Effects of Haematococcus lacustris-Supplemented Diets on the Development of Body Color and Health of Giant Freshwater Prawn (Macrobrachium rosenbergii)

The body color of crustaceans is an important factor influencing consumer preference and marketability, expressed through the accumulation of carotenoids within the body. However, crustaceans cannot synthesize carotenoids internally and rely entirely on dietary sourcess. Deficiency of this pigment can lead to poor body coloration. <i>Haematococcus lacustris</i> is a species of freshwater microalgae that accumulates astaxanthin at high concentrations, possessing significant industrial potential as a natural source of carotenoids. This study investigated the effects of adding <i>H. lacustris</i>, which is rich in astaxanthin, to feed on improving body color and health status in <i>Macrobrachium rosenbergii</i> post-larvae. The experimental results showed that body length exhibited similar growth trends across all groups, while body weight was significantly higher in the control (CON) group compared with the low concentration (LC) and high concentrations (HC) groups. Feed supplemented with <i>H. lacustris</i> exhibited a darkening effect on body color depending on concentration, and this effect persisted even after heating. Superoxide dismutase (SOD) expression levels in the hepatopancreas significantly increased at day 60 in the HC group. Crustin expression also significantly increased in the hepatopancreas on day 60, but no significant differences were observed between groups in the tail muscle. The addition of <i>H. lacustris</i> to the diet aided in the body color development of <i>M. rosenbergii</i> post-larvae, suggesting that this approach may also be applicable to the body color development of various crustaceans.