Dietary additions of lactose, casein and soy protein exerted only moderate effects on calcium homeostasis in calcitriol deficient piglets.

It has been reported from rats and mice that blood and bone calcium can be normalised in the absence of Vitamin D hormone or its receptor by dietary means. It was the aim of this study to test, whether a similar result can be obtained with pigs. Piglets with inherited calcitriol deficiency were fed with high calcium and Pi diets and supplemented with soy protein or casein and lactose or corn starch, which have been shown to normalise plasma and bone calcium in Vitamin D deficient rats and in mice. In the calcitriol deficient piglets none of the diets was capable to prevent the development of hypocalcemia. However, additions of lactose and soy protein improved somewhat plasma calcium (P < 0.001). Feeding of soy protein also had a significant positive effect on plasma phosphate concentration (P < 0.001). The study shows that in contrast to rats, calcitriol is essential for maintaining a normal plasma and bone calcium status. Responses of this type, when obtained with rats or mice can probably not directly be transferred to pigs and perhaps also not to humans.