Protein digestion in early turbot larvae, Scophthalmus maximus (L.)

The ability of early turbot larvae (Scophthalmus maximus) to digest protein has been measured and compared with that of 30-day-old juveniles and adults. Similar proteolytic levels have been found in larvae collected just before first feeding and in the guts of adult turbot after the lumen contents have been removed. However, strong differences in the enzymic patterns and in the specific activity in (rotifer) fed and in unfed specimens of larvae were detected in 6-day larvae and in 30-day-old juveniles. The results obtained indicated that higher levels of neutral and alkaline proteases were produced as a response to ingesting certain live feeds. A possible interpretation of these results is that, because the elevation of protease levels in the gut of turbot induced by live feeds is a slow process, it may involve the synthesis of new enzyme protein. © 1989.