The effect of vitamins C and E in (n-3) highly unsaturated fatty acids-enriched Artemia nauplii on growth, survival, and stress resistance of fresh water walleye Stizostedion vitreum larvae

This study aimed to evaluate the effect of enriching Artemia nauplii with v itamin C (ascorbyl-6 palmitate) or vitamin E (alpha-tocopherol acetate), 20 % w/w, together with a mixture of concentrated eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) on the growth, survival, and stress resistance of fresh water walleye Stizostedion vitreum larvae. Either cod liver oil (CLO) or EPA/DHA ethyl esters concentrate was used as lipid sources in the Artemia enrichment. Walleye larvae were fed ad libitum for 40 days. At day 40, submersion in salt water (25 g L-1) was performed to evaluate larvae resistance to stress. EPA and DHA levels in walleye juve niles fed EPA/DHA-enriched Artemia increased significantly, by an average o f 650% compared with fish fed non-enriched Artemia. A significant increase was found for vitamins C (71.8 +/- 1.0 and 42.7 +/- 1.2 mu g g(-1) wet weig ht (WW)) and E (17.0 +/- 3.7 and 6.5 +/- 0.9 mu g g(-1)WW) concentrations i n fish fed enriched and unenriched Artemia, respectively. Growth was compar able throughout treatments, whereas survival was significantly higher in fi sh fed CLO-enriched Artemia nauplii compared with fish fed Artemia nauplii enriched with EPA/DHA concentrate. The addition of vitamin C increased fish survival by 1.4-fold compared with fish fed Artemia enriched with only EPA /DHA concentrate. The survival of the latter was similar to control fish (A rtemia without enrichment). The supplementation of vitamin E did not affect fish survival significantly. Stress tests revealed that the resistance of walleye larvae to salinity changes increased when Artemia enrichment was su pplemented with vitamin C. However, walleye larvae fed CLO-enriched Artemia had the best performances in the stress test.