مجله علمی شیلات ایران
سال بیست و هفتم شماره 6 (پیاپی 110، بهمن و اسفند 1397)

In this study, the effect of different levels of Malic acid (0.0, 2.5, 5, 7.5 and 10 g/kg diet) was evaluated on growth performance and body composition of juvenile Siberian sturgeon (Acipenser baerii). A total number of 375 fish (33.72±0.60 g initial weight; mean±S.E.) were randomly assigned to 15 circular concrete tanks (1.85 m diameter and 0.25 m depth). The fish were distributed in 5 treatments with 3 replicates and were fed during 8 weeks. The results of growth indices showed that different levels of Malic acid did not have a significant effect on growth performance and food efficiency. food consumption and lipid productive value had a significant difference among the groups (p<0.05). The lowest amount of fat and ash contents was observed in fish fed with 7.5 g/kg Malic acid. Based on the results, the use of Malic acid in this study on juvenile Siberian sturgeon did not have an effect on growth performance, but affected on the body composition.

In this research, indexed articles of faculty members and researchers of the Iranian Fisheries Research Institute (IFRI) based on qualitative and quantitative scientometric indicators in Web of Science database were investigated. Scientometric and citation analysis methods have been used to conduct the research. Findings indicated that 498 authored and co-authored articles indexed in this database from the beginning to 2015. 198 articles (37.95%) published in the Iranian Journal of Fisheries Sciences. Totally, average citation per paper 6.39, average citation per paper excluding self-citation 5-71, immediacy index 0.147, mean of impact factor 0.804 and H-index were 26. Self-citation rate was about 11%. The most articles categorized in the field of Marine freshwater biology (364). In total, the costs of 40.57% of articles are provided by national and international organizations. Of this amount, 31.73% belong to domestic organizations and 8.84% belong to foreign organization.  The researchers of the IFRI had the most international collaboration and co-authorship with their counterparts from Malaysia (64 articles), USA (27 articles) and South Korea (15 articles) respectively. Among the 20 most cited papers, only 6 authored by the researchers of IFRI as first/coressponding author. The great number of the faculty members and researchers of IFRI has been published in Iranian Journal of Fisheries Sciences. This leads to two outcomes is contradictory. On the one hand, led to the publication status and number of articles increased in terms of quantity grow; But, on the other hand, reduces the quality status of articles, including average citation per paper, the mean of immediacy index, and the mean of impact factor.

Diclofenac is a non-steroidal anti-inflammatory and non-steroidal anti-inflammatory drug widely produced and consumed throughout the world. The advancement of this drug through medicinal and urban wastewater and exposure to aquatic organisms leads to changes in the physiology of non-target organisms. The aim of this study was to evaluate the effect of diclofenac on the activity of two antioxidant enzymes (Superoxide dismutase and Catalase) in Cyprinus carpio as a valuable species in the Caspian Sea. For this purpose, two control groups and three treatments with concentrations of 2.5, 5.1 and 5 mg/L diclofenac were selected. Samples from three replications were taken at 7, 14 and 21 days. After extracting the blood serum samples, colorimetric was performed using ELISA reader to determine the activity of Superoxide dismutase and Catalase enzymes by using Zellbio kits. The results of this study showed that two independent variables of time and exposure concentration had a significant effect on the changes of dependent variables of Catalase and Superoxide dismutase (p<0.05). Changes in the activity of Superoxide dismutase in the second and third weeks of treatment with 5 and 2.5 mg/L with 26 U/ml had a significant difference (p˂0.05), the severity of the changes was related to the concentration of the drug. The activity changes of Superoxide dismutase and Catalase enzymes were significantly correlated with the concentration and exposure time of Diclofenac, respectively. These changes in all treatments have been increased in comparison with the two treatments. The highest activity of Superoxide dismutase and Catalase enzymes belonged to treatment 5 (26, 15.3 U/ml), respectively, during the third week.

