The effect of egg fatty acid concentrations on embryo viability in wild and domesticated walleye (Stizostedion vitreum)

Abstract

Eggs from three distinct populations of walleye Stizostedion vitreum, one domesticated (London State Fish Hatchery) and two wild (Lake Erie and Salt Fork Reservoir), were compared in terms of total lipid content and fatty acid profiles (phospholipids and neutral lipids). The concentrations of total lipids in eggs from domesticated broodstock were significantly lower (8.6 ± 1.0 % of wet weight) than those of both wild populations (13.3 ± 0.9 % and 10.9 ± 0.6 % of wet weight for Lake Erie and Salt Fork Reservoir, respectively). The profiles of fatty acids in egg lipids differed significantly among the three investigated populations. Domesticated females fed a formulated diet produced eggs containing significantly higher levels of linoleic acid (18:2n-6), characteristic of plant lipids. However, arachidonic acid (20:4n-6), was at significantly higher levels in eggs of wild walleye stocks. Although eicosapentaenoic acid (20:5n-3) was detected at significantly higher levels in eggs from Lake Erie walleye, docosahexaenoic acid (22:6n-3), the most abundant in polar lipids, was found at similar levels in eggs of all three populations. Survival of walleye embryos was correlated with the concentrations of polyunsaturated long chain fatty acids. Our data suggest that deficiency in n-3 fatty acids might be associated with impaired development of walleye, and thus poor larval and juvenile viability.