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This experiment was conducted to evaluate the effect of zinc, manganese, and copper sources (inorganic vs. organic) in the diet on laying performance and eggshell quality characteristics. One hundred and eighty Hy-Line W-36 layers at 38 weeks of age were allocated to 36-layer cages of five hens each. Each six cages were randomly assigned to one of the six experimental diets fed from 38 to 53 week of age. In three experimental treatments, the basal diet was supplemented with 65-75-7 or 65-75-7 or 40-40-7 mg/kg of Zn, Mn, and Cu, respectively, from their oxide or sulfate sources. Three other groups were fed diets supplemented with 20-20-3.5 or 40-40-7.5 or 60-60-10.5 mg/kg of organic forms of Zn, Mn, and Cu, respectively. Dietary treatments significantly did affect feed intake (P < 0.001), feed conversion ratio (P < 0.001) and percentage of broken eggs (P < 0.05). Substitution of Zn and Mn oxides (65 and 75 mg kg(-1), respectively) with equal amounts of their sulfate forms significantly improved feed intake, feed conversion ratio, percentage of broken eggs, and Haugh Unit (P < 0.05). In addition, laying hens maintained their performance when substitution of Zn and Mn oxides and Cu sulfate (65, 75, and 7 mg kg(-1), respectively) reduced up to 20, 20, and 3.5 mg kg(-1) by amino acid complexes of the microelements. The results showed that a corn-soybean diet supplemented with the organic forms of Zn, Mn, and Cu at a dosage 50% to 75% lower than NRC recommendation is sufficient to maintain laying performance and can improve eggshell and albumen qualities of the egg in laying hens.

This study was conducted to determine the effects of dietary supplementation with Cr nicotinate and Cr chloride and their optimum inclusion rate on performance, carcass traits, meat oxidative stability, serum metabolites, hematological parameters, and liver chromium concentration in heat-stressed broilers. A total number of 420, 1-day-old male broiler chicks were randomly assigned to seven treatments with four replicates of 15 chicks. The dietary treatments consisted of the basal diet supplemented with 0 (control), 500, 1,000, and 1,500 μg/kg Cr in the form of Cr nicotinate and Cr chloride. Chicks were raised for 6 weeks in heat stress condition (33 ± 2°C). Supplements of organic and inorganic Cr particularly at 1,500 μg/kg incorporation increased feed consumption (P < 0.05) and body mass gain of broilers (P < 0.01). Cr supplementation increased carcass yield and decreased abdominal fat (P < 0.01). Supplementation of 1,500 μg/kg Cr nicotinate (P < 0.05) enhanced liver Cr concentration. Storage time increased lipid oxidation of meat (P < 0.01). Cr decreased lipid oxidation of breast and thigh muscles over 2 (P < 0.01) or 6 (P < 0.05) days of storage time. Birds fed 1,500 μg/kg Cr nicotinate, had lower concentration of serum glucose and triglyceride at 21 days (P < 0.05). Hematological parameters tested at 21 and 42 days, were not influenced. The results suggested that dietary Cr supplementation regardless of its source have a positive effect on productive, and carcass traits, also enhances oxidative stability of refrigerated meat in broilers reared under heat stress conditions.

This study was conducted to determine the impacts of two levels of oyster mushroom (Pleurotus ostreatus) powder on productive and carcass traits, humoral immune responses, and blood characteristics of Ross 308 male broiler chicks reared to 42 d of age in comparison with a prebiotic supplement. Two hundred and forty, day-old male broiler chicks (Ross 308) were randomly assigned to one of four treatments with four replicates of 15 chicks based on a completely randomized design. The dietary treatments consisted of the basal diet as control, prebiotic group receiving 1 g/kg A-Max ® (Mannan-oligosaccharides), 10, and 20 g/kg oyster mushroom powder added to the basal diet. The obtained results showed that inclusion of 20 g/kg mushroom powder significantly improved body weight over the starter and grower (P＜0.05) while feed efficiency was improved only over the starter (P＜0.05) period compared to the control group. Considering the entire experimental period, (1-42 d) birds receiving prebiotic supplemented diets exhibited the highest body weight and lowest feed conversion ratio relative to the other treatments (P＜0.05). Carcass yield and internal organs relative weights were not influenced by dietary treatments, but prebiotic supplementation significantly (P＜0.05) decreased abdominal fat pad compared to the control group. Newcastle, influenza and sheep red blood cell antibody responses of chicks did not differ significantly at either level of inclusion of supplements. Chicks fed supplemented diets had the lowest serum triglyceride concentration at 42 day (P＜0.05) compared to the control chicks, but other biochemical and hematological values tested including protein, albumin, globulin, high-density lipoprotein, low-density lipoprotein, and total cholesterol, red blood cell, white blood cell, hemoglobin and hematocrit were not markedly affected by treatments. In conclusion the obtained results indicated that oyster mushroom powder at an inclusion level of 20 g/kg of diet had favorable effects on performance criteria of chicks reared to 28 day of age while, prebiotic supplementation revealed its beneficial impact on chicks productive traits at slaughter age, besides reducing carcass abdominal fat and serum triglyceride concentration at 42 day.