Research On Animal Production

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A 2×2×2 factorial arrangement with control group was conducted to study the effect of different levels of microbial phytase, metabolizable energy and available phosphorus on performance, carcass characteristics and phosphorus and calcium content of tibia in broiler chicks. In this experiment, 1260 Ross 308 male broiler chicks allocated to 9 treatments in a factorial arrangement, with 2 levels of microbial phytase (0 and 500 FTU), 2 levels of metabolizable energy (recommended level and 80 kcal lower than recommended levels), 2 levels of available phosphorus (50 and 75% of recommended levels) with control group (without enzyme and recommended level of available phosphorus), with 4 replications and 35 chicks in each replicate in a completely randomized design (CRD). Use of microbial phytase had significant effect on feed intake, body weight gain in whole period of the experiment (P<0.05). Differences of energy levels had significant effect on feed intake, body weight gain and feed conversion ratio (P<0.05). There were significant differences between treatments for available phosphorus levels for feed intake (3299.5 Vs. 3714.4 g), body weight gain (1531.5 Vs. 1974.6 g), feed conversion ratio (2.17 Vs. 1.91), breast (33.02 Vs. 33.69) and thigh (35.4 Vs. 36.3) percentage, tibia ash (41.69 Vs. 43.66%) phosphorus (7.96 Vs. 8.35%) and calcium (14.65 Vs. 15.81%) content of tibia (P<0.05). Interaction of energy and phosphorus was significant on feed intake, body weight gain, feed conversion ratio and phosphorus percentage of tibia (P<0.05). Results of this experiment showed that use of 500 FTU microbial phytase, with 80 kcal/kg ME lower than recommended levels and 75% recommended available phosphorus level had the best result on performance in broiler chicks.

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This study was carried out to syrvey the effects of conjugated linoleic acid (CLA) on chicken meat traits and sensory characteristics. The fat sources of five experimental treatments were: 7% soybean oil, 7% CLA, 3.5% soybean oil + 3.5% CLA 10% palm oil and a control fat free diet. These diets were used at grower (11-28 d) and finisher (29-42) periods. The Study was carried out as a compeletly randomized design with 5 treatments, four replicate consisted of 15 mixed sex chicks (Ross 308). At first 10 days of experiment all the chickens used a basal fat free diet. The results showed that, dietary fat type didn’t have significant effect on chicken meat taste. unexpectfully, diets containing CLA didn’t decreas abdominal fat pad, although reduced the chicken meat interior fat. Using CLA especially at 7% level adversely affected some physical aspects of meat like juicy, firmness and ease of chewing. Nonetheless, it seems that there is no direct relationship between dietary CLA level and chicken meat crude fat reduction, because the lower dietary CLA concentration resulted to more significant reduction of fat.

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     The effects of conjugated linileic acid on performance and small intestine morphology were studied using 300 broiler chickens in a compeletly randomized design with 5 treatments and 4 replicates and 15 chickens in each replicate. The experimental diets were contained 7% soybean oil, 7% CLA, 3.5% CLA + 3.5% soybean oil, 10% hydrogenated oil and control oil free diet. The lowest weight gain and feed intake were observed in the group fed with 7% CLA, but this treatment improved feed conversion ratio. The villi hieght was reduced in duodenum section of birds fed with diet containing soybean oil or control, but in ileum section just the soybean oil diet caused the same effect. The chicks fed with 3.5% soybean oil + 3.5% CLA had the highest villi length. The diets with 7% soybean oil and 3.5% soybean oil + 3.5% CLA  decreased epithelium thickness. Crypth depth in duodenum and jejunum increased with 3.5% soybean oil + 3.5% CLA diet so that the differences with other treatmernt were significant ecxept with the 7% soybean oil diet in duodenum. The results of the present study showed that CLA at 7% level adversly affect performance but the diet containing 3.5% CLA improved morphological parameters of small intestine especially villi length.

