نشریه پژوهش های ماهی شناسی کاربردی
سال پنجم شماره 4 (زمستان 1396)

Snow trout (S. zarudnyi) is a commercial, ecological and biological valuable species which is native to the southeastern Iran (Sistan). In this study, 41 samples of Snow trout were caught by gill net from Chah nimeh reservoirs, Sistan and Baluchestan Province, and their biological characteristic were investigated. The results showed that the average weight and length of fish were 121.70±57.07g and 22.35± 3.49cm, respectively. The sexual ratio in Snow trout was 1:1.16 (male: female), and the gonadosomatic Index (GSI) of female was 1.08±0.74%. Moreover, the maximum and minimum percentage of GSI was reported in March (1.75%) and May (0.84%), respectively. The changes in the percentage of GSI indicated that the sexual maturity and breeding season of this fish happened in March. The average relative and absolute fecundity recorded was 33140 ± 1905.65 egg/kg and 26964±1001/97 eggs, respectively. The condition factor (CF) was 1.01±0.12 %, and the maximum and minimum amount of CF was reported in March and May, 1.30% and 0.76%, respectively. The relative gut length (RLG), as the ratio of intestine length to body length was 1.73±0.30. Consequently, considering the amount of RLG which was more than one, Snow trout categorized as omnivorous with herbivorous tendency. The average of feeding intensity (IF) was 180.64±108.99%, and the maximum and minimum of IF was found in May and February, 480.54 and 43.02%, respectively. Finally, the relationship between the length and weight for the species was recorded as W=0.0058L3.177 with r=0.98. The b-value as coefficient of WLR indicates that the growth of Snow trout is isometric.

The aim of this study was to evaluate the gastrointestinal tract and biological indices during spawning migration in spring and fall of 2014. Sixty fishes were caught from Shirud River (Tonekabon, Mazandaran province, Southern Caspian Sea). In this study, Caspian lamprey (C. wagneri) was studied in terms of the biological indices including total length, body weight, intestinal length, and the weight of visceral, liver, intestines and ovaries. The fishes were divided into two groups of “mature” and “maturing” groups. The results of appearance observations showed that there was no specific stomach and esophagus, and its digestive tract only consisted of a straight and narrow intestine. In the most migrant fishes, intestine were empty and no significant differences were observed in dry weight of their intestine among all groups. In comparison of the total intestine length, relative intestine length (RLG) and visceral index (VSI), there were no significant differences among all experimental groups in different sex, seasons and maturation stage. Also, in comparison of Hepatosomatic index (HSI), there was significant difference between maturing and mature females in fall, whereas no significant differences were observed among other groups.

Hilsa shad (T. ilisha) is the only anadromous species among the fishes in south of Iran, which has reproductive migration from Persian Gulf to the rivers. In this research, the morphological properties, histological and cellular changes in testes and spermatocytes of Hilsa shad were studied in two different environments (salt water and fresh water) in Khoozestan province during its reproductive cycle. Fish samples were collected from Bahmanshir River (fresh water) and Musa creek (salt water). After biometric measurements (length and weight measured), sample pieces of testis from each fish were fixed in Bouin's fixative solution. The tissues were embedded in paraffin for preparation of section (5µm thickness) for light microscope and then stained with Hematoxylin and Eosin. According to the results obtained from male fishes, five phases of gametes were observed including spermatogonia, primary spermatocyte, secondary spermatocyte, spermatid and spermatozoa. Spermatogonia were the largest germ cells in the testis which were observed during the whole reproductive cycle. Primary spermatocytes were ovoid form and seem to be smaller and darker in comparison with spermatoginia. Secondary spermatocytes had smaller size rather than Primary types. Spermatozoa were ovoid and stained with Hematoxilin properly while their tails showed weak staining capability.

Trace metals are one of the most common pollutants in the aquatic environment which are accumulated in the bodies of aquatic organisms such as fish and considered as a potential risk for organism’s health, especially for human. This study was carried out to assess the concentration of trace metals (Cd, Cu, Zn and Ni) in the edible tissues of Lizard fish (S.tumbil) and Threadfin bream (N. japonicus) from the Oman Sea, and human health risk assessment via the consumption of these fishes, during summer 2016. The concentrations of trace metals were determined by flame atomic absorption spectrometry. The average concentration of cadmium, copper and zinc in the Lizard fish muscle were 0.13±0.03, 0.83±0.08, and 11.33±3.64 μg/g, respectively. The average concentration of copper and zinc in Threadfin bream muscle were 0.61±0.07, and 10/09±1/4 μg/g, respectively. Cadmium concentrations in Threadfin bream and nickel concentrations in both fishes were less than detection limit (dry weight). No significant difference was observed between Cu and Zn concentration in muscle tissue of both species. Metal concentrations in analyzed samples were lower than international standards Food and Agriculture Organization of the World (FAO), the World Health Organization (WHO), The US Food and Drug Administration (FDA), Association of Australia's National Health and Medical Research (NHMRC), the Ministry of Agriculture and Fisheries and food of England (UKMAFF) values. The daily intake of heavy metals (EDI) for children and adult consumers were lower than the reference dose of the EPA and tolerable intake (TI) of the World Health Organization and FAO (FAO/WHO). In the assessment of health risk, the risk potential (THQ) and Hazard index (HI) for both groups were less than 1 for consumption of one, three and seven days per week. Thus, there was not the risk for Non-cancerous diseases and adverse effects on consumer's health in both species.

