Dietary L-Arginine Supplementation during Gestation in Mice Enhances Reproductive Performance andVegfr2Transcription Activity in the Fetoplacental Unit 3

Abstract

Regarded as one of the most versatile amino acids, arginine serves as a precursor for many molecules and has been reported to improve the reproductive performance of rats and pigs. To this end, we sought to determine if dietary L-arginine alters fetoplacental vascular endothelial growth factor receptor-2 (Vegfr2) transcription activity. Eighteen wild-type FVB/N female mice were bred to homozygous FVB/N-Tg(Vegfr2-luc)-Xen male mice. Bred female mice received 1 of 2 experimental diets: one supplemented with 2.00% (wt:wt) L-arginine (+Arg) or 1 supplemented with 4.10% (wt:wt) alanine (+Ala) to serve as an isonitrogenous control for +Arg. In addition, 6 mice were fed a nonsupplemented control (Con) diet to normalize bioluminescent imaging data. All data were analyzed using ANOVA followed by Fisher’s least significant difference. Total feed intake did not differ between groups; however, mice in the +Arg group consumed more arginine (P <0.05). Arginine supplementation increased weight gain during the latter one-third of gestation (d 12– 18), total litter size, number of pups born alive, number of placental attachment sites, litter birth weight, and litter weight of pups born alive but decreased the individual birth weights (P <0.05). During d 12–18, arginine supplementation increased (P <0.05) the mean totalVegfr2transcription activity andVegfr2transcription activity corrected for fetoplacental mass. Moreover, mice in the +Arg group had an earlier rise inVegfr2transcription activity. In conclusion, our results demonstrate that the beneficial effect of dietary L-arginine supplementation on mammalian reproduction is associated with enhancedVegfr2transcription activity in fetoplacental tissues.