The effect of varying levels of dietary vitamin A on immune response in the chick.
The effect of dietary vitamin A on antibody production and T cell proliferative response was determined in broilers from 21 to 39 d old. Chicks were fed soybean meal-sorghum diets with levels of supplemented vitamin A from 0 to 13,200 micrograms/kg retinol equivalents from hatching and were immunized with beta-casein at 21 d of age. T cell proliferation response to beta-casein or an acetone precipitate of antigen to Mycobacterium tuberculosis was determined in vitro at 34 to 37 d old. Antibodies to beta-casein in serum were determined every 5 d from 21 d of age. In chicks with no added dietary vitamin A, antibody production and proliferative response were depressed in comparison with chicks receiving vitamin A. Addition of small amounts of vitamin A enhanced the responses; both antibody production and proliferative responses increased with dietary vitamin A until the diet contained 6,660 micrograms/kg, above which the responses decreased. This suggests that maximal immune responses in the chick may be achieved at dietary intakes considerably higher than NRC recommendations.
Sklan
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D
Department of Animal Science, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot, Israel.
Melamed
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D
Friedman
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A
D000821:Animal Feed; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D000942:Antigens, Bacterial / Q000008:administration & dosage; D002364:Caseins / Q000008:administration & dosage; D002645:Chickens / Q000276:immunology*; D005527:Food, Fortified; D007279:Injections, Subcutaneous; D007958:Leukocyte Count / Q000187:drug effects; D008297:Male; D009162:Mycobacterium avium / Q000276:immunology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D014801:Vitamin A / Q000008:administration & dosage* / Q000097:blood
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D002364:Caseins; D014801:Vitamin A