L-arginine supplementation during the final third of gestation improves litter uniformity and physical characteristics of neonatal piglet thermoregulation.

The study assessed the effects of dietary L-arginine supplementation from days 85 to 115 of gestation on sow performance, litter quality, piglet physiology and survival variables in the first 24 hr of life. Twenty multiparous sows, with a history of hyperprolificacy (more than 14 piglets per litter), were used. A completely randomized experimental design was used, consisting of two treatments: feed supplemented or not with 1% L-arginine from days 85 to 115 of gestation. The experimental unit consisted of the sow and its respective litter, using 10 replicates per treatment. The sows were distributed into the treatments based on body condition and parity. Supplementation with L-arginine reduced the within-litter standard deviation and the within-litter coefficient of variation of piglet weight at 24 hr by 54 g and 4.14 percentage points respectively (p = .029; p = .035). Supplementation with 1.0% L-arginine decreased the percentages of piglets weighing less than 800 g by 5.60 and 5.08 points at birth and at 24 hr of life respectively. Piglets from sows supplemented with L-arginine had higher (p = .088) average rectal temperatures at birth and lower (p = .030) rectal temperature at 24 hr of life in comparison with control piglets. No significant differences in placental weight or estimated colostrum production and intake were observed in the first 24 hr of life. At 24 hr of life, piglets weighing less than 1,000 g and from supplemented sows had lower (p = .048) surface/mass ratios and higher body mass index (p = .070). Piglets from supplemented sows and who weighed 1601 to 1,800 g had lower body mass index and ponderal index (p = .002; p = .003). Supplementation with L-arginine during the final third of gestation reduces the incidence of unviable piglets (<800 g) and improved litter uniformity and piglets' body conformation within the first 24 hr of life.