Avanços metodológicos na avaliação de alimentos e de exigências nutricionais para aves e suínos Methodological improvements in feedstuffs evaluation and nutritional requirements for poultry and swine

A produção industrial de aves e suínos mostrou enormes avanços nos últimos anos, principalmente devido ao aumento dos conhecimentos na área de genética e de nutrição. Na área de avaliação dos alimentos e das exigências nutricionais de animais monogástricos, as melhoras se dão a passos largos, devido á seriedade com que os profissionais encaram a responsabilidade de fazer pesquisa de qualidade dentro e fora do país. Neste trabalho serão abordadas as metodologias que permitem melhorar a utilização dos alimentos de maneira mais eficiente e econômica. Serão citados alguns cuidados e procedimentos essenciais para executar adequadamente experimentos de desempenho com aves e suínos. Na atualidade, para a realização de experimentos com monogástricos, é necessário: definir claramente os objetivos, utilizar animais com peso inicial uniforme, usar número adequado de repetições e de animais por unidade experimental. Testes de médias devem ser usados para as variáveis qualitativas e quando a variável independente for quantitativa aplicar análise de regressão. O nível de significância utilizado (5, 7, 10%) pode variar conforme a importância econômica da característica estudada. A adequada condução dos ensaios, sejam de crescimento ou de digestibilidade, é fundamental para que as ferramentas apresentadas possam ter efetividade, resultando na melhora da produtividade e na redução dos custos e da excreção de nutrientes.<br>Swine and Poultry production showed enormous progress in the last few years, mainly due to the increased knowledge in genetics and nutrition. In the area of feedstuffs evaluation and nutritional requirements the improvement also was big due to the seriousness of the professionals to make high quality research in Brazil and abroad. This paper shows methodologies that can improve feedstuffs utilization more efficiently with lower costs. Procedures are described for adequate execution of growth experiments with poultry and swine. Actually, to run experiments with monogastric animals it is important to: define clearly the objectives, utilize animals with uniform starting weight, to use adequate number of replicates and animals per experimental unit. Mean test comparation should be used for qualitative variable and regression analysis when the independent variable is quantitative. The level of significance applied may vary (5, 7, 10%) depending upon the economic importance of the parameter evaluated. Adequate execution of growth or digestibility trials is of fundamental importance for the recommendations made in this paper to be effective and result in increased productivity and reduction of costs and nutrient excretion

Digestible lysine levels in diets supplemented with ractopamine

In order evaluate digestible lysine levels in diets supplemented with 20 ppm of ractopamine on the performance and carcass traits, 64 barrows with high genetic potential at finishing phase were allotted in a completely randomized block design with four digestible lysine levels (0.80, 0.90, 1.00, and 1.10%), eight replicates and two pigs per experimental unit. Initial body weight and pigs' kinship were used as criteria in the blocks formation. Diets were mainly composed of corn and soybean meal supplemented with minerals, vitamins and amino acids to meet pigs' nutritional requirements at the finishing phase, except for digestible lysine. No effect of digestible lysine levels was observed in animal performance. The digestible lysine intake increased linearly by increasing the levels of digestible lysine in the diets. Carcass traits were not influenced by the dietary levels of digestible lysine. The level of 0.80% of digestible lysine in diets supplemented with 20 ppm ractopamine meets the nutritional requirements of castrated male pigs during the finishing phase