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     This study was carried out to investigate the effect of adding different levels of Nanozeolite (NZ) in aflatoxin (AF) contaminated diets on performance, some blood parameters and ileum bacteria population in male broilers. Chicks from 7 days of age were assigned to one of six experimental diets consisted of a free AF as control diet and contaminated diets containing 0.5 mg/kg AF and various levels of 0, 0.25, 0.5, 0.75 and 1 percent NZ. Four replicate groups of 14 chicks were allocated to each experimental diet. Chicks were raised for 21 day on floor pens. Blood were collected from birds at 18 days of age in order to determin of some blood parameters. Data were analyzed in a completely randomized design. Experimental results indicated that chicks were fed diet containing 0.5 mg/kg AF without NZ had significantly lower weight gain than control diet (P<0.05). Adding NZ to AF contaminated diets resulted to improve body weight gain in young broiler chicks. Experimental diets had not significant effect on feed intake and feed conversion ratio. Young broiler chicks fed AF contaminated diet without NZ had the lowest total protein and triglyceride concentrations (P<0.05). Adding NZ to AF contaminated diet resulted to increase of total protein and triglyceride concentrations. Serum cholesterol concentration was significantly lower in chicks fed AF contaminated diet without NZ than control diet (P<0.05). Experimental treatments did not have significant effect on serum albumin concentration. There was not significant difference among treatments for ileum bacteria population.

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     This study was conducted to evaluate the effects of formulateddiet based on nitrogen-corrected apparent and true metabolizable energy (AME_n, TME_n), total and digestible amino acid of feedstuff on broiler performance and carcass characteristics of Ross 308 broiler chickens. This experiment was carried out as 2×2 factorial arrangement with compeletely randomized desing Main factors including method of formulating diet based on total and digestible amino acid and based on apparent and true metabolizable energy of feedstuff. A total of 400 one day-old chicks were randomly assigned to 4 treatments with 5 replicates and 20 chicks per replicate. Experimental parameters for periods of 1-21, 22-42 and 1-42 days were measured. The results showed that the body weight gain and feed intake increased significantly when the chicks were fed with diet based on AME_n and digestible amino acid in whole periods of experimen (p<0.05). Feed conversion ratio significantly decreased in chicks fed with diet based on AME_n and digestible amino acid during 1-21 and 1-42 days of age. Dietary treatments had significant effect on breast and thigh yield, but had not significant effect on carcass carocteristics (p>0.05). The results obtained in the present study demonstrated that formulation of diets based on AME_n and digestible amino acid improved performance of Ross 308 broiler chicks.

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     A study carried out to compare three feed additives effects on performance and economical efficiency of broiler chickens. This research conducted using a completely randomized design with 4 treatments, 4 replicate and 25 chicks each replicate. The experimental basal diets formulated according to Ross 308 manual and the peribiotic, probiotic and garlic powder was added to the basal diets as additives. The treatments were: basal diet (free of additives), 2- basal diet + 0.3% Fermacto, 3- basal diet + 0.3% primalac and 4- basal diet + 1% garlic powder. All chicks were fed with same corn-soybean meal based additive free starter diet from 1-10 d and then at grower (11-28 d) and finisher period (29-42 d) were fed the experimental diets. The diet containing Fermacto prebiotic significantly increased the daily weight gain of chicks. In grower phase the birds fed with garlic powder consumed more feed, but in the finisher phase the significant difference was observed on feed intake in birds fed with fermacto prebiotic. The best feed conversion ratio achieved in treatment containing prebiotic or probiotic and other groups. The economical comparison of each kg of body weight gain showed an increase in costs of diet  with garlic powder or Primalac probiotic and a decrease in the cost per Kg of body weight gain in treatment containing Primalac prebiotic in comparison to the control group.
 

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     This experiment was conducted in order to determine the effects of corn gluten feed (CGF) on performance and carcass characteristics of broiler chicks. Four hundred commercial Cobb 500 broiler chicks were fed with 4 dietary treatments consisted of a control treatment (without CGF) and treatments containing 5, 15 and 20% CGF in the starter period and 10, 25 and 30% CGF in the grower periods, respectively. Five replicates of 20 chicks were allocated to each treatment. Results showed that utilization of CGF up to 20% in starter and 30% in grower periods had not adverse effect on body weight gain, feed intake and feed conversion ratio of broiler chicks. There was not any significant difference among treatments for carcass characteristics such as edible carcass, drumstick and breast. Based on the results of this experiment, CGF can be used in broiler diets up to 20% in the starter and 30% in the grower periods without any adverse effect on performance and carcass characteristics.
 

