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High levels of nitrogen compounds can lead to acute toxicity in aquatic organisms. Ammonia, a by‐product of protein breakdown, is the most prevalent contaminant in freshwater environments. Increasing salinity in water sources can cause fluctuations in salinity levels within breeding ponds. The interaction of these elements can occur in breeding ponds, significantly impacting the physiology and quality of the aquatic products. The purpose of this study was to examine the relationship between salinity and ammonia‐N stress and their effects on the quality and fatty acid profile of tilapia fish (Oreochromis niloticus). The fish were divided into 12 distinct treatment groups, each characterized by varying salinity levels (0, 4, 8, and 12 ppt) and different concentrations of ammonia‐N (0, 50% of 50% lethal concentration [LC50]‐96 h, and 30% of LC50‐96 h) arranged in a factorial design. The calculated LC50‐96 h for ammonia‐N was 0.86 mg/L. Significant increases were observed in cortisol and glucose levels associated with various salinity treatments and ammonia levels. The levels of carcass protein in the salinity treatments (4, 8, and 12 ppt) did not show any significant differences when compared to the control treatment. However, the protein percentage at 50% of LC50‐96 h of ammonia‐N was lower than that of the control treatment. In salinity treatments and ammonia levels (50% and 30% of LC50‐96 h of ammonia‐N), a significant increase in the percentage of lipid, highly unsaturated fatty acids (HUFA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) was observed. To draw the conclusion, our assessment indicates that a salinity concentration of 8 ppt over a 96‐h period without feeding has produced positive effects on the quality of tilapia carcasses. [ABSTRACT FROM AUTHOR]

The point of our study was to examine the interaction of ammonia-N poisoning and salinity on serum enzymes and oxidative stress factors of blood and liver in Nile tilapia (Oreochromis niloticus). The 50% lethal concentration (LC50) in 96 h was 0.86 mg/L of ammonia-N. A random allocation was used to divide the fish into 12 treatments. These treatments encompassed various combinations of acute ammonia-N levels (0 and 50% of LC50-96 h), sub-acute ammonia-N levels (30% of LC50-96 h), and salinity levels (0, 4, 8, and 12 ppt). The experimental design employed a factorial arrangement of 3 × 4.The findings revealed that the amounts of aspartate transferase (AST) and alanine transaminase (ALT) in treatments 3 and 4 increased significantly compared to the treatment 2 (4 ppt) and control. Salinity levels did not affect serum glutathione levels (GSH), nevertheless the reduction of serum GSH and levels of total antioxidant capacity (TAC) and superoxide dismutase (SOD) and catalase activities (CAT) in ammonia poisoning treatments, 5 and 9, compared to the control, states ammonia can stimulate oxidative stress in fish. Similar to the serum measurements, increasing salinity in acute ammonia poisoning treatments (5, 6, 7 and 8) caused an increasing effect on the liver TAC value, which was presumably due to the improving effect of salinity in reducing ambient ammonia. The findings indicate that while elevated salinity levels can be beneficial in mitigating the effects of ammonia toxicity in water, the combined presence of salinity, ammonia, and their interaction had detrimental impacts on the physiological well-being of fish over a 96-hour testing period. [ABSTRACT FROM AUTHOR]

