Vipin1, Kundan Kumar2, Promod Kumar Soni2
1Ph.D. Scholar, ICAR-National Dairy Research Institute
2ICAR- Indian Veterinary Research Institute
Poultry requires at least 36 dietary nutrients at appropriate concentrations and balance. To prevent nutrient deficiencies, grain-soy based diets are typically supplemented with concentrated sources of all the nutrients. Nutrient deficiencies or toxicities most often result from errors in diet formulation or milling and these supplemented nutrients are the most probable causes of nutritional problems. Vitamin E is usually supplemented to poultry diets as α-tocopherol. In the feed, vitamin E is a very effective antioxidant; it protects unsaturated fatty acids, including the essential fatty acids, as well as many vitamins and xanthophylls. Diets that contain high levels of unstabilized polyunsaturated fatty acids become depleted of Vitamin E and are most likely to cause deficiencies.
DEFICIENCY OF VITAMIN E
During vitamin E deficiency, oxidative damage may cause encephalomalacia, exudative diathesis, and nutritional myopathy (muscular dystrophy) in chicks. Vitamin E deficiency is exacerbated by low levels of dietary selenium, and vice versa. Symptoms in the vitamin E-deficient embryo include cloudy spots in the eyes, blindness, abnormal vascular system, hemorrhages, and stunting. Testicular degeneration occurs in males deprived of vitamin E for prolonged periods. Because of the similarities of vitamin E and selenium deficiency syndromes, measurement of their concentrations in blood plasma will reveal if either or both are deficient.
Encephalomalacia in Chicks
Encephalomalacia is a nervous syndrome characterized by ataxia or paresis (Figure 29.5A), backward or downward retractions of the head (sometimes with lateral twisting), forced movements, decreasing coordination, rapid contraction and relaxation of the legs, and finally complete prostration and death.
Exudative diathesis is edema of subcutaneous tissues (Figure 29.6) associated with abnormal permeability of capillary walls. In severe cases, chicks stand with their legs far apart as a result of the accumulation of fluid under the ventral skin. This green-blue viscous fluid is seen easily through the skin and usually contains some blood components from slight hemorrhages that appear throughout the breast and leg musculature and in the intestinal walls.
Nutritional Myopathy (Muscular Dystrophy).
When vitamin E deficiency is accompanied by a sulfur amino acid deficiency, chicks show signs of nutritional myopathy, particularly of the breast muscle, at about 4 weeks-of-age. The condition is characterized by light-colored Streaks of easily distinguished affected bundles of muscle fibers in the breast, (Figure 29.7A). Similar dystrophy occurs throughout all skeletal muscles of the body in vitamin E-deficient ducks.
Table- Requirements for Vitamin E per kg of Chicken Feeds (IS 2007)
|Characteristic||Broiler Feed||Layer Feed|
|Prestrater||Starter||Finisher||Chick||Grower||Layer I*||Layer II**|
|Vitamin E, mg/kg, min.||30.0||30.0||30.0||15.0||10.0||10.0||10.0|
*Phase I- 21 week to 45 weeks of age of Bird
**Phase II- 46 weeks to 72 weeks of age of Bird