Effects of dietary thiaminase on reproductive traits in three populations of Atlantic salmon targeted for reintroduction into Lake Ontario

The fitness of reintroduced salmonids in Lake Ontario can be reduced by high levels of thiaminase in exotic prey consumed at the adult stage. If sensitivity to dietary thiaminase differs among the three Atlantic salmon populations targeted for reintroduction into Lake Ontario, this could significantly influence their performance. I quantified the effects of experimental diets that contained high or low (control) levels of thiaminase on thiamine concentrations, survival, growth rate, and reproductive traits (sperm and egg quality) in Atlantic salmon from the three candidate source populations. Fish that consumed the high-thiaminase diet had comparable growth rates, but lower survival and muscle thiamine concentrations than control fish. Sperm count, velocity, motility and linearity, did not differ based on diet. Adult females fed the high-thiaminase diet resulted in lower egg thiamine concentrations and embryo survival. The effects of dietary thiaminase on reproductive traits did not differ among the tested populations