Artificial selection is a powerful tool that can be used to make dramatic changes to observable traits in just a few generations. However, when breeders select for one trait, they inadvertently select for or against many other traits that may be important. Artificial breeding programs focused exclusively on production performance metrics commonly fail to identify the associated vulnerabilities, giving rise to stocks that are fast-growing or high-yield, but prone to infectious disease or other hereditary disorders. Consequently, animal breeders have begun to rethink their approach to genetic improvement and are looking to the principles of natural selection, vigor, and biological fitness as guides.
Riverence Brood’s Rainbow Trout breeding strategy includes an iterative research program to screen candidate indicators of biological fitness so that these traits can be targeted for selection. The so-called “Sentinel Program” entails an annual ‘common garden’ experiment in which family groups representing all of the genetic variation within the broodstock (i.e., “sentinels”) are raised to market-size according to routine commercial practices. At harvest, individual fish are evaluated in terms of various candidate fitness indicators and superior performance is then traced back to families who genetics are emphasized in future breeding schemes.
Over the last 5 years, the Sentinel Program has identified fitness-based breeding targets and enabled Riverence Brood to continuously improve upon our genetics. Additionally, the R&D group has leveraged the Sentinel Program to create additional opportunities for scientific inquiry. Each year, roughly 1000 fish are genotyped to determine familial relationships and individually characterized in terms of various morphological, physiological, and performance-related metrics. For each fish, a wealth of metadata is available and virtually any tissue can be sampled for histology, gene expression, or other analysis. Collectively, these data can be used to contextualize or interpret other results or probe other questions related to fish health, nutrition, reproduction, or other topics. Recently, samples collected from sentinel fish and the associated meta-data have been used to collaboratively explore the basis of variation in the prevalence and abundance of external parasites, expression of antimicrobial peptides, and viral pathogen susceptibility and transmission.
First and foremost, the Sentinel Program informs Riverence’s selective breeding decisions for Rainbow Trout. However, it is also an unmatched opportunity for collaborating researchers to gather valuable samples and data to further their own scientific endeavors involving this species. This presentation will provide an overview of the Sentinel Program and outline opportunities for collaborative science and the development of robust, long-term datasets.