Experimental demonstration of prenatal programming of mitochondrial aerobic metabolism lasting until adulthood.

It is increasingly being postulated that among-individual variation in mitochondrial function underlies variation in individual performance (e.g. growth rate) and state of health. It has been suggested (but not adequately tested) that environmental conditions experienced before birth could programme postnatal mitochondrial function, with persistent effects potentially lasting into adulthood. We tested this hypothesis in an avian model by experimentally manipulating prenatal conditions (incubation temperature and stability) and then measuring mitochondrial aerobic metabolism in blood cells from the same individuals during the middle of the growth period and at adulthood. Mitochondrial aerobic metabolism changed markedly across life stages, and parts of these age-related changes were influenced by the prenatal temperature conditions. A high incubation temperature induced a consistent and long-lasting increase in mitochondrial aerobic metabolism. Postnatal mitochondrial aerobic metabolism was positively associated with oxidative damage on DNA but not telomere length. While we detected significant within-individual consistency in mitochondrial aerobic metabolism across life stages, the prenatal temperature regime only accounted for a relatively small proportion (less than 20%) of the consistent among-individual differences we observed. Our results demonstrate that prenatal conditions can programme consistent and long-lasting differences in mitochondrial function, which could potentially underlie among-individual variation in performance and health state.