Three hundred and sixty 45-days old female quails, averaging 137.0 g, were used during four experimental periods of 28 days each. A completely randomized block design, with six replicates and ten females per experimental unit, was used to study the digestible methionine plus cystine requirement and the best digestible methionine plus cystine: digestible lysine ratio (0.60, 0.65, 0.70, 0.75, 0.80 and 0.85), on the rate of eggs production (%), egg weight (g), eggs mass (g of eggs/quail/day), feed intake (g), feed consumption: weight gain ratio (g of diet/g of eggs), body weight (g) and shell percentage (%). No significant effect of treatments on feed consumption: gain diet (g of diet/g of eggs). Quadratic effects were observed for final body weight (g), egg production (%), egg weight (g), egg mass (g of eggs/quail/day) and shell egg (%), and for feed intake (g) the effect was linear. The estimated digestible methionine plus cystine requirement was .727%, for a daily intake of 164 mg of digestible methionine plus cystine, and the best estimated digestible methionine plus cystine: digestible lysine ratio for laying Japanese quails was .80.
Coturnix coturnix japonica; digestibility; egg production; ideal protein; sulfur amino acid
