Iranian Journal of Fisheries Sciences
Volume:19 Issue: 3, May 2020

This study evaluated the influence of dietary garlic (Allium sativum) extract on survival rate and changes in blood and immune parameters of Common carp (Cyprinus carpio), fed with two different concentrations of aqueous garlic extract after exposure to spring viremia of carp virus (SVCV). The experiments have executed in two steps: Firstly, 270 fingerlings of Common carp with an average weight of 15±3.4 g have cultivated in 18 aquaria with 15 liters of water. Fish were fed with 1 and 5 g garlic extract kg-1 basal diet for 8 weeks. In the second step, 240 fingerlings have been randomly divided into 8 groups (A: negative control; B: virus control; C and D: extract controls and E-H: treatment groups) with 3 replicates in each group include of 10 fish in each replicate, and the fish have been exposed to SVCV for 4 weeks. The mortality rate, blood and immune parameters and virus isolation have been determined at the end of experiments. The results have showed that the survival rate of the Common carp fed with 1 and 5 g garlic extract kg-1 basal diet (E-H groups) had a significant increase compared to the control groups (p<0.05) and RBC, hemoglobin, hematocrit, MCH, MCHC had Significant increase compared to the virus control group (B) (p<0.05). WBC in groups D, E, F and G in comparison to control group A and B and lymphocyte in groups D, E and F compared to control group B had a Significant increase (p<0.05). Also, the Common carp fed with two concentrations of garlic extract increased lysozyme and IgM in groups C-H compared to group A (p<0.05). Finally, cell culture and RT-PCR have been applied for detection of SVC virus from fish samples. The results have been indicated that addition of garlic extract (Especially 5 g kg-1) in fish dietary has led to a higher immunity and survival rate of common carp exposed to SVCV.

The present study was conducted to investigate the expression level of cytochrome P450 enzyme in detoxification of water soluble fractions (WSFs) of crude oil in Persian sturgeon, Acipenser persicus. Fish were exposed to WSFs at concentrations of 0 (control), 10, 20, and 50% of the LC50 for 14 days, and then, the expression level of P450 gene was assayed in gill and liver samples. According to the results, the expression level of P450 gene increased in both the gill and liver tissues of fish when exposed to sub lethal concentrations of WSFs. High level of expression in treatment of 50% WSFs was observed compared to the control (p<0.05). However, no significant differences were observed between treatments of 10%, 20%, and 50% WSFs. Additionally, P450 was expressed higher in the gill tissue than the liver. The present research demonstrates that P450 gene expression can be used as a molecular biomarker to assay the severity of oil pollution in the Caspian Sea.

Grass carp is an herbivorous species, which is actually popular in Iran. Monogenean parasites, particularly members of the family Dactylogyridae, have been one of the main causes of mortalities in Iranian fish farms and therefore they have been subject of many studies in Iran. The main aim of the present study was to describe morphological and molecular characteristics of monogenean parasites recovered from the farmed grass carp (Ctenopharyngodon idella) in the Guilan Province during 2015 to 2016. A total of 80 grass carps have been examined for infestation with monogenean parasites. 10923 Dactylogyrus species were recovered from 95% of the farmed grass carp. The parasite was first classified based on their morphological characteristics and identified as Dactylogyrus lamellatus. The parasite was then subjected to PCR and sequencing of the 28S rDNA gene. The phylogenetic tree showed that D. lamellatus genetically was similar to those previously reported from other countries and Mashhad farms in Iran.

The present study investigated the accumulation and depuration of two heavy metals Cd and Pb in the freshwater clam  (Corbicula fluminea) under laboratory conditions. Treated clams were exposed to single and combined treatments of Cd and Pb at the concentration of 5 mg L-1 and 10.5 mg L-1 for 10 days, respectively. The animals were then placed in metal free water for the following 5 days for depuration experiment. Heavy metal concentrations were determined by an inductively coupled plasma optical emission spectrometer (ICP OES).  Results showed that the clams were able to accumulate Cd and Pb at the maximum rate of 0.26 and 0.37 (µg g-1 day-1), respectively; and depurate at the rate of 0.32 and 0.08 (µg g-1 day-1), respectively. At the end of uptake period, the concentrations of Cd and Pb in the soft tissues of single and combined exposures were 1.8 and 1.1 µg g-1 wet  weights (WW) and 1.2 and 0.8 µg g-1 WW, respectively. The clams also showed rapid depuration of Cd and Pb. At the end of depuration, the concentrations of Cd and Pb in the soft tissues were only 0.2 and 0.8 µg g-1 WW in single and 0.17 and 0.4 µg g-1 WW in combined exposure, respectively. The results of the present study showed that there was a competition between Cd and Pb in the tissues of the clams. The total target hazard quotients and the hazard index indicated that people might experience adverse health effects through consuming contaminated C. fluminea.

This study examined the growth response of yellowfin seabream, Acanthopagrus arabicus, reared in floating net cage fed at variable daily feeding frequencies. Thirty healthy fish (49.7±0.3 g initial weight) were stocked in each of the 12 net cages (1.5×1.5×1.5m). Three cages in each group were assigned to four different feeding frequency i.e., two, three, four and six times/day designated as FF1, FF2, FF3 and FF4, respectively. Semi-purified diet (42% protein) was used to feed at seven percent body weight (%BW) day-1 for a total period of forty five days. The fish length and weight were measured fortnightly and the feeding rate was adjusted according to the new weight. At the end of the trial all fish remained healthy and active with survivals recorded 95-100%. The final weight, average daily weight gain (ADG) and specific growth rate (SGR) values were significantly higher for fish in groups FF3 and FF4 compared to FF1 and FF2. The SGR was the highest in groups FF3 (1.30±0.02) and FF4 (1.3±0.04) significantly different from FF1 (1.09±0.01) and FF2 (0.99±0.02) groups. Whole body proximate composition (protein, ash, moisture and lipid) remained similar in all the treatment groups. It may be concluded that yellowfin seabream, A. arabicus, may be grown in floating cages effectively by feeding four times day-1 to achieve significantly better growth.

