[Show abstract][Hide abstract] ABSTRACT: This study utilized maternal undernutrition from early to midgestation in the ewe to determine the impact(s) of intrauterine growth restriction on postpartum growth of male offspring and the potential mechanisms involved. Multiparous ewes were fed 50% (nutrient-restricted) or 100% (control-fed) of their nutrient requirements (NRC, 1985) between d 28 and 78 of gestation, and then all ewes were fed 100% of the NRC requirements from d 79 through lambing. Male lambs born to nutrient-restricted (n = 9) and control-fed (n = 9) ewes exhibited similar BW (5.8 vs. 6.0 +/- 0.3 kg) and crown-rump lengths (53.8 vs. 55.4 +/- 1.0 cm) at birth. At 63 and 250 d of postnatal age, wether lambs were subjected to a glucose tolerance test, in which a bolus of glucose was administered i.v. to evaluate changes in glucose and insulin concentrations. After i.v. glucose administration at 63 d of age, lambs from nutrient-restricted ewes exhibited a greater area under the curve for glucose (AUCg; 6,281 vs. 5,242 +/- 429; P < 0.05) and insulin (AUCi; 21.0 vs. 8.6 +/- 1.9; P < 0.001) than lambs from control-fed ewes. After glucose administration at 250 d of age, lambs from nutrient-restricted ewes had greater AUCg (7,147 vs. 5,823 +/- 361; P < 0.01) but a lower AUCi (6.4 vs. 10.2 +/- 1.9; P = 0.05) than lambs from control-fed ewes. Lambs from nutrient-restricted ewes were heavier (26.6 vs. 21.8 +/- 2.3 kg; P < 0.05) and had more backfat (0.30 vs. 0.21 +/- 0.03 cm, P < 0.05) by 4 mo of age than the lambs from control-fed ewes. At slaughter at 280 d of age, lambs from nutrient-restricted ewes remained heavier than lambs from control-fed ewes, had greater (P < 0.05) amounts of kidney and pelvic-area adipose tissue, and tended (P < 0.10) to have reduced LM and semitendinosus muscle weights as a percentage of HCW. These data demonstrate that a bout of maternal undernutrition during early to midgestation in sheep increased BW and fat deposition during adolescence and dysregulated glucose uptake in the absence of any change in birth weight.
[Show abstract][Hide abstract] ABSTRACT: Under-nutrition during early gestation can affect muscle development in the postnatal lamb. Our purpose was to determine if fetal growth was affected by nutrient restriction of the gestating ewe. Control (C) ewes were fed 100% of the National Research Council (NRC) recommended diet for gestating ewes. Nutrient restricted (NR) ewes were fed 50% of NRC recommendations during days 28 to 78 of gestation. Control and NR ewes were euthanized (d 78 gestation) prior to removal of gravid uteri. The head and internal organs were removed after the fetus(s) were taken from the uterus. Eviscerated ewes and fetuses were hung by the Achilles tendon for 24 to 34 h at 4°C or 15°C, respectively. Subsequently, ewe and fetus Longissimus dorsi (Ld) and Semitendinosus (St) were removed. Whole body, eviscerated body, Ld, and St weights were recorded. Whole body weight tended (P = 0.07) to be lower in NR ewes, although ewe eviscerated weight was not different (P = 0.13). Fetal whole body (P = 0.49) and eviscerated weights (P = 0.58) were not different. However, fetal Ld weight as percentage of fetal whole body weight and as percentage of eviscerated fetal weight were different (P = 0.02) because Ld weights of NR fetuses tended to be heavier (P = 0.10) than C fetuses, 3.34 and 2.92 g, respectively. This relationship was not found for fetal St (P = 0.51). Ewe Ld and St weights were not different (P > 0.10) as percent of ewe whole body and eviscerated weight. Nutrient restriction of ewes during 28 to 78 d of gestation causes differential changes in muscle development.