In this study, the effect of  adding different  levels of  Montmorillonite, on growth indices and some blood factors of rainbow trout frys was investigated. Study carried out during 123 day within 3 experimental treatments,consist of adding different levels of Montmorillonite to the commercial diet with 4 replication in each treatment. In each replication 45pcs of fry with average weight of 500±0.35mlg were distributed. For this study, fiberglass rectangular tanks with 300L capacity, filled with 200L water were used. Frys were fed eight times daily. Weight measurement of frys done each 15 days and blood sampeling from caudal vein was carried out at the end of experimental period. The results showed significant improve in final weight, percentage of weight gain, daily weight gain, SGR and FCR in experimental treatments comparing control (p<0.05). The PER and HSI, showed no significant statistical difference between experimental treatments and control (p˃0.05). The highest final weight and highest percentage of final weight and the best FCR was observed in experimental treatment with 2% Montmorillonite in feed and highest daily weight gain and highest SGR was observed in experimental treatment with 4% Montmorillonite in feed. The blood factors, showed no significant difference between experimental treatments and control (p˃0.05). Based on this results, use of 2% Montmorillonite as a feed additive, in rainbow trout fry feeding, is recommended to improve growth indices without negative effect on blood factors.

Ammonia is one of the problems of the aquaculture industry that causes by aquaculture activities, which can be enriched water body. Ammonia, even in low concentrations may also have negative effects on the tissues and physiological factors of rainbow trout. In this study, the combination of physical absorbents with algae biofilms in a sinusoidal bioreactor was used. Adsorbents were placed in a polyvinyl chloride mesh in a bioreactor. For ten days Zayndr medium was injected into the system to form biofilms on the absorber. Then the storage volume of biorector was replaced by rainbow trout breeding farm effluent in Heraz. Every 12 hours, water factors were measured and recorded. In this study, the coal, the coral shell and the steel wool that were covered with algae-bacterial biofilms and provided a suitable bed for physical and biological removal were used. The initial concentration of ammonia in the bioreactor was 2.5 mg/L and each of the media was tested separately. The rate of ammonia reduction in, lilaki coal, coral shell and steel wool has been 91.5%, 82.1%, and 78.8% during the 72-hour test period, respectively. The efficiency of ammonia removal in the bioreactor was based on the complement that the interactions of media with biofilm in the direction of physical, chemical and biodegradation, which yielded optimum efficiency, compared to similar systems at  the shorter time.

Nitrogen is known to have a strong influence on the metabolism of lipids and protein in various microalgae. In the present study, the production of S. platensis was optimized in terms of biomass and protein by using different Nitrogen sources as NH4Cl, NH4NO3 and Urea. S. platensis was grown in Zarrouk’s medium in a 3000 ml Erlenmeyer flask, in which the NaNO3 was replaced by NH4Cl, NH4NO3 and Urea with concentrations of 0.010, 0.025 and 0.050 M. Cultures were incubated at temperature of 30oC, salinity of 25 ppt and initial pH of 9.5 under 12/12 hour light-dark photo period with normal white light. The results clearly showed that S. platensis successfully cultivated by using different Nitrogen regimes, and though the maximum biomass was produced in medium containing NH4NO3, but there is not significant differences between treatments (p>0.05). The maximum protein content was obtained in culture containing NH4NO3 followed by NH4Cl and KNO3, and there is not significant differences between treatments (p>0.05). Moreover, in all S. platensis cultures, increasing in nitrogen concentrations, led to an increase in maximum biomass and protein content. The chl. content increased with increasing Nitrogen concentrations in all treatments and relatively high values (9.18 µg/ml) were found with KNO3 as a Nitrogen source at 14th day of culturing period. Overall, though the results of present study clearly showed no significant differences between treatments, but using of NH4NO3 could have relatively more effectiveness than the other Nitrogen sources.

