Farzad Bastami; Ali Khatibjoo; Saifali Varmaghany
Volume 24, Issue 1 , April 2022, , Pages 67-80
Abstract
The effects of valine supplementation on performance, immunity and behavoural indices of broiler chickens reared under heat stress condition was evaluated. Total of 420 male and female Ross-308 broiler chickens were allocated to 6 treatments with 5 replicates in a completely randomized design. Experimental ...
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The effects of valine supplementation on performance, immunity and behavoural indices of broiler chickens reared under heat stress condition was evaluated. Total of 420 male and female Ross-308 broiler chickens were allocated to 6 treatments with 5 replicates in a completely randomized design. Experimental groups were as fallows: positive control (fed basal diet and reared under Ross-308 recommended rearing temperature), Nagative control (fed basal diet and reared under heat stress (HS)), and four treatment groups fed basal diet supplemented with 5, 10, 15 and 20 percent valine above the Ross-308 valine recommendation and reared under HS. Heat stress significantly decreased feed intake, body weight and European production efficiency factor (EPEF), antibody titer against NewCastle, lymphocyte percentage, serum total protein concentration and alkaline phosphatase and lactate dehydrogenase activities and increased heterophile percentage, heterophile to lymphocyte ratio, rectal temperature and tunic immobility of broiler chickens (P < 0.05), but 5% valine supplementation improved BW of broiler chicken at the end of grower and BW and EPEF at the end of total period; 10% valine supplementation increased relative weight of breast and thigh muscle and 15 and 20% valine supplementation increased lymphocyte and decreased heterophile percentage as compared to control group (P < 0.05). In conclusion, 5% valine supplementation improved final body weight and feed convertion ratio of heat-stressed broiler chikens and 15 and 20% valin inclusion improved blood immune cell percentages but had no effect on humoral immune response and tunic immobility test of HS broiler chickens.
Reza Salahi Moghaddam; Mohammad Hossein Shahir
Volume 23, Issue 4 , January 2022, , Pages 535-548
Abstract
In order to evaluate the response of broiler chicks to different levels of dietary ideal protein (Ross 308 strain recommendation and 10% less) and digestible valine to lysine ratio (71, 74, 77, 80, and 83%) in the starter period (one to 10 days of age), a study was performed using 500-day-old male broilers ...
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In order to evaluate the response of broiler chicks to different levels of dietary ideal protein (Ross 308 strain recommendation and 10% less) and digestible valine to lysine ratio (71, 74, 77, 80, and 83%) in the starter period (one to 10 days of age), a study was performed using 500-day-old male broilers in a 2×5 factorial arrangements based on a completely randomized design including 10 treatments and 5 replications. The results showed that reducing dietary ideal protein level increased body weight, feed intake and improved feed conversion ratio (P<0.01). The percentage of bone ash and calcium content also increased significantly with decreasing dietary ideal protein (P <0.05). The reduction of the dietary ideal protein level decreased the concentrations of serum cholesterol, glucose, total protein, albumin, globulin, calcium, and phosphorus (P<0.05). The highest average body weight at 10 day of age, weight gain, carcass and breast percentages and the lowest feed conversion ratio were observed at 74% of digestible valine to lysine ratio (P<0.05); while the highest average feed intake, thigh percentage, bone ash and calcium percentage were obtained at 77% of digestible valine to lysine ratio (P<0.05). No significant interaction was observed between the two experimental factors except for the carcass percentage traits (P<0.05) and serum phosphorus concentration (P<0.01). In conclusion, based on the results of this study, a 10% reduction in dietary ideal protein levels is possible by maintaining ideal ratios of essential amino acids. The proper ratio of digestible valine to lysine is recommended to be 74% based on performance indices and carcass traits, and 77% based on bone traits.