Five hundred andforty 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 perexperimental unity was used to study the effect of six digestible methionineplus 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), weightgain (g), feed intake (g), feed conversion (g/g), feather rate (%), chemicalcomposition (%) (dry matter, water, crude protein and ether extract) and bodyprotein and fat deposition (g). The effect of the amino acids on feed intake(g), feed conversion (g/g), feather rate (%), chemical composition (%) (drymatter, water, crud protein and ether extract) and protein deposition was quadraticand the effect on final body weight (g) and weight gain (g) was linear. Thebest estimated digestible methionine plus cystine: digestible lysine ratio was.66 and the estimated digestible methionine plus cystine requirement for growingJapanese quail was .758%, for a intake of 91.43 mg of digestible methionineplus cystine intake.