Rainbow trout fillet is susceptible to microbial and oxidative spoilage. Therefore, it is essential to use preservatives to extend its shelf life. Date extract has significant antibacterial and antioxidant properties. This research was conducted to study the effect of aqueous date extracts on chemical, microbial and sensory properties of farmed rainbow trout during refrigeration. Total phenolic and flavonoid content were determined through Folin-Ciocalteu and colorimetric method. The first step of study was performed for determination the antimicrobial activity of date extracts against the inherent flora of fish fillet, lactic acid bacteria, Pseudomonas and Enterobacteriaceae by disc diffusion method. In parallel with antimicrobial tests, sensory evaluation was also performed for choosing the best concentration of extracts in order to applying on fish fillets. In the second step of study, fish fillet samples were immersed in date extracts (3% w/v for 5 minute), packaged in zip–bags and stored at 4 oC over a period of 17 days. The extract-free fillet was used as control. The samples were analyzed for microbiological (mesophilic, lactic acid bacteria, Pseudomonas and Enterobacteriaceae counts) and chemical (PV, TBARS and TVB-N) parameters. The 5-point hedonic method was carried out for sensory evaluation by 30 trained panelists. Analyses were conducted at 2 h after preparation and 1, 3, 5, 7, 9, 11, 13, 15 and 17 days of storage.  Phenolic and flavonoids contents showed no significant differences between date extracts (p>0.05). Total bacterial counts, Enterobacteriaceae, Pseudomonas, TBARS, PV and TVB-N showed no significant difference in test samples (p>0.05). These parameters were within an acceptable range up to 15 days for test samples while the control samples had a shelf life of 5 days. Samples preserved by Piaroum extract had the longest shelf life while samples preserved by the combination of extracts had the shortest. According to the results, the Piaroum, Zahedi, Mozafati date extracts and their combination could be used as natural preservatives for trout fillet shelf-life extension.

The present study was carried out to assess the population structure and growth with length weight relations, von Bertalanffy equations and artificial neural networks (ANNs) of topmouth gudgeon fish, between May 2015 and May 2016, in the Hirfanlı Dam Lake. The age of topmouth gudgeon caught from the Hirfanlı Dam Lake ranged between I to V years. The von Bertalanffy growth function growth coefficient k was 0.5 and asymptotic length L∞ was 9.13 mm fork length (FL). The weight-length relationship is given by the regression equation W=0.01275334×L3.0005 for all individual. Growth equations in length (mm) and weight (g g) are: Lt = 9.13 [1–e–0.380 (t + 0.5)] and Wt = 10.36 [1–e–0.380 (t + 0.5)]3.0005 for all individual. Minimum and maximum sizes was were 2.7 and 9.2 cm FL for all individuals. Here, we examine the growth properties (length and weight) of topmouth gudgeon by modern (artificial neural networks) and traditional approaches (Length weight Relations and von Bertalanffy growth model) in the Hirfanlı Dam Lake. This study presents the first LWR, von Bertalanffy and ANNs references for this species in the Hirfanlı Dam Lake.

240 Caspian brown trout (Salmo caspius) fingerlings with initial weight of 13.74±0.63 g were stored in 300 L tanks to investigate the effect of starvation and refeeding on compensatory growth and digestive enzymes activity. The fish were introduced to four different periods of starvation during 10 weeks including control (with no starvation:C), 2 weeks (S2), 4 weeks (S4) and 6 weeks (S6) and then fed to satiation during the refeeding period. Sampling for growth and enzymes activity measurements was conducted three times: day 1 (T1), after starvation (T2), after 2 weeks (R2) and 4 weeks (R4) of refeeding. Results have indicated a significant decrease in growth performance after starvation (p<0.05). Final weight (W2) was similar to the control group in treatment of S2 after 2 weeks of refeeding. Body weight increasing (BWI) and specific growth rate (SGR) were the highest in treatment of S6 at the end of trial (p<0.05). Trypsin, chymotrypsin, lipase and amino peptidase declined after starvation while pepsin activity significantly increased in deprived fish (p<0.05). Trypsin and chymotrypsin values were lower in S6 than of control whereas the lowest activity of pepsin was observed in the control fish. After 4 weeks of refeeding, trypsin and chymotrypsin values were similar to that of the control (p>0.05). Generally, results declared that Caspian brown trout fingerlings could recover digestive capacity after 2 weeks of starvation by appropriate refeeding with no negative impact on growth performance.

The present study was investigated on effect of optimum dietary level of Chlorella vulgaris powder (CP) as a feeding supplement on various blood biochemical criterion (Cholesterol (CHO), triglyceride (TG), total protein (TP), glucose (GLU), and lysozyme) and digestive enzymatic activities (amylase, lipase and protease) of the grey mullet (Mugil cephalus L). Four experimental regimens were supplemented with CP at 0, 5, 10 and 15 g kg−1 diet (CP0, CP5, CP10 and CP15). Number of twelve pools (60-L) with three duplicates for analysis groups (n=10 per pool with initial weight average 14.95±2.01 g) and the control group were studied. Upon 60 days of the feeding trial, fish fed CP5 diet had lower serum CHO and TG levels than fish fed CP0, CP10 and CP15 diets (p<0.05). No considerable difference were found in GLU when comparing fish fed CP5 and CP10 diet (p>0.05). Most serum total protein and amylase, protease, lipase and lysozyme activities were observed in fish fed CP5. Also, fish fed CP10 and CP15 diets had higher digestive enzymatic activities, serum total protein and lysozyme activities than fish fed CP0 (p<0.05). The outcomes proved the inclusion of 5g chlorella powder dietary supplementation in the commercial regimen may improve the blood chemical responses and the activity of digestive enzyme in grey mullet.

The aim of this research was to evaluate the effects of dietary nucleotides on performance, immune system and salinity resistance of kutum fingerlings during migration to the sea. Five experimental diets were prepared by addition of Hilyses (0.75 and 1.5%) and/or Augic15 (0.3 and 0.6%) to a control diet. After eight weeks adding nucleotide diets, fish were exposed to saline water for 48h. Supplementation of both nucleotide sources improved fish growth parameters (p<0.05). Fish mortality was also decreased by the additives in both fresh and sea water. Glucose and cortisol levels significantly decreased with the administration of both nucleotide sources (62 to 69 versus 75 mg dL-1 for glucose and 6 to 8.5 versus 9.8 mg dL-1 for cortisol (p<0.05). Supplementation of Hilyses and /or Augic15 increased lysozyme activity in the blood (p<0.05) and maximum activity has observed in fish fed at high doses of Hilyses and Augic15diets. In conclusion, an improved performance of R. kutum fingerlings fed on or with both nucleotide sources may suggest that kutum fingerlings require a larger dietary nucleotide at early life stage to control stress related parameters such as cortisol and glucose.

