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Add To Calendar 24/02/2016 10:45:0024/02/2016 11:05:00America/ChicagoAquaculture 2016PRODUCTION OF TRANSGENIC TILAPIA WITH GROWTH ENHANCEMENT   Vendome BThe World Aquaculture Societyjohnc@was.orgfalseanrl65yqlzh3g1q0dme13067DD/MM/YYYY

PRODUCTION OF TRANSGENIC TILAPIA WITH GROWTH ENHANCEMENT  

Berta Levavi-Sivan*, Naama Mizrahi, Yaron Cohen and Matan Golan
The Robert H. Smith Faculty of Agriculture, Food and Environment, Department of Animal Sciences, The Hebrew University of Jerusalem. Rehovot 7610001. Israel. Berta.sivan@mail.huji.ac.il
 

The Nile tilapia (Oreochromis niloticus, Cichlidae, Perciformes) is now considered one of the most economically important freshwater fish, it has been cultivated for more than 3,000 years, and has been introduced in over 100 countries.  The ability to induce transgenesis is an important attribute in model organisms as transgenic animals offer a wide array of research possibilities, and in the case of tilapia also for agricultural purposes. In the current work, we adopted the tol2 transposon system for the induction of transgenesis in tilapia as a means of increasing germline transmission efficiency in a species in which injection is complicated and transgenesis is relatively hard to achieve. We have succeeded to establish stable transgenic lines of tilapias in which LH and FSH gonadotrophs are fluorescently labeled.

Production of growth-enhanced lines of fish is clearly directed at the goal of improving species for use in aquaculture. Accordingly, transgenic tilapia carrying the iGH construct were generated by micro-injecting embryos at the one-cell by a vector, which contained tiGH cDNA driven by the zebrafish β-actin, flanked by the tol2  transposome sequences. A significant difference between the injected and non-injected fish was evident already at the G0 fish, as compared to non-transgenic siblings. The average body weights of the un-injected fish was 0.68 g ± 0.03 g, while that of the transgenic fish was 1.05 g ± 0.20 g (t-test; p<0.05), at the age of 2 months. Interestingly, GO female transgenic fish reached puberty much later (after two seasons) than non-transgenic siblings, probably due to the effect of high levels of GH in the fish circulation.  However, one of the key concerns about a transgene is that the transgene species will escape from captivity and will outcompetes against wild rivals. Farming reproductively sterile fish is the most environmentally sustainable approach to ensure complete bio-containment in large-scale aquaculture operation. Triploidy and tetraploidy, which are usually used for the production of sterile fish cannot provide a satisficed answer in tilapia. Hence, we are going to approach this aim by the development of several technologies: The first one will be to eliminate or inactivate germ cells in order to produce sterile fish using genetic engineering approaches. The second approach is based on our recent findings on the involvement of novel neuropeptides, namely Neurokinin B and F, in fish reproduction. We have recently developed specific peptide supplement that succeeded to reduce the sperm volume and significantly hindered the development of mature spermatozoa in tilapia mature males.

Acknowledgments

This work was supported by the Israeli Ministry of Agriculture.

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