Efeitos de uma multiprotease no desempenho, funcionalidade intestinal e digestibilidade em frangos de corte

Abstract

Multi-protease supplementation was evaluated for its effects on growth performance, carcass yield, intestinal morphology, microbiota, nutrient digestibility, and enzymatic activity in broiler chickens. Three experiments were conducted. In the first, performance, intestinal morphology, and microbiota were assessed in birds fed diets with reduced crude protein and amino acids levels (–4% and –8%) and supplemented with different enzyme doses (100, 200, and 300 g/t), using 2,250 broilers. The second experiment investigated the ileal digestibility of amino acids and the apparent metabolizable energy of corn, soybean meal, and deactivated full-fat soybeans, with or without protease addition (200 g/t), using 480 birds housed in metabolic cages. The third experiment evaluated in vitro the activity of four types of proteases (multi-protease, alkaline, acid, and neutral) at different pH values (3, 6, and 9), as well as the synergism between endo- and exo- proteases. Multi-protease inclusion significantly improved weight gain and feed conversion, positively modulated the intestinal microbiota by increasing the abundance of Firmicutes and Bacteroidetes, and enhanced intestinal morphology, particularly in diets with reduced amino acids. Protein and amino acid digestibility were significantly higher in enzyme-supplemented diets, especially for limiting amino acids such as methionine+cystine, lysine, threonine, and valine. Apparent metabolizable energy (AME and AMEn) was also increased with protease addition, particularly in diets containing deactivated full-fat soybeans. Enzyme activity varied according to protease type, pH, and concentration. Each enzyme performed best within its optimal pH range, with acid protease showing the highest activity at pH 3, neutral protease at pH 9, and alkaline protease exhibiting increasing activity up to pH 9. It is concluded that multi-protease supplementation is an effective strategy to improve productive performance, intestinal health, and nutrient utilization in broiler chickens, especially in diets with reduced crude protein and amino acid content.