نشریه پژوهش های ماهی شناسی کاربردی
سال دهم شماره 2 (تابستان 1401)

This research was carried out with the aim of investigating the biological reproduction of fish retrieval in the Caspian Sea. Each Month catches were carried from Golestan province from December 2015 to September 2016. In total, 200 pieces of fish were caught to study reproductive production in the study area. In this research, the total length of the fish was 16.6 ± 1.5 mm and the frequency of weight was 89.7 ± 33.6 g. The maximum mean diameter of the egg was at the age of 4 years with the diameter of 1.17 ± 0.1 mm and the minimum diameter of the oocytes was 2 years old at 0.91 ± 0.15 mm. The GSI sexual health index varies from 0.09 to 0.19 for the female fish, and from the beginning of March and during the month of April we ham still the decrease. However, the spawning time began in late March and continued until mid-spring. Also, the mean absolute fecundity of the fish was 11,911.71 egg.The average maturity of 50% of the fish population was 138 mm and the mean age of puberty was 50% of the word of the word was equal to 125 mm. By examining the relationship between length and weight with Fecundity, there was a linear relationship between fork length and total weight with the Fecundity. The results of the Fecundity test with length and weight factors were found to be significant in Pearson test (P <0.05

Proof of species existence in different regions can be useful for studying the migration pattern of the species. The use of non-invasive methods such as eDNA can be very effective in tracking and dispersing and improving the management of water resources and species. In this study, 15 water samples were taken from different areas of the southern Caspian Sea basin. Amino-modified silica-coated magnetic nanoparticles were used to separate DNA from water. In this study, for the first time, the amino magnet method was used to separate environmental DNA from a water sample. DNA of three water samples were properly extracted ,from the water output of Oncorhynchus mykiss farm in Tajan river  in Sari, water samples from salmon cages in Nowshahr and water samples from around Caspian salmon farming cages in Tonekabon were properly examined. The results showed that sample No. 1 was located in the rainbow trout clad and samples No. 2 and 3 were located in the Caspian Sea salmon clad, indicating that the species were properly isolated with amino silicate magnetic nanoparticles and their presence in the aqueous body was confirmed by environmental DNA.

In this study of the some parameters of population dynamics of spirlin (Alburnoides eichwaldii) was performed in reservoir of Shahid Rajaii dam in four seasons. 226 specimens were caught by gill nets, were in 5 age groups 0+ to 4+ years that, 2-year-olds were prevailing in both sexes. The sex ratio of males to females were 1:3.17, that, indicates the predominance of the female sex (p<0.05, χ2=60.84). Specimens ranged from 62 to 131 mm in length and 2.59 to 30.46 gr in weight. In overall, the length and weight of the females was higher than males (p<0.05). The growth pattern was calculated as positive allometric according to the slope of the regression line between length and weight and based on the Pauly growth equation. The Von Bertalanffy growth equations for males and females were calculated respectively   and   that the infinity length in females was more than males. The condition factor almost was equal in both sexes (p>0.05). The average absolute and relative fecundity were 2690±1048 and 193±98 respectively. The average of female egg diameter was 0.86 ±0.21 mm in this study. Examination of the nutritional index showed the tendency of this species to eat carnivores. After 15 years of the formation of the lake, the view of many dynamic parameters of Alburnoides eichwaldii in reservoir better than river.

The aim of this study was to investigate the effect of adding lactic acid to the diet of rainbow trout on growth indices, activity of digestive enzymes and microbial flora of the fish gastrointestinal tract. For this purpose, 4 diets containing 0, 5, 10 and 20 g of lactic acid per kg of diet were made and each diet was offered to fish in three replications for 8 weeks. The results showed that there was no significant difference in growth and survival indices between different treatments (P> 0.05). The highest activity of gastric pepsin enzyme was observed at the level of 10 and 20 g of lactic acid in the diet (P <0.05). The highest alpha-amylase activity was observed at the level of 10 g of lactic acid in the diet (P <0.05). Lipase activity in the control treatment and 10 g of lactic acid in the diet was similar and significantly higher than the treatments of 5 and 20 g of lactic acid in the diet (P <0.05). Intestinal protease activity in treatments of 5 and 10 g of lactic acid in the diet was higher than the control treatment and the highest activity was related to 10 g of lactic acid (P <0.05). Treatment of 20 g of lactic acid in the diet had lower protease activity than the control treatment (P <0.05). The highest number of total intestinal bacteria was observed at the level of 5 and 10 g of lactic acid in the diet (P <0.05). The number of intestinal lactic acid bacteria in lactic acid treatments was significantly higher than the control treatment (P <0.05). The highest number of lactic acid bacteria was observed in the treatment of 10 g of lactic acid in the diet (P <0.05). According to the results, the addition of lactic acid to the rainbow trout diet has no effect on growth, although it does increase the activity of digestive enzymes. However, adding 10 g / kg of lactic acid leads to an increase in lactic acid bacteria in the gut of the fish.

