Variations of digestive enzymatic activity of the longarm river prawn, Macrobrachium tenellum (Smith 1871) adapted from the wild to culture with prepared meals

Macrobrachium tenellum is an omnivorous freshwater prawn living in rivers near the coast and in coastal lagoons with potential to be cultured. It is distributed in rivers, estuaries, and coastal lagoons, and in each of those habitats, it has access to food items with different features and nutritional content. In this research, it has been tested if this variety of food availability has an immediate effect on their digestive enzymatic activity once animals are brought to laboratory and fed with different meals. Wild prawns were captured in a river and coastal lagoon, and after acclimation, they were fed with three different experimental diets. Total alkaline protease, trypsin, chymotrypsin, lipase, and alpha amylase were measured from prawns fed experimental diets at 15 and 30 days. There were significant differences in the enzymatic activity of prawns depending on their original habitat and diet. However, the proportion in which these enzymes are expressed in the prawns from different treatments remains proportional to what was observed in wild specimens, as reported in previous research. We consider that the study of this phenomenon can contribute to a better understanding of the nutritional needs of this species if a species-specific diet needs to be prepared.