Five hundred and forty 7-days old female quails, averaging 21.50 g, were used during 35 days. A completely randomized blocks design with five replicates and 18 females per experimental unity was used to study the effect of six digestible methionine plus cystine: digestible lysine ratios (0.48, 0.53, 0.58, 0.63, 0.68 and 0.75) on the traits evaluated during the growing period. Final weight (g), weight gain (g), feed intake (g), feed conversion (g/g), feather rate (%), chemical composition (%) (dry matter, water, crude protein and ether extract) and body protein and fat deposition (g). The effect of the amino acids on feed intake (g), feed conversion (g/g), feather rate (%), chemical composition (%) (dry matter, water, crud protein and ether extract) and protein deposition was quadratic and the effect on final body weight (g) and weight gain (g) was linear. The best estimated digestible methionine plus cystine: digestible lysine ratio was .66 and the estimated digestible methionine plus cystine requirement for growing Japanese quail was .758%, for a intake of 91.43 mg of digestible methionine plus cystine intake.
Coturnix coturnix japonica; digestibility; ideal protein; laying Japanese quails; sulfur amino acid
