Abstract

Low birth weight is a risk factor for metabolic syndrome, therefore the impact of nutritionally-mediated prenatal growth restriction on growth, body composition and metabolism was investigated in young lambs. Adolescent dams were given control or high intakes during pregnancy to induce normal or compromised placental size, respectively. The resulting normal (N, n=24) or placentally growth-restricted (PGR, n=25) lambs suckled their mothers until weaning at 77 days. Lamb growth rates were measured and a glucose tolerance test (GTT) performed at 49 days. PGR males and females were 49 and 35% lighter than N lambs at birth (p<0.001). Fractional growth rate was elevated in PGR versus N groups (p<0.001) and was highest in PGR males. DEXA body composition assessment at weaning revealed reduced bone mineral density (p<0.02) and increased fat % (p<0.001) in PGR lambs (both genders). Prior to GTT, fasting insulin, glucose, NEFA and glycerol were higher and urea lower in PGR versus N lambs (p=0.023 or less). After GTT, insulin secretion (area under the curve (AUC)) was elevated in PGR versus N groups (p<0.02). Similarly, NEFA and glycerol were increased and urea AUC decreased (p<0.02) in PGR lambs, with the most pronounced effects in males. Thus PGR led to low birth weight, rapid catch-up growth and increased adiposity at weaning. This was associated with increased neonatal insulin secretion and altered indices of fat and protein metabolism after fasting and GTT. These early postnatal changes in body composition and metabolism predict adverse health outcomes in adulthood.