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The body chemical composition in aquatic organisms is related to nutrition, habitat, age and sex. On the other hand, knowing the amount of chemical compositions helps to select the appropriate species for human nutrition and food industry. In this study, the change in chemical composition of common carp in different weights was investigated. For this purpose, 25 two-year-old carp were studied during the second year of rearing from different weight groups from 500 g to 1600 g. Protein, fat, ash and dry matter content of fish meat were measured. The results showed that the mean protein content of carp was 10.209 ± 2.106 %, fat was 9.429 ± 0.937%, ash 1.407 ± 198 % and dry matter 21.13 ± 1.62%, respectively. In addition, the results of this study indicate that there is no significant difference between chemical compositions of carp in different weights (P> 0.05). The results of the present study show that there is no relationship between chemical compositions (protein, fat, ash, dry matter) and the weight of common carp and the weight of fish has no effect on the chemical compositions. Therefore, there is no difference in common carp meat chemical compositions in different weights.

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Temperature is the main environmental factor affecting the development of fish eggs. In this study, the effect of incubation temperature on fertilization rate, hatching rate and growth in goldfish (Carassius auratus) was investigated. Egg and sperm production were obtained by ovaprim injection and artificial propagation. Eggs were incubated at four temperatures (21, 24, 27 and 30 °C) with 3 replicates for each treatment and cultured for 40 days at the same temperature. The larvae were grown in the same aquarium that had been hatched under the same temperature condition for 40 days. The results showed that there was no significant difference in fertilization rate of incubated eggs at different temperatures, but the highest (97%) and lowest (94%) fertilization rates were observed at 24 °C and 21 °C, respectively. The maximum incubation time was recorded at 21 °C and the minimum time required at 30 °C (P < 0.05). The highest percentage of hatching (74.4%) was observed at 24 °C and it decreased with increasing water temperature (P < 0.05). Although, the temperature of 30 °C showed the highest value of length, weight and specific growth rate of larvae in comparison to other temperature treatments, but the highest anomalies (13%) were observed in this treatment, too. The best temperature of incubation and growth of larvae is 24°C and 27°C for goldfish, respectively.

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Due to the increasing demand for nanotechnologies, there is a rising concern about the potential risks of nanomaterials to human health, environment, and aquatic ecosystems. The chemical composition and small size of the nanomaterials are the most important factors in the toxicity of these materials. Histological study of gill and investigation of haematological parameters are important for monitoring of the health status in aquatic animals. Therefore, in this study, the effects of subacute concentrations of copper oxide nanoparticles were examined on some haematological parameters of Caspian Roach (Rutilus rutilus). The experiment was performed at 15 litres aquariums in three experimental groups including 10, 40, 80 ppm copper oxide nanoparticle and the control group for 42 days. Each treatment included three replicates consisting of seven juveniles carp with an approximate weight of 42± 2 gr. The results of this experiment showed that copper oxide nanoparticle caused hyperplasia, lamellar fusion, epithelial hypertrophy, lamellar aneurism, and reduces secondary lamellae length. In addition, red blood cells (RBC) was significantly decreased with the increase in the concentration of copper oxide nanoparticle (P<0.05). At the end of treatment, RBC had a significant reduction from 2.11±0.004 to 1.98±0.005. Hematocrit and haemoglobin reduced from 1.37±0.011 to 1.34±0.001 and 7.8±0.01 to 6.9±1.32, respectively (P<0.05). A significant reduction was recorded in hematocrit among the control groups and other treatments (P<0.05). Conclusion: Eventually it can be concluded that the sub-acute particles may causes damage to the surface of tissues, especially gill tissue, and changes in the level of blood factors in fish, which can be due to the destructive effects of this type of nanoparticle on hematopoietic organs such as liver and kidney. Therefore, a definite conclusion in this regard requires more and more extensive research on the same species and other species.

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Aims Hematological and biochemical parameters are valuable indicators for monitoring fish health and physiological responses, nutritional status and environmental conditions affecting fish health. In this study, the comparison of hematological indices and some biochemical and hormonal factors of blood serum in male and female sea carp were investigated.
Materials and Methods For this purpose, blood samples were taken from two groups of male and female broodstock with 14 fish from each group.
Findings The results of this study on hematological factors showed that in terms of  red blood cell (RBC), hematocrit (HCT), hemoglobin (HB), mean red blood cell volume (MCV), mean concentration of hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), white blood cell (WBC), monocyte (Mo) and granulocyte (Gr), there is no statistically significant difference between the two sexes (P> 0.05). The results of this study showed that there was a statistically significant difference between males and females in terms of glucose, cholesterol, calcium and cortisol (P <0.05). The amount of glucose and cholesterol in males and the amount of calcium and cortisol in females were higher. There is no statistically significant difference between males and females in terms of triglyceride, total protein, albumin, sodium and potassium (P> 0.05).
Conclusion The results of this study show that sex in sea carp during maturity has no effect on the hematological parameters of fish but can affect some biochemical factors in the blood serum of carp such as glucose, cholesterol, calcium and cortisol.

