Dietary Supplementation with Arginine Between Days 14 and 30 of Gestation Enhances Survival and Development of Conceptuses in Gilts

Most embryonic loss in pigs occurs before d 30 of gestation during the peri-implantation period. We conducted this study to test the hypothesis that dietary arginine supplementation between days 14 and 30 of gestation can enhance survival and development of the conceptus (embryo and its extra-embryonic membranes) in gilts. Gilts were fed 1 kg of a corn- and soybean-meal based diet containing 12% crude protein twice-daily beginning on d 0 of gestation (the day of breeding). Either 0.4% L-arginine (as L-arginine-HCl, n=7) or an isonitrogenous amount of L-alanine (n=6) was supplemented to the basal diet between d 14 and d 30 of gestation. On d 30 of gestation, gilts were fed either L-arginine-HCl or L-alanine and hysterectomized 30 minutes later. Uterine tissue, embryos, fetal membranes and fetal fluids were collected. Data were analyzed by X² analysis or the unpaired t-test. Compared to the control group, arginine supplementation increased (P<0.05) embryonic survival by 28% (75.5% in the control group vs. 96.5% in the arginine group), allantoic fluid volume by 25.3%, and amniotic fluid volume by 48.1%. The placentae of arginine-supplemented gilts were more vascularized in terms of the number and size of blood vessels. Maternal body weight, uterine weight, maternal liver weight, number of corpora lutea and relative weights of fetal livers were not different between the 0.4% arginine-treated and control gilts. We conclude that dietary arginine supplementation to pigs between d 14 and d30 of gestation improves survival and development of the conceptuses. Supported by USDA-NIFA grants.