BACKGROUND: Enzymes are organic catalysts that trigger and/or accelerate chemical reactions. OBJECTIVES: This research was done to compare the separate and combined levels of commercial multienzymes on feeding efficiency and carcass chemical composition of common carp (Cyprinus carpio). METHODS: Total number of 96 common carp fingerlings weighing 13.06±2.56g were distributed in six treatments including control (without multienzyme), 1 g/kg Combo, 1.5 g/kg Combo, 1 g/kg Natuzyme Plus, 1.5 g/kg Natuzyme Plus and mixture of 1g/kg Combo+1 g/kg Natuzyme Plus in two replicates for 8 weeks. RESULTS: Growth indices such as the final weight, percentage of body weight increase, specific growth rate, food conversion ratio and average daily growth in treatment 1g/kg Natuzyme Plus showed significant differences compared to other experimental treatments (P<0.05). Also, all experimental treatments had better condition in comparison with the control. The highest condition factor was seen in fish fed 1.5 g/kg Natuzyme Plus which showed significant difference with 1.5 g/kg Combo (P<0.05). Common carp fingerlings fed mixture of Combo+Natuzyme Plus recorded a slight increase in protein content of carcass compared to other dietary treatments. Fish fed multienzymes had less (P>0.05) lipid content of carcass in comparison with the control. There was no significant difference in ash and moisture contents of carcass (P>0.05). CONCLUSIONS: According to results, it can be stated that Natuzyme Plus at the level of 1.5 g/kg can be effective in improvement of growth performance and feed efficiency in farmed common carp fingerlings.

BACKGROUND: Vitamins are considered an essential part in diet of aquatic animals. OBJECTIVES: This study was carried out to assay the effect of different levels of vitamin E on growth performance, carcass compositions and blood parameters of common carp fingerlings (Cyprinus carpio). METHODS: Total number of 96 common carp fingerlings weighing 15.49 ± 3.64 g were randomly distributed into 12 fiberglass tanks in four treatments group including control (without added vitamin), 100, 200 and 400 mg/kg vitamin E in three replicates and kept at a density of 8 fish per tank for 10 weeks. RESULTS: Results showed that the highest weight gain, percentage of body weight increase, mean daily growth, specific growth rate, condition factor and the lowest food conversation ratio were observed in fish fed with 200mg/kg vitamin E but no significant differences were seen compared to other treatments (p>0.05). Fish fed with 200mg/kg vitamin E had the highest (p>0.05) contents of protein and ash compared to control group. There was an increase in values of RBC, Hct and Hb in fish fed with 100, 200 and 400 mg/kg vitamin E in comparison with control group. Significant differences were observed in MCHC in fish fed with 100 mg/kg vitamin E compared to control and fish fed with 400 mg/kg, also treatment 200 mg/kg with treatment 400 mg/kg vitamin E (p<0.05). Fish fed vitamin E in 200 and 100 mg/kg had the highest WBC count. Fish fed with different levels of vitamin E had higher lymphocyte in comparison with control group and fish fed with 100 mg/kg had significant difference with control in lymphocyte (p<0.05). CONCLUSIONS: Vitamin E in level of 200 mg/kg can play an important role to enhance growth performance, nutrition efficiency and improving blood indices and support cell immunity in common carp fingerlings.

