (P<0.05). Amount of blood glucose and HDL levels hadn’t significant difference in broilers (P>0.05), and used L-carnitine in diet significantly reduced blood cholesterol, triglycerides, LDL and VLDL (P<0.05).

This experiment was conducted to investigate the effect of diet and fattening start weight on body growth in the different stages of the fattening periods and carcass compositions of Moghani male lambs. For this purpose, 36 heads of Moghani male lambs with three weights classes (Light, medium and heavy weight) were used with two diets (alfalfa to concentrate ratio of 70 to 30 (diet 1) and 30 to 70 (diet 2)) were fattening up to the time which their weights were 55 kg. The lambs were placed in individual cages for control the amount of feed daily intake and residual collected. The diets of high concentrate compared with diet of high forage were more favorable effect on body weight during the fattening at all stages and also daily weight gain (P<0.05). The significant difference was between heavy weight lambs (112 g/day) with light weight lambs (153 g/day) on daily weight gain (P<0.05). The diet had significant effect on carcass efficiency, hot and cold carcass weight, fat-tail weight and liver weight (P<0.05) and also percentage of fat-tail weight to carcass weight ratio (P<0.05). Negative correlation existed between fat-tail weight with different component of the carcass, especially with its valuable parts (leg, sirloin, breast and shoulder). Generally, high concentrate intake caused increase of fat-tail stores. Fattening with low weight increased daily weight gain, but in higher age was associated with fat stores in Moghani male lambs.

The objective of this study was to investigate the effect of different levels of benzoic acid on performance and carcass characteristics of broiler chickens. To this purpose 120 one-day-old Ross 308 chickens were examined with a completely randomized design with 4 treatments, 3 replications and 10 sub sampling that were reared for 42 days. Dietary treatments included of the 0, 0.25, 0.5 and 1 percent levels of benzoic acid. Properties were measured included weight gain, feed intake and feed conversion rate. Dietary supplementation of benzoic acid significantly decreased feed intake of chickens (P<0.05) and the highest feed intake observed in control group. There was no significant difference between BA0.25 and BA0.5 groups in terms of body weight gain (P>0.05). Supplementing 1% benzoic acid in the diet resulted in significant decrease in body weight gain (P<0.05). Use of 0.25 and 0.5percent benzoic acid in the broilers diet in contest of control group significantly decrease FCR (P<0.05). Also inclusion of benzoic acid in the diet resulted in significant decrease breast to carcass weight ratio in 0.5percent treatment (P<0.05) but thigh to carcass weight ratio significantly increased in the treatment of 0.5 percent of benzoic acid than control group. Regarding to present results, suggested that use of 0.5 percent dietary supplementation of benzoic acid in broiler chickens is possible without negative effects on performance and carcass characteristics.

A ruminal in situ experiment using three ruminally fistulated multiparous non-lactating dairy cows was conducted to determine dry matter (DM) and crude protein (CP) degradation of soybean meal and xylose-treated soybean meal. Samples were suspended in the rumen of cows for 0, 2, 4, 8, 16, 24 and 48 h. Xylose-treated soybean meal had higher soluble digestible fraction (a) of DM than soybean meal (21% vs. 27%). Soluble digestible fraction (a) CP of xylose-treated soybean meal was considerably lower than that of soybean meal (3% vs. 20%). Xylose-treated soybean meal showed higher slowly digestible fraction (b) CP than soybean meal (84% vs. 78%). Effective degradability of CP at outflow rates of k= 0.05 and k= 0.08 h-1 was significantly lower for xylose-treated soybean meal than soybean meal (27 and 20% vs. 62 and 53%). Results from this study showed that xylose-treated soybean meal had lower available protein for rumen microorganisms compared with soybean meal.

In order to study the effects of antibiotic, probiotic, prebiotic and enzyme in pelleted diet on performance and carcass characteristics of broiler chickens, an experiment was conducted as completely randomized design using 10 treatments, 4 replicates and 20 1-day-old male Arian broiler chickens in each. The experimental treatments were: 1) control, 2) diet supplemented with oxytetracycline (1 g/kg) for the first 21 days, 3) lincomycin-spectinomycin (0.75 g/L) in drinking water up to 5 days old, 4) probiotic (1 g/kg), 5) prebiotic (1 g/kg), 6) multi-enzyme (0.5 g/kg), 7) lincomycin-spectinomycin in drinking water within first 5 days and then probiotic, 8) probiotic(1 g/kg) and prebiotic(1 g/kg), 9) probiotic(1 g/kg) and multi-enzyme (0.5 g/kg), and 10) prebiotic (1 g/kg) and multi-enzyme (0.5 g/kg). Body weight of broilers at any week of age was higher in experimental treatments than in the control (P<0.05). Broilers fed either diet supplemented with multi-enzyme or combination of multi-enzyme and probiotic or prebiotic had highest body weight among the treatments. Broilers received multi-enzyme in the diet had lower feed conversion ratio up to 35 day of age. Experimental diets had no effect on relative weights of carcass, wings, thigh, breast and back (P>0.05), although abdominal fat pad was affected (P<0.05). The most abdominal fat was corresponded to multi-enzyme and antibiotic groups. Feeding multi-enzyme in combination with probiotic and prebiotic increased body weight of broiler up to 21 day of age but after this age the combination had no more effect than multi-enzyme alone.