Nutritional requirement of lysine for laying quails in function of the dietary crude protein level

This experiment was carried out to estimate the requirements of total lysine and lysine: crude protein (CP) ratio to laying quails. It was used three hundred and twenty birds offspring from crossing breeding of Japanese and European quails from 60 to 144 days of age, live weight of 178+/-12 g, fed diet with 20 and 23% of CP, and five rates of lysine (0.80, 0.95, 1.10, 1.25 and 1.40%). A completely randomized experimental design in a factorial scheme 2x5 (two CP levels X five rates of lysine) was used, resulting in ten treatments, each one with four replications of eight layers quail submitted to a light schedules of 17 hours daily and ad libitum fed. The studied variables were obtained in four periods of 21 days. There was effect of lysine rates within CP levels on egg production, with requirements of 1.07% lysine with 20% CP and 1.15% with 23% CP. The 23% CP level increased feed intake, egg production, egg weight and egg mass, and also improved feed to egg mass ratio and feed to egg dozen ratio. The lysine: CP ratio did not was affect (5.3 versus 5.0%) when crude protein diets increase 20 to 23%. Results in the present study suggest increase of quantitatively requirement of lysine of quail layer, but not lysine: CP ratio, when increase CP concentration on diet.