Silver carp (Hypophthalmichthys molitrix) skin (SCS) is available as low cost by-product in minced products manufacturing plants. Kilka fish (Clupeonella spp.) oil has a higher omega-3 fatty acids content compared to other Caspian Sea fish oils and higher nutritional value. In the present study, SCS was collected, hydrolyzed with alcalase, and its functional properties was investigated for the microcapsule stability of purified Kilka oil (PKO) at pH 6.8 and 3.4. Results showed significant changes of amino acids profiles during 6 h hydrolysis (p<0.05). Total hydrophobic amino acids decreased from 32.8% at 0.25 h to 24.9% after 6 h. Hydrolysates showed different radical scavengering activity during different hydrolysis periods. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavengering activity and Ferric reducing antioxidant power (FRAP) increased significantly during first hour, peaked at 4 h and then decreased slowly. Microemulsion was more stable at pH 6.8 compared with pH 3.4 and showed significant differences at 2-5 mg/mL of hydrolysate (p<0.05). As a general result, the use of hydrolysis of SCS and its antioxidant role in the production of stable emulsions containing PKO microcapsules is a valuable process for the enrichment of various kinds of foods.

Regarding the importance of increment of fish per capita consumption in the health of the society, it is important to understand the benefits of fish and its nutritional value to prevent and treat some diseases. The research aimed to investigate the awareness of fisheries students about the benefits and fish nutritional value to promote the fish consumption in their household and future occupational in society. Students' information questionnaire of two universities on the content of lipids and proteins, vitamins, minerals, amino acids, fatty acids, reasons for fish consumption and their therapeutic effects were collected in 2017. After analyzing Chi-squared and Friedman test and scoring the correct answers, 64.4% of the students did not affect the consumption of their household fish consumption after their acceptance. Fish per capita consumption of students was calculated to be 23.3 kilograms. In their view, Iodine is the richest element in fish to prevent goiter. Cardiovascular disease, Alzheimer and cancer are prevented using fish consumption. With a mean score of 7.53 and a score of 18 at most, 16.4 % of students had awareness of the benefits of fish. The result of the study revealed the need for more serious training and more attention to the fish benefits and nutritional value of the fisheries course curriculum, so that they can be better promoters for the fish consumption among people and their families.

This study focused on identification, phytoplankton structure and abundance in the Eynak wetland in 2017. Based on the condition of wetland, the samples were collected at 4 stations in the water body. This study identified 30 phytoplankton taxa comprised of Diatoms (9 genus), Chlorophyta (7 genus), Cyanophyta (9 genus), Dinoflagellata (2 genus) and Euglenophyta (3 genus) in the lake. The finding showed, the Cyanophyta abundance dominated (94 %) with average of 31300000 ± 21400000 cells.l-1 in the Eynak wetland. The Cyanophyta Oscillatoria sp. was toxin which had been the highest abundance almost 28200 000 cells.l-1in the wetland. The lowest abundance was comprised of Euglenophyta almost 303000±48000 cells.l-1 during the study. Furthermore, there were the Euglenophyta Lepocinlis sp. and Euglena sp. in the wetland, which are water polluted index. The finding showed, decline of phytoplankton abundance at the Eichhornia crassipes stations and the abundance received from almost 1700000 to 5800 0000 cells.l-1 at the stations of without E. crassipes. The increase in E. crassipes is reason of photosynthesis decries and phytoplankton abundance in the wetland which no control of E. crassipes, would be more negative impact in the Eynak wetland. The decrease of nutrients level and biological, chemical and mechanical control on E. crassipes are important for resuscitation of the ecosystem.

This study was designed to evaluate the effect of Nannochloropsis oculata microalgae supplementation on 120 rainbow trout fingerling (initial weight of 2±0.3 g). Fish were randomly distributed into four groups and stocked into 12 aquaria (20 liter) in triplicates. Four experimental diets contained 0 (control), 7.5 (T1), 15 (T2), and 22.5 (T3) g of the algae powder per kg of feed for 3 months. Lipid, liver enzymes, and some hematological properties of blood (i.e. WBC, RBC, HCT, MCV, HB, and MCHC) were measured at the end of the trial. Results showed that leucocyte population was not significantly different in all treatments (p>0.05). However, the highest erythrocyte counts and hematocrit index were obtained in T2 (p<0.05). Also, the highest and lowest cholesterol content were recorded in control (279.3±1.47 mg/dl) and T2 (173.3±1.47 mg/dl), respectively (p<0.05). Results indicated that supplemented diet with 15 g algae per kg of feed can significantly reduce the liver enzymes i.e. aspartate aminotransferase, alkaline phosphatase and alanine aminotransferase (p<0.05). The highest low-density lipoprotein was obtained in control group (68.00±0.75 mg/dl) and the lowest value was observed in T2 (25.200±0.72 mg/dl) (p<0.05). Therefore, dietary supplementation of the fish diet with N. oculata at 15 g/kg of feed probably improved the blood indices and liver function.

