Biochemical responses of juvenile rock spiny lobster Panulirus homarus under different feeding regimes

Abstract

An experiment was conducted to evaluate the biochemical changes and digestive enzyme activities of juvenile Panulirus homarus lobsters kept under three different feeding regimes, namely starvation, feeding with live clam and feeding with formulated feeds. A marked reduction in the hepatosomatic index (HSI) and a decrease in levels of both protein and lipid in the hepatopancreas of starved animals were observed at the end of the trial. Results indicate that hepatopancreas forms the primary organ for mobilization of energy reserves and that both proteins and lipids are mobilized as energy sources during starvation. Starvation induced a significant increase in proteolytic digestive enzymes of the hepatopancreas. In the group fed on formulated diet, amylase activity was found to be high, probably in response to the high carbohydrate content of the feed used in the present study. These animals also had a significantly lower free amino acid content in the hepatopancreas Histological studies showed that feeding with formulated diet-induced vacuolation in the hepatopancreas caused by hypertrophy of B cells, and a distinct thickening of the lumen walls. These results suggest difficulty in metabolism and mobilization of nutrients absorbed from formulated feeds in tropical spiny lobsters.

Keywords

• Diets
• starvation
• lobster
• enzyme
• histology