Effects of a low-thiamine diet on reproductive traits in three populations of Atlantic salmon targeted for reintroduction into Lake Ontario

Abstract

Exotic prey fishes that have high thiaminase levels are associated with a thiamine deficiency and reduced fitness in many salmonids. If sensitivity to low thiamine availability differs among the three Atlantic salmon (Salmo salar) populations targeted for reintroduction into Lake Ontario, this could substantially influence their performance. We quantified the effects of a low-thiamine diet and a control diet on tissue 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 low-thiamine diet had comparable growth rates but lower survival and lower muscle thiamine concentrations (26 nmol·g–1) than control fish (34 nmol·g–1). Sperm count, velocity, motility, and longevity did not differ based on diet. Embryo survival was lower for females fed the low-thiamine diet, and the low-thiamine diet was associated with significantly lower egg thiamine concentrations (11 versus 17 nmol·g–1). The effects of the low-thiamine diet did not differ among the tested populations, which suggests that source population selection is unlikely to fully overcome this potential challenge for re-establishing wild populations.