No abstract

SUMMARYThe aimed of the study was to evaluate the effect of the inclusion of different levels of an enzyme complex consisting of phytase, protease, xylanase, β-glucanase, cellulase, amylase, and pectinase on the parameters of performance, carcass yield and meat quality of broilers. Six hundred broiler chicks were used, and the animals were females with one day of age, from the Cobb 500 strain, and distributed in a completely randomized design, with five levels of inclusion of the enzyme complex (0, 100, 200, 300 and 400g/ton), and six repetitions, with twenty animals each. The weight gain, feed conversion ratio, feed intake and production viability were assessed in stages between 1 to 21, 1 to 35 and 1 to 42 days of age. The carcass yield and meat quality were evaluated at 35 and 42 days of age. We evaluated the characteristics of weight loss by cooking, shear force, water holding capacity, pH, lightness and color. The parameters of performance, carcass yield and carcass parts, and meat quality were not affected by the enzyme supplementation of diets fed to broiler chickens (P>0.05), except for the performance characteristics of the breast and the wings at 42 days of age (P<0.05).

ABSTRACT. This review aimed to identify the importance of vitamin E dietary supplementation to broilers subjected to heat stress in relation to metabolism, growth performance and quality of animal products and its effects on immune system. Vitamin E is the concentration of tocopherol and tocotrienol, which can be found in natural or synthetic form. This vitamin is essential for the integrity of reproductive, muscular, circulatory, nervous and immune systems of the animals. In order to reduce the harmful effects of high temperatures in poultry production, vitamin E supplementation is a viable alternative for the sector. Some studies indicate its potential antioxidant effect able to modulate inflammatory responses and physiological adjustments to mitigate the undesirable effects of exposure of broilers to high temperatures. Moreover, it has been found increased viability of animals due to the greater activation of the immune system, and improved quality of animal products given to the deposition in tissues with consequent nutritional enrichment of meat products.Keywords: antioxidant, performance, immunity, meat quality, supplementation.Estresse térmico por calor e vitamina E em rações para frangos de corte como medida atenuante RESUMO. Objetivou-se, com esta revisão, identificar a importância da suplementação de vitamina E às rações de frangos de corte submetidos a estresse por calor, em relação ao metabolismo, ao desempenho produtivo e à qualidade dos produtos de origem animal, bem como seus efeitos no sistema imune das aves. A vitamina E corresponde à concentração de tocoferol e de tocotrienol, podendo ser encontrada na forma natural ou sintética. É sabido que, essa vitamina, é essencial para a integridade reprodutiva, muscular, circulatória, nervosa e imunológica dos animais. Para reduzir os efeitos prejudiciais das altas temperaturas na produção avícola, a suplementação de vitamina E apresenta-se como alternativa viável para o setor. Alguns estudos indicam seu potencial efeito antioxidante capaz de modular respostas inflamatórias e ajustes fisiológicos para atenuar os efeitos indesejáveis da exposição das aves a elevadas temperaturas. Além disso, tem sido verificado aumento da viabilidade dos animais, pela maior ativação do sistema imune, e melhora na qualidade dos produtos de origem animal, devido à sua capacidade de deposição nos tecidos, com consequente enriquecimento nutricional dos produtos cárneos.Palavras chave: antioxidante, desempenho, imunidade, qualidade da carne, suplementação.

