Efeitos de uma nova vitamina D3 para dietas de frangos de corte

Abstract

The experiment was conducted with the objective of evaluating the bioavailability of vitamin D3 sources for broilers, using a 7-OHD3 as a reference and evaluating the effects of diets with increasing levels of vitamins on the performance and bone characteristics of birds and the digestibility of calcium in feed. 1,040 day-old chicks, male Cobb-500, from a commercial hatchery and housed in 104 metabolism cages were used. A completely randomized design was adopted, with no 3 x 4 + 1 factorial scheme (three sources of vitamin D with four levels of inclusion and a negative control), with 8 repetitions. The factors under study were sources of vitamin D (D3, First 25D, HyD) and levels of inclusion (200, 500, 1000 and 2000 IU / kg). The experimental diets were formulated based on corn and soybean meal according to nutritional recommendations, and all formulations had a reduction of 0.10% of available phosphorus and 0.15% of calcium to establish a challenge to chickens. Performance evaluation was performed, such as bone and carcass characteristics, digestibility of calcium and phosphorus and intestinal morphometry. Greater (P <0.05) weight gain and better feed conversion were observed when the chickens were fed diets containing semi-active sources of vitamin D3 (25-OHD3), for all studied phases. For the content of mineral matter in the tibia, there was an increasing linear effect (P <0.05) of vitamin D3 supplementation levels only for source B. For Ca and P levels there was an effect (P <0.05) of source and level (P <0.05). Note that sources of vitamin 25-OHD3 have resulted in increased Ca and P practices in the tibia compared to birds fed diets containing Vitamin D3. Regarding the effect of the dietary level of vitamin D on the P content in the tibia, the linear effect was increasing for A and quadratic effect for B. For the percentage of compact bone there was superiority (P <0.05) of D3 in relation to A for the level of 2000 IU / kg. For the spongy bone area, there was an effect (P <0.05) of a source with a larger area, followed by Be D3. There was no significant configuration (P> 0.05) source x level on the apparent digestibility of calcium at 21 and 40 days of age in broilers. However, the use of the source results in greater digestibility of calcium at 21 days. At 40 days of age, there was a greater apparent digestibility of calcium (P <0.05) for semi-active sources of vitamin D in relation to vitamin D3. (P <0.05) for villus height, crypt depth and villus / crypt ratio at 21 and 40 days of age. Based on the performance results from 1 to 40 days, they were suitable as bioavailability of 124 and 114 for source A and B, respectively. Therefore, it is concluded that there are differences in relation to the relative bioavailability between the sources of vitamin D3 and 25OHD3 for bone and performance characteristics, with the sources of semi-active vitamin D having greater value.