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     An experiment was conducted to evaluate of body temperature response and serum metabolites of Ross male broiler chickens subjected to heat stress condition. Treatment diets were different levels of protein and feed restriction program. Two groups were fed ad libitum with a standard protein diet (NRC, 1994) and low protein diet (0.85 NRC, 1994) from 21 to 42 d of age. The third group (feed restriction treatment) was fed with the standard protein diet, but fasted daily for 8 hours from 2 hours before heat stress till the end of heat stress (8:00 to 16:00 h). Broilers had free access to water during the experiment. The feed restriction group had significantly lowered body temperature than others after heat stress (P<0.05). Heat stress increased body temperature from 41.37^oC to 41.98^oC. Before heat stress blood triglyceride was significantly lower in feed restriction treatment than other groups, while the lowest serum uric acid was related to chickens fed with low protein diet (P<0.05). Dietary treatments had not significant effect on other serum metabolites before and after heat stress (P>0.05). Heat stress significantly increased blood cholesterol, triglyceride, total protein, albumin, uric acid, glucose and decreased blood potassium. Heat stress had no significant effect on blood sodium, calcium, globulin and HDL. In conclusion, results of this experiment showed that heat stress increased body temperature and altered serum metabolites up to 13 to 33 percent in male broiler chickens.
 

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     This experiment was conducted in order to evaluate the effect of different sources of mannanoligusaccharide on performance, carcass characteristics and viscosity of intestinal digesta of broiler chickens. A total of 250 broiler chicken (Ross 308 strain) reared in a completely randomized design with 5 treatments and 5 replicates for 42 days. Experimental treatments consisted of different sources of mannanoligusaccharide including yeast, autoclaved yeast, yeast extract and pure commercial mannanoligusaccharide at the level of 1.5, 1.5, 2 and 0.1 percent of diet, respectively. Mortality rate, feed intake, body weight and feed conversion ratio were measured in starter, grower and finisher periods of the experiment. Carcass characteristics and variability of weight and length of different parts of intestine were evaluated. Results of the experiment showed that there was not any significant difference among treatments for feed intake, body weight and feed conversion ratio of birds in starter, grower and finisher periods. There was not significant difference in carcass characteristics among treatments. Viscosity of intestinal digesta was significant among groups so intestinal digesta of chicks fed with yeast extract had the highest and the group fed with commercial mannanoligusaccharide had the lowest viscosity (P<0.05).

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   A study was conducted to evaluate the effect of drinking thyme essence on growth performance and some blood parameters in broiler chickens. A total number of 500 one day old Ross-308 male broiler chicks were randomly allocated to 4 treatments at 5 replicates using a CRD design. Diets were similar with respect of energy, protein and other nutrients for all treatments. Treatments arranged as different levels of drinking thyme essence including: plane water (control group) and levels of 0.1, 0.15 and 0.2 percent of drinking thyme essence. Growth performance traits and blood parameters were measured. Blood samples obtained from two birds in each pen at 21 and 42 days of age. According to the results, the highest total live weight (2.18 kg) and the lowest feed conversion ratio (1.99) belonged to group containing of 0.2 % dietary thyme essence. With increasing thyme essence, at 21 and 42 days serum total cholesterol and triglyceride decreased, but glucose concentration was significantly increased (p<0.05). The highest total serum protein concentration was 41.52 g/lit for the level of 0.1% at 21 days. For all thyme essence treatments albumin concentration was significantly (p<0.05) higher compare to the control group. Serum globulin concentration at 42 days was significantly (p<0.05) different at the level of 0.1 % compare to the control group. The albumin to globulin ratio only at 21 days of age was significantly (p<0.05) higher in all groups compared to control group.  As a final result, inclusion of thyme essence in drinking water of broiler chickens improved performance traits and  blood parameters.
                                     

