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. Environmental conditions experienced before birth have been suggested to programme postnatal mitochondrial biology, but the hypothesis that early-life conditions induce consistent and long-lasting differences in mitochondrial function among individuals remains mostly untested. We tested this hypothesis in an avian model by experimentally manipulating prenatal conditions (incubation temperature and stability), then measuring mitochondrial aerobic metabolism in blood cells from the same individuals during postnatal growth and at adulthood. Mitochondrial aerobic metabolism changed markedly across life stages, and part of these age-related changes were influenced by the prenatal experimental conditions. A high incubation temperature induced a consistent and long-lasting increase in mitochondrial aerobic metabolism, while unstable incubation conditions had a delayed effect, with an increased metabolism only being observed at adulthood. 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 (<20%) of the consistent among-individual differences we observed. Our results demonstrate that prenatal conditions can program consistent and long-lasting differences in mitochondrial function, which could potentially underly among-individual variation in performance and health state.