The effects of dietary Spirulina platensis on haemato-biochemical and immunity responses of Caspian brown trout (Salmo troutta caspius) juveniles was investigated. For this purpose, diets with five S. platensis inclusion levels (control, 2%FMR (13.2 g kg-1 spirulina in diet), 4%FMR (26.4 g kg-1 spirulina in diet), 6%FMR (39.6 g kg-1 spirulina in diet), and 8%FMR (52.8 g kg-1 spirulina in diet) were prepared. Six hundred juveniles with an average initial weight of 11±1.0 g were assigned to 15 experimental tanks. The experiment lasted for 10 weeks. At the end of the experiment, growth performance, haemato-biochemical parameters including white and red blood cell counts, neutrophils lymphocytes counts, hematocrit, hemoglobin, glucose, albumin, total protein, aspartate amino transferase (AST), alanine amino transferase (ALT), triglyceride, cholesterol, as well as immunity parameters including lysozyme, C3, C4, Immunoglobulin (IgM), ACH50 and respiratory burst activity were assessed. The results indicated that fish fed diets supplemented with 6%FMR and 8%FMR had a significantly higher weight gain (26.13 g and 25.88 g) and specific growth rate (1.74 %bw day-1 and 1.71 %bw day-1) compared with control. Furthermore, 6%FMR and 8%FMR treatments had statistically higher protein efficiency (0.76 and 0.78), lipid efficiency (1.89 and 1.94) and statistically lower feed conversion ratio (2.91 and 2.84) compared to the other treatments respectively (p<0.05). The physiological and immunological factors were improved when fish were fed a high level of S. platensis supplement. S. platensis inclusion also increased activity of Lysozyme C3, C4, IgM and ACH50 and respiratory burst activity and reduced AST and ALT formation. These results indicate that S. platensis supplement is promising for disease prevention in S. trutta caspius juveniles, at an optimum dietary level of 6% in diet.

The effects of different light regimes (24L: 0D, 150 lux, 12L: 12D, 300lux, 0L: 24D, 0 lux, and control treatment) on growth, melatonin concentration, and Insulin-like growth factors gene expression of Persian sturgeon (Acipenser persicus) embryos were evaluated. Four groups of Persian sturgeon eggs (450 g) were incubated in Youshchenkov incubators with three replications for each treatment. The experiment was conducted during an 8- day period of incubation. Growth rate, plasma melatonin levels, and IGF-growth factors were investigated at 1, 4, and 8 days post fertilization.  Results showed that higher mean weights growth were observed in fertilized eggs exposed to a 24L: 0D photoperiod with 150lux light intensity (p<0.05). The larval body length and hatching rate of fertilized eggs were significantly higher in embryos incubated at 12L: 12D with 300lux. The melatonin hormone level between sampling days and treatments were significantly different and it would be concluded that it may be related to the species. During the first-day post fertilization, the IGF-I and IGF-IR gene expression were significantly higher than other days. However, IGF-I and IGF-IR gene expression at different treatments showed no significant difference at day 4 and 8 post fertilization. According to the results, the stimulating role of IGF-I and IGF-IR gene expression in growth at the one-day post fertilization under different light regimes can be concluded. These findings suggest that the 12L:12D photoperiod with 300lux light intensity is the appropriate light regime for Persian sturgeon eggs incubation. The results of the present study would provide fundamental information for further use of light regimes during the early development of sturgeon larvae to optimize rearing protocols in sturgeon hatcheries.

Although polychaetes are the most abundant organisms in marine ecosystems, still their genetic diversity is understood inadequately. In this study, molecular identification of Nereididae polychaetes was performed by sequencing a segment of mitochondrial COI gene, isolated from mitochondrial DNA, and comparing nucleotide divergence, Molecular taxonomy, interspecific and intraspecific relations of Nereid species among 4 intertidal stations assigned in Persian Gulf of Iran. Analysis of 109 identified specimens, revealed 78 provisional gene sequences, related to 9 species and 6 genera, in which interspecific divergence was 1.4 times higher than intraspecific divergence (2.82% versus 1.95%). The average pairwise sequence divergence for all sequences was estimated at 1.37%. In three cases maximum divergence within a lineage exceeded the minimum nearest-neighbor distance: Perinereis sp., Platynereis sp. and Platynereis bicanaliculata. Maximum species similarity was observed amongst 3 sampling sites assigned in Bushehr Province whilst Bandar Abbas`s specimens showed less similarity to Bushehr station. Out of the 109 COI gene sequences of Nereididae polychaetes in this study, 34 contained multiple lineages. These results support the assertion that many Nereid populations in the Persian Gulf previously thought of as a single species, actually consist of two or more divergent lineages.

The objective of the study was to examine whether there is a geographical differentiation between the anchovy stocks as well as to carry out otolith morphology and shape analyses work on the otoliths of anchovies caught in Georgia and Marmara. Otoliths obtained from anchovies (Engraulis encrasicolus) caught at two different regions (Georgia and Marmara Sea) were used for otolith morphology and shape analysis in the fishing season of 2011-2012. LAS Image Analysis 3.8 software in MZ75 Leica imaging system was used for biometric measurements and shape analyses of the otoliths. The average lengths of the otoliths were measured to be 2.94±0.263 mm for Georgia anchovy and 2.74±0.123 mm for Marmara anchovy. Additionally, the average widths of the otoliths were measured to be 1.44±0.142 mm and 1.31±0.579 mm for anchovy from Georgia and Marmara, respectively. The shape factor in the otolith shape analyses was measured to be 0.49≤FF≤0.74 for the Georgia anchovy and 0.55≤FF≤0.70 for the Marmara anchovy. The roundness factor for Georgia anchovy was determined to be 1.26≤RD≤1.97 and for the Marmara anchovy it was 1.33≤RD≤1.69. The length/width ratio was determined to be 1.81≤AR≤2.28 for Georgia anchovy and between 1.90≤AR≤2.37 for Marmara anchovy. According to the statistical analyses carried out in the two regions. AR and FF values were calculated to be statistically significant (p<0.05).

The study was aimed to investigate the probable role of mucus in reception and/or repulsion of Lernaea in Indian and Chinese major carps. Ctenophryngodon idella, Hypophthalmichthys moiltrix, Labeo rohita, Cirrhinus mrigala, Catla catla and Cyprinus carpio averaging 830±316 g each were collected and disinfected with KMnO4 (8.0ppm) for collections of contamination free mucus. Total protein contents and size categorization were determined by Bradford Micro Assay and SDS-PAGE analysis. Lectin and alkaline phosphatase activities were also measured by hemagglutination (HA) titer and alkaline phosphatase test, respectively. Protein concentrations were the highest in C. idella and C. catla and the lowest in C. carpio. Considering protein profiles mucus samples from C. catla contained the highest molecular weight proteins while C. carpio has one unique protein band of 14.13 kDa the weight of which resembles the weight of lysozyme, a protective element of mucus. Lectin activity was highest in C. idella indicative of low resistance while it was the lowest in H. molitrix. Alkaline phosphatase level was the highest in C. catla, and was the lowest in C. carpio.  Overall results indicted C. carpio as the most resistant species as it showed better values for the immune components. Higher values of protein contents and alkaline phosphatase for C. catla may be in favor of its higher susceptibility. These studies on mucus contents are good assessment indicators of the possibility of parasitic attacks in Chinese and Indian major carps.