This study was performed to evaluate the best dose of Ovulin hormone in artificial reproduction of female sea carp broodstocks in the spring of 2021 in the bone reproduction and breeding center of Sijual in Bandar-e-Turkmen, Golestan province. 12 adult female sea carp with an average weight of 1750.46 ± 312.58 g were injected at doses of 0.4, 0.5, 0.6 and 0.7 ml / kg body weight of Ovulin hormone. Blood samples were taken from fish in two stages. The first stage was before injection and the second stage was 12-12 hours after injection. The results of hematological indices showed that injection of different doses of Ovulin hormone had no effect on the number of red blood cells, white blood cells, hemoglobin, MCV, MCH and MCHC (P> 0.05). But decreases hematocrit and granulocytes and increases monocytes (P <0.05). The results of biochemical factors showed the amount of glucose and cortisol increased in all treatments and the amount of triglyceride, cholesterol, total protein, albumin, calcium, potassium and sodium decreased in all treatments (P <0.05). Also, the results of steroid hormone analysis showed that by injecting different doses of Ovulin hormone, the amount of testosterone, estradiol and progesterone in all treatments increases (P <0.05). The results of this study showed that doses of 0.6 and 0.7 ml / kg body weight had the best effect on blood indices and steroid hormones studied in female sea carp. However, it is suggested that for maximum efficiency and economic efficiency, a dose of 0.6 ml / kg be used to female sea carp broodstocks.

The presence of nanoparticles affects the physiological condition of fish and reduces the immune function of fish, so the use of immune stimulants such as molasses is very important. 250 juveniles of common carp for 42 days in four categories: ration without molasses (treatment 1), ration containing 0.5% molasses (treatment 2), ration containing 1% molasses (treatment 3) and ration containing 2% molasses (Treatment 4) were divided. Then, 50% of the lethal concentration of nano-iron was added to each group for fourteen days. Histological studies of fish exposed to molasses and iron nanoparticles showed structural abnormalities in liver tissue. So that these changes were very different compared to the tissues of the control group. The final conclusion of the present study showed that nano-iron treatment led to tissue damage in carp liver; Although histopathological complication was also observed in the combination of nano-iron and molasses treatments, but the severity of injuries decreased with increasing molasses concentration. The negative effect of iron nanoparticles on normal carp liver tissue by molasses seems to be minimized.

In this research accumulation of Aluminum (Al), Vanadium (V), and Tin (Sn) and their health risk assessment due to consumption three fish species include Pickhandle Barracuda (Sphyraena jello), Japanese threadfin bream (Nemipteru japonicus), and King soldier bream (Argyrops spinifer) were investigated. Fish was harvested from Jofre in Bushehr afterward preparation, heavy metals concentration of Al, V and Sn in fish muscle were determinate.  Heavy metals concentration compared with standard of World Health Organization (WHO). Target Hazard Quotients (THQ), estimated daily intake (EDI) and estimated weekly intake (EWI) was determined, and in final Consumption Rate Limit (CRlim) was calculated. According to the results, Al concentration in all of the fish muscle (19.65 to 34.44 μger/ger) was more than standard of WHO. THQ of Al in three fish species and THQ of Sn in King soldier bream in two age category more than 1. EDI of Al in King soldier bream (16.31 μger/day) and Japanese threadfin bream (11.41 μger/day) more than Provisional Tolerable daily intake (PTDI). The highest and lowest of CRlim was related to V in Pickhandle Barracuda for adults (4.65 kg/day) and Al in King soldier bream and Japanese threadfin bream for children (0.0004 kg/day). In conclusion, according to the high accumulation of Al in all of fish species muscle, suggested that in order to prevention from undesirable non-carcinogenic in consumers during the long term, limitation of consumption investigated fish to be planning based on Al concentration.

The aim of this study was to investigate the sub-lethal effects Lead Chloride (PbCl2) on blood indices, liver enzymes, cytochrome P450 gene expression in common carp. For this purpose, Fish with a mean weight of 7 33±0.33 g were prepared and divided into 3 treatments and a control group and exposed to effective concentrations (0.05, 0.15, 0.25 mg / l) of sublethal toxicity for a period of 14 days. At the end of the experiment, sampling was done randomly. The results showed that the level of AST and ALT enzymes significantly decreased compared to the control group (P<0.05) whileThe level of ALP increased significantly (P<0.05). The results of hematology test showed that the level of white blood cells, hematocrit and hemoglobin did not change significantly with increasing the concentration of lead chloride compared to the control group; but they had a slight upward trend compared to the control group (P <0.05). Also, the amount of red blood cells, monocytes, total protein and serum immunoglobulin decreased significantly compared to the control group (P <0.05). Levels of lymphocytes, basophils and total mucus protein increased significantly compared to the control group (P <0.05). Mucus lysozyme had a slight decreasing trend compared to the control group but had no significant effect (P <0.05). The expression of P450 gene in liver and gills increased significantly compared to the control group (P> 0.05). In this study, the relative expression of cytochrome P450 gene in liver tissue was significantly higher than gill tissue (P <0.05). In general, it was found that lead chloride has destructive effects on the liver of common carp.