Ontogenic development of the digestive enzymes in common pandora, Pagellus erythrinus, L. larvae

Abstract

Ontogenic development of some digestive enzymes (proteases, amylase and lipase) in common pandora Pagellus erythrinus larva was assayed during larval development. The green-water technique was employed for larval rearing, and whole-body homogenates were used for enzymatic assays in triplicate. Important alterations in specific activities of all digestive enzymes measured during the period of this study were mostly related to metamorphosis and weaning. Mouth opening was observed on day 3 at 2.23±0.01 mm total length synchronously with the first determination of trypsin and chymotrypsin activities. After this date, the specific activities of these slightly increased until 25 days after hatching (DAH), respectively, and then slightly decreased and changed. The pattern determined for pepsin was strongly related to stomach formation on day 25 at 9.72±2.3 mm total length and a sharp increase was found until 30 DAH and then a slight decrease was measured from this date until the end of the experiment. Both amylase and lipase were measured for the first time on days 2 and 4, respectively, and also the specific activities of these showed similar patterns during the first week of the study. Then, slight variations were observed until 30 DAH and while lipase-specific activity had declined, an increase in the specific activity of amylase was found until the end of the experiment. Finally, it is thought that the variations observed in the specific activity in the profile of digestive enzymes were related to either metamorphosis such as formation of stomach (25 DAH) or to changes in characteristics of food (30 DAH). The pattern of development of the main digestive enzymes found in P. erythrinus is similar to that described in other Sparid species.