What is vitamin D3?
Vitamin D3 is formed in the skin from 7-dehydrocholesterol when it is exposed to ultraviolet B light. Animals kept indoors, as in modern poultry and pig production, receive little or no sunlight, so their vitamin D3 must come from the feed.
Cholecalciferol itself is not the active hormone. It is first converted in the liver to 25-hydroxycholecalciferol (25-OH-D3, calcifediol), the main circulating form, and then in the kidney to 1,25-dihydroxycholecalciferol, which acts on the intestine, bone and kidney. By definition, 1 IU of vitamin D3 corresponds to 0.025 µg of cholecalciferol.
What does vitamin D3 do in animal feed?
- Calcium and phosphorus absorption: stimulates the uptake of both minerals from the intestine and their reabsorption in the kidney.
- Bone development: needed for normal skeletal mineralisation; deficiency causes rickets in young animals and osteomalacia in adults, and in broilers it is linked to leg problems such as tibial dyschondroplasia.
- Laying hens and breeders: supports eggshell formation and the vitamin status of the embryo.
- Pigs: supports skeletal development in fast-growing pigs and bone health in sows.
- Dairy cattle: involved in calcium mobilisation around calving.
- Other roles: vitamin D also takes part in muscle function and immune regulation.
Forms of vitamin D in feed
- Cholecalciferol (D3) beadlets: the standard feed form, protected by antioxidants and a gelatin or starch matrix; commonly supplied at 500,000 IU/g.
- Combined A/D3 products: vitamin A and D3 in one beadlet, used in some premix formulations.
- Ergocalciferol (D2): the plant/fungal form; poultry use it much less efficiently than D3, so D3 is the preferred form in poultry feed.
- 25-OH-D3 (calcifediol): a related metabolite marketed as a feed additive in some regions, used alongside or partly instead of D3 according to local authorisations.
How is the vitamin D3 supply assessed?
Vitamin D3 is set in IU per kilogram of feed and is always considered together with the dietary calcium and phosphorus levels, their ratio and the use of phytase. Species, growth rate, laying stage and housing all influence the target level. Vitamin D3 is toxic in excess and can cause calcification of soft tissues, so many jurisdictions set maximum content in complete feed; inclusion should follow recognised recommendations, the product label and local regulations.
Stability and quality criteria
- Declared activity (IU/g) confirmed by analysis; because the inclusion amounts are very small, accurate dilution and mixing are critical.
- Beadlet stability against heat, pressure and moisture during storage and pelleting.
- Sensitivity to oxygen, light and trace minerals: premixes should be stored cool, dry and closed.
- Particle size and distribution: tiny quantities must be spread evenly through the premix and feed.
- Certificate of analysis (CoA) and lot traceability.
CTF Premix and vitamin D3
Vitamin D3 can be included in CTF Premix's vitamin, vitamin-mineral and custom premixes according to the customer's formulation, balanced with the calcium and phosphorus design of the diet. Because D3 is dosed in very small amounts, controlled pre-dilution and mixing are part of our process. Premixes are produced at our Ankara facility under ISO 9001:2015 and GMP, each lot has a certificate of analysis and can be traced on our batch verification page.
This page is for general information. Inclusion rates and product choice should be decided with a nutritionist, taking into account the species, the feed formulation and the applicable regulations.