Dietary arginine supplementation during early pregnancy enhances embryonic survival in rats.
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Four experiments were conducted with 120 pregnant Sprague-Dawley rats to determine effects of dietary arginine supplementation on embryonic survival. Rats were fed a nonpurified diet supplemented with 1.3% (wt:wt) L-arginine-HCl or 2.2% (wt:wt) L-alanine (isonitrogenous control) throughout pregnancy (Expt. 1), between d 1 and 7 of gestation and then the nonpurified diet until parturition (Expt. 2), between d 1 and 7 of gestation for determining the number of surviving embryos on d 7 (Expt. 3), or between d 1 and 4 of pregnancy for blood sampling on d 5 after overnight food deprivation (Expt. 4). Litter size increased (P < 0.01) in response to arginine supplementation throughout pregnancy (14.5 +/- 0.62 vs. 11.3 +/- 0.61) or during the first 7 d of pregnancy (14.7 +/- 0.33 vs. 11.3 +/- 0.37). The number of surviving embryos was greater (P < 0.01) when arginine was supplemented between d 1 and 7 of pregnancy (14.7 +/- 0.39 vs. 11.4 +/- 0.66). Concentrations of nitric-oxide metabolites, arginine, proline, glutamine, and ornithine were higher (P < 0.05), but urea levels were lower (P < 0.05) in the serum of arginine-supplemented rats compared with the control group. The arginine treatment increased (P < 0.05) protein levels for inducible and constitutive nitric-oxide synthase at implantation sites by 35-37%. These results indicate that dietary arginine supplementation enhances embryonic survival, therefore increasing litter size by 30% at term birth. This novel finding has important implications for preventing early pregnancy loss and enhancing reproductive performance in mammals.
author list (cited authors)
Zeng, X., Wang, F., Fan, X., Yang, W., Zhou, B. o., Li, P., ... Wang, J.