Effect of dietary astaxanthin on growth and immune response of Giant freshwater prawn Macrobrachium rosenbergii (de man)

Effects of dietary incorporation of astaxanthin on growth and selected immune parameters of freshwater prawn Macrobrachium rosenbergii were examined. Sub-adult M. rosenbergii were fed diets fortified with astaxanthin at 0 (control), 25, 50, 100 and 200 mg kg^-1 for a period of 28 days. Results revealed a significant increase (P 0.05) in specific growth rate of prawns fed 50, 100 and 200 mg kg^-1 astaxanthin enriched diet compared to the control diet. Among the immune parameters evaluated, phenoloxidase activity and total protein showed a significant increase (P 0.05) in prawns fed diets enriched with 50, 100 and 200 mg kg^-1 astaxanthin. The total haemocyte count was also significantly higher in prawns fed diets enriched with 50 and 100 and 200 mg kg^-1 astaxanthin. Total carotenoid content in muscle, exoskeleton and hepatopancreatic tissues showed a dose dependent increase. The present results showed that dietary incorporation of astaxanthin at 50, 100 and 200 mg kg^-1 level had significant positive effects on growth and immune response of M. rosenbergii.