Iranian Journal of Fisheries Sciences
Volume:22 Issue: 3, May 2023

The extraction method and particularly the type of solvents used in the procedure are one of the most crucial steps for isolating antimicrobial compounds and extracts that potentially affect various microorganisms. This study aimed to evaluate the effects of water, ethanol (100%), methanol (100%), ethanol-water (50:50), and methanol-water (50:50) burdock (Arctiumlappa) root extracts (BE) on total phenol content and polyphenols as well as the antioxidant activity. In the next step, the solvent with the highest efficiency to have phenolic compounds were selected and employed to investigate the antibacterial effects of BE on the pathogenic bacterial strains (i.e. Yersinia ruckeri, Lactococcus garvieae, Pseudomonas putida and Aeromonas hydrophila) in rainbow trout (Oncorhynchus mykiss) by using disc diffusion test and tube dilution techniques. Maximum mean total phenolic content and antioxidant capacity were detected in the water-methanol mixture. Additionally, High-performance liquid chromatography(HPLC) analysis revealed that both hesperidin and trans-ferulic acid compounds existed in all solvents. The antimicrobial activity of water-methanol BE was varied based on the type of microorganism. In this context, Y. ruckeri as a gram negative bacterium was found to be the most susceptible one compared to other pathogens. According to our findings, water-methanol solvent was more efficient to isolate phenolic compounds and exert antioxidant capacity, as the level of phenolic compounds in the extract was increased. Moreover, Y. ruckeri was recognized as the most sensitive pathogen in all tests.

Sponge-associated bacteria have a special position in marine biotechnology due to their unique biological activities. The main objective of this study was to isolate and identify the bacteria associated with sponges around Qeshm Island, Iran, which inhibit the activity of alpha-glucosidase and alpha-amylase enzymes by the produced metabolites. Samples were collected from sponge species living in the study area, including the genera Haliclona and Niphates. Isolation was performed using culture-dependent techniques. A total of 155 bacterial isolates were collected. The diversity pattern of bacteria in the sponge samples showed that the Vibrio and Bacillus constituted the predominant bacterial population. The assessment of alpha-glucosidase inhibitory activity of metabolites extracted from the isolated bacteria showed that 6 isolates could inhibit the enzyme activity with IC50 values ​​ranging from 153.5 to 495.4 μg/ml, while 9 bacterial isolates inhibited the activity of alpha-amylase enzyme in IC50 values ​​at the range of 112.9 to 670.9 μg/ml. The cytotoxic activity of the metabolites extracted on human umbilical cord endothelial cells showed the toxicity of the three extracts at effective concentrations, while seven isolates showed no toxicity. Genetic identification indicated 97% to 100% similarity of the potent isolates with the NCBI gene bank including Bacillus pumilus, Bacillus safensis, Vibrio alginolyticus, Pseudomonas stutzeri, Vibrio parahaemolyticus, Pseudomonas lurida, Bacillus tequilensi, and Streptomyces enissocaesilis. The results of this study provided a new understanding of the diversity pattern of cultivable sponge-associated bacteria and their inhibitory activity on alpha glucosidase and alpha amylase enzymes.

This study is performed to investigate the effects of water-borne Ni2+ on common carp (Cyprinus carpio) liver and bone metabolisms. Fish (N=60; 184.40±18.56g) were exposed to background concentrations of Ni2+ (based on measured LC50-96h: 5.820 mg/L), including 0.058, 0.291, 0.580, 1.750, 2.910 mg/L for 30 continuous days. Ni2+-exposed fish showed a rising trend in the case of serum aspartate transaminase (AST). Serum alkaline phosphatase (ALP) elevated (p<0.05) in all Ni2+ treatments. Serum total protein, globulin, and albumin showed a transient reduction in 0.058, 0.291 and 0.580 mg/L Ni2+ exposures (p<0.05). Although serum calcium level did not change significantly, serum inorganic phosphorus was elevated (p<0.05) in 0.580 mg/L Ni2+. Bone isoenzyme of ALP observed in higher levels in all Ni2+ treatments than the control group (p<0.05). Pathological damages, such as focal necrosis, pycnosis and cytoplasm degeneration were observed in liver tissues of Ni2+-exposed fish. A higher number of osteocytes as well as osteoclasts in bone of Ni2+-exposed fish revealed dual effect of this metal in the case of bone metabolism. Generally, low level of nickel had no significant effect on metabolic parameters of liver and bone while highest nickel treatment had adverse effects, reflecting dual effects of this metal on carp.

