Dietary supplementation of 25-hydroxycholecalciferol as an alternative to cholecalciferol in swine diets: A review.

25-hydroxycholecalciferol (25-OHD3 ) formed via hepatic hydroxylation from vitamin D, cholecalciferol, represents the precursor of the biologically active vitamin D hormone, 1,25-dihydroxyvitamin D. Due to a higher absorption rate and the omission of one hydroxylation, dietary supplementation of 25-OHD3 instead of vitamin D3 is considered to be more efficient as plasma concentrations of 25-OHD3 are increased more pronounced. The present review summarises studies investigating potential beneficial effects on mineral homeostasis, bone metabolism, health status and performance in sows, piglets and fattening pigs. Results are inconsistent. While most studies could not demonstrate any or only a slight impact of partial or total replacement of vitamin D3 by 25-OHD3 , some experiments indicated that 25-OHD3 might alter physiological processes when animals are challenged, for example, by a restricted mineral supply.