Trash fish facilitates protection against the deterioration in nutritional quality of adult female Chinese mitten crabs Eriocheir sinensis during winter

Abstract

In this study, we conducted a cage-culture trial to evaluate the gonadal development and nutritional quality of adult female Chinese mitten crabs (Eriocheir sinensis) fed a formulated diet (FD), traditional diet (TD) or trash fish (TF) during wintering. The results revealed a marked reduction in the hepatopancreatic index (HSI) during 90 days of wintering, and that crabs fed the TF diet had a significantly higher HSI and total edible yield than those fed the TD diet after wintering (p < 0.05). In terms of proximate composition, protein and lipid contents in the ovaries showed significant increases over the wintering period, whereas there was a significant reduction in hepatosomatic protein levels. Among the three overwintering treatments, the contents of ovarian proteins and hepatosomatic lipids were significantly higher in TF crabs. Although the redness (a*) of the carapace and ovaries was found to have increased significantly during wintering, there was a significant reduction in hepatosomatic redness, which was consistent with the total carotenoid contents detected in these tissues. Moreover, among the three treatments, hepatosomatic redness was significantly higher in TF treatment after the overwintering period. In addition, nutritional quality index assessments revealed that crabs in the TF and TD groups were characterized by the highest and lowest values respectively. In conclusion, we found that the nutritional quality of adult female E. sinensis undergoes a marked decline during the wintering period. However, the provision of a TF diet can contribute to protecting against a deterioration in the nutritional quality of crabs maintained over winter.