فهرست مطالب mohammadsheikh asadi

This research was carried in order to study of pathology and changes of some hematology indicators of indigenous and French Rainbow trout fish after following with Aeromonas hydrophila. For this research, treatments were performed in eight treatments and each treatment with three replications (each replicate containing 10 rainbow trout fish with an average weight 16±0.36 g). two treatments as a negative control (including of indigenous and French fish without bacterial injection), Two treatments as a positive control (including of indigenous and French fish with serum physiology injection), two treatments including indigenous fish with 106 and 108 CFU/ml Aeromonas hydrophila bacteria and two treatments including French fish, which were injected with 106 and 108 CFU/ml of Aeromonas hydrophila by intra-peritoneal method. After 20 days, to determine the values of some hemotology parameters including counts of white blood cells (WBC), red blood cells (RBC), hemoglobin, hematocrit, and MCV, MCH and MCHC indices, blood samples were taken from 6 fish of each treatment, and then, in order to study of pathology of the tissues of the kidney, liver and spleen, fishes were fixed in 10% formalin solution. The present study, the results showed that the hematocrit, hemoglobin and counts of red blood cells decreased significantly in the treatments of infected with bacterial infection of Aeromonas hydrophila compared with the control groups, and the number of white blood cells and neutrophils increased significantly. Lesions such as mild degeneration lesions in liver cells and tissue texture and severe cytoplasmic vacuating of liver cells and complications such as degeneration and necrosis of renal tubules and hyperemia, edema and lose of spleen pulmonary defence cells, the most important changes in tissue pathology were in experimental treatments compared to control. The highest survival rate was observed in indigenous Rainbow trout control group without bacterial injection and with serum physiology injection. Due to the greater capability of internal race resistance along with management measures that have been able to increase survival rates, improvement of environmental conditions and elimination of stressors can be effective in reducing Aeromonas lesions.

Viral Nervous Necrosis (VNN) causes viral encephalopathy and retinopathy (VER), a hazardous and devastating disease of many species of cultured and marine fish worldwide. It caused by betanodaviruses a serious concern especially in the fry and young fish. This virus infects most of the cultured fishes causing severe mortality. Our current review focuses chiefly on recent studies performed on VNN disease. Recent outbreaks have been reported in China, Indonesia, Singapore and India, affecting the mariculture and aquaculture industry. It also decreased dramatically Mullet stocks in the Caspian Sea. The four main genotypes of VNN were found in all continentals’ except South America. The economic loss due to the virus is mainly due to mortality and spread of infection both vertically and horizontally. Our investigation in recent years suggest that more research and epidemiological surveys should be conducted, especially in critical areas were mariculture farms are planned to be established. Therefore, finding new rapid diagnosis tools, Monitoring and Surveillance program, and effective vaccines, Control, Prevention and Eradication in the comprehensive program should be considered globally.

Salinity is one of the important environmental factors affecting fish. To determine the effect of different aspects of salinity increase, it is important to determine the maximum salinity tolerance of fish. The salinity tolerance of Hamun mahi (Schizothorax zarudnyi) juveniles was evaluated in the laboratory by gradual and abrupt salinity increases. The mortality, behavior, gill histopathological alternations and chloride cells numbers were evaluated in the fish. In addition, fish were cultivated in 10 g/L for 20 days and at the end of the rearing period, their growth and blood factors were measured. LC50 value (lethal concentration) 24, 48, 72 and 96 hours were 11.44, 10.72, 10.52 and 10.52 g/L, respectively. The gradual transfer of fish to higher salinities resulted in an increase in the salinity tolerance (13g/L). The most observed changes in gill tissue included epithelial lifting (65%) and the smallest observed change was necrosis (14%). Also, the number of chloride cells increased by 16% after exposure to LC50 (96-h) concentration. There was no significant difference in growth rate, total protein, AST, ALP, and cortisol in fish reared in fresh and 10 g/L salt water, while glucose and triglyceride showed a significant difference. In general, the results of this study showed that it is possible to cultivate Hamun mahi in salt water (10 g/L), but due to the low growth of this fish during the cultivation period additional studies are needed to find a proper rearing condition.