Genetic analysis of resistance to acute or chronic temperature stress using isogenic lines of Rainbow trout (Oncorhynchus mykiss)

Abstract Text: Three chronic temperature conditions were applied to ten isogenic lines of Rainbow trout (aged ~6 months): 12°C (L), 20 °C (H) and fluctuating (F): 12°-20°C-12°C every day. Survival and growth were individually monitored during 7 weeks to assess acclimatization to chronic stress. Acute temperature stress were also applied at the end of the period. Survival was high in all groups while growth was significantly lower in F and H groups. Significant genetic variability was evidenced for growth ieacclimatization to chronic stress as well as significant genetic-temperature interactions. Significant genetic variability was found for resistance to acute stress with significant genetic-rearing temperature interactions. However some lines were found resistant or sensible whatever the rearing temperature. Finally, no significant correlation was found between responses to chronic stress and acute stress which will complicate introduction of such traits in breeding programs.

Keywords:

Genetic variability

Genetic correlation

Thermal stress

Rainbow trout