Live feed enrichments using microalgae for pikeperch (Sander lucioperca) larval culture

Abstract

This trial aimed to customize pikeperch (Sander lucioperca) larval nutrition using live feed enrichments based on Chlorella vulgaris and Trachydiscus minutus. Pikeperch larvae were fed with rotifers and Artemia enriched with C. vulgaris and T. minutus during the first 17 days after exogenous feeding (started 4 days post-hatching [dph]) and only Artemia until 20 dph. Larvae were exposed to seven different enrichments: (a) Nannochloropsis occulata (Nanno 3600 reed Mariculture) (Control), (b) C. vulgaris cultured at 20°C in BG-117 medium (BG20), (c) C. vulgaris cultured at 30°C in BG-117 medium (BG30), (d) T. minutus cultured at 15°C (T15), (e) T. minutus cultured at 25°C (T25), (f) C. vulgaris cultured at 20°C in urea medium (U20), and (g) C. vulgaris cultured at 30°C in urea medium (U30). After 20 days, no significant differences were found between treatments on total length, standard length, myomere height, and eye diameter. On the contrary, significant differences were found in larval fatty acid composition after the trial period. Larvae from the BG30 treatment showed a significantly higher concentration of docosahexaenoic acid (5.61%), and larvae from the T25 treatment had a higher concentration of eicosapentaenoic acid 12.95%. Furthermore, larvae from the U20 treatment had a significantly higher arachidonic acid concentration of 0.116%. Overall, regarding essential fatty acid concentration, a significant difference was observed between the control treatment (Nannochloropsis) and the other treatments. No adverse effects were found on growth or survival when Nannochloropsis-enriched live feed was replaced with the other enrichments. This trial's results will help optimize the pikeperch larvae's nutritional requirements and diversify the live feed enrichments used during the first feeding.