ANALYSIS OF CHANGES IN BIOCHEMICAL COMPOSITION IN THE BODY OF JUVENILE PORTUNUS TRITUBERCULATUS DURING OVERWINTERING (BRACHYURA, PORTUNIDAE)

This study analysed the composition and content of nutrients in the muscle and hepatopancreas of juvenile Portunus trituberculatus cultured in a pond at the beginning, middle and end of overwintering, so as to understand the nutrient metabolic patterns in the body of P. trituberculatus during overwintering. The results showed that the muscle index (MY) of P. trituberculatus changed little during overwintering, but the hepatosomatic index (HSI) decreased significantly (7.88% at the beginning of overwintering and only 6.23% at the end of overwintering). The total carbohydrate, crude lipid and crude protein in the muscle and hepatopancreas of juvenile P. trituberculatus decreased to different degrees throughout the overwintering period, in particular, the decrease in total carbohydrate was approximately 50% and the decrease in crude lipid was around 30%. In terms of fatty acid composition, the total saturated fatty acids (ESFAs) in the muscle of juvenile P. trituberculatus slightly decreasing, the monounsaturated fatty acid content (EMUFAs) slightly increasing, while the total polyunsaturated fatty acids (EPUFAs) remained basically unchanged. In contrast, the content of fatty acids in the hepatopancreas changed greatly, and the ESFAs decreased significantly (P <0.05), which was 44.2% at the beginning of overwintering and only 24.02% at the end. The EMUFAs decreased only at the end of overwintering, while the EPUFAs increased significantly (P <0.05), reaching 7.62% at the beginning of overwintering, 18.59% at the middle and 32.83% at the end of overwintering. In general, the energy material of juvenile P. trituberculatus was mainly derived from the hepatopancreas throughout the overwintering period, and it mainly utilized carbohydrates and crude lipids in the body and was highly selective in the oxidative utilization of fatty acids, mainly utilizing SFAs for oxidative energy supply, while PUFAs, HUFAs, EPA and DHA were selectively retained.