Nofima scientist Adrijana Skugor. (Photo: Jon-Are Berg Jacobsen/Nofima)
Vaccine fights sexual maturation in farmed cod
Monday, July 08, 2013, 00:20 (GMT + 9)
Based on the fact that the early onset of sexual maturity is a great problem in cod aquaculture because of the negative effects on growth, feed conversion and health and that farmed cod that escape can also affect the genes of wild fish a researcher of the food research institute Nofima has examined the biological mechanisms that control the development of the sex organs in cod.
As part of her doctorate, the researcher Adrijana Skugor has studied both individual genes and the whole cod genome to obtain more information about how the germ cells of the embryo develop into eggs and sperm.
A "dead end" shows the way
Skugor has previously studied zebrafish and has made use of the knowledge she gained then. In zebrafish, the dead end gene (DnD) is necessary for sexual maturity, and she has now been studying the significance of this gene in Atlantic cod.
This researcher injected cod embryos with a molecule that blocks DnD and found that inactivation of the gene affected the development of germ cells also in cod. In addition, she used micro array screening to study the effects of DnD inactivation in a wider context.
Transferring knowledge to salmon research
"We now know that DnD is a good candidate for preventing the onset of sexual maturity, so that fish become sterile," says Skugor. "But the method used is costly and complicated and cannot be used commercially. It has however been important in the work of developing tools that make it easier to obtain information about how cells develop."
As a commercial method, it may be better to block the dead end proteins in the mother fish, rather than blocking the dead end gene in the embryo. As post doc fellow Skugor will establish this strategy in salmon, because early sexual maturation is a problem also in salmon farming. In this way, much of what has been learned from studying cod can be brought into the work on salmon, in the same way as this researcher previously made use of knowledge from zebrafish studies.
"Adrijana's research has improved our knowledge about the differentiation of germ cells and about the embryonic development of Atlantic cod", says supervisor Øivind Andersen, Senior Scientist at Nofima.
The English title of the thesis is "Transcriptional profiling of maternally deposited factors in Atlantic cod (Gadus morhua) embryos and the role of Dead end in primordial germ cell development".