Effects of maternal and offspring treatment with two dietary sources of vitamin D on the mineral homeostasis, bone metabolism and locomotion of offspring fed protein- and phosphorus-reduced diets.

The present study aims to compare the effects of maternal and offspring treatment with 25-hydroxycholecalciferol (25-OHD) and vitamin D on vitamin D status, mineral homoeostasis, bone metabolism and locomotion in the offspring. Either vitamin D (50 μg/kg diet) or 25-OHD (50 μg/kg diet) was supplemented to the gestation and lactation diets of 49 multiparous sows and/or to the diets of their growing offspring. Treatment of the sows did not affect plasma concentrations of 25-OHD of the offspring. Pigs fed 25-OHD had higher plasma concentrations of 25-OHD than pigs that received vitamin D during rearing and fattening. However, neither plasma concentrations of calcium, phosphate and bone markers during the observation period nor bone ash and bone mineral density at slaughter were clearly affected by the treatment. Maternal and offspring treatment with 25-OHD instead of vitamin D resulted in a slight reduction in the prevalence of leg swelling. In addition, more pigs walked with even steps and normal stride length. Further studies are needed to test whether the slight effects observed in the present experiment are reproducible and of relevance for animal health and welfare. In that case, the underlying mechanisms should be revealed in order to take advantage of potentially beneficial influences especially under certain feeding regimes.