S. Ching and D. C. Mahan1
The Ohio State University Department of Animal Sciences
Abstract
Studies were conducted to evaluate the pig's ability to synthesize ascorbic acid from mid gestation to 42 day of age. We also evaluated the effect of pig birth order, premature births, and weaning age on the pig's ability to synthesize the vitamin. Liver gulonolactone oxidase (GLO) was the enzyme used to express the ability of the pig to synthesize ascorbic acid. The results suggested that fetal pigs synthesize high quantities of ascorbic acid during the early stages of gestation but this capability declined as gestation progressed. Pigs born early (1st or 2nd) in the birthing sequence had higher liver ascorbic acid concentrations than those born at a later (7th or 8th) time in the sequence. Pigs that were born early (113 day) also had lower liver ascorbic acid concentrations than those born naturally (115 day). However, in both situations there was no difference in the pigs ability to synthesize the vitamin. Sow milk was high in ascorbic acid and this high concentration may have suppressed the ability of both the fetal and nursing pig to synthesize ascorbic acid. However, when the dams supply of ascorbic acid was eliminated such as upon weaning the enzyme increased, whereupon, the pig began to synthesize ascorbic acid. Consequently, there was a weaning age effect on pig liver ascorbic acid synthesis. Pigs maintained a low synthesis of vitamin C until they were weaned, whereupon the enzyme activity and the production of the vitamin increased within 2-week postweaning.