BACKGROUND: Biofloc technology is considered  a method that degrades organic waste by microorganisms and produces bacterial flocculation. OBJECTIVES: This study was performed to evaluate of the application of biofloc technology in therearing of common carp (Cyprinus carpio) fingerlings in intensive culture. METHODS: The experiment was designed in four treatments (Commercial diet as a control, 75% commercial diet + Biofloc, 50% commercial diet + Biofloc, 25% commercial diet + Biofloc) with carp fingerlings (Initial weight 58 ± .2 g) over a period of one month. Water exchange in Biofloc treatments was 1% during 24 h while water flow through system was used in control. At the end of experiment, all fish were intraperitoneally injected with 12×107 colony forming units (CFU) of Aeromonas hydrophila per fish. RESULTS:The results of the experiment indicated that the highest weight gain was observed in fingerlings fed 75% commercial diet + Biofloc that differed significantly from the group fed 25% commercial diet + Biofloc (p<0.05). There was no significant difference between control and 50% and 75% commercial diet as well (p<0.05). No significant difference was observed in case of condition factor, viscerosomatic index (VSI) and survival in experimental treatments (p>0.05). Also, Biofloc significantly increased ash content in muscle (p<0.05). The highest mortality (64.2 %) was observed in control inchallenge of Aeromonas hydrophila. CONCLUSIONS: The results suggest that the Biofloc technology can increase growth performances of carp fingerlings in intensive system and decrease water exchange via quality improvement.

BACKGROUND: Application of green chemistry to the synthesis of nanomaterials is of vital importance in medicinal and technological aspects. Recently, synthesis of silver nanoparticles using plants and marine macro algae to adapt this approach to the environment, has become  more popular. Objectives: The purpose of this study is biological synthesis of silver nanoparticles using seaweed, Sargassum angustifolium, and determining its toxicity in common carp. Methods: First, synthesis of silver nanoparticles using Sargassum algae was conducted and then acute toxicity of these silver nanoparticles was investigated at static renewal condition during 96 hours in common carp according to standard methods (1998) OECD. Results: TEM analysis showed that the average size of the bionanoparticles was found to be 32.54 nm and spherical in shape. The toxicity results showed that the LC50 at 24, 48, 72 and 96-h after exposure was 79.54 ± 0.007, 52.17 ± 0.006, 30.62 ± 0.008 and 11.34 ± 0.016 mg/l respectively. Conclusions: Analysis related to the characterization of the properties of silver nanoparticles proves bioreduction of silver ions by sargassum seaweed extract. According to the results the mortality rates of common carp showed an increasing trend with increasing concentration and exposure time, which indicates the toxicity of this substance in high concentration for common carp.

BACKGROUND Agricultural pesticides can cause environmental pollution and damage to aquatic organisms. Bensulfuron-methyl is a widely used herbicide in agricultural fields, especially rice fields. Despite the solubility of Bensulfuron-methyl in water and its entry into aquatic environments, limited research has been conducted on the toxicity of this herbicide in aquatic organisms.OBJECTIVES: This study aims to investigate the effects of chronic toxicity of Bensulfuron-methyl in common carp (Cyprinus carpio).METHODS: The fish were divided into four groups. Group 1 was considered as a control, and groups 2, 3, and 4 were exposed to 10 %, 20 %, and 30 % of the 96 h lethal concentration 50 of Bensulfuron-methyl equal to 0, 0.162, 0.324 and 0.486 g/L.  After 21 days, blood samples, serum levels, and liver tissue of fishes were analyzed.RESULTS: The number of white blood cells increased in groups 2 and 3 (received 0.162 and 0.324 g/L Bensulfuron-methyl) compared to group 1, while a significant decrease was observed in group 4 (received 0.486 g/L Bensulfuron-methyl) compared to other groups. The number of red blood cells, the amount of hemoglobin, and the percentage of hematocrit in groups 3 and 4 showed a significant decrease compared to other groups, and the values of mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were not significantly different in any groups. The amount of total serum protein in groups 3 and 4 decreased significantly compared to the control group. Serum glucose showed a significant increase in groups 3 and 4 compared to other groups. The values for aspartate aminotransferase, alanine transaminase, and alkaline phosphatase enzymes showed an increasing trend with the increase of Bensulfuron-methyl concentration. The most liver tissue damage was observed in group 4, which included hyperemia, hepatocyte vacuolar degeneration, edematous cell infiltration, bile duct hyperplasia, and hepatic necrosis.CONCLUSIONS: The increase in the concentration of Bensulfuron-methyl can cause liver tissue damage and changes in hematological and serum biochemical markers in common carp.

