Impact of embryo donor adiposity, birthweight and gender on early postnatal growth, glucose metabolism and body composition in the young lamb

Abstract

Intrauterine growth restriction (IUGR) is a risk factor for metabolic syndrome, notably when associated with rapid postnatal catch-up growth. A sheep paradigm was used to assess relationships between prenatal and early postnatal growth trajectories, metabolism and body composition. Singletons (single-sire embryo transfer from obese and control donors) were gestated and suckled by overnourished adolescent dams and categorised by birthweight as IUGR or normal (N). Gestation length was equivalent in both categories and all lambs were delivered spontaneously preterm (PT; mean (±s.e.m.) 139.8±1.7 days; term=145-147 days). The IUGR lambs were smaller at birth, but fractional growth rates (FGR) for eight anthropometry parameters were higher and independent of gender (except thorax girth; males (M)<females (F)). At Day 48, fasting glucose (IUGR>N; M>F) and first-phase insulin response (to 20min; IUGR<N; M<F) after glucose were influenced by prenatal growth and gender. Embryo donor adiposity influenced glucose tolerance only. Plasma insulin, insulin-like growth factor-1 (M>F) and leptin (M<F) were influenced by gender but not prenatal growth. At necropsy (Day 77), IUGR plus PT lambs had decreased carcass and visceral organ weights, but carcass composition was not different from N plus PT. In contrast, M were heavier, with lower internal fat mass, carcass fat percentage and perirenal fat leptin mRNA than F. Therefore, IUGR was associated with increased postnatal FGR and altered glucose handling, but, without absolute catch-up growth, gender had the predominant influence on postnatal leptinaemia and adiposity.