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Vitamin E Deficiency

Avian Encephalomalacia, Crazy Chick Disease, Hypovitaminosis E

Vitamin E Deficiency Overview


Vitamin E deficiency is an essential nutrient for chickens of all ages, and its deficiency causes several disorders. These include erythrocyte hemolysis, nutritional muscular dystrophy, cerebellar encephalomalacia, and exudative diathesis.
  • 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.
The National Research Council’s Committee on Animal Nutrition recommends that chickens receive 10 IU of vitamin E per kg feed (1 IU = 0.67 mg dl-α-tocopheryl acetate) from hatch until they are up to six weeks old, and then 5 IU/kg feed for chickens older than six weeks of age.

Clinical Signs

Ataxia
Torticollis
Muscle spasms
Greenish-blue skin discoloration
Edema
Loosely hanging crop
Inability to stand or walk
Bow-legged posture
Outstretched legs
Prostration
"cycling" with legs
Reduced egg production
Poor egg quality
Reduced fertility

Diagnosis

  • History
  • Clinical signs
  • Diet analysis
  • Necropsy

Treatment

NameSummary
Vitamin EProvide supplemental vitamin E. The recommended dietary level of vitamin E for chickens under 6 weeks of age is 10 IU of vitamin E per kg feed and 5 IU/kg feed for chickens older than 6 weeks of ageNRC 1994
Supportive care

Prevention

  • Feed a balanced diet with proper dietary supplements with vitamin E and inorganic selenium.
  • Use only fresh feed that has been stored properly in an air-tight container, and not more than 2 weeks old
  • Don't feed vitamins that have passed their expiration date
  • Provide chickens intended for breeding a breeder feed and/or additional vitamin supplements.

Prognosis

Good if treated during the early stages.

Scientific References

Age Range

Signs tend to develop in young chicks between 2-6 weeks old.

Risk Factors

  • Feeding chicks starter feed that is more than 2 weeks old
  • Improperly storing feed
  • Purchasing poor quality feed
  • Feeding breeding chickens laying hen feed, without providing additional vitamins and minerals needed for breeding
  • Feeding vitamins that are past their expiration date
  • Feeding chicks a diet high in rancid fat
  • Diet lacking antioxidants