فصلنامه فیزیولوژی و بیوتکنولوژی آبزیان
سال دهم شماره 1 (بهار 1401)

Increased entry of pesticides such as chlorpyrifos into aquatic ecosystems can cause harmful damage to aquatic animals. The aim of this study was to investigate the effect of dietary supplement of Pleurotus ostreatus mushroom powder on the relative expression of immune-related genes (P450 and Hsp70) in the liver tissue of Nile tilapia (Oreochromis niloticus) in response to chlorpyrifos toxin. In this study, 120 juveniles of Nile tilapia with an average weight of 20±0.4g were divided into four treatments in three replications and fed with diet containing 0 (control), 0.05, 0.1 and 0.2% fungus for 42 days. At the end of the feeding trial, all treatments were exposed to the sub-lethal concentration of chlorpyrifos for 14 days. Liver tissue samples were taken to evaluate the relative expression on the last day of the mushroom feeding period and on the 14th day of exposure to chlorpyrifos. The relative expression of P450 in treatments of 0.2 and 0.1 were significantly increased, but the treatments of 0.05 and 0.1 after exposing to poison was not significantly different from the control group (P>0.05). Expression of Hsp70 gene in treatments fed with dietary supplement before and after exposure to toxin was significantly different (P<0.05). It increased in 0.2 treatment, but it was not significantly different in 0.05 treatment from control (P>0.05). The results of this study indicate the positive effects of Pleurotus ostreatus prebiotic dietary supplements on the relative expression of Hsp70 and P450 genes in Nile tilapia juveniles and its immune system strengthen in the face of contaminants and stressful substances such as chlorpyrifos

Due to the high importance of beluga sturgeon breeders and to determine the appropriate time for hormonal induction, the present study was performed with the aim of selecting the breeders with high quality eggs for artificial reproduction. Two groups of eggs from 7 female beluga were incubated with 5 µg of progesterone per mL or hormone-free group in Ringer medium at 16°C for 18 hours. Pre- and post-exposure, the germinal vesicle migration (GVM) index was determined in 10 oocytes. The results showed that the GV position was 13.0±3.4 pre-treatment and changed after in vitro culture of oocytes in control and progesterone groups to 11.7±4.1 and 9.6±2.2, respectively, which showed a significant difference. During this period, the GVM exposed to progesterone was determined to be 31.2% closer to the animal pole. This study suggests that due to high economic value of beluga breeders, this method can be used to select suitable fish to induce artificial reproduction.

In the present study, effect of different solvents (methanol 100%, methanol 60%, methanol 20% and water 100%) were evaluated on the extract yield and antioxidant properties of three red seaweed species including Gracilaria arcuata, Gracilaria textorri and Leveillea jungermannioides) from Chabahar coasts. Antioxidant activities of different extract were measured by DPPH free radical scavenging activity, reduction power and iron chelating activity methods. There was a significant difference between the extract yield of different seaweed and the highest amount of the extract (6.02g/100g seaweed) was obtained from L. jungermannioides with methanol 100% as solvent. The most antioxidant activities, measured by different assay were observed in methanol 60% extract of G. arcuata which was significantly higher than other species. The amount of the extract and antioxidant properties were significantly different between different treatments depending on the solvent ratio and the type of seaweed species. The results of the present study showed G. arcuata can be considered as potential sources of natural antioxidants.

The algal cell wall is the primary site for interaction with nanoparticles and creates a barrier against the entry of nanoparticles into its cell. Therefore, the effect of zinc oxide (ZnO), copper (II) oxide (CuO) and iron (III) oxide (Fe2O3) nanoparticles was investigated on the cell wall structure of Nannochloropsis oculata. Calculation of EC50 using microalgae cell count showed that the order of nanoparticles toxicity in N. oculate was CuO>ZnO>Fe2O3. The interaction of ZnO, CuO and Fe2O3 nanoparticles with microalgae cell wall was proved in FTIR analysis. The highest interaction of the studied nanoparticles was with carbonyl (C=O), methoxy (C-O) and methyl (C-H) functional groups of N. oculata cell wall. On the other hand, transmission electron microscopy (TEM) images showed that ZnO and CuO nanoparticles caused the shrinkage of cell wall. The accumulation of these nanoparticles was observed on the surface of the cell wall. Accumulation of nanoparticles and shrinkage of the cell wall could be the possible reason for the higher toxicity of CuO and ZnO nanoparticles than Fe2O3 nanoparticles in N. oculata.