In the present study, the effect of salinity was studied on the toxicity of cypermethrin. A. sophiae as euryhaline species is able to tolerate salinities from 0 to 14 ppt salinity. The purpose of this study was to determine the effect of salinity on its vulnerability to agricultural pesticides. Specimens were exposed to a concentration 0.02 μg L-1 cypermethrin and two levels of salinity (0 and 14 ppt) for 14 days in laboratory conditions. The gill tissue was changed significantly with different levels of salinity. The most changes were as follow; hyperplasia of epithelial cells of secondary lamellae, hyperplasia of the mucous cell of primary lamellae, epithelial lifting, bending of secondary lamellae, scaling of epithelial secondary lamellae, pilar cell hypertrophy, fusion, shortening of the secondary lamellae and aneurism. The results showed that the sensitivity to cypermethrin decreased in lower level of salinity and its vulnerability to cypermethrin was different in various levels of salinity. Therefore, A. sophiae may not be a suitable indicator for measurement of the presence of cypermethrin in the environment.

The present study evaluated the effect of inulin supplementation on resistance of intestinal lactobacillus against environmental stress; salinity, temperature aerial exposure, pH and density in Zebra fish (D. rerio). In this study, during the experimental period (60 days), the larva received ad libitum four experimental diets. Four different treatments were as follow: T0 = control; T1 = 1 g/kg; T2 = 2 g/kg and T3 = 3 g inulin/ kg diet (three replicates per diet). The results showed that the resistance to environmental stresses in the fish fed with different levels of inulin was higher than in the control fish group. Moreover, the results of the acidity resistance test in fish fed with T2 and T3 was significantly higher than the control and T1 group. The results showed that the fish fed with experimental diets had significantly higher resistance to salinity stress compared with control group and fish fed with 3 gr inulin/kg diet (T3), had shown the highest level of salinity resistance. No significant difference was observed in survival percentage and temperature stress resistance between control group and experimental treatments. Resistance to aerial exposure test indicated that the minimum survival was observed in T0 and there was no significant difference between T2 and T3. According to the results, no significant difference was observed in density of lactobacillus among different treatments but there was significant difference between control group and experimental diets. Finally, the consumption of 3 g inulin/kg diet is recommended for achievement of high resistance to environmental stress and improvement the intestinal flora in Zebra fish.

The aim of present study was to investigate the effects of A. millefolium hydroalcoholic extract on mucosal immune response (lysozyme, total immunoglobin and protease) as well as immune related (TNF-alfa) gene expression in Goldfish (C. auratus). For this purpose, 180 fish (average weight=0.192± 0.014 g) were randomly divided in 6 aquaria (two replicate) and were fed with A. millefolium extract (at three levels 0, 2 and 4 gr/kg) for six months. Evaluation of mucosal immune parameters revealed that supplementation of diet with A. millefolium significantly increased the lyzozyme and protease activity in fish fed with 4 gr/kg extract compared to control group and diet with 2 gr/kg. No significant differences were observed in total immunogloubin in fish fed with supplemented diet compared to control group). TNF-alfa gene expression data significantly increased in fish fed with A. millefolium extract compared to control group in a dose-dependent manner. According to the results obtained from this study, diet supplemented with A. millefolium extract could modulate skin mucus immunity as well as expression of inflammatory cytokine in goldfish.

This study was performed to examine the efficiency of garlic peel on growth and non-specific immunological parameters of juvenile Great Sturgeon (H. huso). Fish were divided into 4 groups before fed with diets containing 0%, 0.5%, 1%, and 1.5% garlic peel and unsupplemented commercial diet as the control for 90 days. At the end of the trial, serum samples were collected from caudal stem of apparently healthy fish. Results showed that there was a significant difference in weight gain in fish fed with 1.5% garlic peel powder diet compared to the control, while no significant differences were observed in condition factor, feed conversion ratios and specific growth rate between juveniles fed with control and garlic peel supplements. In addition, alternative complement activity (ACH50), serum total immunoglobulin (Ig) and lysozyme activity were not significantly different in garlic peel fed fish. As a conclusion, the results suggest that the growth and immune function of juvenile beluga might be improved by using 1.5% of garlic peel extract.

The aim of this study was to investigate the effects of peppermint supplementation on growth performance and some immune parameters in the Caspian Roach (R. caspicus). A total of 540 specimens (2.4±0.12 g) were allocated into 12 tanks and triplicate groups were fed with diets containing 0, 2, 3 and 4 g/kg peppermint powder for 60 days. At the end of the trial, parameters including growth performance, epidermal mucus protein level, alkaline phosphatase as well as lysozyme activity were measured. The results showed that body weight gain and specific growth rate of fish fed with diets containing peppermint increased significantly. While, the feed conversion ratio in fish treated with peppermint decreased significantly compared with the control group. Additionally skin mucus protein levels, alkalin phosphatas and lysozyme activity increased significantly compared to control group. These results indicated that peppermint as dietary supplement affects the growth performance and immune parameters of the Caspian roach beneficially.

The purpose of this study was to assess the effluents from a rainbow trout (O. mykiss) farm located in Golestan Province, and their impact on the water quality. Water samples were taken from input and output waters of farm every 20 days during four months. Water quality analysis results showed that rainbow trout farm had a significant impact on temperature, pH, TSS, Dissolved Oxygen (DO), No2, No3, and NH3 concentrations. The amount of dissolved oxygen (DO) in the effluent water of farm decreased compared to the water input significantly, while the values of pH, TSS, NO2, NO3, NH3, increased. According to the results of this study, the water quality and physicochemical factors are influenced by the effluent from rainbow trout farm due to the changes in the environmental conditions and the farm activities.