Transient high glycaemic intake in the last trimester of pregnancy increases offspring birthweight and postnatal growth rate in sheep: a randomised control trial

OBJECTIVE Investigate the effect of transient hyperglycemic intake (analogous to snacking on high glycaemic foods) in the third trimester of pregnancy on offspring birthweight and subsequent growth in sheep. DESIGN Randomised trial. SETTING University research farm. SAMPLE Third trimester pregnant ewes. METHODS Ewes were blocked on weight, age and litter size and were randomly assigned to receive oral administration of 100 ml of propylene glycol (PG; n = 51) or 100 ml of water (control, C; n = 53) twice/day. Twice during treatment, 12 ewes from each group were selected and blood samples collected to determine the glucose and insulin response to treatment. MAIN OUTCOME MEASURES At birth, blood was collected from the lambs, their body dimensions measured and body weights recorded at 0, 6 and 12 weeks of age after which lambs were slaughtered when they reached 40 kg live weight. RESULTS Administration of PG elevated (P < 0.05) plasma glucose and insulin concentrations for 2 hours post administration compared with control ewes. Lambs (C: n = 80; PG: n = 70) born to ewes fed high glycaemic meals had higher birthweights (C: 5.01 +/- 0.18 kg; PG: 5.27 +/- 0.22 kg, P = 0.032), plasma glucose concentrations (P = 0.001) and ponderal index (weight/height(3), P = 0.043) and reached a similar (P > 0.05) slaughter carcass weight (C: 20.0 +/- 0.51 kg; PG: 20.6 +/- 0.55 kg) at an earlier age (PG: 166.0 +/- 13.2; C: 183.4 +/- 13.8 days, P = 0.039) compared with control lambs. CONCLUSIONS Transient high glycaemic intakes in the third trimester of pregnancy resulted in heavier offspring at birth that had faster growth rates in early postnatal life. This animal model is relevant for studying the relationship between maternal diet, fetal size and the risk of childhood obesity.