The objective of this study was to estimate the nutrient requirements of digestible threonine for meat-type quails (Coturnix coturnix sp) in the growth phase. A total of 1350 not sexed meat-type quails were distributed in a completely randomized design with six threonine levels (10.80, 11.50, 12.20, 12.90, 13.60 and 14.30 g/kg as fed), five replications and 45 quails per experimental unit, from 1 to 14 days of age. The threonine levels in the diet had a quadratic effect on body weight, feed intake and weight gain. Estimates for highest body weight (79.41 g), feed intake (128.96 g/bird) and weight gain (70.73 g) were observed with diets containing 12.60 g/kg of digestible threonine. According to the LRP model, the threonine intake was estimated at 13.40 g/kg of digestible threonine. Protein deposition rate and energy retained in the carcass showed quadratic effect, with estimated digestible threonine levels of 11.80 and 12.00 g/kg in the diet for maximum protein deposition rate (2.00 g/bird) and retained energy in the carcass (15.88 kcal/g), respectively. There was a linear effect on feed cost per kg of live weight gain as threonine levels were increased. Nutritional requirement of digestible threonine for meat-type quails for maximum growth is 12.60 g/kg, corresponding to a digestible threonine:digestible lysine ratio of 67.02.

Foram conduzidos dois experimentos com o objetivo de avaliar os efeitos da suplementação enzimática das rações à base de milho e farelo de soja sobre o desempenho e metabolizabilidade dos nutrientes em codornas de corte. Os tratamentos foram: controle positivo para atendimento das exigências; controle positivo suplementado com complexo enzimático e controles negativos suplementados reduzidos em 2 e 4% nos teores de energia metabolizável e aminoácidos. Na fase inicial, observou-se aumento no consumo de ração (p < 0,05) no tratamento controle negativo reduzido em 4% na energia metabolizável e aminoácidos em comparação aos tratamentos controle positivos. Na fase de crescimento o consumo de ração, conversão alimentar e rendimento de carcaça não diferiram (p > 0,05). Conclui-se que o complexo enzimático pode ser utilizado em dietas reduzidas em energia metabolizável e aminoácidos sem prejudicar o desempenho de codornas de corte. No ensaio de metabolismo, não foram observadas diferenças (p > 0,05) entre os tratamentos para os coeficientes de metabolização das matérias seca e orgânica, proteína bruta e energia bruta. O coeficiente de metabolização da FDN melhorou (p < 0,05) com a adição de enzimas.

Two experiments were carried out to evaluate the effects of enzyme supplementation (xylanase + β-glucanase) of diets based on corn and soybean meal on: performance in initial (1-14 days) and growing (15-35 days) phases, and nutrient metabolization of meat-type quails. The treatments were: positive control to meet the nutritional requirements of the specie; positive control supplemented with enzyme complex; and negative controls with two reduced supplementation levels of metabolizable energy and amino acids (by 2% and 4%). In the initial phase, the negative control treatment reduced by 4% of metabolizable energy and amino acids increased feed intake (p < 0.05), compared to positive controls. In the growing phase, there were no differences (p > 0.05) in feed intake, feed conversion ratio and carcass traits. In conclusion, this supplementation can be used successfully in diets with reduced metabolizable energy and amino acid contents for meat-type quails. In the metabolism trial, there were no differences (p > 0.05) in metabolizable coefficients of dry matter, organic matter, crude protein and gross energy among treatments. The metabolization coefficient of NDF improved (p < 0.05) with enzyme supplementation.