Abstract
Three experiments investigated the combined effects of supplemental vitamin E (a-tocopherol acetate) with 1) vitamin A (retinyl acetate), 2) 9-carotene, or 3) canthaxanthin (CX), on the performance of Single Comb White Leghorn cockerels (SCWL). Hemagglutination inhibition (HI) antibody titers to Newcastle disease virus (NDV) were used to determine immune response. For each experiment vitamin E at either 0, 10, 100, 500, or 1000 ppm was crossed with five concentrations of either vitamin A, 9-carotene or canthaxanthin in a fractional factorial (modified central composite) design consisting of 11 dietary treatments. In the first experiment, vitamin E was combined with five levels of retinyl acetate (0, 0.5, 50, 500, or 1000 ppm) and fed for six weeks. There were no significant differences in the HI titers or relative bursa weights between diets. Relative liver weights increased significantly as vitamin A increased. The toxic effects (higher feed conversion, lower BW and higher mortality) of 1000 ppm or 500 ppm vitamin A could be reduced by the addition of 1000 or 500 ppm vitamin E. Although not significant, optimal feed conversion, mortality, and HI titer-resulted from the 0 ppm vitamin E plus 50 ppm vitamin A diet and the highest BW resulted from the 10 ppm vitamin E plus 0.5 ppm vitamin A diet. In the second experiment, vitamin E was combined with five levels of 9-carotene (0, 1, 100, 1000, or 2000 ppm) and fed for eight weeks. No significant differences in HI antibody titer, mortality, feed conversion, BW or relative organ weights were observed. In the third experiment, vitamin E was combined with five levels of Cx (0, 0.5, 50, 500 or 1000 ppm) and fed for six weeks. The,1000 ppm CX diets resulted in significantly lower feed conversion than lower CX level diets. There were no significant differences in HI antibody titers or other production variables.
Cahill, Maureen Grace (1994). The combined immunoenhancing effects of vitamins E & A, E & Beta-carotene and E & canthaxanthin. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1994 -THESIS -C1324.