Efficacy and safety of a novel source of dietary 25-hydroxycholecalciferol in growing pigs

A randomized complete block design experiment was conducted to determine the safety and efficacy of supplementation of increasing concentrations of a novel, bacterial fermentation-derived vitamin D source on growth performance and tissue deposition of 25-hydroxycholecalciferol (25OHD3) in growing swine. Dietary treatments were as follows: commercial control with vitamin D3 (CON) at NRC recommended concentrations and three diets composed of CON + increasing inclusions (25, 50, and 250 µg/kg equivalent) of 25OHD3 from a novel source (CON + 25; CON + 50; and CON + 250, respectively). Pigs (n = 144) were assigned to 24 pens which were allotted to one of the four dietary treatments and fed for 42 d. Blood samples were collected for 25OHD3 concentration determination and individual body weights (BW) were measured on experimental day 0, 39, and 63. On day 42, tissues from 48 pigs (12 pigs per dietary treatment) were analyzed for 25OHD3 concentration. No differences were observed in growth performance. Day 39 serum 25OHD3 concentrations were greatest in CON + 250-fed pigs and linearly decreased as dietary 25OHD3 inclusion decreased (P < 0.0001). On day 42, tissue 25OHD3 concentrations increased linearly as 25OHD3 increased in the diet (P < 0.0001). On day 63, 21 d after dietary 25OHD3 withdrawal, serum 25OHD3 concentrations of all 25OHD3-fed pigs decreased to that of or within 2.76 ± 0.89 ng/mL of CON-fed pigs which demonstrates that feeding 250 µg/kg 25OHD3 is well tolerated by growing pigs and will clear the body within 21 d.Pigs require several essential nutrients to meet their needs for maintenance, growth, reproduction, and other functions. It is important to provide these nutrients to the animals properly to assure their health and wellbeing as well as the profitability of production. Vitamin D is a nutrient that plays an important role in bone development and mineralization since it regulates calcium and phosphorus metabolism. Vitamin D has also been reported to aid in additional functions including immunity. Vitamin D can be synthetized in plants and is also produced in humans and animals when ultraviolet rays from sunlight strike the skin and lead to vitamin D synthesis. In pigs, vitamin D requirements can also be satisfied by dietary sources. The objective of this experiment was to determine the efficacy and safety of supplementation of a novel, bacterial fermentation-derived vitamin D source on growth and tissue accumulation in growing swine. Based on the results obtained, it can be concluded that concentrations of vitamin D in serum and tissue samples increased as dietary vitamin D supplementation increased, but did not alter growth performance, nor did there appear to be any safety issues with feeding up to 250 µg per kg feed of this vitamin D source to growing pigs.