Vitamin E is a fat-soluble vitamin and antioxidant. Naturally occurring vitamin E includes eight fat-soluble isoforms: α-, β-, γ-, and δ-tocopherol and α-, β-, γ-, and δ-tocotrienol. Vitamin E has been shown to be essential for integrity and optimum function of reproductive, muscular, circulatory, nervous, and immune systems. Vitamin E is stored throughout all body tissues, with highest storage in the liver. Vitamin E an essential nutrient for chickens of all ages, and its deficiency causes several disorders.
- Encephalomalacia: Encephalomalacia is a serious disorder that causes permanent tissue damage to the chicken's brain, as a result of localized softening of the cerebral. This form of vitamin E deficiency occurs most often in chickens that are getting fed a diet containing high levels of polyunsaturated fatty acids of the linoleic acid series (such as that found in many cooking oils) and low levels of vitamin E. Dilauryl succinate has also been documented to induce encephalomalacia in chickens.
- Exudative diathesis (ED): ED occurs as a result of selenium deficiency in chickens, and it primarily affects the capillary walls. Clinical signs observed include greenish-blue discoloration of the skin in localized areas of the chick's body, along with edema and hemorrhages, often resulting in bow-legged posture and pendulous (loosely hanging) crop in the throat latch area.
- Nutritional muscular dystrophy: Nutritional muscular dystrophy, also known as white muscle disease or nutritional myopathy, is a disease that primarily affects the chicken's striated muscles. It involves progressive weakness and degeneration of the muscles that control movement. Affected chicks are often unable to stand or walk and are seen on the ground with their legs spread laterally.
Nutritional Recommendations for Vitamin E in Chickens
Vitamin E levels recommended in the Nutrient Requirements of Poultry (NRC, 1994) are extremely low and were determined solely based on enhancing productivity traits of broilers and laying hens, and not in relation to immune enhancement and long-term health and well-being. Based on latest research studies, vitamin E requirements recommended for chickens at various stages of growth include:
Vitamin E Recommendations for Chickens
|Newly Hatched Chicks (0 - 10 wks)
|Young & Growing (10 - 20 wks)
|Laying hens (Actively laying eggs)
|Breeders (20 wks & older)*
|Broiler/'Meat' Breed Chicks (0-18 wks)