The present study evaluates the effect of dietary ginger (Zingiber officinale) on growth performance, haematological parameters, antioxidant status of common carp (Cyprinus carpio). Fish with initial weight of 14±1.95 g were allocated into twelve tanks at density of 18 fish per tank. Fish were fed four experimental diets containing 0 (as control diet), 0.5, 2 and 5% ginger powder for 56 days. After 56 days of culture, fish fed with 2 and 5% ginger diets showed significant increase in final weight, weight gain, specific growth rate (SGR) and feed conversion ratio (FCR) (p<0.05) compared to the control diet. Significant higher number of leucocytes (WBC), erythrocytes (RBC), haematocrit, lymphocyte, monocyte and neutroplil neutrophil were found in the fish fed with 2 and 5% ginger diets compared to the control diet. Superoxide dismutase (SOD), catalase (CAT) and Glutathione peroxidase (GPX) enzyme activities and Malondialdehyde (MDA) levels were significantly higher in the groups fed 2 and 5% ginger diets (p<0.05). SOD, CAT and GPX mRNA expression levels of fish fed with 2 and 5% ginger diets were significantly down-regulated compared to the control diet (p<0.05). The results suggested that dietary ginger can improve the growth performance, health status and antioxidant capacity of common carp.

Titanium dioxide nanoparticles (TiO2 NPs) have been incorporated into a large range of materials for different usages and they are very likely to come in wastewater and sewage, finally reaching the aquatic ecosystems. Therefore, valuating the impact of TiO2 NPs on aquatic environment is a major concern. The aim of this work was to study the effects of TiO2 NPs on metabolic enzymes activity and haematological indices of the Caspian trout juveniles. After determining 96h-LC50, juveniles have been exposed to 0.1 LC50-96h TiO2 NPs in three replicates for 28 days. The blood samples were collected from fish after acute (24, 48, 72, 96 hours) and sub chronic (7, 14, 21 and 28 days) exposure to the TiO2 NPs. The analysis showed that the red blood cells count (RBC), haemoglobin (Hb), haematocrit (Hct), white blood cells count (WBC) and lymphocytes have been increased after acute and sub chronic exposure to TiO2 NPs. Levels of neutrophils and monocytes were increased mostly in acute treatments. Mean Corpuscular Volume (MCV), Mean Corpuscular Haemoglobin (MCH) and Mean Corpuscular Hemoglobin Concentration (MCHC) showed no significant differences. According to analysis of metabolic enzymes activities, levels of Alkaline Phosphatase (ALP) and Aspartate Amino Transferase (AST) after acute and sub chronic exposure as compared to control group were increased/decreased, respectively. Alanine Aminotransferase (ALT) levels showed significant decrease (p<0.05) after 28 days. Lactate Dehydrogenase (LDH) enzyme level increased mostly after acute exposure. The obtained results indicated that the presence of very low amount of TiO2 NPs could affect most haematological and metabolic enzymes of Caspian trout juvenile.

The experiment was conducted to determine the effect of salinity and dietary protein levels on  physiological and haematological changes as well as growth of the juveniles of hybrid tilapia (Oreochromis mossambicus×Oreochromis niloticus). Fish were stocked at 20 fish 50L-1. The initial average weight of the juveniles was 2.1±0.02 g and they were kept in salinities 0, 10, 20 and 35 ppt (S1, S2, S3 and S4, respectively) and fed with 30% (P1) and 40% (P2) dietary protein levels for 45 days. The harvesting weight and SGR were not significantly (p>0.05) different between S2 and S3 treatments for 30% to 40% protein levels varied in connecting S2-S3 with P1diets or in between S2-S3 with P2 diets. The food consumption significantly (p<0.05) increased with decreasing protein levels (40% to 30%) in diets at 10-20 ppt salinities. The survival rates were not significantly (p>0.05) different between 10-20 ppt salinities with P1 and P2 diets. The lowest FCR and highest muscular hydration were achieved at intermediate salinities with low protein diets. No obvious changes occurred in Hct%, Hb, plasma protein, muscles and liver protein levels in all treatments. Furthermore, the plasma cortisol and glucose levels tended to increase at higher salinities but were not significantly (p>0.05) different among all treatments. The physico-chemical parameters of water (i.e. dissolved oxygen: DO, temperature, ammonia etc.) were at a normal range throughout the study. Results showed that environmental salinity (0-35 ppt) had no adverse effects on growth and biochemical changes and also no required high protein levels in diets at any salinity.

Rearing of ornamental fishes allocated high levels of annual income from the aquaculture industry. Spirulina is a blue-green algae, spiral shape with a diameter of 12 microns and rich source of protein, vitamins, amino acids and essential fatty acids, minerals and antioxidant pigments. Using different levels of spirulina was evaluated on immune indicators, digestive enzymes and reproductive parameters (fecundity and sexual maturation) of dwarf gourami.  One hundred and forty five dwarf gourami with an average weight of 3.6±0.23g were randomly distributed in twenty 12-liter aquarium. Four diets were prepared consisting of spirulina at levels of 3%, 7% and 10% substituted by fish meal and with a control diet. Parameters related to body biochemical, reproductive, digestive enzymes and immune index were measured. Increasing spirulina up to 7% enhance the ovarian weight (p<0.05). Hatching percentage and fecundity working has shown a significant increase with spirulina increased (p<0.05). Lipase, amylase and protease has significantly increased with increasing spirulina (p<0.05). Lysozyme and serum bactericidal have significantly increased with the increase of spirulina (p<0.05). Based on results 3% of spirulina due to improved reproductive factors and 10% to enhance immune indices and digestive enzymes in dwarf gourami considered as the best levels of substitution with fishmeal.

