PSII-15 Effect of 25-hydroxyvitamin D3 supplementation on growth performance of nursery pigs

Abstract This study was conducted to evaluate the effects of 25-hydroxyvitamin D3 (25OHD3) supplementation on the growth performance of nursery pigs. A total of 48 newly weaned piglets (5.27 ± 1.42 kg initial body weight; weaned at 18.7 ± 0.78 d of age) were allotted to 3 treatments in 4 replicates with 4 pigs per pen based on body weight, sex, breed, and littermates. Treatments were: 1) VD-2: basal diet with 2,000 IU/kg vitamin D3, 2) 25D-1: basal diet with 1,000 IU/kg 25-OHD3 supplementation, and 3) 25D-2: basal diet with 2,000 IU/kg 25-OHD3 supplementation. All pigs were housed in nursery pens with free access to water and feed in the environmentally controlled nursery facility. Corn-soybean meal-based diets that met or exceeded the NRC (2012) nutrient requirement estimates were fed to all piglets in two phases for d 0-14 (Phase 1) and d 14-28 (Phase 2) postweaning. In each phase, a basal diet without vitamin D was mixed first, and then each vitamin D source was added to the basal diet at the assigned level. Body weight and feed disappearance were measured weekly to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F). There was no significant difference in body weight throughout the entire nursery period, ADG, ADFI, and G:F in d 0-14 postweaning except for a slightly greater G:F in the 25D-2 treatment than the 25D-1 treatment in d 0-7 postweaning (P = 0.11; 0.368, 0.357, and 0.519 for VD-2, 25D-1, and 25D-2, respectively). In d 21-28 postweaning, the 25D-1 and 25D-2 treatments tended to have greater ADG (P < 0.08; 0.576, 0.632, and 0.634 kg/d for VD-2, 25D-1, and 25D-2, respectively) and ADFI (P < 0.05; 0.862, 0.932, and 0.932 kg/d for VD-2, 25D-1, and 25D-2, respectively) than the VD-2 treatment, resulting in slightly greater ADG (P < 0.08; 0.502, 0.536, and 0.534 kg/d for VD-2, 25D-1, and 25D-2, respectively) and ADFI (P = 0.10; 0.782,0.818, and 0.820 kg/d for VD-2, 25D-1, and 25D-2, respectively) in both 25OHD3 treatments than the VD-2 treatment in d 14-28 postweaning. In the overall period, the ADG tended to be greater in the 25D-2 treatment than the VD-2 treatment (P = 0.10; 0.353, 0.367, and 0.373 kg/d for VD-2, 25D-1, and 25D-2, respectively), and the G:F was numerically greater in both 25OHD3 treatments compared with the VD-2 treatment (0.646, 0.660, and 0.670 for VD-2, 25D-1, and 25D-2, respectively). In conclusion, supplementing 25-OHD3 to the nursery pig diets could enhance feed intake and growth rate in the late nursery period compared with vitamin D3 supplementation.