Professor Goro Yoshizaki and the project: artificially bred yamame salmon. (Photo: Stockfile)
Researchers breed salmon using surrogate parents
Wednesday, January 16, 2013, 03:00 (GMT + 9)
Researchers from Tokyo University have managed to artificially breed one species of fish using surrogate parents from a related species -- an achievement that could eventually help scientists conserve endangered species.
"I would like to make a bank of reproductive cells of the world's endangered fish, and we would store them until rivers became healthy environments again, after which we would raise the fish and release them," said Tokyo University of Marine Science and Technology professor Goro Yoshizaki, who worked on the research.
The research results appeared this week in the online journal Proceedings of the National Academy of Sciences.
This development began in 2006, when the researchers conducted an experiment consisting of transplanting cells that later become sperm cells into newly hatched fish, such as salmon or trout. They found that this process yields either sperm or eggs, depending on the sex of the fish.
For their most recent work, the researchers freeze-preserved the testes of seema, or yamame salmon, for 54 days, and subsequently extracted cells from them that turn into sperm. These cells were then inserted into the bodies of young, sterilized male and female rainbow trout.
As these rainbow trout reached adulthood, the male trout began producing seema sperm and the female trout began producing seema eggs. The scientists then artificially united these sperm and eggs, and seema fish were born.
According to Yoshizaki, this method is complete and allows the team to recreate sperm and egg cells and individual salmon successfully, at least with yamame salmon and rainbow trout at this time, The Japan Daily Press reports.
"We have confirmed the technology can also apply to tiger pufferfish as well," he added, AFP reports.
The research team will soon preserve testes of the black kokanee fish, which was found recently for the first time in 70 years in Lake Saiko, Yamanashi Prefecture. Additionally, the team hopes to eventually be able to apply the same technology on amphibians, reptiles and later mammals as well.
"But the hurdle is still high because the sets of genes are much more different between male and female mammals," Yoshizaki said.
By Natalia Real