Oral Administration of L-Arginine-HCl to Low-Birth-Weight Piglets Improves Their Growth and Survival

Pigs exhibit severe naturally-occurring intrauterine growth restriction (IUGR). Under current feeding programs, approximately 20 to 25% of piglets are born with a birthweight of < 1.1 kg. The IUGR accounts for 76% of pre-weaning deaths. To date, IUGR piglets are culled on farms and there are no effective nutritional means to prevent their death or enhance their growth. In the present study, we conducted an experiment to determine the effects of L-arginine supplementation on the growth and survival of IUGR piglets. In this experiment, 88 IUGR piglets (with a mean birth-weight of 0.85 kg) from 22 sows (4 IUGR piglets/sow) were randomly assigned into four groups. They were nursed by sows and orally administered 0, 0.1, 0.2 or 0.4 g L-arginine (in the form of L-arginine-HCl) per kg BW twice daily. The total doses of L-arginine were 0, 0.2, 0.4 or 0.8 g/d per kg BW. Appropriate amounts of L-alanine were added to the oral L-arginine solutions so that all groups of piglets received the same amount of nitrogen. Piglets were weighed on d 1, 7, and 14 of age. On d 14, blood samples (1 ml) was obtained from the jugular vein of piglets at 1 h after suckling, and their milk consumption was measured over a 9-h period using the weigh-suckle-weigh technique. Milk intake did not differ (P > 0.05) among the four groups of piglets. Oral administration of Arg increased (P < 0.05) Arg concentrations in the plasma in a dose-dependent manner. When compared to the control group (ADG = 152 g/d between d 1 and 14), IUGR piglets administered 0.2 and 0.4 g L-arginine/d per kg BW increased (P < 0.05) by 19% and 31%, respectively. The ADG did not differ (P > 0.05) between the controls and the IUGR piglets receiving 0.8 g L-arginine/d per kg BW. The survival rates of the IUGR piglets were 50%, 75%, 90% and 90%, respectively, for the 0, 0.2, 0.4, and 0.8 g L-arginine/d per kg BW groups. Growth and survival of IUGR piglets can be improved through supplementation of L-arginine-HCl. Supported by USDA-NIFA grants and Texas A&M University.