Role Of Vitamin D In Production And Immunity In Poultry Nutrition

Vitamin D deficiency in poultry feeds has a direct impact on chicken growth and production. The inadequacy of Vitamin D manifests as rickets in chicks, and osteomalacia in adult poultry birds, in which their bones become soft and rubbery. As a result, broiler growth is a concern, as are production issues in layers and breeders. Insufficient Vitamin D leads to ineffective calcium absorption in the body of the bird. Calcium is needed for eggshell formation, and its deficiency causes high mortality and decreased hatchability in breeders and more egg breakage in layers. Hence, checking for early signs of Vitamin D deficiency becomes a necessary task for farmers. Studies show that supplementing Vitamin D for poultry shows favorable results in production and performance.

Role Of Vitamin D In Immunity

  In response to invasion of pathogens, the immune system first executes the innate, and then the acquired host defense systems.

  Recent discoveries indicate that Vitamin D is required for the activation of critical innate immune defenses of animals against microbial pathogens.

  When there is a deficiency of Vitamin D, functions of the immune system may be impaired even though the animal does not have symptoms of classic Vitamin D deficiency.

  In that condition of Vitamin D insufficiency, animals may be vulnerable to infectious diseases. Therefore, it is critical to make sure animals are getting adequate Vitamin D.

Metabolites Of Vitamin D In Animal Nutrition

Vitamin D or the Sunshine Vitamin is synthesized in the form of Vitamin D₃, also known as Cholecalciferol, in animals from the sun’s exposure on the skin. However, the vitamin produced by poultry is not enough and thus needs regular supplementation through animal feed additives. Also, research shows that Vitamin D₃ metabolites are more effective than cholecalciferol. Following is the list of supplemental forms of Vitamin D or its available metabolites.

Vitamin D₃-

Cholecalciferol is produced in the body either through the conversion process of 7-dehydrocholesterol on the skin or through animal feed supplements. 

25-Hydroxy Vitamin D₃-

It is the circulating form of cholecalciferol produced after its hydroxylation in the liver. The 25-(OH) D₃ is transported to the kidney to get converted into multiple compounds of which, 1,25 dihydroxy-Vitamin D₃ is the most important.

1-α-Hydroxyvitamin D₃-

Alfacalcidol is a Vitamin D hormone analog that requires activation by the enzyme 25hydroxylase in the liver. It is important for the regulation of calcium balance & bone metabolism. 

1,25 Dihydroxy-Vitamin D₃

Also known as calcitriol, 1,25(OH)2 D₃ is a steroid hormone in the form of a biologically active Vitamin D₃ metabolite. It directly acts on the intestine, thereby intensifying the absorption of calcium and phosphorus besides stimulating the parathyroid hormone. As a result, the metabolite is more effective for preventing and curing rickets.

Glycoside Form Of 1,25 Dihydroxy-Vitamin D₃

The metabolically active form of Vitamin D₃ is a plant-derived glycosidic form of calcitriol. It is produced by the waxy leaf nightshade (Solanum Glaucophyllum). Studies prove that it has better heat stability than other metabolites of Vitamin D₃, hence making it an ideal choice as a poultry feed supplement.

Avitriol- Animal Feed Supplement For Vitamin D Deficiency

Avitriol is a naturally derived metabolite of Vitamin D3 from the waxy-leaf nightshade plant. Composed of the glycosidic form of 1,25-dihydroxycholecalciferol, this poultry feed supplement does not require activation in the liver and kidney. It helps maintain the homeostasis of calcium and phosphorus by ensuring sufficient Vitamin D in the body.


Avitriol should be added at the rate of 50-100 gm/MT of the total feed for poultry, on top of normal Vitamin D3 supplementation.