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   This study was conducted to investigate the effects of 3.5% and 7% dietary CLA on blood parameters, body fat storage and correlation of these parameters in broiler chickens. In this study 320 chicks were used in a completely randomized design with 4 treatments and 4 replications. Four isocaloric and isonitrogenous diets formulated containing 7% Soybean oil, 3.5 Soybean oil + 3.5% CLA , 7% CLA and another diet containing palm oil which inevitably had more fat. Serum HDL was not affected by dietary treatments. Chicks fed diets with 7% CLA and 3.5% Soybean oil + 3.5 % CLA had higher Serum TG concentration in compare to the palm oil treatment. Serum cholesterol concentration increased following CLA consumption, but the only significant difference was observed in diet containing 7% soybean oil which significantly decreased serum cholesterol. Soybean oil and CLA decreased abdominal fat pad in compare to the chicks fed palm oil. The soybean oil + CLA diet decreased breast fat content in compare to the palm oil treatment. The notable observation was ineffectiveness of higher dosage of CLA on breast and drumstick fat. Abdominal fat pad showed a negative correlation with serum TG and a positive correlation with serum glucose and HDL. Drumstick fat content had not any significant correlation with serum parameters but breast fat concentration showed a significant correlation with serum TG concentration. This study showed that one of the possible paths on body fat deposits in tissues of broiler birds following CLA administration may be the changes in the production of lipoproteins that responsible for fat transportation in blood circulation. Nonetheless unexpected an increase in dietary CLA dosage did not cause in reduction of body fat.
 

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      An experiment was conducted to evaluate the effect of replacement of different levels of broken rice with corn on performance of broiler chicken in grower period. Four hundred one-day-old broiler chicks (Ross 308) were used in a completely randomized design with 5 treatments and 4 replicates for 42 days. Five treatments included control diet and different levels of broken rice 10, 20, 30 and 40 instead of corn meal diets (R1, R2, R3 and R4 respectively). Diets were calculated to be isocaloric and isonitrogenous and formulated according to National Research Council (NRC, 1994) recommendation. Body weight gain, feed conversion ratio and feed intake were measured weekly. Highest body weight were observed in control, R1 and R2 diets in the 4^th, 5^th  and 6^th weeks of experiment (P<0.05). Results of this experiment showed that using different levels of broken rice had significant effect on live weight, feed intake and body weight gain (P<0.05). The results showed that broken rice can be included in broiler diet up to 20% without any advers affect on growth performance.
 

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     An experiment was conducted to evaluate the effect of L-glutamine (Gln) supplementation on growth performance and small intestinal morphology of broiler chickens. One hundred and ninety two day-old male broilers (Ross 308) were used in a completely randomized design with 4 treatments and 4 replicates with 12 birds in each replicate. Four experimental diets were formulated to be isonitrogenous and isocaloric with different levels (0, 0.5, 1.0 and 1.5%) of Gln supplementation and were fed for the first 21 days of rearing period. Results showed that body weight and average daily weight gain increased in the birds consumed 1% Gln supplemented diet compared to the control birds fed a standard corn-SBM diet (P<0.05). Birds fed diets supplemented with 1 or 1.5% Gln had heavier duodenum and jejunum relative weight compared to the control birds (P<0.05). Morphological assays showed that villus height and villus surface area of the duodenum and jejunum increased as 1 or 1.5% Gln was supplemented in broiler diets comparing to the control group (P<0.05). Goblet cells density was not significantly affected by dietary Gln inclusion. The results of this study indicated that adding 1% Gln to diet for the first 21 days of rearing period improved growth performance and small intestinal morphology of broiler chickens.
 

