Hepatic fatty acid and transcriptome profiles during the transition from vegetable- to fish oil-based diets in rainbow trout (Oncorhynchus mykiss)

Traditional aquafeeds contain high amount of fish oil that increase heart-healthy omega-3 fats in the rainbow trout fillet. Transition to more sustainable plant oils reduces fillet omega-3 content, but this can be combated by feeding a fish oil-rich finishing diet in the weeks prior to harvest. By analyzing the fat and gene expression profiles, this study determined that the liver exhibits a unique metabolic response that differs depending on the type of dietary oil that is being consumed. Transitioning to a finishing diet also appears to force the remodeling of liver tissue which may compromise its metabolic capacity. These findings suggest that a gradual transition to the finishing diet may be an optimal approach for improving aquaculture sustainability while maintaining high levels of omega-3 fatty acids in rainbow trout fillets.