Nitrogen metabolism and reproductive response of gravid swine fed an arginine-free diet during the last 84 days of gestation.

Based upon nitrogen retention and urinary excretion of orotic and citric acid, previous experiments have shown that the gravid gilt does not require a dietary source of arginine during late gestation. This experiment was designed to evaluate effects of feeding an arginine-free diet for a major portion of gestation. Three diets, 0% L-arginine, 0.38% L-arginine and a fortified corn-soybean meal control, were fed to two litter-mate trios from day 30 of gestation until parturition. The experimental diets contained crystalline amino acids as the sole source of nitrogen and provided 12.6% crude protein equivalent. All gilts received 2 kg of diet daily and were housed throughout the 84-day feeding period in metabolism crates. Nitrogen retention tended to increase with advancing pregnancy, but was uninfluenced by dietary treatment. Averaged across all three gestational trimester periods, nitrogen retention was 11.2, 9.7 and 12.0 g/day for the 0% arginine, 0.38% arginine and cor-soybean meal diet, respectively. Urinary excretion of orotic acid was not significantly affected by arginine intake. Moreover, number and weight of pigs at birth and weaning were unaltered by dietary treatment. Thus, it is evident that satisfactory reproductive response can be achieved with gravid swine fed an arginine-free diet during the last 84 days of pregnancy.