This study was conducted to assess the effect of crude oil on some immunophysiological variables of Huso huso weighing 8.5±1g at 22°C. The 96h-LC50 value was first measured under static conditions and hematological and biochemical parameters were then assessed in treated fish exposed to 96h-LC50.  The LC50- 96h of 17.4 mg L-1 was obtained. The leucocyte and erythrocyte counts were declined in the treatments compared to the control, while the mean corpuscular volume and hematocrit were significantly higher than those in the fish exposed to crude oil LC50 concentration.  An increase in serum glucose was seen in sera samples of the treatments while levels of alanine aminotransferase, alkaline phosphatase and lactate dehydrogenase were lower than those the control. The alterations of the hemato-biochemical parameters can be used as suitable biomarkers in monitoring of crude oil pollution in the aquatic environment and to protect aquatic organisms such as great sturgeon.

This study was conducted to evaluate the effects of different levels of a commercial herbal oil mixture (Mix-oil®) on the hematological, biochemical and immunological responses of rainbow trout as well as the resistance against infection with Yersinia ruckeri. The Mix-oil® includes, Thymus vulgaris, Origanum vulgare and Eucalyptus sp. essential oils. Experimental diets were supplemented with Mix-oil® at 0 (control group), 50, 200 and 400 ppm. Fish with an initial weight of 31.0± 0.1 g were divided into four groups and reared for 56 days. The anti-bactericidal activity of Mix-oil® revealed that the minimum inhibitory concentration (MIC) value for Streptococcus iniae, Aeromonas hydrophila and Lactococcus garviae was 6.25 μl ml-1 while it was 12.5 μl ml-1 for Y. ruckeri. Significant improvements in red blood cell count, hematocrit, immunoglobulin, lysozyme, total protein, complement component C3 and C4, and alternative complement pathway (ACH50) in fish fed with 400 ppm Mix-oil® were observed compared with the control group (p<0.05). No significant difference was observed between different treatments in terms of MCV, MCH, MCHC levels and hemoglobin percentage aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels (p>0.05). The results suggested that dietary administration of Mix-oil® at the level of 400 ppm could enhance hematological parameters and immune function of rainbow trout as well as the resistance against Y. rukeri. Thus, using Mix-oil® as an immunostimulant is recommended for farmed rainbow trout.

This study was conducted to remove contaminations from fish farms effluents using iron oxide nanoparticles in a laboratory system. For this purpose, a 5-liter semi-industrial reactor has designed with a mixer blade, a porous plate, and a compressor. The results showed that the levels of nitrate, nitrite, phosphate, ammonium, TDS, TSS, and BOD were 2.78, 3.27, 0.43, 7.46, 2.25, 3.38 and 5.34 mg L-1 at the entrance to the reactor, respectively. Also, pH and EC were 6.36 and 1362 µmho cm-1. At the reactor outlet, the levels of nitrate, nitrite, phosphate, ammonium, TDS, TSS and BOD were 1.84, 2.09, 0.27, 3.05, 1.61, 1.78 and  4.96 mg L-1. Furthermore, pH and EC were 7.22 and 1466 µmho cm-1. Also, this study has been showed that the system efficiency from the beginning up to 6 hours has been increased, but it has been reduced at the 18th hour, which has been caused by the sequestration and the formation of an oxide layer on nanoparticles. Therefore, it can be concluded that iron nanoparticles in the reactor fluid space have the potential to reduce the discharge burden of the effluent from fish farms.

A two-month feeding trial was conducted to evaluate the effect of partial replacement of fish meal (FM) by soybean protein (SP) alone or in combination with lysine (Lys) and methionine (Met) supplementation in practical diets for silvery-black porgy juveniles (16.7±0.1 g). Seven isoproteic (ca. 50% crude protein) and isoenergetic (ca. 22.4 MJ kg-1 ) diets were formulated in which 45% (SP45), 60% (SP60) and 75% (SP75) of FM protein were replaced by SP and the control diet (FM) was prepared with FM as the major source of protein. In SP45+ , SP60+ and SP75+ diets, 45 to 75% of FM was replaced by SP with supplementing blends of Lys and Met. Growth performance, feed utilization, and protein and lipid digestibility decreased with increasing dietary SP levels (p<0.05). Fish fed SP75 had the highest whole body lipid content, but with the lowest whole body arginine, lysine, histidine, phenylalanine and taurine concentrations (p<0.05). Supplementing Lys and Met in SP based diets did not improve growth performance, suggesting that the anti-nutritional factors in soybean protein products rather than Met and Lys deficiency might limit FM substitution with SP in silvery-black porgy juveniles

Urmia Lake is one of the largest permanent hypersaline lakes in the world. The lake can be characterized as an oligotrophic lake concerning phytoplankton production. Due to low precipitation in recent years in Urmia Lake’s catchment area, the water level has declined as much as 4 m compared to 15 years ago. Irrespective of its recent evolution, Urmia Lake has always shown fluctuations in historical and geological times, which may cause some ecological partition. Regarding allopatric speciation model of Artemia we assume that several populations of Artemia are generated during last years and living in Urmia Lake. To investigate Artemia population diversity in Urmia Lake, A. urmiana Günther 1890 cysts were collected from five sites in Lake Urmia, Iran. These sites in part represent areas with different physicochemical conditions. To detect possible differences between stations, discriminant analysis (DA) was performed on data of survival, growth, and reproduction at two salinities (75 and 150 g L -1 ) in laboratory culture tests. The performed DA implied that for the reproductive and life span characters, in both salinities, the stations of Golmankhaneh can be determined as the separated group among the studied stations which can be considered for industrial projects and evolutionary studies.

The antimicrobial activity of brown alga methanol, ethyl acetate, hexane, and chloroform extracts on gram positive and gram negative bacteria, and fungi was evaluated by using nutrient broth macro dilution test. Sargassum glaucescense was collected around the coastal area of Chabahar (south of Iran) the protected marine area of the Oman Sea in April and May 2015. Six pathogenic organisms including; Enterococcus faecium ATCC 51299, Streptococcus mutans ATCC 35668, Shigella boydii ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 13883, Salmonella enteritidi PTCC, 1709, Candida albicans ATCC 10231 and Aspergillus fumigatus PTCC 5009 were investigated by the broth dilution method. Methanolic extract of six strains showed good activity amongst eight strains. Hexane extract, after methanolic extract has a good effect on the antimicrobial activity against five strains. All bacterial strains in this survey showed resistance against ethyl acetate and chloroformic extracts. S. glaucescens using four various solutions extracts against eight different human pathogens showed an important antimicrobial and antifungal activity. However, more investigation has to be done on separation, purification and detection of the active ingredients in order to recognize their antifungal and antifungal activity.

