Dietary l-arginine supplementation enhances placental growth and reproductive performance in sows

Abstract

Suboptimal embryonic/fetal survival and growth remains a significant problem in mammals. Using a swine model, we tested the hypothesis that dietary L-arginine supplementation during gestation may improve pregnancy outcomes through enhancing placental growth and modulating hormonal secretions. Gestating pigs (Yorkshire×Landrace, n=108) were assigned randomly into two groups based on parity and body weight, representing dietary supplementation with 1.0% L-arginine-HCl or 1.7% L-alanine (isonitrogenous control) between days 22 and 114 of gestation. Blood samples were obtained from the ear vein on days 22, 40, 70 and 90 of gestation. On days 40, 70 and 90 of gestation, concentrations of estradiol in plasma were higher (P<0.05) in arginine-supplemented than in control sows. Moreover, arginine supplementation increased (P<0.05) the concentrations of arginine, proline and ornithine in plasma, but concentrations of urea or progesterone in plasma did not differ between the two groups of sows. Compared with the control, arginine supplementation increased (P<0.05) the total number of piglets by 1.31 per litter, the number of live-born piglets by 1.10 per litter, the litter birth weight for all piglets by 1.36 kg, and the litter birth weight for live-born piglets by 1.70 kg. Furthermore, arginine supplementation enhanced (P<0.05) placental weight by 16.2%. The weaning-to-estrus interval of sows was not affected by arginine supplementation during gestation. These results indicate that dietary arginine supplementation beneficially enhances placental growth and the reproductive performance of sows.

Within-litter variation in birth weight: impact of nutritional status in the sow

“…This positive result is consistent with the presence of unusually high concentrations of amino acids in the arginine family in porcine allantoic fluid at the stage of blastocyst expansion and implantation in vivo (Wu et al, 1996;Gao et al, 2012) and of an increase in endometrial angiogenesis between Days 13 and 18 of gestation (Keys et al, 1986). Furthermore, arginine stimulates the AKT1-mTOR/FRAP1-RPS6K-RPS6 cell signaling pathways to increase proliferation and migration of porcine (Kong et al, 2012) and ovine (Kim et al, 2011) trophectoderm cells during peri-implantation period.…”

“…Therefore, nutrient partitioning among fetuses is less variable as is within-litter variation in birth weight of piglets. However, there are other reports that do not indicate positive effects of dietary supplementation with L-arginine during mid-gestation to term on within-litter uniformity (Mateo et al, 2007;Gao et al, 2012). These different findings may be explained by differences in the total amounts of dietary L-arginine and other amino acids consumed by gestating pigs (Wu et al, 2013b;2013c).…”

“…Amino acids in the arginine family (arginine, glutamine, glutamate, proline, aspartate, asparagine, citrulline, and ornithine) have been studied extensively given their prominent effects in improving litter size (Greenberg et al, 1997;Hazeleger et al, 2007;Mateo et al, 2007;Gao et al, 2012;Li et al, 2014). At the same time, dietary supplementation with 25.5 g/d L-arginine from Day 77 of pregnancy until term reduced within-litter variation in birth weight of live-born piglets by 20.6% and 25.4% in arginine and control groups, respectively (Quesnel et al, 2014).…”

Effects of dietary arginine supplementation on reproductive performance and immunity of sows

“…By excluding the early gestation period, dietary Arg supplementation starting from day 22 or 30 of gestation and continuing until farrowing markedly improved placental growth and litter performance (Mateo et al, 2007;Gao et al, 2012). In this study, Arg supplemented to sows from day 30 to day 90 (Arg90 group) or 114 of gestation (Arg114 group) did not markedly increase total pigs born, however, the less dead pigs in sows receiving Arg between days 30-114 of gestation resulted in more live-born pigs, compared with sows with no Arg supplementation.…”

“…putrescine, spermidine, and spermine), which are crucial for placental angiogenesis, trophoblast growth, and uteroplacental blood flow, thereby stimulating nutrients transfer and wastes exchange, consequently fetal growth and development (Wu et al, 2006). It has been reported that dietary Arg supplementation from early gestation until day 114 of gestation enhanced sow placental growth, litter size, and weight (Mateo et al, 2007;Gao et al, 2012). However, the sow placental growth has reached maximum in late gestation (McPherson et al, 2004;Freking et al, 2007), instead the efficient placenta in late gestation is physiologically required for rapid fetal growth in the last 20 days of gestation (Biensen et al, 1999;Macpherson et al, 2004).…”