Effect of triploidy on digestive enzyme activity of early stages of turbot (Scophthalmus maximus).

In the present work, growth and digestive enzyme activities of total acid and alkaline proteases, pepsin, trypsin, lipase, and α-amylase, as well as partial characterization of enzyme activity, were studied in diploid and triploid turbot. Growth was similar between both groups. Acid protease activity increased consistently during the experiment, for both diploid (2n) and triploid (3n) fish. The alkaline protease activity was always higher for triploids throughout the experiment. Proteolytic acid activity (pH 2) was generally higher for diploids, at all temperatures tested. Higher activity was at pH 2 and 3 for 2n and 3n fish, respectively. Regarding temperature, acid and alkaline protease activity was higher at 37 °C and 60 °C, respectively, for both groups. The general increase in pancreatic enzymes (trypsin and amylase) before 35 days after hatching (DAH) and posterior decrease until 60 DAH. There was a marked effect on enzyme activity when changing from live prey to pellets (35 DAH), especially on triploids.