Streptococcosis is an infectious disease with significant economic and sanitary repercussions for trout farms in the world. The objective of this study was characterize the chemical constituents and in vitro antibacterial properties of Mentha piperita L., Satureja khuzistanica Jamzad, Matricaria recutica L., Zataria multiflora Boiss and Rosmarinus officinalis L. extracts against streptococcus iniae. The chemical components of the selected hydroalcoholic extracts were also analyzed by GC/MS. The most constituents were menthol (24%) in the M. piperita L., carvacrol (85.88%) in the S. khuzistanica Jamzad, guaiazulene (25.6%) in the M. recutica L. carvacrol (51.12%) in the Z. multiflora Boiss and α-pinene (12.5%) in the R. officinalis L. Among plant extracts under study Z. multiflora had the lowest MIC (4.896 mg ml -1 ) and MBC (9.792 mg ml -1 ) and the maximum MIC and MBC were belonged to M. piperita (18.55 mg ml -1 ) and R. officinalis (33.645 mg ml -1 ) respectively. Also, the inhibition zone diameter of bacteria had determined by disc diffusion method and compared to erythromycin. The highest and the lowest Inhibition zone diameter were belonged to Z. multiflora (14.43±0.55 mm) and M. recutita (13.23±0.35 mm) respectively. Results showed that Z. multiflora extract exhibited highest antibacterial effect against S. iniae among all plant extracts in this study.

During a fish disease outbreaks in 2015-2016 suspected to viral hemorrhagic septicemia virus (VHSV), moribund rainbow trout fries were obtained from fish farms. Samples of kidney, heart and spleen tissues were taken  for examination. The full coding region of the G gene was amplified by RT-PCR reaction. Genotyping was carried out by phylogenetic analysis with reference sequences of four VHS genogroup. A phylogenetic tree was constructed with the maximum likelihood method and the Kumara 2- parameter substitution model by using MEGA software version 6.06. A maximum likelihood phylogenetic analysis reveals that all the Iranian VHS   strains belonged to clade Ia-2 of genotype Ia. The intra- sequence comparison of Iranian VHS strains ranged from 99.1% to 100% (average was 99.55%). In this study, two strains (Chaharmahal and Bakhtiari (1) and Chaharmahal and Bakhtiari (3) showed 100% identity but 0.1% differences with Isfahan strain. The Iranian strains belonging to European genogroup are related (99% identity) to VHSV from recent Italian strains (VHSV/O.mykiss/I/TN/133/Apr10).

Saprolegnia growth on trout eggs is a problem frequently encountered in fish hatcheries worldwide. In the present study silver nanoparticles (Ag NPs) were effectively grafted on the zeolite and bentonite framework using the chemical reduction method. Zeolite and bentonite, silver nitrate (AgNO3), and sodium borohydride (NaBH4) were used as inorganic solid supports, a silver precursor, and a chemical reduction agent, respectively. Silver ions were introduced into the porous zeolite through an ion-exchange path, in the external and interlamellar space of bentonite at room temperature. AgNO3 and NaBH4 were used as a silver precursor and reducing agent, respectively. The Ag/zeolite and Ag/bentonite nano compounds were characterized by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared (FTIR), X-ray powder diffraction (XRD), Energy-dispersive X-Ray spectroscopy (EDX) analysis. The results showed that Ag NPs form a spherical shape with uniform homogeneity in the particle size. The antifungal activity of Ag NPs in zeolites and bentonite were investigated against Saprolegnia sp. with different loads of nano composites and exposure time. All Ag/zeolite NCs and Ag/bentonite NCs were found to have antifungal activities. These results revealed that Ag NPs could be used as effective growth inhibitors in different biological systems, for instance in aquatic animal hatchery facilities.

Integrated multi-trophic aquaculture (IMTA) system can increase production of aquaculture with additional economic value in addition to a biological purification of the effluent from the float net cage (KJA). This study aims to evaluate daily growth, feed conversion rate, and survival rate of marine commodities in KJA that are implemented through the IMTA system. This research was conducted in waters of Karang Lebar Semak Daun Island, Seribu Islands, Jakarta, Indonesia. The IMTA model developed is a combination of white shrimp (Litopenaeus vannamei), rabbit fish (Siganus doliatus) and seaweed (Euchema cottonii). The results showed that for 60 days maintenance period of white shrimp cultivated by IMTA system showed better effect than shrimp cultivation with monoculture system.  The daily growth of white shrimp, rabbit fish, and seaweed was 0,12±0,001 g day-1, 0.10±0.013 g day-1 and 14.30±4.33 g day-1.  The conversion rate of white shrimp feed was 2.73±0.73%, and the survival rate of white shrimp was 71.00±14.53% and for rabbit fish was 84.39±1.00%. The results of this study indicate that IMTA model of IMTA system is more effective in improving the performance of shrimp productivity and visible effects of mutual benefits between organisms incorporated in IMTA system and can be applied as a model of development of sea cultivation that is environmentally sound.

The growth performance, body composition and blood chemistry of Nile tilapia (Oreochromis niloticus) reared under different salinities (0 ppt, 5 ppt, 10 ppt and 20 ppt) and different diets (0.5% yeast [Saccharomyces cerevisiae] supplement diet and basal diet) were investigated during 90 days. Fish fed with yeast supplement diet and reared at 5 ppt water salinity showed significantly improved (p<0.05) growth performances as weight gain (WG), specific growth rate (SGR) and average daily growth gain (ADG) compared to fish fed with basal diet. Feed conversion ratio (FCR) of fish fed with yeast supplement diet reared at all salinity levels (0, 5 and 10 ppt) was significantly lower than fish fed with basal diet (p<0.05). Cortisol levels of fish fed with yeast supplement diet were significantly lower than those of the basal diet group at 10 ppt (p<0.05). Both fish groups showed significant increases in cortisol and malondialdehyde (MDA) levels at salinity of 10 ppt compared to fish reared at 0 and 5 ppt (p<0.05). Crude protein content of fish fed with yeast supplement diet and reared at salinity levels of 0 and 10 ppt was higher than those fed with basal diet (p<0.05). Fish fed with yeast supplement diet showed a decrease in crude lipid content under salinity regime up to 10 ppt (p<0.05). Thus, Nile tilapia fed with yeast supplement diet at 0.5% showed improved growth performance, body composition and blood chemistry under salinity treatments (0 ppt and 5 ppt).

