Supplementation of Underfed Twin-Bearing Ewes with Herbal Vitamins C and E: Impacts on Birth Weight, Postnatal Growth, and Pre-Weaning Survival of the Lambs.

Twin-bearing pregnancies of sheep reared in harsh environmental conditions result in maternal undernutrition and feto-maternal oxidative stress, leading to intrauterine growth restriction (IUGR). We assessed the efficiency of supplementation with antioxidant herbal vitamins C and E alone or in combination with concentrate throughout gestation on pregnancy outcomes, pre-weaning growth, and survival of twin lambs from grazing ewes at the Magellan Steppe. Four groups (n = 30 each) of twin-bearing ewes received a base natural prairie (P) diet, supplemented with either herbal vitamins C 500 mg and E 350 IU per day (V) or concentrated food (S); groups were: P, P + V, P + S, and P + VS. Vitamins and concentrate were supplemented until parturition. At birth, lambs were weighed, and blood was drawn for total antioxidant capacity (TAC) evaluation. Lamb body weight (BW) and survival rate were evaluated at mid-lactation (60 days) and at weaning (120 days). Vitamin supplementation resulted in increased lamb birth weight and TAC, with a trend towards higher BW at weaning, while nutritional supplementation only had a positive effect on birth weight. Lamb survival was higher in both vitamin supplemented groups. In conclusion, supplementation with herbal vitamins C and E alone or in combination with concentrate food during pregnancy may constitute a good nutritional strategy for sheep reared in harsh environmental conditions.

Maternal Supplementation with Antioxidant Vitamins in Sheep Results in Increased Transfer to the Fetus and Improvement of Fetal Antioxidant Status and Development.

Twinning and maternal nutritional restriction leads to fetal hypoxia, oxidative stress, and intrauterine growth restriction (IUGR) in near-term sheep pregnancies. Our aim was to determine the effect of oral supplementation of vitamins C and E in pregnant sheep on maternal and umbilical cord blood concentrations of vitamins C and E and the effects on fetal antioxidant status, growth, and placental efficiency. Sixteen single- and sixteen twin-bearing ewes, grazing natural Patagonian prairies, were selected after transrectal ultrasound at day 30 after mating. Half of ewes from each pregnancy rank were supplemented daily with vitamins C and E, administered orally, from 30 to 140 days of gestation, when maternal jugular and fetal venous cord blood samples were obtained during cesarean section. Fetuses were weighed and sexed. Placental weight in each fetus was also obtained. Blood plasma was harvested for measurements of maternal and fetal vitamins concentration and fetal antioxidant capacity. Maternal administration of vitamin C and E was associated with increased fetal cord levels of both vitamins, improved antioxidant status, and enhanced fetal growth in both singleton and twin pregnancies associated with increased placental efficiency. These results highlight the potential of vitamin C and E supplementation to reduce the impact of IUGR in both livestock and humans.

Rapid Communication: Maternal melatonin implants improve fetal oxygen supply and body weight at term in sheep pregnancies.

Fetal hypoxia, resulting in oxidative stress in pregnancies, contributes to reduced fetal growth. Melatonin, a potent antioxidant, has been associated with improved oxidative status. Maternal oral melatonin supplementation in sheep from day 50 of gestation ameliorates the consequences of fetal growth restriction in sheep. In rats, melatonin supplementation increases fetal weight via improved placental efficiency and reduction of oxidative stress. The objective of this study was to evaluate whether melatonin supplementation of single (S)- or twin-bearing (T) ewes using either 0 (0MEL), 1 (18-mg MEL), or 2 (36-mg MEL) slow release 18-mg melatonin implants (Regulin) from 100 to 140 d of pregnancy (n = 8 per group) influenced fetal oxygen supply and fetal weight. Fetal umbilical vein blood samples were collected at P140 and partial pressure of oxygen (PO2) and hemoglobin saturation by oxygen (SatHb) measured. The placenta from each fetus was excised and placentomes individually weighed and typed (A-D). Pregnancy rank, sex of the fetus, number of implants, and their interaction on fetal weight, blood gases, and placentome weight were analyzed using ANOVA. A 22% and 14% increase (P < 0.05) in body weight was obtained in 36- and 18-mg MEL compared with 0 MEL twin male fetuses, respectively, but no treatment effects were observed in singletons or females from twin pregnancies. Fetuses from ewes receiving 36-mg MEL had an 18% to 20% increase in cord PO2 (P < 0.05) compared with 18-mg MEL and 0MEL fetuses, which in turn did not differ. Fetal weight was positively correlated with PO2 (r = 0.37; P = 0.02), SatHb (r = 0.26; P = 0.03), and O2 content (r = 0.236; P = 0.048). No treatment effect on placentome average weight, total placentome weight per fetus or per ewe, nor total number of placentomes per fetus was observed. However, placentae from 36-mg MEL fetuses had a greater proportion of Type C (P < 0.05) than 0MEL and 18-mg MEL ewes, and tended to have a lower proportion of Type A (P = 0.1) and a greater proportion of Type D (P = 0.06) placentomes, compared with 0MEL ewes. These results indicate that maternal melatonin implants, independently of sex, improve oxygen supply to the fetus, which could potentially improve lamb vigor at birth. In addition, melatonin can increase fetal weight of twin males, by improving placental adaptation and fetal blood oxygenation.

Hypoxia and Oxidative Stress Are Associated with Reduced Fetal Growth in Twin and Undernourished Sheep Pregnancies.

Low birth weight has profound implications for perinatal mortality and morbidity in lambs, causing higher mortality and lower growth potential. Low birth weight, as a consequence of fetal growth restriction, occurs in undernourished and multiple pregnancies, where hypoxia and oxidative stress could play a critical role. Our aim was to establish the effects of nutritional deprivation and pregnancy rank on fetal growth, oxygenation, and oxidative status in sheep pregnancies under extensive Patagonian conditions. At 30 days after mating, single- and twin-bearing ewes were offered only natural pasture (undernutrition group) or natural pasture plus concentrate supplementation (well-nourished group). At day 140 of gestation, blood gases and redox status were evaluated in venous cord blood, and fetal biometric characteristics were obtained after cesarean section. Both maternal undernutrition and twinning led to decreased oxygen supply to the fetuses (p = 0.016 and p = 0.050, respectively), which was associated with decreased intrauterine growth (r = 0.446, p < 0.01). Moreover, twinning increased oxidative stress in cord blood (p < 0.05), which might also contribute to fetal growth restriction. These results reinforce the importance of maternal nutrition, especially for those ewes bearing multiples, and opens new possibilities for nutritional or antioxidant interventions for preventing fetal hypoxia and oxidative stress.