Membrane peroxidation index and maximum lifespan are negatively correlated in fish of the genus Nothobranchius.

The lipid composition of cell membranes is linked to metabolic rate and lifespan in mammals and birds but very little information is available for fish. In this study, three fish species of the short-lived annual genus Nothobranchius with different maximum lifespan potential (MLSP) and the longer-lived outgroup species Aphyosemion australe were studied to test whether they conform to the predictions of the longevity-homeoviscous adaptation (LHA) theory of ageing. Lipid analyses were performed in whole-fish samples and the peroxidation index (PIn) for every phospholipid (PL) class and for the whole membrane was calculated. Total PL content was significantly lower in A. australe and N. korthausae, the two species with the highest MLSP, and a negative correlation between membrane total PIn and fish MLSP was found, meaning that the longer-lived fish species have more saturated membranes and, therefore, a lower susceptibility to oxidative damage, as the LHA theory posits.