Estudo sobre a utilização de níveis supranutricionais de vitaminas hidrossolúveis na produção de frangos de corte

Abstract

Studies on the effects of supra-nutritional levels of water-soluble vitamins on broiler production Vitamin requirements for chickens may increase in adverse conditions, such as stress, diseases, and poor environment. Increased dietary supplementation may be needed for broilers to reach higher growth levels, improve their feed absorption and welfare. Therefore, in the present study, a series of three experiments were designed to evaluate the effect supranutritional levels of the vitamins riboflavin, pantothenic acid, niacin, folic acid and vitamin B12 on broiler production. Two experiments were conducted in batteries to assess the supra-nutritional levels of the vitamins mentioned above (control, threeor six-times control), and the dietary nutrient density (lowor high-level) on chickens’ performance. The basal feed differed between experiments: Exp. I – corn and soybean meal-based diet; Exp. II – diet containing oxidized animal by-products and soybean oil. In Exp. I, birds showed greater weight gain (741.1 g vs. 697.3 g) and feed intake (920.2 vs. 878.5 g) when lowdensity diets with supra-nutritional level six-times control were fed. Nevertheless, there was no effect of supranutritional level of the selected B vitamins on performance of chickens in Exp. II. It was therefore decided to study the effects of supra-nutritional levels of the selected B vitamin (control or sixtimes control) on performance, uniformity, and carcass traits of chickens raised in floor pens under two environmental stress levels (low or moderate). Stocking density (10 birds/ m2 or 11.5 birds / m2) and the challenge with coccidiosis vaccine (without or with vaccination) were used as stress agents. At 7d, chicks raised under the moderate condition of stress was challenged with a dosage 10times higher than the supplier s recommendation of a coccidiosis vaccine. The coccidiosis infection impaired the performance of chickens after the challenge. Supra-nutritional level of the B vitamin had no effect on broiler performance. However, the carcass yield was higher when chickens fed super-dose of vitamins six-times control compared to the control treatments (73.16 vs. 72.77%, P = 0.008). Conditions of stress in this study were not severe as in the field and because of this the use of supra-nutritional vitamins had no effect on recovering of chicken performance. Nonetheless, there was a potential improvement in the carcass yield with the use of these levels.