The effect of varying dietary concentrations of vitamin A on immune response in the turkey.
1. The effect of dietary vitamin A on antibody production and T-cell proliferative response was determined in poults from 21 to 41 d old. Poults were fed on soyabean meal-sorghum-based diets with concentrations of supplemented vitamin A from 0 to 13.2 micrograms/g retinol equivalents from hatching and were immunised with Newcastle disease virus (NDV) and turkey pox vaccines. T-cell proliferation response to concanavlin A was determined in vitro at 31 d old. Antibodies to NDV and turkey pox in serum were determined at 10 and 20 d after inoculation. 2. Poults receiving the diet with no added dietary vitamin A died by 22 d and had very low concentrations of plasma and liver vitamin A. 3. Increasing dietary concentrations of vitamin A enhanced the proliferative response until the diet contained 6.0 micrograms/g, above which the response began to decrease. The antibody titres to NDV and turkey pox increased as dietary vitamin A increased, with maximal values found 10 d after inoculation with 6.0 micrograms/g. At 20 d after inoculation low antibody titres were found with low vitamin A intake. 4. These data suggest that maximal immune responses in the poult may be achieved at dietary intakes of vitamin A at or higher than those recommended by NRC (1984, 1994).
Sklan
D
D
Department of Animal Science, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot, Israel.
Melamed
D
D
Friedman
A
A
D000704:Analysis of Variance; D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis; D018150:Avipoxvirus / Q000276:immunology; D002455:Cell Division / Q000187:drug effects; D004032:Diet; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D007109:Immunity / Q000187:drug effects*; D008297:Male; D009522:Newcastle disease virus / Q000276:immunology; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D014422:Turkeys / Q000276:immunology*; D014801:Vitamin A / Q000494:pharmacology*
D000914:Antibodies, Viral; D014801:Vitamin A