Moringa oleifera is an important herbal plant with a valuable source of major essential nutrients and nutraceuticals. In this study, we supplemented the diet of Litopenaeus vannamei with different levels of M. oleifera leaf powder (MLP) and extract (MLE) and evaluated the growth, survival, body and fatty acid composition, hemolymph biochemistry, antioxidant status, and salinity stress resistance after six weeks of feeding. In total, 840 shrimp (2.6±0.02 g) were divided into seven groups including the shrimp fed with the basal diet (control), and the diets containing different levels of MLP [25 (MLP25), 50 (MLP50), and 100 (MLP100) g kg-1] and MLE [0.25 (MLE0.25), 0.5 (MLE0.5), and 1.0 (MLE1.0) %]. The results showed a lower FCR value in MLP25 and MLE0.5 fed shrimp as well as a higher survival rate in MLP100 and MLE0.5 fed shrimp than those of the control group. Dietary MLP enhanced the body contents of lipid and fatty acids (i.e., the pentadecanoic acid and the omega-3 and -6 polyunsaturated fatty acids). The MLP100 diet remarkably enhanced the hemolymph total protein, albumin, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels of shrimp. On the other hand, the AST and ALT activities were significantly reduced in the shrimp fed with MLP25, MLE0.25 and MLE0.5 diets. MLP and MLE in the diet of shrimp also led to a significant increase in the hemolymph antioxidant enzymes activity. Moreover, the shrimp fed with MLP50 diet showed a significantly higher survival rate in response to the high salinity stress compared to the control group. In conclusion, the supplementation of both MLP and MLE in the diet of L. vannamei showed beneficial effects on the performance of the shrimp farming industry.

This study was conducted to assess the effects of Tenebrio molitor larvae meal (TM) in partial substitution of fishmeal (FM), on growth performance, hematological indices, plasma biochemical and antioxidant enzyme activities of Asian Seabass (Lates calcarifer). Experiment carried out with 144 pieces of Asian Seabass (mean weight±SE, 54±1.2 g) in a semi-recirculating fish culture system. Fishes were randomly distributed into four groups with three replicates as completely random design. All treatments were fed with iso-nitrogenous and iso-energetic diets at a substitution rate of 0, 20, 40 and 60 % of TM. The experiment was setup for eight weeks and feeding carried out at 3% of body weight/day. Results showed that there is no significant differences (p>0.05) in the growth performance, chemical body composition and protein utilization at the end of the experiment. However, weight gain, lipids and viscerosomatic index showed significant differences among the examined treatments (p<0.05). The red blood cells was not affected by TM diet, but the hemoglobin, hematocrit and mean corpuscular hemoglobin concentration levels decreased with increasing levels of TM (p<0.05). Plasma biochemistry analysis of triglyceride, glucose, cortisol, lysozyme and alkaline phosphatase levels increased significantly with increasing TM in the diet (p<0.05). Increasing the level of TM in fish diets caused an increase in the activity of glutathione peroxidase and catalase, while no significant differences were observed in the activity of superoxid dismutase and malone di aldehyde among the different diets. Overally, this study demonstrates that meal of T. molitor can be used as fishmeal replacement up to 40% of diet and is an alternative source of protein in Asian seabass diets.

Heracleum persicum (HP) is an annual herbbelonging to Apiaceae (Umbelliferae) family and traditionally cultivated in Iran for its medicinal properties. Preliminary phytochemical analysis of H. persicum extract has shown that it possesses antioxidant properties, which may be attributed that to the presence of furanocoumarin compounds. In an experiment involving Danio rerio were, six groups of fish were exposed to different concentration of HA-PA ranging from 470 to 500 mg distributed among six groups in triplicates included G1 (control), G2 (1000 mg/kg), G3 (2000 mg/kg), G4 (4000 mg/kg), G5 (8000 mg/kg) and G6 (16000 mg/kg). The probit value for HA-HP and associated concentrations indicated low toxicity in D. rerio. The LC50 of HA-HP for D. rerio exposed to various concentrations for 24 hrs was found to be 6020.37 mg/kg with lower and upper bounds of 4477.5 and 8117.9, respectively at a 95% confidence limit. The maximum value of buccal movement rate was observed in animals exposed to 16000 mg/kg of HA-HP measuring between 134.0-192.66 N/min. However, increased doses of HA-HP led to respiratory distress and a decrease in oxygen uptake in fish. Moribund fish were observed at 1000 and 2000 mg/kg with signs of darting swimming, circular movement, and settling on the bottom of the aquarium for up to 12 hrs. The exposure of D. rerio to increasing concentration of HA-HP also resulted in the Loss of schooling behavior, which could affect their ability to move in coordination with their peers. Based on these findings, it can be concluded that the LD50 of HA-HP for D. rerio after 24 hrs is high indicating it can be used safely as an immunostimulant or for other purposes in fish at lower dosages.

