Influence of dietary L-arginine supplementation of sows during late pregnancy on piglet birth weight and sow and litter performance during lactation

Two experiments were conducted to determine the effect of feeding supplemental L-Arg during late pregnancy on piglet birth weight and pre-weaning performance. In Exp. 1, 97 gilts and sows were allotted (gestation d 93) to receive a control diet (CON; 19.8 g standardized ileal digestible [SID] Arg/d) or the CON + 1.0% L-Arg (ARG; 46.6 g SID Arg/d). Gilts and sows were weighed on gestation d 93 and 110, 48 h after farrowing, and at weaning. Data, including number born alive, number weaned, individual birth and weaning weight, and placenta weight, were recorded. Blood samples were collected on d 93 and 110 and analyzed for plasma IGF-1, insulin, and blood urea nitrogen concentration. In a second experiment, 383 sows in a commercial research farm were allotted to receive CON or ARG. An L-Arg premix was provided daily by top dress beginning at gestation d 81 (+/- 0.1 d) and fed for an average of 35 d (+/- 0.2 d). Sows received 2.73 kg feed/d with CON sows provided 17 g SID Arg/d and ARG sows receiving a total of 44 g SID Arg/d. Litter birth weight was recorded and average birth weight was computed. In a subset of 82 sows, individual birth weights were recorded. In Exp. 1, there was a tendency for greater late pregnancy maternal BW gain (P = 0.06) in ARG compared with CON. A tendency for a parity x treatment interaction was observed for late pregnancy BW gain, with first litter sows fed ARG gaining the most, gilts fed ARG intermediate, and all other treatments gaining the least (P = 0.10). No differences between treatment groups were observed for maternal plasma IGF-1, insulin, and urea nitrogen and in progeny performance to weaning (P > 0.28). In Exp. 2, piglet birth weight was more effectively tested because of the large number of multiparous sows involved. There was a tendency for individual birth weight to decline in ARG compared with CON (P < 0.08), but birth weight distribution between < 0.80 and > 2.8 kg was similar. No other differences were observed (P > 0.18). In conclusion, late pregnancy supplementation with L-Arg had no effect on number of pigs born alive, piglet birth weight, or lactation performance.