Astaxanthin: The ubiquitous and abundant carotenoid as a pivotal interior factor of anti‐oxidation and immune for the moulting of Portunus trituberculatus

Abstract

This study was designed to demonstrate the pivotal carotenoid(s) contents and its correlation with anti-oxidative capacities in the moulting of P. trituberculatus. Experiments were carried out to investigate the cyclic fluctuations of carotenoids contents, anti-oxidative indices activities (contents) and non-specific immune indices activities (contents) in the hepatopancreas, haemolymphs and epithelia of juvenile P. trituberculatus during the moulting cycle. Further, a regressing analysis was made on the correlation between carotenoids contents and anti-oxidative indices values during the moulting cycle. The results showed that the total anti-oxidative capacity and immunity (in haemolymphs) at ecdysis decreased drastically, even though other anti-oxidative indices activities increased, when compared to those in the intermoult duration (or premoult) respectively. The decreases in T-AOC mean juveniles suffer excess oxidative damages at ecdysis. Both triglycerides and carotenoids were taken up in hepatopancreas during the inter-moult, then consumed mostly in the moulting process. The carotenoids compositions analysis results not only illustrated astaxanthin was the only carotenoid species exiting ubiquitously in hepatopancreas, haemolymphs and epithelia in all moulting stages, but also showed astaxanthin was the only one detected in haemolymphs in all moulting stages. Following correlation regression results showed astaxanthin contents were positively related to total antioxidant capacity values in haemolymphs. Accordingly, astaxanthin should be an important anti-oxidative factor in haemolymphs during the moulting. In conclusion, those results clearly suggested astaxanthin should be the ubiquitous and abundant carotenoid for anti-oxidation in P. trituberculatus during the moulting cycle. This awareness may provide a understanding of astaxanthin physiological mechanism in P. trituberculatus.