This study was carried out to investigate the effects of vitamin E on the prevention and treatment of Babesia gibsoni. Fifteen mongrel dogs, uninfected with Babesia spp, were assigned to three groups according to vitamin E(α-tocopherol) concentrations in the RBC. The concentrations in each of the three groups were, respectively : α-tocopherol in RBC less than 30㎍/㎕(Group I ), 30㎍/㎕-60㎍/㎕(Group II ), more than 60㎍/㎕(Group III). Artifical infection was accomplished by injecting 2 × 10^7 ∼ 2 × 10^8 erythrocyte of Babesia gibsoni -infected dog into the cephalic vein. We investigated the clinical signs, vitamin E concentrations in RBC and serum, Vitamin A concentrations in serum, hematological values, white blood cell(WBC) viability and RBC membrane osmotic fragility after infection of Babesia gibsoni for a period of 20 days at 5 day intervals.
The results obtained are summarized as follows :
1. After infection by Babesia gibsoni, clinical examination revealed depression, anoroxia, pale mucous membranes, dark brown urine and diarrhea in proportion as time went on. After 10 days of infection, one dog each of Groups I , II and III revealed depression and anorexia. Two dogs in Group I and one dog each of Groups II and lII showed dark brown urine after 15 days. Diarrhea was observed in one dog in each of the 3 groups after 20 days of infection.
2. After 5 days of infection, two dogs in each of Groups I , lI and III showed Babesia gibsoni in RBC of blood smear stained with Giemsa. At the 15th day after infection with Babesia gibsoni, they were observed in all experimental animals. After both 5 days and 10 days of infection, the rate of Babesia gibsoni parasitized RBC(permillage, ‰) was 1‰, and increased as time went on.
3. After 5 days of infection by Babesia gibsoni , Group I , which had the lowest vitamin E concentration, showed significantly decreased RBC and PCV levels(p $lt; 0.01). Group II and group III also showed significantly decreased RBC and PCV levels after 15 days of infection(p $lt; 0.05). Particularly after 10 days of infection, Group I showed lower values in RBC and PCV levels compared to Groups II and III. WBC, RBC, fibrinogen and total protein levels between the groups did not differ during experimental periods.
4. According to the WBC differential counts, the ratios of neutrophil to lymphocyte showed a tendency to be slightly higher in Group III (more than 60㎍/㎕) than in Groups I and II.
5. WBC viability did not differ between the groups.
6. RBC membrane osmotic fragility did not differ between the groups.
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