Researchers from The University of Western Australia have found that a change in a male’s diet can have profound negative effects on sperm quality, and that these effects can influence the quality of his offspring.
The study, published in the Royal Society journal Biology Letters, shows these paternal effects can be transmitted to offspring exclusively via semen, influencing their offspring’s size and potentially their survival prospects.
A team from the UWA Centre for Evolutionary Biology carried out a series of feeding trials on male guppy fish and found harmful effects of diet quantity on the males’ sperm traits, including sperm count, viability and velocity.
They then used these high and low-quality sperm samples to artificially inseminate female guppies. The researchers measured the size of the offspring and tested the male offspring’s sperm to determine whether the effects of diet on sperm quality had carryover effects that influenced offspring traits.
They found that juveniles fathered by males fed the low-quantity diet were significantly smaller than those fed the high-quantity diet. However, as adults, male offspring showed no differences in sperm traits between high and low-feed groups.
Lead author Associate Professor Jonathan Evans, from UWA’s Centre for Evolutionary Biology, said the results may have important implications for the many mating systems in which environmentally induced changes could influence semen quality.
“We know that in many species a male’s diet can have important direct effects on sperm quality and fertility,” Associate Professor Evans said. “What this new research shows is that these environmental effects on male fertility can transcend generations, such that the offspring may also pay a heavy price for their father’s poor diet.
“Whether similar sperm moderated paternal effects extend to other species, including humans, remains to be tested. However, given the known effects of a range of environmental stressors on sperm quality in numerous species, it would be surprising if similar effects were not more widespread than currently reported.”
Associate Professor Evans said it was one of a handful of recent studies to show that paternal effects could be transmitted exclusively via semen and a rare example where maternal influences on offspring traits were controlled through the use of artificial insemination.
“These findings have potentially important fitness implications for the juveniles in terms of how they are likely to perform, and ultimately survive, in the wild,” he said.