ABSTRACT. Two experiments were carried out to evaluate the effects of protease addition to the diet of broilers at a higher level (1× or 2×) than the nutritional value proposed for the enzyme. The first experiment, 1280 day-old chicks (Cobb500®) were randomly allocated (randomized block design, 2×2+1 factorial arrangement), five treatments, eight replicates containing 32 birds/replicate. Treatments consisted: control diet without protease (CD); CD + 1× nutritional value of the enzyme (CDM1); CD + 2× nutritional value of the enzyme (CDM2); CDM1 + protease; and CDM2 + protease. The experimental period was 42 days. The mean weight (AFW), feed intake (FI), weight gain (WG), feed conversion, and carcass yield were evaluated. Significant differences were observed for AFW, WG, FI, abdominal fat yield, and feet percentage in the carcass. In the second experiment, 120 Cobb500® chicks at 14 days of age were allotted in a completely randomized design, 2×2+1 factorial arrangement, five treatments, six replicates with four birds/replicate. The treatments were consistent with the first experiment. Significant improvements in the nitrogen balance were observed for the broilers that received protease. The use of the enzyme tested is recommended with the recommended nutritional matrix, improving the zootechnical indices of broilers.

RESUMO: Objetivou-se avaliar o comportamento de pintainhas de postura na fase de cria, alimentadas com dietas formuladas com aumento de fibra bruta e dois alimentos com composições de fibra diferentes. O trabalho foi realizado na Universidade Federal de Goiás, Goiânia, GO, utilizando-se 300 pintainhas Bovans White, em delineamento inteiramente casualizado e arranjo fatorial 2x2+1, com dois níveis de fibra bruta na dieta (3,0% e 3,5 % de FB), duas fontes de fibra (farelo de trigo e bagaço de cana) e o tratamento testemunha (ração a base de milho e farelo de soja), totalizando cinco tratamentos e seis repetições de 10 aves cada. Foram avaliados padrões de comportamento de manutenção e bem-estar aos 21 e 42 dias de idade. Não houve diferença no comportamento e na classificação por ordem de importância das atividades realizadas pelas aves alimentadas com fibra e observadas aos 21 e 42 dias pelo teste de Kruskal Wallis (P>0,05). Obteve-se condições média e boa com farelo de trigo e 3,5 e 3,0% de fibra bruta, respectivamente, com 21 dias de idade. Aos 42 dias, o uso de bagaço de cana ao nível de 3,5% de fibra bruta e o farelo de trigo ao nível de 3,0%, mostraram boas condições de comportamento. A utilização de fibra bruta na alimentação de frangas não alterou o comportamento das aves.

ABSTRACT: This study evaluated the behavior and welfare conditions of laying chicks in the starter phase, fed with diets formulated with increasing levels of crude fiber (CF) and two feedstuffs with different fiber compositions. The experiment was developed at the Federal University of Goiás, in Goiânia - GO, Brazil. Three hundred Bovans White chicks were evaluated in a completely randomized design with a 2×2+1 factorial arrangement corresponding to two levels of CF in the diet (3.0 and 3.5%) and two fiber sources (wheat bran and sugarcane bagasse), plus a control treatment (maize- and soybean meal-based), totaling five treatments with six replicates of 10 birds each. Maintenance behavioral patterns and welfare were assessed at 21 and 42 days of age. There was no difference in behavior and classification by order of importance of the activities performed by the fiber-fed birds observed at 21 and 42 days, according to the Kruskal Wallis test (P>0.05). Medium and good welfare conditions were obtained with wheat bran at 3.5 and 3.0% CF, respectively, at 21 days of age. At 42 days, the use of sugarcane bagasse at the CF level of 3.5% and wheat bran at the level of 3.0%provided good behavior conditions. The use of crude fiber in the feeding of hens did not change their behavior.

ABSTRACT Two experiments were carried out to evaluate the effects of digestible valine supplementation in pre-starter and starter diets on the productivity, nutrient metabolizability coefficient (NMC), and immune response of broilers from breeders of different ages. Experiments I and II were conducted with broilers in the pre-starter (1 to 7 days of age) and starter (8 to 21 days of age) phases, respectively. Broilers were fed diets that differed in their digestible valine content. In each trial, 400 male Cobb 500® chicks were randomly housed in a 2 × 4 factorial arrangement with eight treatments and five replicates of 10 birds each. The main effects were breeder age (37 vs. 52 weeks) and the digestible valine level in pre-starter (9.2, 10.2, 11.2, and 12.2 g/kg) and starter (8.3, 9.3, 10.3, and 11.3 g/kg) diets. Productive performance, intestinal histology, and immune response of broilers were evaluated. Supplementation with 11.2 g/kg valine in pre-starter diets improved NMC and increased villus height and villus:crypt ratio in the duodenum, jejunum development, and lymphocyte proliferation in the spleen of broilers at seven days of age, without improving performance (body weight gain, feed intake, and feed conversion ratio). In the starter phase, valine supplementation reduced feed intake but did not affect NMC, intestinal development, or immune response. The present results suggest that the same level of digestible valine should be used in the diet of broilers born to breeders of different ages, and the use of 9.2 and 8.3 g/kg digestible valine in pre-starter and starter diets, respectively, is sufficient to ensure satisfactory broiler performance. However, to improve the duodenum and jejunum development and immune response of broilers in the pre-starter phase, higher digestible valine levels are required.

ABSTRACT We aimed to evaluate the performance, nutrient digestibility, and intestinal histomorphometry of broilers fed diet supplemented with chondroitin sulfate and glucosamine sulfate. The experiment was carried out with 320 male broiler chicks distributed in a completely randomized design in a 2×2 factorial scheme (0 and 0.1% chondroitin sulfate and 0 and 0.3% glucosamine sulfate), with eight replications of 10 birds. Performance was evaluated at 7 and 21 days of age, nutrient digestibility of the diet was performed from 18 to 21 days of age, and small intestine histomorphometry was evaluated at 21 days of age. Broilers fed diet supplemented with 0.3% glucosamine sulfate showed high final weight and weight gain. A significant interaction was observed between sulfates for digestibility coefficients of nitrogen, mineral matter, and calcium. The use of 0.1% chondroitin sulfate without glucosamine sulfate resulted in a reduced digestibility of nitrogen but increased digestibility of total minerals and calcium. Diets without chondroitin sulfate with 0.3% glucosamine sulfate increased the digestibility coefficients of mineral matter and calcium. A significant interaction was found for jejunum villus height, which was higher in broilers fed diet supplemented with 0.3% glucosamine sulfate, regardless of the inclusion of chondroitin sulfate. Thus, supplementation with glucosamine sulfate in broiler diets contributes to high weight gain and villus height. Sulfates used in isolation promote high digestibility of minerals.