This study compared the efficacy of different diets on the population density, specific growth rate, doubling time, and fatty acids composition of the freshwater cyclopoid copepod Acanthocyclops trajani. The experimental diets consisted of fresh binary microalgae (Scenedesmus obliquus+Spirulina maxima), dry binary microalgae (S. obliquus+S. maxima), dry Gracilaria corticata, and mixed dry vegetables (including spinage, coriander, and parsley). Results have showed that the highest population growth rate (0.145), mean density (1445 ind L-1), and the shortest doubling time (4.76 d) have been obtained in copepods fed on dry binary microalgal diet. The amounts of fatty acids in A. trajani could be modified by feeding copepod with different diets. The amount of C22: 6n-3 (DHA) was significantly higher in copepods fed dry binary microalgae (3.75±1.08 %) compared to the other diets. This cyclopoid copepod had higher levels of EPA and DHA than those in corresponding diets, suggesting that the A. trajani is probably able to accumulate EFA (essential fatty acid). This study indicates the potential of using specifically dry microalgae to improve the nutritional composition in copepods as a suitable supplementary live food for freshwater fish larvae.

The purpose of this study was to evaluate the physiological responses of Rainbow trout fed on diets supplemented with methanolic extract of Spirulina platensis. 150 fish with a mean initial weight of 12.6±0.3 g were randomly divided into five groups. The juveniles were fed for 8 weeks with the diets containing 0, 250, 500, 1000 and 2500 mg of S. platensis extract per kg of diet. After eight weeks, 12 fish from each treatment were subjected to confinement stress. It has been shown that 250 mg of the algae extract per kg of diet resulted in the highest final weight and lowest feed conversion ratio in fish. There was no significant difference between treatments in fat, protein and moisture contents. The results showed that three hours after the air exposure and confinement stress, minimum (2.42 mg dl-1) and maximum (6.18±2.5 mg dl-1) levels of plasma cortisol were observed in 2500 and 500 mg kg-1 treatments, respectively. Moreover, the minimum (66±14 mg dl-1) and maximum (168±18 mg dl-1) level of glucose has been observed in 0 and 500 mg kg-1 treatments, respectively. After eight hours, Plasma cortisol and glucose have showed the highest level in 500 mg kg-1 treatment. There was no difference in lysozyme and catalase enzyme activities, but higher Spirulina extract in diet led to an increase in superoxide dismutase enzyme activity in the liver of Rainbow trout. This study suggests that addition of 250 mg kg-1 of Spirulina extract to Rainbow trout diet can improve growth performance and stress condition.

The present study was conducted to evaluate the effects of nanochitosan with sodium acetate and none-sodium acetate coating on Pseudomonas fluorescens and the shelf life of refrigerated rainbow trout (Onchorhynchus mykiss). 45 samples of rainbow trout filet in five positive and negative treatments including a control, 1% NCH(T2), 2% NCH(T3), 1% NCH+5% NaOAC1 (V/V, T4), 2%NCH2%+ 5%NaOAC1(V/V,T5), the negative groups  incubated by P. fluorescens bacteria (PF+NCH (1 and 2%) +5% NaOACl (V/V) (PF+NCH(1 and 2%)) and a negative control during the 16 days. Comparisons of microbial, chemical and sensory analyses were purely done on safe treatments periodically using one way ANOVA and Duncan tests. Results detected significant differences between the control group and both NCH+5% NaOAC1 (V/V), and NCH free of 5% NaOAC1 (V/V) in all amounts of microbial and chemical indices (p<0.05) and there were no significant differences between the two NCH groups (p>0.05). Sensory indices illustrated that filets treated with each groups of NCH±5% NaOAC1(V/V) received good points and their shelf life was 16 days, but control group settled in this status on sixth day of the test. For the two other treatments, shelf life storage increased and remained on 12 th and 16 th day, respectively. Furthermore, third day of the test showed high amounts of bacteria in the PF incubation treatment.  High levels of bacteria same as that in the control group were determined on sixth day in desirable samples and in NCH+ P. fluorescens, while there was an obvious bacterial reduction in bacterium mixed with NCH+NaOAC and kept for 12 days. Overall, utility of NCH+NaOAC increased the shelf life in refrigerator storage and decreased the amount of P. fluorescens in it.

Apparent digestibility coefficients (ADCs)  of ten feedstuffs were investigated in yearling Siberian sturgeon, Acipenser baerii, (290±22 g), using 1% chromic oxide as the inert marker. The ingredients included: fish (Clopeonella sp) meal (FM), meat and bone meal (MBM), poultry by-product meal (PBM), spray-dried blood meal (BM), feather meal (FeM), solvent extract soybean meal (SBM), canola meal (CM), corn gluten meal (CGM), wheat gluten meal (WGM) and bakers’ yeast (BY). ADC values of crude protein varied from 60% to 92.9% (FeM and FM, respectively). ADCCP of FM, MBM, PBM (animal origin), WGM, and CGM (plant origin) were significantly higher than the other treatments (p<0.05). ADCs of amino acid in feedstuffs followed a similar trend to the ADCCP, but it is not thoroughly correspondence with protein digestibility. The lowest dry matter (65.5%), and lipid (64.8%) digestibility were recorded in BM and FeM, respectively. The WGM (81.5%) exhibited the highest digestibility of gross energy (ADCGE); the lowest was in CM (68.1%). According to the results of this research, FM, MBM, PBM (animal origin) and also WGM and CGM (plant origin) were the more digestible feed ingredients for yearling Siberian sturgeon.

Nile tilapia Oreochromis niloticus as a species with high growth rate and high tolerate to environmental conditions and stocking density, have been culturing in the world more and more. Because of feed expenses necessity and better growth rate and feed conversion efficiency in brackish water, despite of existing many studies on protein requirements, lipid utilization and protein sparing effect of Nile tilapia, they were studied on all males in brackish water, again. A 4 × 3 factorial design with three replicates was planned based on the proximate and amino acids analysis of protein sources to contain four crude protein (15, 22, 29 and 36 %) and three crude lipid (5, 9 and 13%) levels. Growth indices including weight gain and specific growth rate improved by protein accretion and reduced by lipid increasing. The best growth performance was obtained in 5% crude lipid. Feed conversion ratio reduced by protein increasing, and the best one observed in the diet containing 36% crude protein. Protein efficiency ratio and Protein conversion efficiency increased by protein accretion up to 29% crude protein. Protein efficiency, except 15% crude protein, increased up to 9% crude lipid and then reduced but not significantly; so, protein-sparing effect appeared, unclearly. In this study, at 25.6% crude protein with 265 mg protein per gram body weight, fish can keep their carcass protein percentage. In economic point of view, based on growth, feed and protein performances, the levels of 29% crude protein and 5% crude lipid are sufficient for convincing growth rate. The results show that isotonic environment cannot Change protein and lipid requirements compared to the other studies in the fresh water.

