Does dam pre-breeding nutrition and/or birth rank affect the glucose and fat metabolism of 18-month-old female offspring?

Abstract

Twin- and triplet-born lambs are smaller and lighter at birth than singletons and remain so until at least 1 year of age. However, there is little evidence in the literature to demonstrate if these smaller/lighter twin- and triplet-born lambs are metabolically different to singletons later in life. Additionally, many studies have demonstrated that dam nutrition during the periconceptual period can program the fetus in utero, influencing development, growth and performance later in life. However, little is known regarding the impact of differing levels of maternal nutrition before the periconceptual period, during the period of preantral follicle development. This study aimed to determine if dam pre-breeding nutrition (High versus Maintenance, 113–71 days pre-breeding) and birth rank (single versus twin versus triplet) affected the metabolic responses of ewes at 18 months of age, to an intravenous glucose (0.17 g/kg liveweight) (GTT) and insulin (0.15 IU/kg liveweight) (ITT) tolerance test. Dam pre-breeding nutrition had no effect (P > 0.05) on glucose and insulin responses to GTT, or glucose and cortisol responses to ITT. However, before both GTT and ITT, ewes born to High-fed dams had greater (P < 0.05) β-hydroxybutyrate (β-HBA) baselines than those born to Maintenance-fed dams, and also had greater (P < 0.05) maximum β-HBA change in response to both GTT and ITT. Birth rank tended (P = 0.06) to affect maximum glucose concentration change in response to glucose administration, with twin-born ewes having a greater increase in glucose compared with both singletons (P = 0.06) and triplet-born (P < 0.05) ewes in response to a glucose challenge. Insulin area under the curve 0–120 min after glucose administration of twin-born ewes was lower (P = 0.05) than both single- and triplet-born ewes. Prior to ITT, baseline β-HBA concentrations of single-born ewes were lower (P < 0.05) than triplet-born ewes. Single-born ewes had a reduced (P < 0.05) decrease in β-HBA change compared with twin- and triplet-born ewes in response to ITT. In summary, this study showed little difference in glucose and insulin metabolism of single-, twin- and triplet-born lambs at 18 months of age. However, the level of dam nutrition 113–71 days pre-breeding appears to have lasting effects on β-HBA metabolism in ewe progeny. The next step is to determine if these metabolic differences result in any measurable animal performance differences, as this would have implications for feeding regimes of ewes before mating and selection of appropriate ewe progeny for use as replacement animals.