Effects On The Physiological And Biochemical Of Redclaw Crayfish, Cherax Quadricarinatus Under The Nitrite And Ammonia Nitrogen Stress

Redclaw crayfish, Cherax quadricarinatus is commonly known as Australia crawfish, which belonging to Cherax,Parastacidae,Decapoda,Crustacea, and it is native to Australia. Because its applicability, fastgrowth, easy-breeding, and many other advantages, it is introduced to try to raised in China from 1992, and its reproductive biology, embryonic development have been learned, etc for a in-depth research, while in immunology and environmental toxicology, the research is relatively shortage. This study used the technique of histology and transmission electron microscopy, combined with enzymatic methods to study the the variations of the activity of immune-related enzymes in hepatopancreas, gills and muscles, and the morphological changes of the hepatopancreas and gills of redclaw crayfish, Cherax quadricarinatus under different concentrations of nitrite stress and ammonia nitrogen stress. The mainly results and conclusions of this study are as follows:The results showed that, under the stress of nitrite, the activity of ACP, AKP, SOD and GSH-PX were significantly lower (P<0.05) in three tissues compared with the control group; with the increase of the nitrite concentration, the activity of enzymes decreased gradually; In gills, the activity of Na+K+ATPase and Ca2+ Mg2+ ATPase also decreased with the increase of nitrite, the test result of the activity of lysozyme (UL) cannot be checked out in both muscles and hepatopancreas.As well as under the stress of nitrite, compared with the control group, and under the stress of ammonia nitrogen, the activity of ACP, AKP, SOD and GSH-PX were significantly lower (P<0.05) in three tissues too; with the increase of the ammonia nitrogen concentration, the activity of enzymes decreased gradually; In gills, the activity of Na+K+ATPase and Ca2+Mg2+ATPase also decreased with the increase of ammonia nitrogen concentration, the test result of the activity of lysozyme (UL) cannot be checked out in both muscles and hepatopancreas.Histology shows that with the increase of nitrite concentration, the cuticle of the gills damaged or even disintegrated; epithelial cell arranged loosely, as well as the phenomenon of vacuolization emerged; morphological changes were also obviously found in organelles; the phenomenon of vacuolization emerged in haemocoel, and the hemocytes deformed. Hepatopancreatic epithelial cells arranged in haphazard, or even has cell lysis, and severe vacolation phenomenon; microvilli structural damaged, some broken; hepatopancreatic tubules arranged in chaos, the distance between the hepatopancreatic tubules expanded, connective tissues became thin, and hemocytes deformations were found; in high concentration, the number of lipid droplets in R cells reduced, nuclear membrane disintegrated, cell membrane ruptured, vacolation increased; in F cells, ribosomes decreased, the rough endoplasmic reticulum reduced, vacolation increased as well as the endoplasmic reticulum edema emerged.Under the stress of ammonia nitrogen, the cuticle of gills damaged; hemocytes were deformed; epithelial cell dissolved, vacuolization emerged in haemocoel. As well as gills organization, low concentrations of ammonia nitrogen intimidation of morphological changes, did not appear in hepatopancreas organization. In medial concentrations group, hepatopancreatic tubules structural damaged mainly. The space between the hepatopancreatic tubules expanded, the connective tissue increased. Numerous hepatopancreatic tubules arranged chaos, and the sizes varied. Epithelial cell loosely arranged, microvilli structural damaged. In high concentrations group, hepatopancreatic tubules structural damaged significantly, undergone the phenomenon of dissolution, the space between the hepatopancreatic tubules expanded significantly, microvilli structural damaged more seriously. Epithelial cell is dissolved, content of the cell released, vacuolization seriously. The connective tissue got thinner. Blood cells deformed or cracked. R cell lipid drops increased, while its nucleus is deformed. In addition, F cells in high concentration group in endoplasmic reticulum reduced, vacuolization and mitochondrial deformation appeared.According to our study, the activity of immune-related enzymes were influenced by the nitrite stress and the ammonia nitrogen, besides, the morphological structures of the hepatopancreas and gills were also affected, as well as their biological functions.