Viral Nervous Necrosis (VNN) is considered as one of the most important threats for mariculture and aquaculture in the world and up to now, it has been affecting more than 70 fish species. This study was aimed to detect and identify fish betanodavirus, the causative agent of VNN, using nested RT-PCR from brain tissue of Caspian Sea Mullet. Forty samples of subclinical golden grey mullet fish (range: 50-250 gr) were collected from the coastal areas of Caspian Sea in 2016. The target organ (brain) was excised and the reverse transcription (cDNA synthesis) was carried out followed by the RNA extraction. In the present study, detecting of the virus was performed with Nested RT-PCR using two pairs of primers F2/R3 and NF2/NR3 in two steps. After optimization of PCR, all of the forty specimens were negative by the first-step PCR (RT-PCR) while 20 out of 40 grey mullet were positive using Nested RT-PCR (second-step PCR) and a strong band of the expected size (300 bp) was clearly observed. Therefore, it seems that Nested RT-PCR is a method of choice for rapid detection of the low level of infection and in asymptomatic carrier fish. In addition, the result of sequencing revealed that the virus belonged to the RGNNV genotype.

The objective of this study was to evaluate the freshness of gutted greenback grey mullet Chelon subviridis stored on ice up to 18 days. Changes during storage were observed with sensory evaluation (Quality Index Methode QIM), pH, total volatile basic nitrogen (TVB-N), trimethylamine nitrogen (TMA-N), thiobarbitoric acid (TBA), free fatty acid (FFA), color and microbiological analyses (mesophilic, psychritrophic, Staphylococcus, Entrobacteriaces and H2S- producing bacteria counts). The maximum shelf life of gutted greenback grey mullet stored in ice was determined with loss of freshness (sensorial, physico-chemical, color and microbiological evaluations). High correlation r2= 0.922 between Quality Index (QI) and storage time was verified. QI ranged from zero (maximum freshness) to 15 (total loss of freshness) and reached the acceptable limit for consumption (QI=12.66), which corresponds to a period of 12 days. QI showed a linear relationship to storage time (QIM= 8.00× storage time-9.733, R2= 0.990), and the remaining storage time could be estimated with an accuracy of ± 3 days. The microbiological results showed an increase of mesophilic, psychritrophic, Staphylococcus, Entrobacteriaces and H2S- producing bacteria counts along the storage time. TVB-N ranged from  5.93 to 32.66 mg N/ 100g, TMA-N from 3.58 to 16.00 mg N/100g, pH from 6.87 to 7.26, TBA from 0.66 to 1.93 and FFA from 1.05 to 8.41 in the first and 16th day of storage, respectively. It is suggested that gutted greenback grey mullet has to be fresh and acceptable for consumption by cooling up to 12 days.

The aims of the present study were to investigate the effects of garlic at four levels including 0 (T0), 0.10 (T1), 0.15 (T2) and 0.20 (T3) gram of garlic essential oil per kilogram of diet on growth indices and survival rate, some blood biochemical parameters and digestive enzymes of zebrafish (Danio rerio). The larvae were fed from the time of their first active feeding with experimental diets for 60 days. Results showed that the growth indices and survival rates of all groups fed with experimental diets containing garlic were significantly increased as compared to the control group (p<0.05). According to the results, the lowest amounts of glucose (18.35±0.08 mg/dl) and cholesterol (3.55±0.06 mg/dl) were observed in the T3 group as compared to the other experimental groups and the control group (p<0.05) whereas, the highest amounts of total protein (2.51±0.09 g/dl) were measured in the T2 and T3 groups that were significantly different from the control and T1 groups (p<0.05). Protease enzyme levels were increased in all groups fed with experimental diets containing garlic (p<0.05), but levels of lipase and amylase enzymes were significantly influenced by garlic only in the T2 and T3 groups (p<0.05). The highest levels of amylase (9.11±0.13 U/mg protein), lipase (2.55±0.10 U/mg protein) and protease enzymes (4.03±0.10 U/mg protein) were observed in the T3 group. There was no significant differences between the levels of protease enzyme in the T2 and T3 groups (p>0.05). According to the results of the present study, dietary supplementation of garlic had positive effects on improving the general condition, growth indices and activity of digestive enzymes of zebrafish.

