| Summary: | 5 pages, 3 figures.-- International workshop Development and aquaculture of marine larvae, Bergen, Norway, August 12-15, 1990 In turbot larvae rearing, dietary lipid digestion relies on esterare activity both from the rotifer and the larvae, before Artemia nauplii is added as food. The effect of selected variables (pH, temperature and salt concentrations) on these enzymes has never been tested. The two enzymes were dependent on these factors but followed a different pattern. Larval esterase has a slightly acidic pH optimum, is inhibited by high NaCI levels and its activity decreases with increasing temperatures. On the other hand, esterase from rotifer seems to have a maximum activity at alkaline pH, activates with high salt levels and is temperature independent. Both activities are fairly stable at neutral-alkaline pHs and low temperatures. In light of these findings, the importance of dietary (rotifer) esterase on lipid digestion in early turbot larvae may have been underestimated, and may account for a 95-98% of the total esterase activity present in one single larva, at first feeding. It is also postulated that dietary esterases may act in the intestinal lumen of the larvae, while larval esterases would be involved in intracellular lipid digestion This work has been supported by the Contract-Project "Turbot larvae nutrition" with Cultivo de Peces, S.A. (CULTIPESCSA, O Grove, Pontevedra, Spain) No
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