Em vista da constante evolução do melhoramento genético de frangos de corte, torna-se necessária a determinação das exigências nutricionais dessas aves, para assegurar seu desempenho. Assim sendo, dois experimentos foram realizados, com o objetivo de avaliar diferentes relações de metionina + cistina / lisina digestível sobre o desempenho de frangos de corte, nas fases de 11 a 21 e 22 a 35 dias de idade. O delineamento experimental nas duas fases avaliadas foi o de blocos casualizados, em arranjo fatorial 2x5+2, (2 sexos e 5 diferentes relações met+cis/lis digestível e um tratamento controle para cada sexo), com oito repetições de 23 e 20 aves (COBB 500) por unidade experimental, nas fases descritas. As dietas atenderam às exigências, exceto para metionina + cistina e lisina. Para evitar o excesso de lisina digestível, seu nível foi calculado para 97% do recomendado para todas as fases. O tratamento controle foi adequado em lisina e metionina + cistina. As relações metionina + cistina/lisina digestível, para máximo desempenho de frangos de corte, machos e fêmeas, respectivamente, são de 75,53 e 78,23%, na fase de 11 a 21 dias, e 78,83 e 79,82%, na fase de 22 a 35 dias.

The continual evolution of poultry breeding brings about the need to determine the nutritional requirements of these birds to ensure performance. Therefore, this study carried out two experiments to evaluate different methionine + cystine / digestible lysine ratios on the performance of broiler growing phases starter (11 - 21 days) and growth (22 - 35 days). The experiment evaluated the two phases using a randomized block design in a factorial arrangement 2x5 +2, (2 sexes and 5 different Met + Cys / digestible Lys ratios and a control treatment for each sex) with 8 repetitions of 23 and 20 birds (COBB 500) per experimental unit in the two phases. The diets met the requirements except for methionine + cysteine and lysine. To avoid excess lysine, its level was calculated to be 95% of the recommended level for all phases. The control treatment was adequate in lysine and methionine + cystine. The methionine + cystine / digestible lysine ratios for maximum performance of male and female broiler chicks, respectively, are 75.53 and 78.23% in the phase 11 to 21 days and 78.83 and 79.82% in the phase 22 to 35 days.

Two experiments were conducted to evaluate different digestible isoleucine/lysine ratios on diets for broiler chickens in the starter (7 to 21 days) and finishing (30 to 43 days) phases. For the tests, the experimental design was of randomized blocks with seven treatments (six different digestible isoleucine/lysine ratios and a control treatment) and eight repetitions of 25 and 20 birds (COBB males) per experimental unit in the starter and finishing phases, respectively. The diets met the requirements, except for isoleucine and lysine. To avoid excess lysine in the experimental diets, the digestible lysine content was calculated to be 87% and 89% of the recommended for the starter and finishing phases, respectively. The control treatment was adequate in lysine and isoleucine. Feed intake, weight gain, feed conversion and carcass yield in the two phases were evaluated. There was quadratic effect of different ratios on feed intake in the finishing phase and on weight gain and feed conversion rate in both phases. There was quadratic effect on breast meat yield and breast fillets in the starter phase, but there was no significant effect on carcass yield in the finishing phase. The digestible isoleucine/lysine ratio recommended for broilers in the starter phase (7 to 21 days) is 66% and for the finishing phase (30 to 43 days), it is 68%.

The objective of this study was to estimate the values of apparent metabolizable energy and apparent metabolizable energy corrected for nitrogen balance and determine the chemical composition of the following feedstuffs: babassu meal, sunflower meal, corn gluten meal, babassu starch flour, meat and bones meal, beans, millet, cookies residue, pasta residue and bread-making residue. The traditional method of excreta collection was used with broilers in the period of 14 to 24 days of age, which were distributed in a completely randomized design with eleven treatments and six replicates of six birds each. Each feedstuff replaced the reference diet at levels of 30 or 40% depending on the type of feedstuff. Chicks were housed in cages fitted with trays to collect the excreta. The apparent metabolizable energy corrected for nitrogen balance (kcal/kg) on the natural matter of feedstuffs were: babassu meal, 1,116; sunflower meal, 1,607; corn gluten meal, 3,826; babassu flour starch, 1,731; meat and bone flour, 2,524; common beans, 693; millet, 3,046; cookies residue, 3,351; pasta residue, 3,543 and bread-making residue, 3,494.

