Early exposure of striped catfish (P. hypophthalmus) to increased salinities could elicit conditioning hormesis in juvenile fish

Details

Supervisors

Kestemont, Patrick ; Hieu Dang Quang

Faculty

Faculté des sciences

Degree label

Master [120] en biologie des organismes et écologie, à finalité approfondie

Abstract

Striped catfish is a valuable species in Vietnam’s growing aquaculture industry and has become a national staple good exported worldwide. Only, sea-level rise scenarios and increased frequency of extreme weather events are predicted to erode its production as freshwater ponds salinity is expected to rise and reach higher levels than those tolerated by the species. In the scope of such events, we study the potential to grow individuals adapted to these conditions through conditioning hormesis. Striped catfish larvae were treated with 5 psu water for 5 days and once in the juvenile stage, exposed to salinity increase of 10 days to reach 0 psu, 10 psu and 20 psu for 30 days followed by a Cadmium challenge. 5 psu treated juvenile fish showed slight changes in their gene expression pattern and physiological parameters (blood, glucose levels, ion concentration). These changes appeared to bring no advantages in 0 psu but made the fish slightly better adapted to higher salinities by showing an enhanced stress response. Treated fish in 10 psu grew 21.6% bigger than non-treated fish. The chronic hyperosmotic stress from 20 psu conditions drove fish into type 1 allostatic overload which eclipsed the possible benefits brought by the treatment. This method could be a viable approach to the problem of sea-level rise in the Vietnamese aquaculture industry. However, more research is needed to determine, on the one hand, which stages of the fish’s life cycle allows for the best conditioning response and, on the other hand, how treated fish with salinities ranging between 10 psu and 20 psu react to hyperosmotic stress.