BACKGROUND: Ammonia accumulation in warm-water fish pond can lead to mortality or reduction in growth and body immune indices.OBJECTIVES: The present study aimed to investigate the effects of chronic sub-lethal unionized ammonia (NH3) on growth indices and gill and kidney histopathology l, after a 30 – day trial in common carp (Cyprinus carpio).METHODS: Herein, 180 fish with an average weight of 4.5±0.5 g were divided into six tanks. Two groups, including one control group and one treatment group (with three replicates for each one), were considered. The treatment fish were exposed to 0.1 mg/l on un-ionized ammonia (NH3) for 30 consecutive days. Following one -month, ammonia exposure growth indices and histological analysis of gill and kidney were investigated.RESULTS: The results showed that exposure to 0.1 mg/l of NH3 led to a significant reduction in growth indices. Additionally, edema and epithelial lifting with hyperplasia in the second lamella were detected in the gill of the treatment group. The kidney was characterized by focal renal tubules degeneration and necrosis, congestion, and increase in the melano-macrophage centers.CONCLUSIONS: Although chronic exposure to 0.1 mg/l of unionized ammonia was not found to cause mortality in common carp, it could have some side effects, such as a decline in growth indices and histopathological effects in kidney and gill tissues. Thus, for higher production, sublethal levels of ammonia should also be taken into account in common carp ponds.

BACKGROUND: Parasite effects on biometric characteristics of common carp, C. carpio from Anzali Wetland. OBJECTIVES: Identifying parasites in C. carpio and evaluating their effects on biometric characteristics of fish. METHODS: A total of 78 individuals were collected on the seasonal basis (from spring through winter 2016) from the wetland, transported to the laboratory and after biometry, dissected to recover parasites. Cestodes and trematodes were stained with alum carmine and nematodes were cleared with glycerin alcohol, then their prevalence, abundance and mean intensity were determined. RESULTS: Thirteen parasite species including Ichthyophthirius multifiliis, Trichodina sp., Epistilis sp., Gyrodactylus sp., Dactylogyrus extensus,  Diplozoon nipponicum, Diplostomum spathaceum, Posthodiplostomum cuticola, Asymphlodora sp., Caryophyllaeus fimbericeps, Raphidascaris acus, Pseudocapillaria tomentosa and Lernea cyprinacea were identified. Epistylis sp., P. cuticola, Asymphlodora sp. and P. tomentosa are reported for the first time from C. carpio in Anzali Wetland. The average weight in healthy and infected fish were recorded to be from 23.68 ± 3.54g to 686.73 ± 100.28 g, and from 32.47 ± 4.51 to 633.62g ± 64.64 g respectively. The condition factor in healthy and infected fish was from 1.09 ± 0.50 to 1.17±0.03, and from 1.24 ± 0.13 through 1.19 ± 0.03 respectively. It was also true for gonadosomatic index which was recorded in healthy and infected fish from 0.45 ± 0.16 through 3.56 ± 3.54, and from 1.78±0.67 through 2.74 ± 0.62. The instantaneous growth rate was 1.25 in healthy  2+ and 1+ year old individuals, and 0.72 in 3+ and 2+ year olds, while it was 0.94 and 0.65 in the same-aged infected fish, respectively. CONCLUSIONS: Parasites could induce some negative influences on the biometric characteristics of infected fish, decreasing their growth rate. So that, it is necessary to monitor the parasite communities continuously in the native and commercially important fish species in Anzali Wetland to protect them and prevent introducing infected fish into the adjacent fish farms.

