Transcriptome and Immune Defense Profiling of Stress Response of Different Robust Rainbow Trout Strains

Robustness is a sparsely observed trait in rainbow trout aquaculture; however, the different stress adaptation potential of fish and its commercial relevance is undervalued. Compared with other economical traits, such as growth or body weight, characterization of robustness and specific statements about the trait are very complex. Therefore, trait analyses have been performed based on global transcriptome studies, immunological experiments, and phenotypic studies in healthy and differently stressed fish of a local strain selected for survival under regional conditions and a generally imported strain selected for growth. Such analyses uncovered numerous significant strain specific differences. cDNA GRASP and 44K oligomer microarray analyses complemented with qRT-PCR validations revealed strain specific expression of first barrier genes and genes involved in innate immune defense. Furthermore, we detected phenotypic and molecular strain specificity after stress with Aeromonas salmonicida and moderately increased ambient temperatures, respectively. Analyses of peritoneal leukocyte cell kinetic and transcriptome activity after pathogen impact indicated different innate defense mechanisms. In sum, data suggest better growth, higher survival rates, earlier and different innate immune responses, earlier and more effective adaptive immune responses, and the use of alternative metabolic pathways of regional selected trout. The improved productive adaptation of the regional strain under local aquaculture conditions indicates clearly that the use of those breeding strains for farming ensures progressive gains on the long term compared to aquaculture of strains from a few origins with worldwide distribution. ESF Grant AU11040.