Key points To investigate loss of skeletal muscle mass in intrauterine growth‐restricted (IUGR) fetuses near term, which may result from myoblast dysfunction, we examined semitendinosus myofibre and morphology placental insufficiency‐induced IUGR sheep fetuses; also isolated cultured fetal myoblasts to determine whether reduced rates proliferation were due intrinsic cellular defects or extrinsic factors associated with serum. Using tests for myogenin pax7 identify differentiated...

Intrauterine growth restriction (IUGR) reduces muscle mass and insulin sensitivity in offspring. Insulin varies among fiber types, with Type I fibers being most sensitive. Differences fiber-type ratios are associated resistance adults, thus we hypothesized that near-term IUGR sheep fetuses exhibit reduced size proportions of fibers. Placental insufficiency-induced were ∼54% smaller ( P < 0.05) than controls exhibited hypoxemia hypoglycemia, which contributed to 6.9-fold greater plasma...

Abstract In pregnancies complicated by placental insufficiency and intrauterine growth restriction (IUGR), fetal glucose oxygen concentrations are reduced, whereas plasma norepinephrine epinephrine elevated throughout the final third of gestation. Here we study effects chronic hypoxemia hypercatecholaminemia on β-cell function in sheep with insufficiency-induced IUGR that is produced maternal hyperthermia. control fetuses underwent a sham (intact) or bilateral adrenal demedullation (AD)...

Abstract Heat stress (HS) triggers oxidative stress, systemic inflammation, and disrupts growth efficiency of livestock. β-adrenergic agonists supplemented to ruminant livestock improve performance, increase skeletal muscle mass, decrease carcass fat. The objective this study was understand the independent interacting effects HS zilpaterol hydrochloride (ZH) supplementation on transcriptome subcutaneous white adipose tissue longissimus dorsi in steers. Twenty-four Red Angus-based steers were...

Bacterial lipopolysaccharide endotoxins (LPS) elicit inflammatory responses reflective of acute bacterial infection. We determined if feeding ewes high-CP (15.5%) or low-CP (8.5%) diets for 10 d altered to an intravenous bolus 0 (control), 0.75 (L75), 1.50 (L150) μg LPS/kg BW in a 2 × 3 factorial arrangement treatments (n = 5/treatment). Rectal temperatures, heart and respiratory rates, blood leukocyte concentrations, serum cortisol, insulin, glucose concentrations were measured 24 h after...

In pregnancies complicated by placental insufficiency (PI), fetal hypoglycemia and hypoxemia progressively worsen during the third trimester, which increases circulating norepinephrine (NE). Pharmacological adrenergic blockade (ADR-block) at 0.9 gestation revealed that NE inhibits insulin secretion enhanced β-cell responsiveness in fetuses with PI-induced intrauterine growth restriction (IUGR). concentrations PI 0.7 were threefold greater compared age-matched controls, but levels similar to...

Intrauterine growth-restricted (IUGR) fetuses experience prolonged hypoxemia, hypoglycemia, and elevated norepinephrine (NE) concentrations, resulting in hypoinsulinemia β-cell dysfunction. Previously, we showed that acute adrenergic blockade revealed enhanced insulin secretion responsiveness the IUGR fetus. To determine whether chronic exposure to NE alone enhances afterward, continuously infused into fetal sheep for 7 days and, after terminating infusion, evaluated glucose-stimulated...

Key points Hypoxaemia was previously shown to lower fetal plasma insulin at euglycaemia and hyperglycaemia. Lowering redistributes nutrients spares glucose oxygen. also stimulates adrenal medullary secretion of adrenaline noradrenaline, but the impact catecholamines versus local noradrenaline by sympathetic neurons has not been evaluated on concentrations. To determine insulin, we surgically demedullated glands in sheep challenged them with acute hypoxaemia. We found that chromaffin cells...

