Growth, survival, and quality of juvenile walleye Stizostedion vitreum as influenced by n-3 HUFA enriched Artemia nauplii

We quantified how addition of n-3 highly unsaturated fatty acids (HUFA) to brine shrimp (Artemia sp.) nauplii influenced growth, survival, osmotic cha llenge and fatty acid composition of juvenile walleye. Four groups of 6-day -old walleye were fed enriched Artemia. Lipids were altered to provide four treatments: (1) 100% cod liver oil (CLO), (2) 60% CLO/40% n-3 HUFA concent rate, (3) 40% CLO/60% n-3 HUFA concentrate, and (4) 100% n-3 HUFA concentra te. Different enrichments influenced neutral lipids of Artemia, but not the ir phospholipids. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA ) concentrations in Artemia neutral lipids in treatment 4 were doubled comp ared to treatment 1, Fatty acid composition of walleye body lipids, in both neutral and phospholipid fractions, reflected the changes in EPA and DHA c oncentrations found in enriched Artemia. After 3 weeks, walleye fed Artemia enriched with a combination of CLO and n - 3 HUFA concentrate grew faster than those fed 100% n - 3 HUFA enriched Artemia. Walleye fed Artemia naupli i enriched with 100% CLO survived better than all other treatments (25.0 +/ - 4.5 vs, 11.4-13.1%). Walleye recovery after osmotic challenge was ordered treatment 1 through treatment 4; as n-3 HUFA in Artemia increased, so did susceptibility to this challenge. Furthermore, both survival and vitality o f walleye were negatively correlated with the EPA/(arachidonic acid) AA rat io in their whole body phospholipids. The present work extends our knowledg e on the effect on n - 3 HUFA at higher levels in walleye juveniles diets ( 12.5% EPA, 5% DHA), and alterations in whole body fatty acids balance. We c onclude that high EPA/DHA diet can be responsible for a decreased survival and higher susceptibility to stress in freshwater fish. (C) 1999 Elsevier S cience B.V. All rights reserved.