Effects of vitamin D3 dietary supplementation of broiler breeder hens on the performance and bone abnormalities of the progeny.

Six experiments were conducted using Ross x Ross chicks hatched from eggs laid by broiler breeder hens fed various levels of vitamin D3 (0 to 4,000 IU/kg of diet) to determine the effects of vitamin D3 level in the maternal diet on the performance and leg abnormalities of their progeny. Chicks hatched from eggs laid when hens were 27, 41, 29, 36, 45, and 52 wk of age were used in experiments 1, 2, 3, 4, 5, and 6, respectively. The studies were conducted in a ultraviolet (UV)-light-free environment. Experiments 1 and 2 were conducted as complete randomized designs with the maternal diets as the treatments, and experiments 3, 4, 5, and 6 were conducted as split plot designs, with vitamin D3 in the chick diets as the whole plot and vitamin D3 in the maternal diet as a subplot. Chicks in experiments 1 and 2 were fed a vitamin D3-deficient diet, whereas chicks in experiments 3 and 4 were fed 4 levels of vitamin D3 (0 to 400 IU/kg of diet), and chicks in experiments 5 and 6 were fed 6 levels of vitamin D3 (0 to 3,200 IU/kg of D3). The highest body weight gains and tibia ash were observed in chicks hatched from hens fed the highest levels of vitamin D3 in all experiments. Reductions in the incidence of Ca rickets were observed in experiments 3 and 6, whereas increases in tibia ash were observed in experiments 2 and 6 as the level of vitamin D3 in the maternal diet increased. Body weight gain and tibia ash increased and Ca rickets incidence decreased as the vitamin D3 level in chick diets increased. An evaluation of the study indicates that chicks hatched from eggs laid by hens fed 2,000 or 4,000 IU of D3/kg as the maximum level of vitamin D3 had the highest body weight gains, and chicks fed 3,200 IU had the highest body weight and tibia ash and the lowest TD and Ca rickets incidences.