No abstract

A avicultura de corte é uma atividade de grande destaque no agronegócio e a ambientação correta é um parâmetro de extrema relevância para obter melhores rendimentos na criação. Neste sentido, o trabalho visou realizar o balanço energético para determinar a quantidade necessária de calor para aquecimento de galpões avícolas visando a criação de frangos de corte e, assim, determinar a fonte de energia mais viável. Para isso, foram utilizados modelos de trocas de calor levando em consideração o calor gerado pelos animais e radiação da superfície do galpão, além do calor perdido por convecção e evaporação. Os dados climáticos foram considerados como os da cidade de Viçosa – MG onde, nas proximidades existem diversos produtores de frangos de corte. Observou-se que é necessário fornecer 20.207,67 kWh de energia calorífica por ano para manter o aviário em condições otimizadas para o crescimento dos animais, sendo julho o mês mais crítico. Por fim, analisou-se o custo do aquecimento automatizado com gás natural, gás liquefeito de petróleo, biogás, cavaco de madeira, energia elétrica e cama de frango. A partir disso, determinou-se que a cama de frango é a fonte energética que proporciona os melhores resultados financeiros, custando apenas R$705,53 por ano. Contudo, a sua baixa disponibilidade pode ser um problema para manter o aquecimento contínuo, sendo assim recomendado o uso do cavaco de madeira (custo 85% maior), a fonte que apresenta o melhor resultado depois da cama de frango e que possui ampla disponibilidade.

Two experiments were carried out to determine the energy values and the true ileal digestibility of amino acids of nine toasted full-fat soybeans (FFSB), without or with the addition of monocomponent protease. In the first experiment, to determine the energy values, the method of excreta collection was used with 1120 broiler chicks at 14 days old, distributed in randomized blocks in a 10x2 factorial arrangement with nine full-fat soybeans (30% included) plus a control diet (70%) without or with the addition of protease, totaling 20 treatments with 8 replicates and 7 birds per cage. In the second experiment, 1120 broiler chickens from 24 to 28 days of age were distributed in randomized blocks in a 10x2 factor arrangement, with nine full-fat soybeans (40% included) + a protein free diet (60%), without or with the addition of protease, totaling 20 treatments with 8 replicates and 7 birds per cage. Ileal digesta collection was used to determine the true digestibility coefficients and the digestible amino acid content of full-fat soybean. The average values of nitrogen-corrected apparent metabolizable energy (AMEn) and their respective metabolization coefficients (CAMEn) were 3207 kcal/kg and 62.57%, respectively. The average values of digestibility coefficients of crude protein and essential and nonessential amino acids were 86.79, 87.90 and 84.34%, respectively. The inclusion of protease improved (P<0.05) all evaluated parameters. Therefore, its use is recommended in diets containing full-fat soybeans for broiler chickens.Index terms: Digestibility coefficients; metabolizability; monocomponent enzyme. RESUMOForam realizados dois experimentos para determinar os valores energéticos e os coeficientes de digestibilidade ileal verdadeiros de aminoácidos de nove sojas integrais tostadas, sem ou com a adição de protease monocomponente. No primeiro experimento, para a determinação dos valores energéticos, foi utilizado o método de coleta total de excretas, com 1120 pintos de corte com 14 dias de idade, distribuídos em blocos casualizados, em arranjo fatorial 10x2, com nove sojas integrais (30% de inclusão) + uma ração referência (70%), sem ou com adição de protease, totalizando 20 tratamentos, com 8 repetições e 7 aves por gaiola. No segundo experimento foram utilizados 1120 frangos dos 24 aos 28 dias de idade, distribuídos em blocos casualizados, em arranjo fatorial 10x2, com nove sojas integrais (40% de inclusão) + uma ração isenta de proteína (60%), sem ou com adição de protease, totalizando 20 tratamentos, com 8 repetições e 7 aves por gaiola. A coleta da digesta ileal foi utilizada para determinar os coeficientes de digestibilidade verdadeiros e o teor de aminoácidos digestíveis da soja integral. Os valores médios de energia metabolizável aparente corrigida para balanço de nitrogênio (EMAn) e o seu respectivo coeficiente de metabolizabilidade (CEMAn) foram de 3207 kcal/kg e 62,57%, respectivamente. Os valores médios dos coeficientes de digestibilidade da proteína bruta e dos aminoácidos, essenciais e não essen...

