ABSTRACT:
The objective was to estimate the most appropriate digestible methionine + cysteine:lysine ratios for growing meat-type quails (Coturnix coturnix) from 1 to 21 days of age. Quails were fed with a basal ration deficient in digestible methionine + cysteine, with five levels of DL-methionine, in substitution of glutamic acid and starch, resulting in digestible methionine + cysteine:lysine ratios of 0.61, 0.66, 0.71, 0.76 and 0.81. Feed and methionine + cysteine intake, body weight gain, feed conversion and uniformity were assessed. From 1 to 7 days, an increasing linear effect was observed for feed and methionine + cysteine intake, body weight gain, and uniformity, and a linear decrease for feed conversion. From 8 to 14 days, the 0.70 methionine + cysteine: lysine ratio was the best for feed intake and body weight gain, and for uniformity, the 0.75 methionine + cysteine:lysine ratio was the most appropriate. For methionine + cysteine intake and feed conversion, an increasing and decreasing linear adjustment was observed, respectively. From 15 to 21 days, an increasing linear effect was observed for feed and methionine + cysteine intake and body weight gain; a decreasing linear effect was observed for feed conversion. The 0.81 ratio was the most efficient for feed conversion during all evaluated experimental periods. In conclusion, the 0.81 dietary methionine + cysteine:lysine ratio is the most appropriate for meat-type quails during the first 21 days of age.
Key words:
Coturnix coturnix; ideal protein; performance; sulfur amino acids