Optimum Dietary Standardized Ileal Digestible Isoleucine to Lysine Ratio for Meat-Type Quails in the Growing-Finishing Phase

ABSTRACT

ABSTRACT This study was conducted to determine the optimum standardized ileal digestible isoleucine to lysine (SID IleLys) ratio for meat-type quails from 15 to 35 d of age. Three hundred fifty not-sexed meat-type quails (Coturnix coturnix coturnix) were randomly assigned into five treatments, with seven replicates of 10 quails each. An isoleucine-deficient corn-soybean meal-based diet was formulated and graded supplemented with L-isoleucine (99%) to obtain diets containing SID IleLys ratios of 55,61, 67, 73, and 79%. Data were analyzed as one-way ANOVA and optimum SID IleLys was estimated by polynomial (linear and quadratic) regression. Statistical differences were considered when p 0.05. Quail performance from 15 and 21 d and 15 and 28 d of age was not affected by the treatments. From 15 to 35 d of age, body weight gain and body weight exhibited a quadratic response to increasing dietary SID IleLys ratios, and were optimized at 66 and 67% SID IleLys, respectively. Feed conversion ratio was not influenced by SID IleLys ratios in any of the phases assessed herein. Based on the results, the optimum SID IleLys ratio for meat-type quails from 15 to 35 d of age is 67%.