Although phytase has been researched, new enzymes have been produced, leading to different animal responses. In this scenario, the present study proposes to evaluate the inclusion of a bacterial phytase produced by Escherichia coli in broiler diets based on corn and soybean meal, with or without nutrient reductions, on the performance, nutrient digestibility, phosphorus bioavailability, and bone minerals of those animals and on the economic viability of this practice. A total of 896 male broiler chickens were distributed into 32 experimental units, each housing 28 broilers. The experiment was set up as a completely randomized design with four treatments (Positive Control (PC)-diet meeting the nutritional requirements of the broiler chickens; Negative Control (NC) with reductions of 100kcal/kg of ME, 0.14% av P and 0.11% t Ca; NC + phytase (500 FTU/kg); PC + phytase (500FTU/kg)) and 8 replicates. Phytase increased (p < 0.05) feed intake and body weight gain and improved feed conversion ratio in starter (1 to 21 days) and total (1 to 42 days) phases, respectively, compared with Negative Control diet without supplementation. The Negative Control + phytase diet also led to a feed intake similar to Positive Control in the starter and total phases. The inclusion of phytase without nutrient reductions improved (p < 0.05) feed conversion ratio in the starter phase, compared to Positive Control diet. There was an increase (p < 0.05) in the digestibility of dry matter, crude protein and phosphorus and in apparent digestible energy in the Negative Control + phytase diet compared to the Negative Control diet. Phytase supplementation increased (p < 0.05) the digestibility of crude protein, calcium and phosphorus, and apparent digestible energy compared to Positive Control diet. Ash, phosphorus, and calcium contents were higher in the Negative Control + phytase diet compared with those observed in the Negative Control diet without enzyme (p < 0.05). The Positive Control + phytase diet provided higher ash contents (p < 0.05), but calcium and phosphorus deposition was similar to those obtained with Positive Control diet. Phytase inclusion allows for a reduction in the diet cost per ton of produced feed. In conclusion, dietary supplementation with bacterial phytase produced from Escherichia coli for broiler chickens is recommended, as it provided increases in production performance, nutrient digestibility, and energy metabolizability and a reduction in the diet cost. ResumoEmbora a fitase tenha sido estudada, novas enzimas foram produzidas, levando a respostas animais diferentes. Nesse sentido, o presente estudo teve como objetivo avaliar a inclusão de fitase bacteriana produzida por Escherichia coli em dietas à base de milho e farelo de soja, com ou sem redução de nutrientes sobre o desempenho, digestibilidade dos nutrientes, biodisponibilidade de fósforo, minerais ósseos e viabilidade econômica. Foram distribuídos 896 frangos de corte machos em 32 unidades experimentais, cada unidade constituída por 28 frangos. O delineamento f...

This study aimed to evaluate the effect of different reductions in digestible amino acids content (lysine, methionine, and threonine), according to two nutritional requirements in corn, soybean meal, and meat and bone meal based diets, with protease supplementation, on performance parameters and carcass characteristics. A total of 1080 day-old chicks, male, Cobb 500, were allotted to a completely randomized design, in a factorial arrangement 3 x 2, three reductions in digestible amino acids content (lysine, methionine, and threonine) and two nutritional requirements (Rostagno et al. 2005 and Cobb-Vantress Guidelines 2008), and all diets were supplemented with protease (200 ppm) with 6 replicates of 30 birds per pen. There was no significant interaction (p<0.05) between digestible amino acid reductions and both nutritional requirements for the performance variables and carcass yield and cuts. There was an effect of amino acid reduction and protease supplementation only on slaughter weight (p<0.05). Broilers fed according to the nutritional requirements of Rostagno et al. (2005) showed better (p<0.05) performance when compared to broilers fed as specified by the nutritional requirements of Cobb-Vantress (2008) with no significant differences in carcass characteristics. Protease supplementation of corn, soybean meal, and meat and bone meal based diets allows a reduction in the inclusion of crystalline amino acids (lysine, methionine, and threonine).