BACKGROUND: Probiotics and prebiotics are the most important bioactive compounds for aquatic health. OBJECTIVES: In this study, the effects of prebiotic (immunowall) and probiotic (primalac) were assessed on growth performance, survival, body composition, and blood biochemical parameters in the Caspian Sea common carp Cyprinus carpio fingerlings. METHODS: Juveniles (n = 100 per tank, 21 tanks) were distributed in four inclusion levels (each in three treatments) of 0, 0.05, 0.1 and 0.15% of immunowall and primalac inclusions for a period of 56 days. Growth, body composition, and hematological parameters have been evaluated in different inclusion levels at the end of culture period. RESULTS: The increment of body weight, specific growth rate, and feed conversion ratio in fish fed with diets containing 0.15% prebiotic and 0.1% probiotic improved considerably compared to other treatments. The survival rate of the juveniles was not significant between treatments, and the group fed with the pre- and probiotics revealed higher survivals. Protein content in the group fed with the pre- and probiotic showed significantly higher contents compared to the control group, and lipid content showed increasing trend in different inclusions. The red blood cells contents showed no differences between treatments; but the white blood cells contents revealed higher performances in the fish-fed probiotics compared to prebiotic and control groups. CONCLUSIONS: These results recommend the addition of 0.1 % immunowall and 0.15 % primalac in the diets of the juveniles in terms of growth, feeding, and hematological indicators in the Caspian carp.

BACKGROUND: Based on previous studies, aquaculture systems affect on flesh quality in cultured species. In biofloc system, as a modern and new aquaculture system, animals use microbial flocs as feed and it seem such flocs affect on bodycomposition. OBJECTIVES: The aim of this study was to evaluate growth and chemical, microbiological and sensory properties of common carp meat cultured in Biofloc system. METHODS: Three hundred healthy fingerlings were randomly distributed in 12 tanks (70 L) at a density of 8.3 kg m-3 and fed experimental treatments: commercial diet as a control and three biofloc treatments including sugar beet molasses biofloc (SBM+BFT), sugar biofloc (S+BFT) and corn starch biofloc (CS+BFT). Fish in BFT treatments were fed at 75% of the daily feeding rate of control. At the end of experiment, growth performance and survival investigated. In addition to evaluate cultured fish meat quality, sensory properties of raw fish (day 0), rigor mortis (3, 6 and 24 h after catch), bacterial count, pH, expressible moisture and TVN were also assessed during 16 days, (every 4 days). RESULTS: The results indicated that the lowest food conversion ratio (FCR) and highest condition factor was observed in fish fed BC which differed significantly from control (P<0.05). No significant difference among treatments was observed in rigor mortis and bacterial count (P>0.05). pH in carp flesh increased gradually during storage time (P<0.05), but at the end of the storage period no significant difference was found between the treatments (P>0.05). The lowest primary TVN was seen in BS treatment (9.0 ± 0.2 mg N/100g flesh) but in other treatments TVN was higher than 20 mg/ 100g flesh (P<0.05). CONCLUSIONS: Overall, based on the results of this study, biofloc cultured fish flesh had acceptable quality in comparison with control fish.

Koi herpesvirus (KHV) has infected farmed common carp in Poland clinically and asymptomatically since 2004. The role of non-carp species as vectors of virus transmission is well known except for in the case of KHV. The aim was to better understand this virus’ infection and transmission pathways in common carp, looking at the potential vector role of fishes kept with them. Eight species were experimentally infected with KHV by immersion in a suspension at 20°C ±1 and transferred to a tank after 45 minutes. Specimens were euthanised at intervals up to 56 days post infection (dpi) and tissue was examined for KHV DNA. Surviving infected fishes were introduced at intervals, each time into a separate tank, to naïve common carp for experimental infection. These were observed daily for symptoms, sacrificed along with controls after three months, and dissected to provide tissue samples. Also fish from 14 species collected from a farm with a history of KHV were sampled from 3 to 22 months after disease was confirmed. Organ sections from single fish were collected in a single tube. Viral DNA was detected in tench and roach samples up to 49 dpi, but in three-spined stickleback and stone maroko samples only up to 14 dpi. Transmission of KHV to naïve carp occurred after cohabitation. KHV DNA was detected in three fish species three months after the farm outbreak. We confirmed that grass and Prussian carp, tench, roach, and brown bullhead can transfer the virus to naïve common carp.