Valores de energia metabolizável de alguns alimentos obtidos com aves de diferentes idades Metabolizable energy values of feedstuffs obtained from poultry at different ages

Foram realizados quatro ensaios de metabolismo com a finalidade de determinar a energia metabolizável aparente (EMA) e a energia metabolizável aparente corrigida (EMAn) de dez alimentos em aves em diversas idades. Os alimentos testados foram: milho, farelo de soja, sorgo, farelo de trigo, farelo de arroz integral, duas farinhas de penas, duas farinhas de vísceras e plasma sangüíneo. Utilizou-se o método de coleta total de excretas, em delineamento experimental inteiramente casualizado, com 11 tratamentos (dez alimentos e uma ração-referência) e seis repetições. No primeiro ensaio, foram utilizados 528 pintos de corte machos de 10 a 17 dias de idade, totalizando oito aves por repetição; no segundo ensaio, 396 frangos de corte machos de 26 a 33 dias de idade, com seis aves por repetição; no terceiro ensaio, 264 frangos de corte machos de 40 a 47 dias de idade, com quatro aves por repetição; e, no quarto ensaio, 132 galos, com duas aves por repetição. A idade das aves influenciou os valores de EMA e EMAn do farelo de soja, do sorgo, do farelo de arroz integral, das farinhas de penas e do plasma sangüíneo, enquanto, para o farelo de trigo, teve efeito apenas sobre a EMAn.<br>Four assays were carried out to determine the apparent metabolizable energy (AME) and the corrected apparent nitrogen metabolizable energy (AMEn) of ten feeds for poultry at different poultry ages. The feeds studied were: corn grain, soybean meal, ground sorghum, wheat bran, integral rice bran, two kinds of feather meal, two kinds of poultry viscera meal and spray-dried plasma. The method of total excreta collection was used to determine the AME and AMEn values. The broiler chicks were distributed on a completely randomized experimental design, with 11 treatments, six replications, with different number of animals by replication according to the assay. In the first assay, 528 male broiler chicks in the period from 10 to 17 days of age were used, with eight animals per replication. In the second assay, 396 male broiler chicks in the period from 26 to 33 days of age were used, with six animals per replication. In the third assay, 264 male broiler chicks in the period from 40 to 47 days of age were used, with four animals per replication. In the fourth assay, 132 roosters were used, with two animals per replicate. There was an effect of age on the AME and AMEn values of the following feeds: soybean meal, ground sorghum, integral rice bran, two kinds of feather meal and spray-dried plasma, where the oldest broilers provided the highest AME and AMEn values. Wheat bran was affected by age only for the AMEn values.