Bisphenol A in Eggs Impairs the Long-Term Stress Performance of Rainbow Trout in Two Generations

Salmonids are ecologically, economically, and culturally important fish species in North America, but whether contaminants in the environment play a role in their population decline is unclear. We tested the hypothesis that bisphenol A (BPA) deposition in eggs, mimicking a maternal transfer scenario, compromises the stress axis functioning and target tissues stress response in two generations of a model salmonid species, rainbow trout ( Oncorhynchus mykiss). Eggs were enriched with 0, 4, or 40 ng of BPA, fertilized, and reared in clean water for two generations. The fish were subjected to an acute stressor after a year in both generations to test their stress performances. Trout raised from BPA-enriched eggs showed impaired stressor-mediated plasma cortisol and lactate response in the F1 and F2 generations, respectively. Key genes involved in cortisol biosynthesis in the head kidney, as well as stress- and growth-related transcripts in the liver and muscle, were impacted either in the F1 and/or F2 generations. Our results underscore the long-term impact associated with BPA in eggs, mimicking a maternal transfer scenario, on the stress performance of trout in two generations. The results highlight the need for developing novel biomarkers to predict long-term and generational toxicities in salmonids.