THE EFFECT OF EXCESSIVE DIETARY VITAMIN-A ON PERFORMANCE AND VITAMIN-E STATUS IN SWINE FED DIETS VARYING IN DIETARY VITAMIN-E

A study was conducted to evaluate the effects of high dietary vitamin A on vitamin E status and performance of growing-finishing pigs fed di ets supplemented with varying levels of vitamin E. Treatments consiste d of corn-soybean meal-based diets supplemented with retinyl acetate t o provide 2,000 or 20,000 IU of vitamin A/kg of diet and with DL-alpha -tocopheryl acetate to provide, 15, or 150 IU of added vitamin E/kg in a 2 x 3 factorial arrangement. The trial involved 84 crossbred pigs ( 26 kg initial BW) allotted to pens of two pigs each (one gilt, one bar row). Serum was obtained from all pigs on d 0, 3, 7, 21, 35, 63, and 7 7 of the 83- or 90-d feeding period. Tissue samples (liver, leg, and n eck muscle, backfat, and leaf fat) were collected from one pig (barrow ) in each pen at the end of the feeding period. Average daily gain and gain:feed were .93 kg and .30, respectively, without treatment differ ences (P >.10). Serum or-tocopherol increased linearly (P <.01) by d 3 with increasing level of dietary vitamin E supplementation. High diet ary vitamin A resulted in a small decrease (P <.01)in serum alpha-toco pherol on d 3, but serum alpha-tocopherol concentration was not affect ed (P >.10) on other days. Tissue alpha-tocopherol increased linearly (P <.001) as dietary vitamin E increased in all tissues examined. No c onsistent evidence was found to indicate that a high level of dietary vitamin A interfered with performance or with blood serum or tissue al pha-tocopherol concentrations in growing-finishing swine.