In the present study, the accumulation of heavy metals (Pb, Zn and Cd) in blood and muscle, eggs and hatchlings of hawksbill were measured in July 2018 in Ommolgorm Island, Bushehr Province. In the breeding season, blood and muscle tissue from breeder samples were taken and then normal and abnormal eggs as well as hatchlings muscle were sampled. Normal eggs were divided into three parts including shell, albumin and yolk and abnormal eggs were divided into two parts including albumin and shell. After separating the samples and preparing for the measurement of heavy metals, the amount of heavy metals lead, zinc and cadmium were measured by ICP-Mass. According to the results, the highest bioaccumulation of heavy metals was related to zinc and then lead and the lowest was related to cadmium. The highest accumulation was in breeder blood, normal egg yolk and hatchlings muscle, respectively, and the lowest bioaccumulation was related to cadmium metal in these tissues. The highest amount of cadmium was observed in normal and abnormal eggshells. The present results showed that blood, yolk and eggshell are as a bioindicator for zinc, lead and cadmium, respectively, and the bioaccumulation of all three metals in breeder blood and muscle tissues and different parts of normal and abnormal shell as well as hatchling muscle was less than the WHO standard.

Due to use of ovulin hormone in the carp breeding centers and lack enough information about the effect of its different concentrations on this fish broodstocks, evaluation of the effectiveness of ovulin hormone in artificial reproduction of carp is essential. This study was performed on 12 male broodstocks of carp with an average weight of 1307.85±169.57g. Fish in 4 groups (each group with 4 fish) were injected at doses of 0.2, 0.25, 0.3 and 0.35mg/kg body weight of ovulin hormone in one time. The injection method was performed peritoneally and below the pectoral fin. Blood samples were taken from fish in two times, before injection and 10 hours after injection. Based on the results, it was found that injection of different doses of ovulin hormone had no effect on red blood cell counts (RBC), mean corpuscular hemoglobin (MCH) and white blood cell counts (WBC) (P>0.05). However, the amount of hemoglobin, hematocrit and granulocytes in all treatments decreased in the blood of male broodstock after the injection of ovulin hormone and the percentage of monocytes increased (P <0.05). It had no effect on total protein and sodium (P>0.05). However, glucose and calcium levels increased and triglyceride, albumin and potassium levels decreased in the studied doses (P<0.05). The levels of cortisol and sex hormones testosterone, estradiol and progesterone in male broodstocks increased in all doses studied (P<0.05). Also, the highest sperm motility and spermatocrit were observed in 0.2 mg/kg, pH in 0.3 mg/kg, triglyceride and alkaline phosphatase in 0.35mg/kg and calcium, sodium and potassium in 0.25mg/kg (P<0.05). The results of this study showed that doses of 0.25 and 0.3mg/kg body weight had the best effect on blood indices, steroid hormones and sperm indices in male broodstocks of carp.

This study aimed to investigate the effects of interaction between nitrite and different salinities on blood, immunity, and stress parameters in juveniles of stellate (Acipenser stellatus) in two stages. In the first stage, the lethal concentration (LC50 96h) of nitrite in different salinities (0, 4, 8, and 12g/L) to juveniles of stellate was determined. In the second stage, 240 juveniles of stellate (with a mean weight and length of 15.23±2.17g and 17±1.96cm) were exposed to half (50%) of LC50 96h (37.56, 46.77, 120.80, and 176.579mg/L) under the same salinities for 4 days (8 treatments, triplicate). The results showed that the highest mean of white blood cells and neutrophils was in Treatment 7, the highest mean of red blood cells, hemoglobin, MCV and hematocrit was related to treatment 5 and the highest mean of eosinophil belonged to Treatment 8 (P<0.05). Moreover, the highest IgM and total immunoglobulin, lysozyme, cortisol and glucose, and lactate was found in treatments 8, 7, 4, and 3, respectively (P<0.05). The increased nitrite concentration in subjects exposed to salinity plus half of the LC50 96h of nitrite significantly increased the tolerance and immunity parameters and reduced the stress level of subjects. This indicates that salinity could reduce the toxicity of nitrite to subjects. Blood indices also considerably changed in subjects exposed to the same conditions. It can be hence concluded that saline or brackish water (mixed with freshwater, 0 to 12g/L) plus half of the LC50 96h of nitrite is suitable for the culture of stellate juveniles.

Vibrio cholerae is an aquatic pathogenic bacterium whose various strains cause diseases such as cholera, acute diarrhea, meningitis and sepsis. Due to the resistance of the strains to different antibiotics, the production of low-risk vaccines that affect all pathogenic strains can be the best method of control. Therefore, in this study, the vaccine potential of VceC outer membrane protein against V. cholerae was evaluated using bioinformatics methods. In addition to determining antigenicity, virulence, and physicochemical properties, B and T cell epitope mapping was performed to design the best peptide subunit vaccine. The results showed that the protein has optimal properties such as presence in all the studied strains, stability and long half-life, good temperature resistance, and solubility during overexpression. Numerous antigenic regions and linear and spatial epitopes were also observed along the protein sequence and structure. According to the location and antigenic properties, two linear and conformational subunit vaccines were designed that can be tested and used against the pathogenicity of different strains of V. cholerae.