This experiment was conducted to determine the digestible threonine requirement for laying Japanese quail. Four hundred quails were used during 63 days. A completely randomized experimental design was used with five treatments, eight replicates and ten quails per experimental unit. The basal diet was deficient in threonine, containing 17.8% crude protein, 2.900kcal of ME/kg and supplied with four levels of L-threonine 98% (0.000; 0.052; 0.104; 0.156 and 0.208%), corresponding digestible threonine: digestible lysine ratio 0.55; 0.60; 0.65; 0.70 and 0.75, respectively. The following parameters were evaluated: feed intake, threonine intake, egg production, egg weight, egg mass, feed conversion per egg mass, feed conversion per egg dozen, egg quality (yolk, albumen and shell) and specific gravity. Linear increase (P<0.01) was only observed in the threonine intake. The conclusion is that the Japanese quail demand 0.55% of digestible threonine to provide the best productive performance and quality of eggs, a daily consumption of 144.61 mg of digestible threonine/quail, corresponding to the digestible threonine: digestible lysine ratio of 0.55.
Coturnix coturnix japonica; digestible amino acid; egg production; ideal protein
