Ácidos biliares na nutrição de frangos de corte: efeitos no desempenho, metabolismo do cálcio e fósforo e estresse oxidativo hepático

Abstract

Diets with reduced metabolizable energy (ME) can compromise the performance of broiler chickens, especially in the early stages of rearing, due to their limited digestive capacity for lipids at this stage. Supplementation with emulsifying additives emerges as a nutritional alternative to improve the energy utilization of these diets. The objective was to evaluate the effect of adding a bile acid-based product, with different inclusion levels, to diets with reduced ME on the zootechnical performance, productive characteristics, energy metabolism, antioxidant parameters, intestinal morphology, and absorptive quality of broiler chickens. Two experimental trials were conducted. In trial I, the performance of animals aged one to 45 days was evaluated, with 1,188 one-day-old male Ross 308 chicks distributed in a completely randomized design, with nine treatments, two levels of metabolizable energy, and diets supplemented or not with bile acids. In trial II, 240 birds were distributed in a completely randomized design in a 2 × 4 factorial scheme, considering two levels of ME and four levels of inclusion of a bile acid and salt-based product to evaluate the digestibility of ether extract, dry matter, and calcium and phosphorus. The reduction of metabolizable energy without supplementation decreased weight gain and worsened feed conversion. The inclusion of bile acids in diets with reduced energy attenuated these losses, promoting increases of up to 6% in weight gain and an improvement of approximately 2–3% in feed conversion at intermediate inclusion levels, while high levels compromised performance. The treatments did not influence bone strength. However, supplementation with bile acids promoted an increase of approximately 70 kcal/kg in the apparent metabolizable energy of the diets and increased the digestibility of ether extract (3–8%), calcium (3–7%), and phosphorus (1–9%). Variable effects were observed on dry matter digestibility, and no consistent effect on crude protein digestibility, in addition to promoting changes in serum antioxidant parameters and intestinal absorptive quality. It is concluded that supplementation with intermediate levels of bile acids (200 and 300 g/ton) can mitigate the negative effects of energy reduction in rations, by improving the utilization of dietary lipids and the digestibility of mineral nutrients, especially calcium and phosphorus.