ASCORBIC ACID METABOLISM IN SWINE. THE EFFECTS OF FREQUENCY OF FEEDING AND LEVEL OF SUPPLEMENTARY ASCORBIC ACID ON SWINE FED VARIOUS ENERGY LEVELS

Abstract

The effects of supplementary ascorbic acid and frequency of feeding on the performance of 3-wk-old, castrated, male swine fed 140, 240 and 340 kcal/kg W0.75 of metabolizable energy (ME) was investigated using a 3 × 3 × 2 factorial experiment. Frequency of feeding had no influence on the growth rate within any one energy group. Supplementary ascorbic acid up to the level of 1,000 mg per day produced improvement in growth rates at all levels of ME intake. The improvement in rate of growth appeared not to be due to water retention because there were no differences in creatinine excretion rates (per kg of body weight per day) between any of the groups. Ascorbic acid supplementation at the rate of 1,000 mg/day resulted in an increased proportion of the label from glucose-U-14C incorporated into the saponifiable fraction of an adipose tissue biopsy from the group fed a daily ration of 140 kcal ME/kg W0.75 in five equal amounts during the day. Supplementary ascorbic acid appeared to have no other effects on lipid metabolism. Excretion of ascorbic acid was significantly increased when there was an increased ME intake and an increased level of vitamin supplementation. These observations confirm an earlier report that the ascorbic acid available to the swine is a function of the energy level in the diet. It is suggested that observations (vide supra) made in ME-deprived animals may be due to decreased amounts of ascorbic acid physiologically available to the pig.