Effects of 25(OH)VD(3) on Growth Performance, Pork Quality and Calcium Deposit in Growing-Finishing Pigs

SIMPLE SUMMARY: 25-hydroxyvitamin D(3) [25(OH)VD(3)] plays an important role in regulating calcium and phosphorus metabolism via upregulating the expression of calcium ion channel proteins, resulting in improved bone quality. Many publications have reported that dietary supplementation of 25(OH)VD(3) could improve the antioxidase activity and immune function of weaned pigs. However, evidence has proven that the biological response of 25(OH)VD(3) on pig nutrition depends on the inclusion doses in the diets. This study was conducted to explore the roles of 25(OH)VD(3) with different inclusion doses in growing-finishing pigs. ABSTRACT: The study was conducted to evaluate the effects of 25(OH)VD(3) with different inclusion levels of 0, 25, 50 and 75 μg/kg in the diet on growth performance, nutrient digestibility, bone properties and pork quality in growing-finishing pigs. The results showed that the average daily gain (p < 0.05) and body weight (p < 0.10) of pigs showed a trend of increasing quadratically as inclusion levels of 25(OH)VD(3) increased. Dietary supplementation of 50 μg/kg 25(OH)VD(3) increased calcium digestibility compared with the 0 μg/kg group (p < 0.05), and calcium and phosphorus digestibility increased quadratically as inclusion levels of 25(OH)VD(3) increased (p < 0.05). Dietary supplementation of 50 μg/kg 25(OH)VD(3) increased concentrations of polyunsaturated fatty acids, and decreased contents of saturated and monounsaturated fatty acids in the longissimus dorsi of pigs (p < 0.05). The addition of 25, 50 and 75 μg/kg 25(OH)VD(3) to the diet increased breaking strength and bone stiffness in the tibia compared with the 0 μg/kg group (p < 0.05). Dietary supplementation of 50 μg/kg 25(OH)VD(3) improved the activities of superoxide dismutase (SOD) and catalase (CAT), and increased the messenger RNA (mRNA) expression of Cu/Zn SOD in the longissimus dorsi compared with the 0 μg/kg group (p < 0.05). Supplementing 50 μg/kg 25(OH)VD(3) improved the mRNA expression of calcium-binding protein D9k (CaBP-D9k) and D28k (CaBP-D28K) in the liver compared with the 0 μg/kg 25(OH)D(3) group (p < 0.05). In conclusion, a diet with an added dose of 50 μg/kg 25(OH)VD(3) showed a greatest growth performance of growing-finishing pigs, and 25(OH)VD(3) enhanced calcium deposition and antioxidant capacity in the longissimus dorsi, which may be associated with improved expression of calcium ion channel proteins.