| Mysidacea are sensitive experimental animals to environmental pollution, and they play important role in water ecosystem. Neomysis awatschensis and Neomysis japonica are the most common types in Chinese estuary. Eriocheir sinensis belong to Decapoda,Reptantia,Grapsidae,Eriocheir. It is called hairy crab, which is widely aquacultured in China. In recent years, in order to meet consumer demands for aquatic products, aquaculture has rapidly grown, and so trash fish are often extensively utilized as feeds by the industry. If the trash fish or fish meal were not stored properly, they would produce a lot of biogenic amines which may have potentially harmful effects on aquatic animals. Histamine is one of biogenic amines, which is considered to be toxic when it present in foods or feedstuffs at high levels. At the present time, the effects of histamine on aquatic animals are unclear, and the relevant studies of the effect mechanism have not seen at home and abroad. Therefore, we use Neomysis awatschensis and Eriocheir sinensis as experimental animals, and study the effects of histamine on marsupial development of the mysis Neomysis awatschensis, the growth of the juvenile crab Eriocheir sinensis and the immune responses of the adult crab Eriocheir sinensis. The effect mechanism was briefly discussed, wish it would be good to lay the foundation of the mysis Neomysis awatschensis used as model organism, and wish it would be good to provide reference information for the crab culture.Embryos of the mysid Neomysis awatschensis were exposed to histamine solution, observing the metamorphosis rate and duration of each developmental time at nauplius, post-nauplius and eyestalk stage, and hatching success. We fed diets supplemented with different concentrations of histamine to the juvenile crabs, observed the growth indicators and the molt situation, and detected the content of biogenic amines and the activities of the digestive enzymes of the whole body.The adult crab Eriocheir sinensis were fed with formulated diet and trash fish stored in different time (0h, 12h and 24h) at the temperature of 30℃, observing the survival rates and hepatopancreas index (HSI). With the means of immunology, we studied the effects on the adult crab Eriocheir sinensis fed with formulated diet and trash fish stored in different time at high temperature. The results demonstrated that:1. Effect of different concentrations of histamine on the embryogenesis in vitro of the mysid Neomysis awatschensis Embryos of the mysid Neomysis awatschensis were exposed to the concentrations0 (control), 5, 10, 15 histamine mg/L. Metamorphosis rate and duration of each developmental time at nauplius, post-nauplius and eyestalk stage were observed. Hatching success was analyzed.1), No significant differences on metamorphosis rate in nauplius stage and post-nauplius stage were observed by exposing to histamine solution, but metamorphosis rates in eyestalk stage were decreased by histamine.2), Histamine containing in solution had the effects on the duration of the different stages, which showed that the duration of the different stages were extended.3), Histamine containing in solution could derease mysid larval hatching success. These results demonstrate that histamine has the effect on the embryogenesis, and affect significantly with the extension of immersion time.2. Effect of dietary histamine supplementation on growth and tissue amine concentrations in the juvenile Chinese mitten-handed crab Eriocheir sinensis Four experimental diets were supplemented with histamine at 0, 1000, 2000 and 4000 mg/Kg. The present study evaluated the effects of dietary histamine supplementation on the growth of the Chinese mitten crab Eriocheir sinensis and the impact on biogenic amine concentration in crab tissues.1), No significant differences on weight gain, special growth ratio and feed conversion of the juvenile crabs fed diets supplemented with histamine were observed.2), Histamine concentration in whole crab tissue increased with dietary histamine supplementation. In contrast, spermine concentration in whole crab tissue deceased with dietary histamine supplementation.3. Effect of dietary histamine supplementation on molt and the activities of digestive enzymes in the juvenile Chinese mitten-handed crab Eriocheir sinensis. Four experimental diets were supplemented with histamine at 0, 1000, 2000 and 4000 mg/Kg. The molt rate and digestive enzymes were analysed.1), Histamine not only had no significant effect on the molt rates of Eriocheir sinensis during the development of CⅢto CⅣand CⅣto CⅤ, but the molt duration of CⅢmolted to CⅣ.2), Feeding diets supplemented with histamine to the juvenile crab Eriocheir sinensis reduced the activities of pepsin enzyme and trypase. The activities of amylase in 2000mg/Kg and 4000mg/Kg groups were lower than the control group. The activities of cellulose enzyme in 1000mg/Kg group reached higher value compared to the control group. The activities of lipase did not change significantly among different diet groups.4. Effects on the survival and immune responses of the Chinese mitten crab Eriocheir sinensis fed with trash fish and formulated diet1), The adult crab Eriocheir sinensis were fed with formulated diet and trash fish which were stored in different time (0h, 12h and 24h) at the temperature of 30℃for 30d. The TVBN values of trash fish stored in different time at 30℃were described as fresh and stale. The TVBN value of the trash fish stored in 0h was 12.0mg/100g, which showed that the trash fish stored in 0h was fresh. However, the TVBN values of trash fish stored in 12h and 24h were respectively 64.2mg/100g and 180.2mg/100g, which showed that the trash fish stored in 12h and 24h were stale. The content of biogenic amines (including histamine, cadaverine, putrescine and tyramine) increased with the extension of storage time.2), There was no significance between the survival rates of the group fed with formulated diet and that of the group fed with trash fish stored in 0h (P>0.05), while that of these groups were significantly higher than the survival of the group fed with trash fish stored in 24h(P<0.05). And the survival rates of the groups fed with trash fish were slowly declined as the stored time of the trash fish extended from 0h to 24h.3), The HSI of the group fed with formulated diet was significantly higher than the other three groups (P<0.05), however, the THC and haemocyanin content were not significantly different in the other three groups (P>0.05).4), The total protein of the group fed with trash fish stored in 24h was significantly lower than the other three groups (P<0.05). The activities of ACP of the group fed with formulated diet was the highest in the four groups, and that of the group fed with trash fish stored in 24h was significantly lower than the other three groups(P<0.05). The activities of AKP of the group fed with trash fish stored in 24h was significantly lower than the group fed with trash fish stored in 0h (P<0.05), but there was no significance among other groups (P>0.05). |
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