In Asia, trash fish have been routinely used in aquaculture often due to their local availability and lower costs compared to formulated feed. However, stale trash fish contain high levels of biogenic amines, which have been reported to be harmful to poultry and some aquatic animals. The present study elevated the effects of histamine levels in the water on survival, growth, sexual maturity and tissue histamine accumulation of two estuarine mysis, Neomysis awatschensis and Neomysis japonica Nakazawa. Newly hatched neonates of each mysis species were cultured in brackish water containing 0 (control), 5, 10 and 15 mg/L histamine until they reached sexual maturity. The results showed that compared to the control, survival of N. awatschensis was significantly lower in both 10 and 15 mg/L histamine treatments (69.5 and 62.5% vs. 86.5%). In the case of N. japonica Nakazawa, significantly lower survival was found for the 15 mg/L treatment (53.9% vs. 72.4%) (P < 0.05). In a separate experiment, neonates of each mysis species were cultured individually (15 neonates/treatment) to assess the sub-lethal effects of histamine. It was shown that at the level of 15 mg/L, histamine had a significant impact on body weight and length of sexual matured N. japonica Nakazawa, which were only 87.7 and 78.7% of that of the control. However, no significant difference in intermolt period was detected. In the case of N. awatschensis, no significant differences in both body weight and length among treatments were detected (P > 0.05) but the intermolt period was substantially prolonged at all histamine levels tested when compared to that of the control. Meanwhile, the timings required to reach sexual maturity for both male and female of the two mysis were generally increased with increasing histamine level, and such differences were often statistically significant (P < 0.05). Compared to the control, the tissue histamine concentration of the mysis increased significantly at histamine concentrations of 10 and 15 mg/L for N. japonica Nakazawa (P < 0.05). In the case of N. awatschensis, however, no significant differences were found among all treatments. Our findings indicate that histamine had clear negative effects on both mysis species although their responses and sensitivity appeared somewhat different. Our results suggest that further research is needed to assess the effects of water borne histamine on various aquatic animals.

The juvenile Chinese mitten crabs Eriocheir sinensis (1.40 ± 0.43 g) were cultured in water of 5.34 ± 0.43 (hypoxia, treatment group) and 21.02 ± 0.06 kPa (high dissolved oxygen (DO), control group) DO for 24 h, respectively. The total hemocyte counts (THC), the hyaline hemocyte counts were measured at 0 and 24 h in the treatment group, and superoxide dismutase (SOD) activity, concentrations of lactic acid and hemocyanin (Hc) in hemolymph and the metabolism of hepatopancreas (concentrations of glucose, total cholesterol, uric acid, total protein, urea, triglyceride in hepatopancreas) were assayed at 0, 2, 8, and 24 h in both treatment and control groups. The hyaline hemocyte counts and THC decreased significantly by 66 and 49% after exposure to hypoxic water for 24 h, respectively. SOD activity, Hc and lactic acid content were significantly affected in treatment group, and there were significant differences between treatment and control groups. In the treatment group, the concentration of glucose, cholesterol and uric acid in hepatopancreas had a significant variation for 24 h. The concentration of total protein, urea and triglyceride between treatment and control groups was not significantly different after 0, 2, 8, 24 h. However, there were significant differences between treatment and control groups in terms of total protein, glucose, and uric acid concentration. Taken together, the effect of hypoxia is comprehensive in juvenile Chinese mitten crab Eriocheir sinensis.

The nutritional value of various edible parts of the blue swimmer crab (Portunus pelagicus) was evaluated, and gender differences in terms of edible yield, proximate composition, amino acids, lipid classes and fatty acid content were compared. The results showed that females (44.3%) had a higher edible yield than males (35.9%) (P < 0.05). Although higher protein and lipid contents were detected in the meat and gonad of females, the males contained higher docosahexaenoic acid (DHA) (P < 0.05). Significant differences in fatty acid composition were also found among various edible parts and between genders (P < 0.05). For example, the meat was shown to have higher total highly unsaturated fatty acids (HUFA) (36–39%) than the hepatopancreas (16–18%) or gonads (16–24%). A balanced amino acid composition was found in both meat and gonads. The results obtained from the present study indicate that the meat and ovaries of the blue swimmer crab are one of the healthiest seafoods, and they are also suitable for making processed products.

Estrogen induces oocytes development and vitellogenesis in crustacean by interacting with estrogen receptor (ER) subtypes. In the present study, we detect for the first time the ERα in oocytes and follicle cells and hepatopancreas cells of mysis by immunohistochemistry using a specific ERα antibody. ERα was mainly localized in the nuclei of oocytes and follicle cells, while mainly detected in nuclei of oogonia (OG), previtellogenic oocyte (PR) and endogenous vitellogenic oocyte (EN) at previtellogenic and early vitellogenic stage (I–early III). Follicle cells in all stages of ovary (all vitellogenic stages) showed strong ERα positive reaction, and they were able to gradually move to oocytes during the development of oocytes. In addition, ERα was also localized in the nuclei and cytoplasm of four hepatopancreas cells (including E-, R-, F- and B-cell) in all ovary stages. These findings suggest, for the first time to our knowledge, that there could be a close link between oogenesis, follicle cells, hepatopancreas cells and endocrine regulation, and estrogens might be involved in the regulation of oocytes at early ovarian stage in mysis.