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.