This study was aimed to evaluate the single and combined effects of acidifier and probiotic on growth performance, digestive enzymes activities and intestinal histomorphology of Salmo trutta caspius. The juvenile fish with mean body weight 15±3 g were divided into 8 different treatments (in triplicates), including control, 5, 10 and 15 g sodium diformate kg-1 diet, respectively as T1, T2 and T3. Treatments namely T4, T5, T6 and T7 were received diets containing 0.2 g kg-1 commercial probiotic Bio-Aqua® in combination with 0, 5, 10 and 15 g sodium diformate kg-1 diet for 60 days, respectively. The results showed that T2 and T3 fish growth performance were improved significantly (p<0.05), following 30 days after administration, while T1 did not show the same pattern over the 60 days (p<0.05). The single probiotic treatment did not induce significant improvements in fish growth rate, digestive enzymes activities and intestinal morphometry though the combined treatments have been showed an intermediate level of improvement. The higher levels of chymotrypsin and trypsin have been observed at day 30 and the higher activities of lipase, protease and amylase could be seen at day 60 in the most acidifier treatments (p<0.05). The villi height and the thickness of epithelium have been reduced (p<0.05) because of single acidifier while the combined treatments led to either significant increase (p<0.05) or no change compared with corresponding single treatment. The addition of 1.0 g sodium diformate kg-1 diet can improve the fish growth rate in long-term by changing digestive enzymes activities, and combined treatments of probiotic and acidifier are mostly revealed antagonist effects.

Viral haemorrhagic septicaemia (VHS) is one of the most important viral diseases in rainbow trout that has caused great losses to the Iranian rainbow trout aquaculture industry in few recent years. In the early autumn of 2015, in order to identify the possible causes of loss, farmed fish were sampled from the epicenter where massive mortalities and economic losses had occurred. Three samples were collected from relevant tissues (i.e. liver, kidney, spleen, heart, and brain) of the rainbow trout with clinical signs of VHS disease. The samples were stored in 70% ethanol, Eagle’s minimum essential medium (EMEM) and 10% formalin to perform RT-PCR, cell-culture and histopathology examinations, respectively. A virus was isolated using fish cell lines inoculated with a homogenate of the internal organs. Sequencing analysis of truncated N gene confirmed the existence of VHS virus. RT-PCR and histopathology tests indicated the suitability and simplicity of the test as a paraclinical diagnostic method for VHS virus in the region. Haemorrhage, necrosis and other changes in histological sections of the diseased fish demonstrated pathological changes identical with the typical VHS pathology in target organ of the virus (i.e. heart, spleen, liver and kidney). To our knowledge, this is one the first studies that fully focused on the identification of VHSV from farmed trout in Iran by using histopathology examinations.

The study was carried out to estimate the effects of phytase, and citric acid (CA) supplemented guar meal based diet on growth performance, nutrients and mineral digestibility in Cirrhinus mrigala fingerlings. The experiment consisted of nine test diets. Diets were formulated by spraying graded levels of phytase (0, 500 and 1000 FTU kg-1) and 0% (0g), 2.5% (75g) and 5% (150g) citric acid supplementation to a guar meal-based diet. Chromic oxide was added as an indigestible marker. Fingerlings were fed at the rate of 5% of live wet weight. The maximum growth performance, minerals, and nutrients digestibility value were observed in fingerlings fed diet supplemented with 1000 FTU kg-1 level of phytase and 2.5% CA. These values were significantly different from fish fed the control and other test diets. It was concluded that the phytase and CA supplementation to a guar meal based diet at 2.5% CA and 1000 FTU kg-1 level is optimum to release sufficient amount of chelated minerals and nutrients for C. mrigala fingerlings. Our findings also suggested that phytase and CA supplementation can help in the development of sustainable aquaculture by reducing the feed costs and nutrient discharge through feces into the aquatic ecosystem.

Fishes have been widely documented as useful bioindicator for ecotoxicological studies because of their differential sensitivity to pollution. Thus, the present study was carried out to determine the sub-lethal effects of commercial herbicide thiobencarb (CITRON®, 50EC) on the African catfish (Clarias gariepinus). Females fish were exposed to sub-lethal concentration of thiobencarb (½ LC50, 0.72 ppm) for 3, 9 and 15 days. Severe abnormality in the swimming behavior was observed in fish groups exposed for 9 and 15 days.  Adverse effects on the ovary and liver weights were observed. The absolute fecundity was significantly decreased by all thiobencarb-treatments, for which the lowest value  was observed at 15-day treatment in comparison with that of the control. A significant decline (p<0.01) in the activities of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) was observed in fish as the exposure period continued as compared to the control. Similarly, glucose and total protein levels were also significantly declined (p<0.01) with the exposure period. Histopathological changes in the liver tissue of fish exposed to thiobencarb were characterized by necrosis, changes in nuclear shape, formation of vacuoles and atrophy of hepatocytes. The ovary of fish exposed to thiobencarb for 15 days showed atretic vitellogenic oocytes and proliferation of follicular cells as well as inflammatory cells infiltration. These results indicate that thiobencarb is toxic and has the potential to impair on the physiological activities in African catfish. Therefore, the use of thiobencarb should be strongly controlled and carefully monitored to minimize its negative impacts on the aquatic ecosystems.

Among the viral diseases in trout farming, viral hemorrhagic septicemia (VHS) could be mentioned as the most devastating worldwide viral infection. In the present investigation, the influence of the omy-miR-731 Antagomir pretreatment on VHS in rainbow trout was examined. Trout (20±1) g were examined in four main groups subdivided into three subgroups, including a negative control without any injection, a vehicle that received saline, a positive control that was infected by VHSV, and an experimental group that received omy-miR-731 Antagomir by injection, then they were challenged by VHSV. The survival rate, average weight gain, histopathology, Immunohistochemistry and Blood-brain barrier impermeability were assessed in each group. The survival rate and average weight gain in the positive control group was significantly decreased in comparison with other groups. Remarkable histopathological changes and virus detection by immunohistochemistry test were observed in the positive control, whereas no sign of the virus was observed in the vehicle and the negative control groups. The histologic changes in the experimental group were significantly less than the positive control group. Also, the Blood-brain barrier impermeability was significantly decreased in the other groups compared to the positive control group. Although more studies are needed to verify the exact mechanisms of pretreatment potential effects of omy-miR-731 Antagomir, the present results proved that pretreatment potential of omy-miR-731 Antagomir can protect the brain tissue against signs of VHS and preferably would be a new approach against VHSV infection in rainbow trout.