Sperm transplant could save endangered fish
Picture: D Morel
Scientists from the Tokyo University of Marine Science and Technology have developed a surrogacy method that shows great potential in conserving endangered (or even extinct) fish species.The results are published in a report in the latest issue of the journal Science by Tomoyuki Okutsu, Shinya Shikina, Megumi Kanno, Yutaka Takeuchi and Goro Yoshizaki.
The method, dubbed “surrogate broodstocking” by the authors, involves the transplantation of primordial germ cells or spermatogonia from the target species into a related species for which rearing techniques are well developed.
This causes the recipient species to produce the eggs and sperm of the target species.
As an experiment, the authors introduced spermatogonia and primordial germ cells of adult rainbow trout, Oncorhynchus mykiss, via intraperitoneal microinjection into embryos of triploid sterile masu salmon, O. masou (the hybrids of the two species do not survive).
The testes of the control fish, in which no transplantation took place, were immature and contained only spermatogonia, while those of the transplanted fish were normal and mature.
Of the fish receiving the spermatogonia, 10 of the 29 male recipients produced milt, which when used to fertilise wild-type rainbow trout eggs, produced normal rainbow trout young (confirmed by DNA fingerprinting).
Similarly, 4 of 8 female recipients produced vitellogenic oocytes after 17 months (the ovaries of intact triplod salmon of the same age contained no vitellogenic oocytes).
These eggs, when fertilised with milt from male recipient salmon, also produced normal rainbow trout young at a hatching rate of 89.5%.
A bigger step for surrogate broodstocking is to be taken next month, when scientists from Idaho attempt to produce the sockeye salmon (which is highly endangered in the state) using this method on more plentiful trout.
For more information, see the paper: Okutsu, T, S Shikina, , M Kanno, Y Takeuchi and G Yoshizaki (2007) Production of trout offspring from triploid salmon parents. Science 317, p. 1517.
This article may not be reproduced without permission.
Heok Hee Ng: 14.9.2007Views: Read 4,990 times
Comments feed
"Fascinating stuff… How do they come up with these ideas. It would be interesting to see what those “against” animal testing think about this subject. In reality this is just another angle and this is beneficial to the animal world… Where will this lead to… What are the pluses for the animal kingdom? "
Posted by: Paul M (kozmiktramp) - 2 years, 2 months agoDate: Saturday September 15th, 2007, 9:41 pm
"Wow..... nothing more needs to be said. Its research and breakthroughs like this that keep me working hard for my A levels and aspirations of a degree in Zoology and Marine Biology. I Just hope when my time comes enough species will still survive for me to help. *sigh* only 5 years to go :)"
Posted by: Alex Roff - 2 years, 1 month agoDate: Saturday September 22nd, 2007, 11:05 pm
Please login to leave a comment
Login
 | Singapore-based ichthyologist Dr Heok Hee Ng is a leading expert on Asian catfishes and has described dozens of fish ranging from catfishes, to nandids and cyprinids. |
| More articles by Heok Hee Ng » | |
.jpg)
"Amazing!"
Posted by: Matt Clarke - 2 years, 2 months agoDate: Friday September 14th, 2007, 11:57 am