National Institute of General Medical Sciences [1P20GM104320]; Nebraska Agricultural Experiment Station; USDA Food and Agriculture [1011126, 1011055, 1009410]; NIH (NIGMS) COBRE IDeA award [NIH 1P20GM104320]

Abstract Heat stress hinders growth and well-being in livestock, an effect that is perhaps exacerbated by the β1 agonist ractopamine. deficits are mediated part reduced feed intake, but other mechanisms involved less understood. Our objective was to determine direct impact of heat on ractopamine-supplemented feedlot lambs. Commercial wethers were fed under (40 °C) for 30 d, controls (18 pair-fed. In a 2 × factorial, lambs also given daily gavage 0 or 60 mg Growth, metabolic, cardiovascular,...

Zoological institutions, which were once exclusively for entertainment, are now leaders of wildlife conservation. This centuries-long transition was punctuated by key milestones that reformed wild animal exploitation into a mission protection. Modern zoos perform ex situ activities to preserve natural resources, enabled the housing species. Zoo-managed animals facilitate new scientific knowledge, public education, and strategic breeding maintain genetic diversity. Prioritizing welfare...

GSIS is often measured in the sheep fetus by a square-wave hyperglycemic clamp, but maximal β-cell responsiveness and effects of fetal number sex difference have not been fully evaluated. We determined dose-response curve for (0.9 gestation) increasing plasma glucose from euglycemia stepwise fashion. The glucose-insulin response was best fit curvilinear third-order polynomial equations singletons (y = 0.018x(3) - 0.26x(2) + 1.2x 0.64) twins -0.012x(3) 0.043x(2) 0.40x 0.16). In singles,...

Abstract Feedlot performance is reduced by heat stress and improved β adrenergic agonists (βAA). However, the physiological mechanisms underlying these outcomes are not well characterized, anecdotal reports suggest that βAA may confound effects of on wellbeing. Thus, we sought to determine how affect growth, metabolic efficiency, health indicators in lambs a feedlot diet. Wethers (38.6 ± 1.9 kg) were housed under thermoneutral (controls; n = 25) or (n 24) conditions for 21 d. In 2 × 3...

Complications in pregnancy elevate fetal norepinephrine (NE) concentrations. Previous studies NE-infused sheep fetuses revealed that sustained exposure to high NE resulted lower expression of α 2 -adrenergic receptors islets and increased insulin secretion responsiveness after acutely terminating the infusion. In this study, we determined if compensatory increase chronic elevation is independent hyperglycemia whether it persistent conjunction with islet desensitization NE. After an initial...

Maternal inflammation causes fetal intrauterine growth restriction (IUGR), but its impact on metabolism is not known. Thus, our objective was to determine the of sustained maternal in late gestation inflammation, skeletal muscle glucose metabolism, and insulin secretion. Pregnant ewes were injected every third day from 100th 112th (term = 150 d) with saline (controls) or lipopolysaccharide (LPS) induce IUGR (MI-IUGR). Fetal femoral blood vessels catheterized 118 assess β-cell function 123,...

An ACTH challenge was conducted to determine if salivary cortisol concentration reflects serum in ewes. Twelve yearling ewes (64.0 +/- 1.2 kg) were administered (100 IU, intravenously) or saline. Serum and samples collected at 30-min intervals for 2 h before administration, 15-min after treatment, an additional 3 h, determined by RIA. Although responded saline, greater (P < 0.001) ACTH-treated from 15 120 min tended be = 0.054) 150 serum. In saliva, 30 0.092) challenge. No difference...

Previous studies in fetuses with intrauterine growth restriction (IUGR) have shown that adrenergic dysregulation was associated low insulin concentrations and greater sensitivity. Although whole-body glucose clearance is normal, 1-month-old lambs IUGR at birth higher rates of hindlimb uptake, which may compensate for myocyte deficiencies oxidation. Impaired glucose-stimulated secretion due to lower intra-islet availability not from sensing. We investigated receptor (ADR) β2 desensitization...

Abstract Maternal inflammation induces intrauterine growth restriction (MI-IUGR) of the fetus, which compromises metabolic health in human offspring and reduces value livestock. The objective this study was to determine effect maternal at midgestation on fetal skeletal muscle myoblast profiles term. Pregnant Sprague-Dawley rats were injected daily with bacterial endotoxin or saline (controls) from 9th 11th day gestational age (dGA; term = 21 dGA). At necropsy dGA 20, average mass upper...