Effects of Metabolic Rate and Sperm Competition on the Fatty-Acid Composition of Mammalian Sperm

Document Type

Article

Publication Title

Journal of Evolutionary Biology

Publication Date

1-1-2014

Keywords

lipid peroxidation, mass-specific metabolic rate, polyunsaturated fatty acids, sperm competition, sperm membrane

Abstract

The sperm membrane is a key structure affecting sperm function and thus reproductive success. Spermatozoa are highly specialized and differentiated cells that undergo a long series of processes in the male and female reproductive tracts until they reach the site of fertilization. During this transit, the sperm membrane is prone to damage such as lipid peroxidation. The characteristics and performance of the sperm membrane are strongly determined by the fatty‐acid composition of membrane phospholipids. Polyunsaturated fatty‐acids (PUFAs) are the most prone to lipid peroxidation. Lipid peroxidation and other types of oxidative damage increase with higher metabolism and with higher levels of sperm competition due to the increased ATP production to fuel higher sperm velocities. Consequently, we hypothesized that, in order to avoid oxidative damage, and the ensuing impairment of sperm function, sperm cells exhibit a negative relationship between PUFA content and mass‐specific metabolic rate (MSMR). We also hypothesized that higher sperm competition leads to a reduction in the proportion of sperm PUFAs. We performed a comparative study in mammals and found that high MSMR and high levels of sperm competition both promote a decrease in the proportion of PUFAs that are more prone to lipid peroxidation. The negative relationship between MSMR and these PUFAs in sperm cells is surprising, because a positive relationship is found in all other cell types so far investigated. Our results support the idea that the effects of MSMR and sperm competition on sperm function can operate at very different levels.

Funding Source

This work was supported by a Ramón y Cajal fellowship (RYC‐2011‐07943) to J.d.‐T. and grants from the Spanish Ministry of Economy and Competitiveness (CGL2011‐26341 to E.R.S.R. and CGL2012‐37423 to J.d.‐T.).

Comments

This article was originally published as delBarco-Trillo, J., and Roldan, E.R.S. (2014) Effects of metabolic rate and sperm competition on the fatty-acid composition of mammalian sperm. Journal of Evolutionary Biology, 27(1): 55-62. https://doi.org/10.1111/jeb.12275.

DOI

https://doi.org/10.1111/jeb.12275

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