Encephalomalacia broke out on 2 broiler farms. Experiments were performed to study this disease etiologically.
Experimentally affected chicks manifested typical nervous symptoms. The incidence was the highest among 2- to 3-week-old birds of an experimental group, as was the case with the natural outbreak.
Pathological examination was conducted on 19 spontaneous and 11 experimental cases. Principal lesions were observed in the brain both macroscopically and histopathologically, as was reported by Tajima et al. In addition, lesions were present in the spinal cord of some spontaneous and experimental cases. This finding had never been made by any previous investigator.
The causes for the disease were considered to be absolute deficiency of vitamin E in the ration, deterioration of vitamin E in the ration after long storage, excessive fat content of the ration, individual difference in the demand' of vitamin E, and progeny of vitamin E-deficient birds.
Effective prevention seemed to be achieved in broiler. chicks by addition of vitamin E to the ration and abstaining from excessive fat intake.
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