Effects of dietary L‐arginine supplementation to early pregnant mares on conceptus diameter—Preliminary findings

Abstract

ContentsThe importance of the amino acid L‐arginine (ARG) for conceptus growth and litter size has been demonstrated in various species. L‐arginine is part of embryo‐derived polyamines, a substrate for nitric oxide synthase and stimulates protein synthesis by the embryo. In the present study, we have investigated whether dietary L‐arginine supplementation stimulates early conceptus growth in mares. Warmblood mares with singleton pregnancies received either an arginine‐supplemented diet (approximately 0.0125% of body weight, n = 12) or a control diet (n = 11) from days 15 to 45 after ovulation. Diameter of the embryonic vesicle (days 14, 17, 20 of pregnancy) and size of the embryo respective foetus (length and maximal diameter, days 25–45 of pregnancy at 5‐day intervals) were determined by transrectal ultrasound. At foaling, weight and size of the foal and the placenta were determined. Blood for determination of equine chorionic gonadotrophin (eCG) and progestin concentrations was collected repeatedly. Neither eCG nor progestin concentration in plasma of mares differed between groups at any time. No effects of arginine treatment on diameter of the embryonic vesicle between days 14 and 20 of pregnancy were detected. Diameter of the embryo/foetus on days 40 to 45 of pregnancy strongly tended to be enhanced by arginine supplementation (p = 0.06). Weight and size of neither the foal nor placenta at birth differed between groups. In conclusion, L‐arginine supplementation was without negative effects on early equine embryos and may support embryonic growth at the beginning of placentation.

Effects of dietary arginine supplementation in pregnant mares on maternal metabolism, placental structure and function and foal growth

“…In the present study, L-arginine supplementation appeared harmless but long-term effects for both the mare and the foal have not been studied. Moreover, effects of earlier supplementation 51 or longer supplementation should be explored.…”

Oral Administration of Spirulina platensis at Early Gestation Modulates Litter Size and the Expression of Inhibin, Insulin, IGF-I, CO Q10, and BMP-15 in Ewes Induced for Twinning

“…Subsequently, Zeitoun and his associates orally administered Larginine during the frst 56 days postmating in Najdi ewes and obtained a heavier birth weight by 35% than control lambs [9]. Tis fnding was later confrmed in mares, since Larginine supplementation in early pregnancy supported embryonic growth and the initiation of placentation [10].…”