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     An experiment was conducted to study the effect of L-carnitine (0, 125 mg/kg) in diets with different sources of fat (Soybean oil, tallow, blend  of soybean and tallow) on performance, body composition and blood parameters on 108 broiler chicks (Ross 308) in a factorial arrangement (2×3) with completely randomized design with 6 treatments, 3 replicates and 6 chicks in each replicates. During the experiment (11-28 d) feed intake, body weight gain feed conversion ratio body composition and blood parameters were measured. Based on the results of this experiment, different sources of fat had not significant effect on chick performance. However, carcass fat decreased significantly in chicks fed with diets supplemented with soybean oil but carcass Protein and fat percentage were not affected  by different sources and levels of fat and L-carnitine. L-carnitine supplementation in diet had not significant effect on body weight, feed intake and feed conversion ratio, but it significantly decreased total carcass fat. Adding of soybean oil to diet, significantly reduced, blood glucose, cholesterol and LDL concentration compared with diets containing tallow or a mixture of tallow and soybean oil, while triglyceride, HDL and VLDL concentrations increased. Adding L-carnitine to diets containing soybean oil reduced carcasses fat and glucose, cholesterol and LDL concentrations compared with diets containing tallow or a mixture of tallow and soybean oil in Ross 308 broiler chickens.
 

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      This experiment was conducted to evaluate the effect of Ziziphora clinopodioides L. on performance, blood biochemical parameters and cells of broiler chickens. The experiment was conducted in a completely randomized design with 300 broiler chickens (Ross 306) in 5 treatments and 3 replicates (with 20 chicks per replicate) from day 1 to day 42 of age. The experimental groups were 1), control without using medicinal plant  2), 0.5% Ziziphora clinopodioides L., 3), 1% Ziziphora clinopodioides L., 4)  1.5% Ziziphora clinopodioides L., 5), 2% Ziziphora clinopodioides L. The results showed that the addition of Ziziphora clinopodioides at 1.5 and 2% significantly increased feed intake in grower period and adding 1% Ziziphora clinopodioides to diet decreased feed conversion ratio, when compared to control group. In comparison to control diet, supplementation of 1% Ziziphora clinopodioides significantly decreased abdominal fat and increased breast percentage (p<0.05). There were not significant (P>0.05) differences in dressing, thigh and relative weight of liver, gizzard and small intestine. The addition of Ziziphora clinopodioides had not significant effect on cholesterol and triglyceride concentrations and heterophil and lymphocyte percentage. The overall results showed that using of 1% of Ziziphora clinopodioides medicinal plant could be helpful in improving performance and immunity parameters of broiler chickens. 
 

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     To investigate the effects of feed restriction and Coenzyme Q₁₀ supplementation on incidence of ascites and immune system in broilers, a factorial arrangement with completely randomized design with two levels of CoQ₁₀ (0, 20 mg/kg of diet) and three levels of feed restriction (0, 10 and 20 %) was carried out. Six hundreds 1-d-old Arian broiler chicks were randomly allocated into 6 groups with 5 replicates and 20 chicks in each replicate. From d 15, the diets were supplemented with CoQ₁₀ at levels of 0 and 20mg/kg. During the experimental period (42 days) chick mortality for ascites problem were investigated. Also, the RV/TV ratio, total red blood cell (RBC), hematocrit (PCV), hemoglobin(Hb), leukocyte differential counts (including heterophils (H), lymphocytes (L), H: L ratio) were investigated. In this experiment SRBC response, IgG and IgM were investigated as immune responses. According to results, RV/TV ratio, hematocrits, hemoglobin and  total red blood cell number were not affected by feed restriction and CoQ₁₀ (p>0.05). Feed restriction had no positive effect on SRBC response but it was affected by CoQ10 which found to be significant (p<0.07). Feed restriction and CoQ₁₀ had not significant effect on immunoglobulin M and G (p>0.05). White blood cells, lymphocytes, hetrophils and also hetrophil to lymphocytes ratio were not affected by feed restriction and CoQ₁₀ (p>0.05).
 

