Phylogenetic analysis and genotyping of Iranian infectious haematopoietic necrosis virus (IHNV) of rainbow trout (Oncorhynchus mykiss) based on the glycoprotein gene.

BACKGROUND: Infectious haematopoietic necrosis (IHN) is known as one of the most contagious systemic viral diseases in salmonids which can lead to significant mortality rates and negative impacts on the salmonid farming industry. Infectious haematopoietic necrosis virus (IHNV) was first detected in rainbow trout (Oncorhynchus mykiss) farms in Iran in 2003. OBJECTIVES: We conducted the present study to determine the detection of IHN genotypes in rainbow trout (O. mykiss) in farms in the central parts of Iran, using molecular and phylogenetic techniques. METHODS: Samples were collected from fries exhibiting clinical signs such as darkening of the skin, abdominal swelling, and loss of appetite. Phylogenetic analysis was performed by the neighbour-joining method, using MEGA 5.1 software. For phylogenetic analysis and genotyping of IHNV from central parts of Iran, the sequences of the glycoprotein gene were determined for two Iranian isolates (Jahad-UT1 and Jahad-UT2). RESULTS: Phylogenetic analysis revealed that the detected strains (Jahad-UT1 and Jahad-UT2 isolates) are closely related (97.23%-100%) to European isolates within genogroup 'E'. CONCLUSIONS: This finding indicates that Jahad-UT1 and Jahad-UT2 isolates have been widely transferred to Iran from European countries. Moreover, the nucleotide diversity of these Iranian isolates showed a close relationship with the North American and Asian isolates, although the Iranian isolates were collected from a smaller geographical area and within a shorter time period between 2014 and 2015.

Effect of water salinity on total protein and electrophoretic pattern of serum proteins of grass carp, Ctenopharyngodon idella.

In this study the effects of water salinity on serum total protein and its components in grass carp were investigated. The aim of this study was to determine the effect of salinity tolerance of fish on total serum protein level and its components as an indicator of liver and kidney activity. One hundred and twenty grass carp were divided into four groups, randomly. The first three groups were reared in concentration of 4, 8 and 12 g L(-1) of salt solution, respectively, and the fourth group was reared in freshwater and served as control. After 3 weeks, blood samples were collected and after harvesting the blood serum, serum total protein and protein components were measured with Biuret and electrophoresis methods, respectively. Results showed that mean value of serum total protein in the control and three salinities groups were 2.75, 3.28, 2.90 and 3.13 g dL(-1), respectively. Five fractions of serum protein were electrophoretically observed as: albumin (Alb), alpha-1 globulin (α1-glu), alpha-2 globulin (α2-glu), beta globulin (ß-glu) and gamma globulin (γ-glu). There were not any significant differences between the average mean of serum total protein of experimental and control groups (p > 0.05). However, Alb, α1-glu and ß-glu levels in the experimental groups were significantly higher than in the control group (p < 0.05). The average of α2-glu and γ-glu revealed no significant difference between the experimental groups (p > 0.05). In conclusion, our results showed that increasing water salinity could have a significant effect on Alb, α1-glu and ß-glu levels but not on total serum protein in grass carp.

Study on effect of salinity level of water on electrocardiogram and some of blood serum minerals in grass carp, Ctenopharyngodon idella.

In this study the effects of salinity on the electrocardiogram and some of blood serum minerals in grass carp were investigated. For this purpose, grass carp were exposed to concentrations of 4, 8 and 12 g L(-1) salinities and electrocardiogram of all fish was recorded. Blood samples were also collected from all fish and serum minerals were measured. Our results indicated that mineral level in the studied groups was significantly different. The average of heart rate per minute in control group and 4, 8 and 12 g L(-1) were 10.15, 10.06, 12.17 and 7.79 beat per min, respectively. In 8 g L(-1) group only the average of QT and ST segment decreased significantly in comparison with the control group (p < 0.05). In 12 g L(-1) group the average of heart rate per minute decreased significantly in comparison with 8 g L(-1) group (p < 0.05) and no difference in the average of heart rate per minute was observed in all groups. The average of RR, PT and ST segment in the 12 g L(-1) group were significantly more than the other groups (p < 0.05). The results showed that water salinity level increased to concentrations above 8 g L(-1) can have significant effect on the electrocardiogram and mineral level of blood serum in grass carp. These changes are probably can be considered as one of the causes of impairment of health and death of this fish species in the salinities more than 8 g L(-1) due to ion imbalance and cardiovascular disorders.

Effect of salinity level on TSH and thyroid hormones of grass carp, Ctenophayngodon idella.

Thyroid hormones (T3, T4) have marked effect on body metabolism and in controlling osmoregulation activity in fish. The aim of this study was to determine the effect of water salinity changes on thyroid hormones level and thyroid-stimulating hormone (TSH) of grass carp. For this purpose 120 grass carp were divided randomly in to four groups (10 fish in each group and three replicates per treatment). Three groups were held in three different salinities at concentrations of 4, 8 and 12 g L(-1). The fourth group was reared in fresh water and considered as control. After three weeks blood samples were collected from the caudal peduncle vein. Then serum was separated and serum thyroid hormones and TSH were measured by LISA on Microwell plates. Our results indicated that the average of T3 levels in 4, 8 and 12 g L(-1) groups were 0.43 ± 0.11, 0.22 ± 0.04 and 0.21 ± 0.04 µg dL(-1), respectively. T3 levels in all experimental groups were significantly lower than those of control group (p < 0.05). Serum T4 level in 4, 8 and 12 g L(-1) groups were 0.29 ± 62955/40.06, 0.24 ± 43129/50.05 and 2.85 7958/± 05768/40.55 µg dL(-1), respectively. Thyroxine level was significantly higher only in 12 g L(-1) group in comparison with the control and other experimental groups (p < 0.05). Thyroxine level in other groups had not any significant difference with the control group (p > 0.05). The level of TSH in salinities of 4 and 8 g L(-1) groups was significantly higher than that of control group (p < 0.05). The results showed that increasing water salinity can have significant effect on thyroid activity by decreasing T3 and increasing T4 level in serum of grass carp in experimental condition.