Adverse metabolic phenotype in low-birth-weight lambs and its modification by postnatal nutrition

Both high and low maternal dietary intakes adversely affect fetal nutrient supply in adolescent sheep pregnancies. Aims were: (a) to assess the impact of prenatal nutrition on pregnancy outcome, offspring growth and offspring glucose metabolism and (b) to determine whether the offspring metabolic phenotype could then be altered by modifying postnatal nutrition. Dams carrying a single fetus were offered either an optimal control (C) intake to maintain adiposity throughout pregnancy, undernourished to maintain weight at conception but deplete maternal reserves (UN), or overnourished to promote rapid maternal growth and adiposity (ON). Placental weight and gestation length were reduced in ON dams and lamb birth weights were C>UN>ON (P < 0·001). All offspring were fed ad libitum from weaning to 6 months of age. ON offspring exhibited rapid catch-up growth and had increased fasting glucose and relative glucose intolerance compared with C offspring (P < 0·05). Irrespective of prenatal diet and sex, birth weight correlated negatively with these indices of glucose metabolism. From 7 to 12 months offspring either had continued ad libitum diet (ADLIB; to induce an obesogenic state) or a decreased ration appropriate for normal growth (NORM). At 12 months, the negative relationship between birth weight and indices of glucose metabolism persisted in ADLIB females (for example, fasting glucose, r - 0·632; P < 0·03) but was absent in NORM females and in both male groups. Therefore, low-birth-weight offspring from differentially achieved prenatal malnutrition exhibit an early adverse metabolic phenotype, and this can apparently be ameliorated by postnatal nutrition in females but not in males.