AsianScientist (Jun. 23, 2016) – Researchers in Japan have revealed how female chickens are able to store sperm for long periods of time: droplets of fat transferred from female cells to sperm cells may contribute to keeping sperm alive.
All chickens have the same basic reproductive biology; the research published in Theriogenology is thus relevant to both the meat and egg varieties of farm chickens.
Females of some types of insects, reptiles and birds can store sperm from multiple males within specialized sperm storage areas of their reproductive tracts. The storage time differs, and it ranges from days to years. Stored sperm can fertilize multiple eggs over time, meaning females do not need to mate again to fertilize additional eggs.
“Farmers may be able to more successfully breed their flocks if we could understand how the sperm stays viable in the sperm storage tubules of female chickens,” said lead researcher Professor Yukinori Yoshimura from the Graduate School of Biosphere Science at Hiroshima University.
“Fertility studies like this are especially relevant to countries that breed native chickens with lower reproductive rates.”
The research team identified five types of lipid, or fatty acids, that exist as droplets inside the cells of female chickens’ sperm storage tubules. After the chickens were artificially inseminated, a gene responsible for breaking down those lipids became 2.5 times more active. These broken-down lipids may be released into the sperm storage tubules and improve the sperm’s survival.
Next, the researchers stored freshly collected chicken sperm in solutions containing different concentrations of the individual lipids. They found that high concentrations of two types of lipid, oleic acid and linoleic acid, increased the number of sperm still alive after 24 hours.
“We are doing ongoing research into the cell biology of how the female cells and sperm cells use these lipids, but I also want to examine if supplementing the female chickens’ diet with olive fruits or sunflower seeds, foods high in oleic acid, could enhance fertility,” said Yoshimura.
The article can be found at: Huang et al. (2016) Expression of Lipases and Lipid Receptors in Sperm Storage Tubules and Possible Role of Fatty Acids in Sperm Survival in the Hen Oviduct.
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Source: Hiroshima University; Photo: Shutterstock.
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