EFFECTS OF DIFFERENT DIETS ON THE DIGESTIVE PHYSIOLOGY OF ADULT NORWAY LOBSTER NEPHROPS NORVEGICUS

Abstract

Rearing Norway lobsters for restocking is a management option to compensate fishing overexploitation, but this requires, among other topics, developing specific pellet diets. The activity of digestive enzymes and the histological organization of the hepatopancreas were analyzed to assess the effectiveness of a pellet diet on digestive performance. Thirty animals were reared individually for 6 mo, fed with mussels and pellets or starved. Comparisons with wild lobsters were also conducted. Survival rate of lobsters fed with frozen mussels was the greatest. Trypsin and amylase activity in the hepatopancreas of the lobsters fed pellets was greater than that of other treatments. In contrast, pepsin activity in the gastric juice of starved animals was the greatest. Levels of alkaline proteases in the gastric fluid were greater in lobsters fed with mussels and the pellet diet in contrast to fasted animals. Amylase was greater in specimens fed frozen mussels. The greatest level of lipid accumulation observed in lobsters fed with the pellet diet indicated a physiological imbalance between the absorptive and transport capacity of the hepatopancreatic cells resulting from an excess of dietary lipids. These results might serve as a reference for future studies for formulating feeds specifically designed for Nephrops norvegicus.