Seafoods are the main source of animal protein in our daily diet and their consumption has been increased due to its high health benefits over red meats. This study aimed to evaluate the heavy metals accumulation in a freshwater catfish muscle (Wallago attu) and the detection of heavy metal resistance genes (HMRGs) in Pseudomonas aeruginosa isolated from the fish intestine. W. attu (n = 60) was collected from four different sites (Qabula Shakh, Magsi Shakh, Umrani Shakh, and Jamali Shakh) of Pat Feeder Canal, Balochistan. The heavy metals and HMRGs were detected using atomic absorption spectrophotometer and polymerase chain reaction. The concentrations of Cd (0.27±0.001 mg/L), Fe (1.23±0.001 mg/L), and Pb (1.23±0.0005 mg/L) were found to be above the permissible limits of WHO in the samples from Jamali Shakh. Moreover, a strong Pearson’s correlation of the metal Cd was observed with Zn, Fe, Cr, Cu, Pb, and Ni. However, Zn has a strong correlation with Fe and Cr; Fe with Cu, Ni, and Cu. Cr with Pb and Cu; Cu with Ni and Pb; while Ni has a strong correlation with Pb and Mn. P. aeruginosa was also identified from 41 species out of all fish intestine specimens (68%). Similarly, different heavy metal resistance genes (MRGs) including czcA 4 (36.3%), ncc 4 (36.3%), chrR 2 (18.1%), and copA 1 (9%) were confirmed using PCR. In conclusion, Cd, Fe, and Pb concentrations were higher than the WHO permissible limits. However, other heavy metals (Ni, Zn, Cr, Cu, and Mn) were permissible limits in the fish muscle. The results of this study have shown a correlation between the buildup of heavy metals and the presence of MRGs.

The present study aimed to investigate the effect of Lactococcus lactis and Weissella cibaria as potential probiotics on growth performance, some blood and immune parameters, digestive and liver enzyme activity, and intestinal bacterial flora, in common carp (Cyprinus carpio) juvenile. Fish (17.00±1.3 g) were divided into 10 treatments. The experimental diets of treatments 1, 2, and 3 were supplemented with Lactococcus lactis in doses of 1.5×107, 3×107, and 4.5×107 CFU kg-1, the diets of treatments 4, 5, and 6 were supplemented with Weissella cibaria in doses of 1.5×107, 3×107 and 4.5×107 CFU kg-1, these two potential probiotics were equally mixed for preparation the diets of treatments 7,8 and 9 which has been added in doses of 1.5×107, 3×107, and 4.5×107 CFU kg-1. A basal diet (19 mJkg-1 of energy and 38% protein) without probiotic was fed to the fish in the control group. Fish were randomly divided into 30 tanks and reared in the water with an average water temperature of 24.5°C. They were fed two times a day at 3% of body weight for 8 weeks. Results showed a significant increase in body weight (about 4 g), specific growth rate, and average daily growth in the most of the probiotic supplemented treatments (p<0.05) sespecially in treatments 8 and 5. Also, the highest amount of white blood cells, neutrophil, monocytes, Immunoglobulin M, alternative complement pathway activity (ACH50), lysozyme activity, digestive enzymes, and the lowest amount of liver enzymes (Aspartate aminotransferase and Alanine transaminase) were observed in the groups treated with potential probiotics. According to the results, adding 3 to 4.5×107 CFU kg-1 of the potential probiotics mixture, or 3×107 CFU kg-1 W. cibaria, could improve the growth performance and health status in common carp.