Considering the importance of estuaries as sensitive ecological areas and temporary habitat of many aquatic animals and also importance of Chironomidae larvae in the food chain and fish feeding, density and distribution of the chironomid larval and their relationship with environmental factors in Cheshmeh Kileh estuary of Tonekabon (South Caspian Sea basin) were investigated. Bimonthly from November 2014 to September 2015, in three stations (S1 in the river environment, S2 in estuary environment and S3 in the marine environment) samples were collected using Van Veen grab (0.03 m2) and Surber (0.1 m2, 0.2 mm-mesh size) with three replicates. Environmental factors of water including temperature and salinity and sediment relevant factors such as grain size and total organic matter percentage (TOM) were measured. In the present study, three subfamilies were identified, including Chironominae (5 genera), Orthocladinae (4 genera) and Tanypodinae (1 genera). 10 genera were reported from the river and estuary of cheshmeh Kileh for the first time. Among identified genera, the highest and lowest average densities were related to Orthocladius (235 ind. m-2) and Eukiefferiella (45.5 ind. m-2), respectively. Results of monthly distribution showed that the highest and lowest densities of chironomid larval were in March (320±133 ind. m-2) and in September (33.3±11 ind. m-2) respectively which were significantly different, by Duncan's test (p<0.05). Among sampling stations, river station (S1) showed higher density (248.3±93.6 ind. m-2) than estuary station (S2) (90.5±29.6 ind. m-2) and marine station (S3) (0±0 ind. m-2) which were significantly different (p<0.05). A significant Pearson correlation (p<0.05) between the density of chironomid larvae and environmental factors of water and sediment was found.

The protein concentrate of fish from minced carp meat was obtained during three stages of using the solvent (isopropanol), pressed and dried using a dry temperature (60°C), and this concentrate had 93% protein, which according to aquatic protein sources have a high nutritional value and are used to enrich other food products. Given that current pasta products are from carbohydrate sources and lacking in the lysine and threonine amino acids, this gives the opportunity to be used to enrich and enhance its nutritional quality. In this research, 5 and 15 percent of fish protein concentrates were used for enrichment of pasta and samples were prepared in three replicates and stored at ambient temperature for 3 months and tested for nutritional value and amino acids, with a control sample (no concentrate) were compared. According to the results of experiments, it was determined that in terms of nutritional value and amino acid profile, the treatment with fish protein concentrate was better and in the overall evaluation of concentrate-enriched treatment fish protein was 5% better than other samples and had a significant difference (p<0.05).

In this research, measurement of serum blood glucose of cultured rainbow trout (Broodstocks) had done in two different treatments. First treatment consists of fish which were fast, and second treatment had feed. Each treatment includes 10 fish (50% male, 50% female). Blood extracted from caudal vein of each fish by a syringe. Then, serum separated with centrifugation. The amount of serum glucose measured by a kit (Man® Company, Iran). The kit worked based on glucose oxidase method. The average of blood glucose in fasting treatment, was 92.2±14 mg/dl while the average of feed treatment was 189.2±17.2 mg/dl. Statistical analysis had done by SPSS software. Comparison of mean blood sugar concentration between two treatments by t-test showed significant difference between two treatments (p<0.05). The final conclusions showed that fish feeding gives change in blood glucose concentration. It is appeared that, bleed of fish for measurement of the serum glucose needs to do 8 hours after feeding for future research and accuracy tests and standardization of tests.