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Malathion and diazinon are widely used organophosphate pesticides in the agriculture fields, especially in the north provinces of Iran. In the current study, lethal concentrations of diazinon and malathion were determined based on big head carp calculated death rates at 24, 48, 72 and 96 hours using probit analysis. Then, in a separate experiment and according to the obtained LC₅₀, the effects of these toxins on fish hematological parameters was evaluated in which fish were disturbed in 10 treatments with 3 replicates (4 different doses of diazinon, 4 different doses of malathion and 1 control for each toxin) for 7 days. Fish were exposed to different sub-lethal concentrations of each toxin (12.5, 25, 37.5 and 75% of lethal concentration (LC50 96h). After 7 days, blood samples were collected and hematological parameters including hematocrit, hemoglobin, red blood cells count, the total number of white blood cells and white blood cell differential count (the percentage of lymphocytes, monocytes, neutrophils and eosinophils) were examined. The results of acute toxicity test showed that diazinon is more toxic to big head carp compared to malathion. Also, hematological studies of big head carp exposed to diazinon showed a significant reduction in red blood cells and white blood cells with increasing toxin concentration. Meanwhile, the percentage of neutrophils remarkably increased while lymphocytes significantly decreased along with increasing the concentration of diazinon.

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The present study was designed to evaluate the effect of acetaminophen on hematologic and blood biochemistry of rainbow trout in a 4-day period. To that end, total 300 fingerlings with an average body weight of 12.5±2.5 g were randomly allocated into 15 polyethylene tanks (with 100L volume). Fingerlings were exposed to five concentrations of acetaminophen, namely, 0, 0.01, 0.1, 1. 10 mg/L for 4 days. Hematologic and Biochemical Parameters of Rainbow Trout (Oncorhynchus mykiss) exposed to Acetaminophen were measured. According to the results, the number of white blood cells was significantly different compared to the control group and other treatments at concentration of 10 mg/l. The number of red blood cells, hemoglobin, mean hemoglobin volume (MCV) and hematocrit were higher in the control group and And the lowest amount was observed at a concentration of 10 mg/l and There was a significant difference between these parameters in different treatments. There wasn´t significant difference in mean corpuscular hemoglobin concentration (MCH) between experimental treatments. There was a significant difference in serum lysozyme enzyme and complement (ACH50) activity in fingerling exposed to acetaminophen. There was a significant difference in cortisol and glucose levels in different treatments so that the most amount of cortisol and glucose showed in the control group and the less amount was observed in treatment 5.

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Because of the importance of osmoregulation in success of the juvenile Caspian Roach (Rutilus caspicus) release, maintenance and their restoration, this study was performed with the aim of the evaluation of these fish (average weight of 1.4 g± 0.018 g) to the salinity tolerance of the Caspian Sea by abrupt and gradual transfer methods on two different occasions of short-term (24 hours) and long-term (21 days). For this reason, 360 juvenile roaches were distributed to 9 different experimental treatments (each of them with 3 replicates) with 1) increased abrupt salinity (direct transfer to the Caspian Sea water), 2) increased gradual salinity (3 ppt for every 24 hrs) and 3) the Control group (freshwater). In order to evaluate the ion regulation, osmolality, Na⁺, K⁺ and Cl^- were measured in fish. Some immune responses related to the increased salinity (immunoglobulin and lysozyme) and stress indices (cortisol and glucose) were also measured. Based on the obtained results, the fish in both treatments of increased salinity showed high percentage of survival. All parameters related to ion regulation were decreased after a primary increase. Furthermore, the trend of cortisol and immunoglobulin changes were negatively correlated showing decreased stress response and increased immune system for both salinity transfer methods. Thus, the roach juveniles (1-2 g) are able to be transferred into the Caspian Sea directly.

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               Abstract
In the present study, The effect of phthalate ester toxicity (0.1 and 1 mg/L) was investigated on some non-specific mucus parameters of common carp (Cyprinus carpio). 180 common carp (17.60±2.22gr) is gathered from warm water fish center and they were allocated into 9 tanks (20 Fish per tank). Fish adapted to new condition for a week. During this time; they were feed twice a day with same diets. Fishes were exposed at 3 concentration treatments containing 0; 0.1 and 1 mg/L DEHP under laboratory condition (25±0.5°C; pH: 7.4-8) for a period of 96 hours. Alkaline phosphatase, lysozyme, soluble protein, and immunoglobulin of mucus was measured and evaluated. The results showed that the levels of lysozyme, alkaline phosphatase and immunoglobulin in common carp skin mucus decreased when exposed to DEHP (with increasing concentration and exposure duration) And the level of soluble protein of common carp skin mucus increased when exposed to DEHP (with increasing concentration and exposure duration). These results indicated that concentrations of DEHP beneficially affects Amino Acid profiles of skin mucus in carp and they were categorized in 4 branches. There were Significant differences between exposed and control groups. Therefore; fish skin mucus can be a biomarker for showing contaminants and toxins. And the high consumption of plastic materials can be a warning to the health of aquatic animals and humans.