Digestive Enzymes in the Crayfish Cherax albidus: Polymorphism and Partial Characterization

In this study we will deal with the partial characterization and the activity of the following digestive enzymes: amylase, pectinase, alginase, lipase and protease present in the digestive tract of juvenile freshwater crayfish Cherax albidus. Gastric juices, the hepatopancreas and the intestine were sampled for enzyme analysis. Among carbohydratases, amylase activity was the highest. It was significantly higher in the intestine than in the gastric juice and hepatopancreas. Lipase activity was significantly higher in the hepatopancreas and the intestine compared to the gastric juice. Both alkaline and acid proteases were found. Alkaline proteases were characterized by employing specific protease inhibitors. Both trypsin and chymotrypsin activity was detected. The majority of alkaline protease activity was ascribable to trypsin. Several isoforms of digestive enzymes were identified by gel electrophoresis. This work provides basic information to study the digestive abilities of crayfish.