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This study was carried out to evaluate the impact of litter additives on growth performance, immune system response and the incidence of ascites syndrome in broiler chickens. This experiment was investigated in a completely randomized design with four treatments and four replications and 24 day-old chicks in each pen. Experimental treatments were addition of 1) aluminum sulfate + CaCO₃, 2) natural zeolite + citric acid, 3) treatments 2 and 3 together, to litters and a group with no litter additive was considered as control. Litter additives were applied on surface of the litters by 1.115 kg/m², at 24 h before arrival of the birds. Weight gain, feed consumption and feed conversion ratio were not affected by the treatments (P>0.05). On day 42 posthatch, mortality, the incidence of ascites, heart relative weight, right ventricular relative weight, heart ascites index (AHI) hematocrit and dermal and humoral antibody response to phytohemaglotinin and sheep red blood cells inoculation were not affected by the treatments (P>0.05). Birds reared on the litters treated with aluminum sulfate + CaCO₃ and natural zeolite + citric acid showed significantly greater means for bursa and spleen relative weights respectively (P>0.05), while there was not significant difference among other treatments. The pH value and moisture percentage were significantly affected by treatments until 5wk (P>0.05). On day 42, pH value, moisture and nitrogen (%) in litter were not affected by treatments (P>0.05). It could be concluded that while litter additives enhanced some of litter characteristics, it did not have effect on broilers performances. ­
 

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     The main aim of this study was to determine the effect of dietary Anethum graveolens essential oil on some blood parameters, egg yolk cholesterol concentration, hatchability and chick quality in broiler breeder hens. A total number of 80 hens and 8 cocks of Ross 308 strain (105 weeks age) were divided into 4 groups with 2 replicates with 10 hens and 1 cock in each replicate. One group was given a control diet and other group diets supplemented with 10, 20, 40 ml essential oil/100kg diets for 4 weeks. Essential oil significantly increased plasma cholesterol concentration (P<0.05), but plasma triglyceride, high density lipoprotein cholesterol (HDL-C) and egg yolk cholesterol concentrations were not influenced by dietary essential oil. Essential oil supplementation to diet did not significantly affect chick quality, while hatchability of total eggs set were positively affected by supplementation of the essential oil in the diet (P<0.05). The results of this study showed that supplementation of diet with 10 mg/100 kg diet Anethum graveolens essential oil improved hatchability of total eggs set of broiler breeders.
 

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     This study designed to survey the effects of Saccharomyces cerevisiae probiotic and organic acids on performance and intestinal morphology of broiler chickens. At 1-42 days of age, the experimental birds fed the experimental diets containing probiotic , organic acid mixture  (a commercial mixture of formic acid, lactic acid, malic acid, citric acid, tartaric acid and orthophosphate acid) or the both the above supplements. The type of the dietary supplement did not affect broiler chickens performance.  The birds received diet containing both the probiotic and organic acid mixture the villi height increased and the epithelium thickness and goblet cell numbers decreased and the crypt depth increased.  The results of the present study showed the positive effects of organic acids on villi height and favorite effects of both supplements on reduction of small intestine epithelial thickness, but these observed intestinal morphological differences did not have significant affect on broiler chickens performance.
 

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     A factorial arrangement with three levels (0, 50 and 100 mg/kg of diet) of fennel extract (FE) and three levels (0, 3500 and 4200 IU/kg of diet) of Vitamin D₃ (VitD₃) was carried out with 360 Ross 308 broiler breeders after molting (84 - 92 weeks). Broiler breeders were weighed at 18 weeks after molting (82 weeks of age) and then randomly distributed into 36 pens with a similar mean body weight. Each pen consisted of 10 hens and 1 rooster. The birds received experimental diets during 84-92 weeks of age. Performance data were recorded daily and egg quality traits were recorded every 4 weeks. To determine the settable hatch and fertile hatch eggs, eggs collected three times a week and incubated for 21 days. Four blood samples were taken from each pen to assay serum calcium and phosphorus concentration at the end of the experiment. Fennel extract supplementation to breeder diet significantly decreased deformed eggs and increased yolk color index and serum calcium. There were significant interactions between FE and Vit D₃ levels for egg production, egg mass, feed conversion ratio, shell weight and serum calcium. The results of this experiment showed that incorporation of 50 mg/kg FE and 3500 IU/kg Vit D₃ to the diet exhibit beneficial effects without any adverse effect on productive performance.