Effects on performance, tissue integrity, and metabolism of vitamin E supplementation for beef heifers fed a diet that contains gossypol
1998
Velasquez-Pereira, J. | McDowell, L.R. | Risco, C.A. | Prichard, D. | Martin, F.G. | Calhoun, M.C. | Williams, S.N. | Wilkinson, N.S. | Ogebe, P.
We conducted an experiment for 112 d with yearling beef heifers to evaluate the effects of cottonseed meal (CSM) fed with various concentrations of vitamin E on hematological and tissue components. Heifers were assigned randomly to four treatments, with eight heifers per treatment. The treatments consisted of the following dietary supplements: 1) CON, based on soybean meal with 30 IU vitamin E/kg; 2) GOS, based on CSM with 30 IU vitamin E/kg; 3) G+2E, based on CSM with 2,000 IU vitamin E.animal-1.d-1; and 4) G+4E, based on CSM with 4,000 IU vitamin E.animal-1.d-1. Supplements based on CSM provided 4.5 g of free and 50.5 g of total gossypol.animal-1.d-1. The total gossypol present in the supplements was 29.1% of the negative isomer (-) and 70.9% of the positive isomer (+). Blood samples were collected at the start of the experiment and every 2 wk thereafter up to 16 wk. There was a time x treatment interaction (P < .01) for plasma alpha-tocopherol (alpha-T) concentration; however, feeding gossypol did not decrease plasma alpha-T. Weight gain, retinol palmitate, retinol, beta-carotene (beta-C), hemoglobin, and hematocrit were not affected by treatment. Erytbrocyte osmotic fragility (EOF) increased (P < .05) in gossypol-fed animals; however, vitamin E supplementation lowered EOF (P < .05). Heifers fed the supplements GOS, G+2E, and G+4E had greater (P < .01) plasma (-)-, (+)-, and total gossypol than heifers fed CON from Collection 2 to the end of the experiment. There was a treatment effect (P <.05) on vitamin E and gossypol concentrations in different tissues, with no effect (P > .05) for trace minerals (Cu, Zn, Fe, and Se). Vitamin E concentration in tissue increased with increased dietary supplementation of vitamin E. In heart and neck muscle, (-)-gossypol was greater (P <.05) than (+)-gossypol, but the reverse was true for liver. Gossypol decreased in vitro lipid peroxidation of liver homogenate in tissues. Gossypol deposition in tissue was liver > heart > muscle. In summary, gossypol from CSM did not decrease concentrations of antioxidant vitamins, including alpha-T, vitamin A, and beta-C, or have any detrimental effect on performance of beef heifers.
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