Effect of low protein diets supplemented with free amino acids on growth performance, slaughter yield, litter quality, footpad lesions, economical performance and the ecological footprint of male broilers

Providing diets with a reduced crude protein (CP) content that are supplemented with increased contents of free amino acids (AA) to cover the AA requirement might be helpful in reducing the soybean meal content of South American origin, and thus in reducing the amount of non-EU protein in the diet. For maintaining performance levels of broilers that are fed low CP diets, the AA supply is essential. Broiler diets are usually at least optimised for minimum requirements of digestible lysine, methionine + cysteine, threonine and tryptophan. In low CP diets, the requirements for the AA valine, isoleucine, serine and glycine should also be taken into account as well. The impact of using diets with a low CP content and a high amount of free AA content on the ecological footprint is not known. This report describes the results of an experiment with male broilers in which the effect of low CP diets, with a partial replacement of soybean meal by free AA, on technical performance, slaughter yields, litter quality, footpad lesions, economical performance and the ecological footprint was evaluated.