Scatophagus argus of family Scatophagidae is a venomous fish. Rough spines insulated from scat possessed potent venom composed of several proteins. Envenomation is associated with local necrosis and severe pain. Following our previous report regarding the hemolytic activity of scat crude venom, this work aimed at purification and evaluation of its hemolytic protein, hereafter designated as Scatotoxin. Specimens were collected from coastal waters of the Persian Gulf, Iran. Proteins were extracted from bone tissue by solubilization buffers and subsequently refolded in a refolding buffer. Purification was performed by reverse-phase HPLC method using a linear gradient protocol. To evaluate the hemolytic activity of Scatotoxin, a quantitative microscopic assay was developed using cell counting by which measurement of activity of the least amount of a sample was achievable. Scatotoxin was isolated in 85% acetonitrile. It is an interesting highly hydrophobic protein. Because hemolysis was observed immediately, scatotoxin is considered a very fast-acting hemolytic agent. Scatotoxin indicated as a 72 kDa protein by SDS-PAGE. The amount of 0.5µg crude venom produced 100% hemolysis and HD50 determined at 0.18µg. HD50 for scatotoxin recorded at 0.003µg. High efficiency of both extraction method and microscopic-scale assay led to the reduction of collected specimens and consequently avoiding harmful effects on the Persian Gulf ecosystem. This issue is ethically important due to decreasing the number of samples too. Among the previously reported hemolytic proteins, Scatotoxin is the first report of a highly hydrophobic protein.

This study was conducted to compare the effectiveness of Ovaprim™ and Ovapass™ hormones to induce spawning in Schizothorax zarudnyi. The female (n=48; 1535.12±180.09 g) and male broodstocks (n=53; 752.00±48.30 g) were randomLy allocated in 4 experimental groups including T1: females which received 0.2, 0.5 and 0.5 mL /kg body weight (BW) Ovaprim with 24-h time intervals, T2: females which treated with 0.5 and 0.5 mL /kg BW Ovapass with 12-h time intervals, T3: females were injected with 0.2, 0.5 and 0.5 mL /kg BW Ovapass with 24-h time intervals, and T4: females were injected with a combination of Ovaprim (0.2 mL/kg) and Ovapass (0.5 and 0.5 mL/kg BW) with 24-h time intervals. The amount of injection in the first stage was 10%, the second stage was 90%, and the male fish were simultaneously injected with the second stage of the females at 0.3 mL/kg. The results showed that the highest rate of fertilization was detected in treatments 2 and 4 (93.33% and 92.33%, respectively), which had a significant difference with other groups (p<0.05). No significant differences were observed between the treatments in the indices of relative and working fecundity and dry egg diameter (p>0.05). The lowest and highest latency period was observed in treatments 2 (27.33± 0.66 h) and 1 (36.20±3.77 h), respectively (p<0.05). The results of this study clearly suggested that the Iranian Ovapass hormone is highly effective for S. zarudnyi reproduction and might be successfully replace with Ovaprim.

In this study, trypsin was extracted from the viscera of yellowfin sea bream (Acanthopagrus latus) and used as an additive in Sobaity sea bream, Sparidentex hasta, larvae microdiet. The microdiet was supplemented with the extracted enzyme and its efficiency was evaluated in the growth performance of S. hasta larvae. There were five treatments containing zero (control), 1000, 1500, and 2000 IU/kg of the extracted trypsin with 500 IU/kg of a commercial diet of porcine trypsin. S. hasta larvae (mean initial weight of 0.021±0.001 g) were fed with experimental diets for 28 days. Fifteen round polyethylene tanks (300 L, a water volume of 100 L) equipped with a water circulation system and an air stone were used for the treatments. The highest body weight gain (BWG), specific growth rate (SGR), daily growth, survival rate, and protein efficiency ratio (PER) were observed in the larvae fed the diet containing 2000 IU/kg trypsin (p<0.05). In addition, the lowest and the highest values of the feed conversion ratio (FCR) vs daily feed intake and trypsin activity were significantly recorded in 2000 IU/kg trypsin and the control groups, respectively (p<0.05). A positive correlation was observed between the increasing levels of trypsin in the microdiets and growth performance (i.e. BWG, SGR, daily growth rate, survival rate, and PER). Besides, the dietary addition of external trypsin reduced the values of FCR, daily feed intake, and trypsin activity in the larvae. Overall, trypsin at different doses, particularly at 2000 IU/kg, can significantly improve the performance and feed utilization of S. hasta larvae.

