How to boost piglet immune response with vitamin D.

The benefits of vitamin D in pig feed go beyond the well-known function of calcium regulation and phosphorus homeostasis and its effect on bone development. Studies are showing that optimizing feed intake of vitamin D can boost piglet immunity in a number of different ways. The post-weaning phase is a critical period in a piglet's life. The development of a strong immune system at this early stage is key to securing its health and future optimum performance. However, a piglet has limited ability to mount and regulate an immune response when it is weaned from the sow at between three and five weeks old in commercial practice. Its immunity needs to develop as the passive protection from the sow's antibodies fade away and viral, bacterial and parasitic infections are at their highest risk. Any compromise to a piglet at this period has repeatedly been shown to impact negatively on its later performance. Vitamin D is an essential nutrient which is routinely added to animal feed, primarily because animals' blood levels of vitamin D vary considerably. It has become the focus of renewed attention by nutritionists and swine producers worldwide in recent years, because of findings that indicate that the benefits of vitamin D go beyond the function of the regulation of calcium and phosphorus homeostasis and its effect on bone development. Vitamin D metabolites control the expression of more than 200 genes through activation of the vitamin D receptor, which regulates or modulates gene expression within the target cell. This gives the vitamin a role in many functions in swine, including immunity, muscle function and reproduction. The vitamin D receptor is not only found in the intestinal enterocyte, the osteoblast, and the renal cells, but it is also found in a wide range of cell types whose function does not relate to calcium metabolism, such as the intestine, pancreas, heart, eye, brain, thyroid, parathyroid, muscle, or immune cells. The newborn piglet is exposed to a vast array of antigens from the moment it is born. It relies on maternally-derived immunity for protection, until it develops its own active immunity. Prior to weaning, sow's milk provides most of the nutrients that the piglet will receive for maximal growth and health. However, sow's milk provides little vitamin D. Supplementing sows with vitamin D before birth could provide a nutritional strategy to increase vitamin D status of the piglet, through placental transport or via sow's milk. story credit; pig progress.