Efeito da suplementação com aminoácidos sobre a digestibilidade, balanço de nitrogênio e ácidos graxos de cadeia curta de equinos em trabalho leve

Abstract

This study aimed to evaluate the effects of amino acid supplementation from a liquid molasses-based product (Líquida Equinos®) on the digestibility, nitrogen balance and short-chain fatty acids of horses in light work, receiving a standard diet composed of commercial concentrate and Tifton 85 hay. Six male Pantaneiro horses, aged 10 ± 4 years and weighing 395 ± 41 kg, were used in a crossover design, receiving two treatments: control (simple molasses) and supplement. The diets were formulated based on the nutritional requirements of adult horses in light work. Apparent digestibility was calculated based on monitoring intake and fecal excretion of: dry matter (DM), crude protein (CP), mineral matter (MM), ether extract (EE), and neutral detergent fiber (NDF). Nitrogen balance (NB) and concentrations of short-chain fatty acids (SCFAs; acetate, propionate, and butyrate), and pH in fecal fluid were also evaluated. No differences (P > 0.05) were observed in nutrient intake, excretion, or digestibility. However, supplementation increased (P < 0.05) fecal concentrations of propionate (C3) (P = 0,01), butyrate (C4) (P = 0,005), and total SCFAs (P = 0,04), in addition to reducing fecal pH (P = 0,03). The relative proportions of SCFAs remained unchanged. An effect of supplementation was observed in the treatment x time interaction on the relative proportions of butyrate (NC4%) (P = 0,03) for the supplemented group in the period from 0 to 3 h (F1) after concentrate feeding. No significant differences were observed for excretion and nitrogen balance. There was a trend toward increased fecal N excretion and a significant reduction in urinary N excretion (P = 0,04) in the supplemented group. Amino acid supplementation had positive effects on SCFA production, demonstrating enhanced fermentative activity without compromising digestive stability, in addition to reducing urinary N excretion without affecting BN, indicating optimization in nitrogen metabolism.