Effects of dietary thiaminase on three strains of Atlantic salmon

Session: Thiamine Deficiency in the Great Lakes (2)

Bryan Neff, Western University, [email protected]
Aimee Lee Houde, Department of Fisheries and Oceans, [email protected]
Kimberly Mitchell, University of Western Ontario, [email protected]
Chris Wilson, ON Ministry of Natural Resources and Forestry, Trent University, [email protected]

Abstract

The reintroduction of Atlantic salmon into Lake Ontario is a top priority for management agencies and conservation groups. One major factor that has been hypothesized to obstruct these efforts is the abundance of exotic prey fishes—rainbow smelt and alewife—in the Great Lakes. Unlike historical prey, these species contain high levels of the enzyme thiaminase, and their consumption has been associated with thiamine deficiency in many Great Lakes salmonids. Importantly, if sensitivity to dietary thiaminase differs among the three Atlantic salmon strains targeted for reintroduction into Lake Ontario (i.e. as a result of local adaptation), then strain selection could help mitigate these negative effects. We quantified the effects of experimental diets that contained high or low levels of thiaminase on tissue thiamine levels, survival, growth rate, swimming performance and reproductive traits in Atlantic salmon from the three candidate strains. We found that the high-thiaminase diet generally had negative effects on these traits, although the magnitude of the effects differed among strains. Strain selection may thus help to mitigate the effects of exotic prey fishes on reintroduced salmon in the Great Lakes.