The objective of this study was to evaluate the effects of dietary nutrient levels on performance, carcass yield, commercial cuts, digestibility and economical viability of broilers from 1 to 42 days of age. During the experiment, 180 COBB 500™ chicks were housed in metal batteries and subjected to a completely randomized design in a 2x3 factorial arrangement, of two sexes and three diets (male, female and mixed), totaling 6 treatments and 6 repetitions of 5 birds each. Data were subjected to statistical analysis and the means were compared using the Tukey test, at 5% probability. The results indicate the effect of sex on performance and commercial cuts, except for breast and thigh fillets, in which males and females showed similar results when given the mixed diet. The influence of the nutritional levels on performance, digestibility and commercial cuts was observed, in which the female diet showed the highest results for feed intake, body weight and weight gain, in addition to greater retention of protein and crude energy. For drumstick and abdominal fat yield, the highest values were obtained using the mixed diet and the female diet, and the lowest values were obtained using the male diet. Regarding economic viability, the female diet showed the highest return per unit of Real (R$) spent on feed. Therefore, these data prove that the female diet had a positive effect when provided to both sexes, and it may be a promising alternative for its application at the production level.

This experiment was conducted to investigate the effects available phosphorus levels and dicalcium phosphate particle size on the live performance, and egg parameters and bone parameters of Japanese quails in lay. The experimental diets were based on corn and soybean meal and formulated to contain 2900 kcal metabolizable energy (ME) kg-1 , 200 g kg-1 crude protein (CP) and 30.5 g kg-1 calcium (Ca). Feeds were supplied ad libitum. Laying Japanese quails (n=720, 20-wk-old) were distributed in a completely randomized design in a 5 x 2 factorial arrangement, with five levels of available phosphorus (avP; 1.0, 2.0, 3.0, 4.0, 5.0 g kg-1) and two dicalcium phosphate particle sizes (fine orcoarse), totaling ten treatments with eight replicates of nine birds each. Egg laying rate, feed intake per bird per day, egg weight, egg mass, feed conversion ratio per egg mass and per dozen eggs, eggshell, yolk and albumen relative and absolute weights, as well as bone ash, phosphorus, calcium, and magnesium contents were evaluated. Based on the results, avP recommendations for 20-to 32-wk-old laying Japanese quails varies according with phosphate source particle size and the dietary avP levels of 4.40 g kg-1 and 3.85 g kg-1 avP levels when using fine and coarse particle dicalcium phosphate, respectively, yielded the best results.

RESUMO O objetivo deste estudo foi determinar a exigência de lisina digestível para frangos de corte machos sob as características de desempenho, composição corporal e rendimento de carcaça dos animais, de 22 a 42 dias de idade. As dietas diferiram quanto aos níveis de lisina digestível, mantendo-se a relação dos demais aminoácidos com a lisina. Foram utilizados seis níveis de lisina digestível: 0,88%; 0,96%; 1,05%; 1,13%; 1,22%; e 1,30%. Distribuídos em 36 unidades experimentais de 36 aves cada, 1296 animais da linhagem Cobb - 500® tiveram as seguintes características de desempenho avaliadas: consumo de ração (CR), peso corporal (PC), ganho de peso (GP), conversão alimentar (CA), viabilidade criatória (VC) e índice de eficiência produtiva (IEP). Aos 42 dias de idade, foram selecionadas ao acaso cinco aves para avaliação do rendimento de carcaça, e duas para avaliação da composição corporal. A CA, o IEP e o rendimento de peito foram influenciados, sendo sua exigência de 1,30%, sugerindo que níveis maiores de lisina digestível que as recomendações utilizadas como base neste estudo (1,13%) trouxeram benefícios aos animais sobre essas características.