Vitamin A Activity of Fermentation β-Carotene for Swine

Abstract

Two experiments were conducted with 171 weanling pigs to provide an estimate of the biopotency of fermentation carotenoids produced by Blakeslea trispora, and to estimate the vitamin A and β-carotene requirement of the depleted 50-kg pig. Vitamin A depletion for 7 weeks lowered serum vitamin A concentration from 23 to 4 µg/100 ml, and lowered liver vitamin A concentration from 35 to 2 µg/g of dry tissue. Repletion levels of fermentation β-carotene ranged from 0.5 to 3.5 mg/kg of diet and of all-trans vitamin A1 palmitate from 250 to 2000 IU/kg of diet. Using total liver vitamin A after 9 weeks of repletion as the criterion, one mole of fermentation β-carotene had 11.5% of the biopotency of one mole of all-trans vitamin A1 palmitate. The minimal requirements for gains from 50 to 100 kg body weight did not exceed 0.5 mg of fermentation β-carotene or 250 IU of vitamin A palmitate/kg of diet. However, 3.5 mg of fermentation β-carotene or 1000 IU of vitamin A palmitate/kg diet were required to restore serum vitamin A concentration to predepletion levels. Liver vitamin A concentration or total liver vitamin A increased linearly with increasing dietary increments of either fermentation β-carotene or vitamin A palmitate. This relationship was represented by the equation Y = -0.636 + 0.002 X for fermentation β-carotene and by Y = -4.87 + 0.0174 X for all-trans vitamin A1 palmitate, where Y = milligrams of total liver vitamin A after 9 weeks repletion and X = international units of fermentation β-carotene or of vitamin A palmitate per kilogram of diet.