A 90-day feeding trial was run to evaluate the effect of replacement of soybean meal (SBM) with sesame seed cake (SSC) at 0, 25, 50, 75, and 100% in the isonitrogenous (30% crude protein) and iso-lipidic (8% crude lipid) experimental diets on growth, nutrient and economic efficiency, and biochemical body composition of juvenile Cyprinus carpio. Common carp with an average initial weight of 83.09±0.06 g with a density of 30 numbers were randomly fed experimental diets in 15 tanks (300 L) with the flow-through system. The results showed that survival and growth rate, visceral indices, and proximate biochemical composition of the whole body and the fillet except protein did not significant between treatments. The feed intake, feed conversion ratio and protein efficiency ratio, calcium and phosphorus, nitrogen retention efficiency, nitrogen wastage except for SSC25, and phosphorus wastage except for SSC25 and SSC50 were not significantly affected by the dietary treatments. Economic conversion ratio of diets decreased, whereas profit index increased with increasing levels of dietary SSC. Reduced cost of SSC100 was about 35.10%. The number of white blood cells was significantly higher in SSC0 than in other experimental treatments. Hemoglobin was higher in SSC75 than in SSC0. Among serum parameters, cholesterol was significantly lower in SSC0 treatment than in SSC25 treatment. Comparable growth performance, nutrient wastage, economic efficiency, and some blood factors indicated that SBM could be replaced by 75 to 100% SSC in the formulated diet of C. carpio juveniles.

Sex reversal and producing a monosex population is one of the most preferred growth promotion techniques of rainbow trout culture. Thus, the effects of 17α-methyltestosterone (2 mg/kg), tamoxifen (2, 20, and 100 mg/kg), letrozole (2, 20, and 100 mg/kg), and a combination of tamoxifen (100 mg/kg) and letrozole (100 mg/kg) on growth, masculinization and serum steroid content of rainbow trout were investigated in this research. Ethanol-dissolved chemicals were sprayed on commercial trout diet, and ethanol was evaporated overnight. The fish were fed the treated diet for two months and afterward, they were fed a commercial diet for six months. Results showed that 17α-methyltestosterone reversed the sex of rainbow trout effectively. The proportion of males, intersex, and females in this group were 76.67%, 10%, and 13.33%, respectively. In contrast with 17α-methyltestosterone, using tamoxifen and letrozole showed no effect on sex reversal of rainbow trout. Growth performance was adversely affected by all chemical-treated diets. However, compensatory growth occurred during first month after ending treatment period.

In the present study, the dietary effect of Ganoderma lucidum extract (GLE) on growth performance, antioxidant status, and some blood biochemical parameters was investigated in Huso huso. The fish were divided into four groups and fed with different concentrations of 0, 0.5, 1, and 2 g/kg GLE for 6 weeks. The results showed that the growth indices including weight gain and specific growth rate were increased significantly compared to the control group. However, the food conversion rate was significantly decreased in 1 and 2 g/kg GLE-supplemented groups. An increasing trend of serum total protein and IgM was observed in the groups fed with GLE, while the fish fed with 1 and 2 g/kg GLE showed significant differences compared to the control group (p<0.05). The serum glucose level decreased in the groups fed with GLE compared to the control group, however, it was not significant. The triglycerides and cholesterol levels were significantly reduced in 1 and 2 g/kg GLE added groups compared to 0.5 g/kg GLE and control group (p<0.05). An increase in the serum total antioxidant capacity was observed in GLE-supplemented groups, which significantly raised in 1 and 2 g/kg GLE (p<0.05). Serum malondialdehyde decreased in the groups fed with GLE, which significantly reduced in 2 g/kg GLE compared to the other groups (p<0.05). In conclusion, dietary GLE showed a proper effect on growth performance, antioxidant capacity, hypolipidemia, and immunity in H. huso.

Investigation of fish neoplasms is one of the most important topics in aquaculture research. In addition to the necessity of this kind of research on edible fish (as excellent sources of protein), those with significant economic role should be attended as well. An ornamental fish with visible tumors is not a proper one to sell, therefore looking for causative agents and prevention methods also in some cases treatment, is required. In this study, swellings on the lips of 100 specimens of Angelfish (Pterophyllum scalare) were analyzed through histopathological method with preparing histology slides using hematoxylin and eosin (H&E) and also Masson’s Trichrome staining techniques and examined by light microscope. Electron microscopy was also used to observe the virus particlesIn the histopathological investigation, the smooth and cauliflower-like tumor lesions were identified with both characteristics of fibroma and papilloma known as fibropapilloma. Moreover, the interpreted results of electron micrographs declared the existence of papillomavirus-like particles. Given that the environmental carcinogenic factors and other oncogenic infectious agents are among the suspects of neoplasia causers in the aquatic ecosystems, based on the outcomes of the present research, papillomavirus-like agents were identified as the culprit of neoplasia in studied specimens of P. scalare which could be a notice for the aquaculture industry to take more considerations than ever, on the biosafety and health-protective issues including filtration, disinfection, water quality control and using the broodstocks free of oncogenic agents, to be immune from neoplasm.