Effect of sperm competition on the fatty-acid composition of the sperm membrane

Abstract

The characteristics and performance of sperm membranes are strongly determined by the fatty-acid composition of the membrane phospholipids. During the transit of sperm towards the ova, sperm membranes are prone to damage such as lipid peroxidation caused by reactive oxygen species (ROS). To avoid such damage, and the ensuing impairment of sperm function, there may have been a reduction in the polyunsatured fatty-acid (PUFA) content of sperm cells, since PUFAs are the fatty acids most prone to lipid peroxidation. This should be especially the case in species with high levels of sperm competition, because in these species there is selection to maximise sperm function. We performed comparative and experimental studies in several mammalian species that differ in their levels of sperm competition. Among other findings, we determined that high levels of sperm competition promote a reduction in the proportion of PUFAs in sperm membranes.