| الوصف: |
Vitamin D (cholecalciferol) is essential to humans and animals. Vitamin D 3 , the form active in poultry, can be synthesized endogenously but, as this process has very low efficiency in this species, vitamin D 3 must be supplemented via feed. To become active, vitamin D 3 must be hydroxylated twice in the body: first in the liver to 25OHD 3 and then in the kidney to the active, hormonal form 1,25(OH) 2 D 3 . The 25OHD 3 level in blood plasma is the indicator of the vitamin D nutritional status. Primary function of vitamin D 3 is to regulate both calcium and phosphorus metabolism, hence it plays a pivotal role in bone and skeletal development. For almost two decades now, 25OHD 3 has been commercially available. By feeding this metabolite directly, plasma levels are higher than when fed vitamin D 3 This occurs even more clearly when intestinal diseases or stress impair vitamin D 3 absorption. Both experimental trials and commercial use have indicated that supplementing broiler diets with 25OHD 3 can help improve bone and skeletal health; reduce the incidence of lameness and other bone disorders (e.g. tibial dyschondroplasia); modulate immune response; and improve performance, including having a direct effect on muscle growth mediated by molecular and cellular mechanisms. |
