Location: Cool and Cold Water Aquaculture Research
Title: Genomic analysis of the stress response of rainbow trout to crowding Authors
Submitted to: Animal Genetics International Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 3, 2010
Publication Date: July 26, 2010
Citation: Rexroad III, C.E., Vallejo, R.L., Liu, S., Castano, C., Palti, Y., Weber, G.M. 2010. Genomic analysis of the stress response of rainbow trout to crowding [abstract]. Animal Genetics International Conference Proceedings. Paper No. 4023. Technical Abstract: Genomic analyses have the potential to impact selective breeding programs by identifying markers as proxies for traits which are expensive or difficult to measure. One such trait is the physiological response of rainbow trout to the stresses of the aquaculture environment. Typical stressors can be categorized under handling and overcrowding, sub-optimal water quality parameters, and social interactions. These stressors negatively impact growth, feed intake, feed efficiency, disease resistance, flesh quality, and reproductive performance. In general, fish respond to stress by activating the neuro-endocrine system leading to elevated blood concentrations of cortisol, the principle corticosteroid in salmonids. Plasma cortisol concentrations following a ~3 hour confinement has been used as a measure for stress responsiveness in rainbow trout, however, only weak associations with production traits have been identified. Characterization of the stress response of NCCCWA germplasm identified a heritability >46% and a positive correlation between high cortisol response and body weight at 300 days. To identify the genes affecting stress response, we conducted a genome scan with over 400 loci from the NCCCWA genetic map on a three generation pedigree characterized for stress response. To date, three significant QTL have been observed. The fourth generation of this pedigree (F2s) has been bred to generate true breeding high and low (cortisol) responders (F3s) for use in functional genomic analyses and to facilitate fine QTL mapping. Identification and characterization of the genes affecting stress response will improve our understanding of the genetics of this trait and its impact on other production traits.