Objetivou-se avaliar o efeito da adição da enzima xilanase (Econase XT25) sobre o metabolismo de nutrientes e o desempenho de poedeiras no período de 24 a 48 semanas de idade. Foram utilizadas 288 poedeiras, distribuídas em delineamento experimental inteiramente casualizado em arranjo fatorial 2 × 2, com dois níveis de energia metabolizável (2.900 e 2.755 kcal/kg) combinados ou não com a adição de xilanase (37,5 g/t de ração), totalizando quatro tratamentos (controle positivo; controle negativo; controle positivo + xilanase; e controle negativo + xilanase), avaliados com 12 repetições de 6 aves por unidade experimental. As dietas controle positivo e controle positivo + xilanase foram formuladas seguindo as recomendações das Tabelas Brasileiras (100% de energia metabolizável), enquanto as dietas controle negativo e controle negativo + xilanase foram calculadas reduzindo 5% da energia metabolizável. A adição da enzima xilanase à dieta controle negativo proporcionou produção de ovos e massa de ovos semelhante às observadas no grupo controle positivo. A redução de 5% de energia metabolizável ocasionou diminuição na produção de ovos, na massa de ovos, piora da conversão alimentar e aumento do consumo de ração. A composição dos ovos não foram influenciada pelas dietas. Os valores médios de energia metabolizável aparente corrigida são maiores em dietas com maior nível de energia metabolizável. A adição de xilanase melhorou a utilização da energia e a produção de ovos em dietas para galinhas poedeiras.

The objective of this study was to evaluate the effect of the addition of xylanase enzyme (Econase XT25) on the metabolism of nutrients and the performance of laying hens from 24 to 48 weeks of age. It was used 288 laying hens, distributed in a completely randomized design in a 2 × 2 factorial arrangement, with two levels of metabolizable energy (2,900 and 2,755 kcal/kg) combined or not with addition of xylanase enzyme (37.5 g/t of ration), totaling four treatments (positive control, negative control, positive control + xylanase; and negative control + xylanase), evaluated with 12 replicates of 6 birds per experimental unit. Positive control and positive control + xylanase diets were formulated following the recommendations by Tabelas Brasileiras (100% metabolizable energy) while negative control and negative control + xilanase diets were calculated by reducing 5% of metabolizable energy. The addition of xylanase enzyme to the negative control diet provided egg production and egg mass similar to the ones observed in the positive control group. Reduction of 5% of metabolizable energy resulted in a decrease in egg production, in egg mass, worsening in feed conversion and increase in feed intake. Composition of the eggs was not affected by the diets. The average values of corrected apparent metabolizable energy are higher in diets with higher level of metabolizable energy. The addition of enzyme xylanase improved the use of energy and egg production in diets for laying hens.

Foi realizado um experimento para avaliar os efeitos da inclusão de farelo de girassol em rações para frangos de corte sobre o desempenho, o rendimento de carcaça e dos cortes e a viabilidade econômica. O delineamento experimental foi em blocos casualizados com cinco níveis de farelo de girassol (0, 5, 10, 15 e 20% da dieta basal), oito repetições e 20 aves por unidade experimental. As aves e as rações foram pesadas no início e ao final de cada fase do período experimental (1 a 21 dias e 22 a 42 dias) para obtenção do consumo de ração, do ganho de peso e da conversão alimentar. Duas aves de cada repetição foram abatidas aos 42 dias de idade para avaliação da carcaça. Com a inclusão do farelo de girassol, o consumo diminuiu linearmente na fase inicial (y = 1185,1 - 2,1x; R² = 0,97), enquanto a conversão alimentar melhorou de forma linear no período total (y = 1,6404 - 0,0018x; R² = 0,62) e de forma quadrática na fase inicial (y = 1,3943 - 0,0069x + 0,0002x²; R² = 0,96). Não foi encontrada diferença significativa no rendimento de carcaça e dos cortes. Os melhores desempenhos econômicos foram obtidos quando as aves foram alimentadas com rações contendo 5% de farelo de girassol na fase inicial e 0% na fase de crescimento e no período total. A adição de 20% de farelo de girassol em rações para frangos de corte até os 42 dias de idade não prejudica o desempenho produtivo das aves.

A trial was carried out to evaluate the effect of sunflower meal inclusion in the broiler diets on the performance, carcass yield and cuts and the economics viability. A randomized block experimental design was used, with five treatments and eight replications of 20 birds per experimental unit. Treatments consisted of including 0, 5, 10, 15, or 20% sunflower meal in a basal diet. Birds and diets were weighed at the beginning and at the end of each experimental phase (1 to 21 days and 22 to 42 days) to determine feed intake, weight gain, and the feed:gain ratio. Two birds per replication were slaughtered at 42 days of age for carcass evaluation. Feed intake was linearly reduced in the starter phase (y = 1185.1 - 2.1x; R² = 0.97), with sunflower meal inclusion in the basal diet, and the feed:gain ratio linearly improved in the total period (y = 1.6404 - 0.0018x; R² = 0.62), whereas a quadratic effect on the feed:gain ratio was observed in the starter phase (y = 1.3943 - 0.0069x + 0.0002x²; R² = 0.96). No significant differences were observed for carcass yield and cuts. The best economic performances were achieved when the birds were fed diets containing 5% sunflower meal in the starter phase, and 0% in the grower phase and total period. The inclusion of 20% sunflower meal in the diet of broilers up to 42 days of age did not show harmful effects on performance.