Recently, there has been increasing attention regarding the potential application of biodegradable nanoparticles (NPs) as adjuvants in injectable vaccines. In this study, encapsulated antigens of Aeromonas hydrophila in alginate/chitosan polymers were used as injectable vaccines in common carp. Formalin‐killed bacteria and extracellular products (ECPs) of A. hydrophila were encapsulated via emulsification method. In total, 480 juvenile common carp (32.1 ± 3.64 g, mean ± SD) were randomly divided into eight triplicate groups (20 fish for each replicate). Groups 1–3 were injected with bacterin, ECP, and bacterin + ECP, respectively. Groups 4–6 were injected with encapsulated bacterin, encapsulated ECP, and encapsulated bacterin + ECP, respectively. Groups 7 and 8 as controls were injected with alginate/chitosan and phosphate‐buffered saline (PBS), respectively. Blood samples were collected on days 0, 30, and 60 of the experiment. Immunological parameters, including antibody titer against A. hydrophila, serum lysozyme, bactericidal and complement activities, and nitro blue tetrazolium (NBT) reduction, as well as serum globulin and protein levels, were compared among the groups. Hematological parameters (red blood cell [RBC], white blood cell [WBC], hemoglobin [Hb], and hematocrit (Hct) were evaluated too. Remained fish were challenged with severe A. hydrophila, and mortality was recorded for 10 days. Results showed that anti‐A. hydrophila antibody titer, survival rate following bacterial challenge, NBT reduction, serum lysozyme activity, globulin, and protein levels were significantly higher in encapsulated bacterin and encapsulated bacterin + ECP groups compared with the control group (p < 0.05). Serum bactericidal and complement activity showed no significant change in different groups of sampling points. Then, it can be concluded that the encapsulation of bacterin and bacterin + ECP of A. hydrophila using chitosan/alginate NPs enhanced the protection and immune responses in common carp and this method is a promising candidate for a vaccine adjuvant in fish. [ABSTRACT FROM AUTHOR]

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Lactobacillus probiotic enriched diets can modulate host immune response. In this study, we investigated whether the three species Lactobacillus plantarum, L. bulgaricus and L. rhamnosus up-regulated two T-cells specific antigens and exerted the protective effect when administrated with formalin-killed Streptococcus agalactiae in Nile tilapia. For this purpose, a total of 180 Nile tilapia (average body weight 45.8 ± 22 g) were randomly divided into 6 experimental groups, i.e.: one control group and 5 vaccinated groups: Formalin killed cell (FKC); FKC+ Adjuvant; FKC+ L. plantarum; FKC+ L. bulgaricus and FKC+ L. rhamnosus. All groups were fed with normal commercial pellets and three groups were fed with pellets sprayed with three different lactobacilli. The results showed that the survival rate in the groups of Formalin killed cell (FKC) combined with oral administration of lactobacilli was from 70.0% to 75.0%. Protection in the control group amounted to 31.3% illustrating a significant difference with other experimental groups. In this research, gene expression of CD4 and CD8 which have essential functions in the immune response quantified by qRT-PCR in the head kidney, skin, and spleen was reported in the form of fold change. The analysis of fold change (Mean ± SD) related to CD4 and CD8 at 30- and 60-days post-immunization (dpi) respectively showed an increase in fold change in all probiotic groups compared to the FKC group in two of which it was significant at the level of p<0.05. The results revealed that vaccination with FKC administrated lactobacilli-enriched diets increased the expression of genes related to immune response which can indicate higher protection against Streptococcus agalactiae in the probiotic groups compared with FKC vaccination alone similar to the results observed in FKC coupled with adjuvant vaccination. [ABSTRACT FROM AUTHOR]

The cichlidae family has more than 1300 species which in turn have great species morphologic differences. In this study, histology of liver, spleen and pancreas of four cichlid species (green terror cichlid, Oscar, giraffe cichlid and Texas cichlid) were compared. For this purpose, four apparently normal fish specimens from each species were selected after killing of which, tissue samples were taken. The sections stained with two methods (Haematoxillin- Eosin and Periodic acid Schiff). The results showed that all liver sections contained pancreas tissues around the liver blood vessels. Liver cells size in two species (green terror cichlid and giraffe cichlid) was significantly bigger than the two other species. The liver cell to pancreatic cell ratios also was significantly higher in two species. The liver size in giraffe cichlid, was even significantly bigger than the green terror cichlid. Exocrine pancreatic cell size in all 4 species showed no significant difference. The spleen in four fish species showed different degrees of amount and intensity in melanomacrophage centers. In PAS stained sections, only the pancreatic tissues showed more PAS positive reaction that may be due to the more glycogen content. The liver showed a weak PAS reaction. The bigger size formation of liver cells in two species can be due to feeding regime or simply a species specific trait. Yet more investigation is still needed to determine the importance of these findings. [ABSTRACT FROM AUTHOR]

In recent years, using suitable probiotic bacteria is one of the big concerns in aquaculture industry. For each species presence of lactic acid bacteria in the gut of that species, makes them a suitable probiotic candidate as food additive. In this study, lactic acid bacteria of intestine of common carp from captured fish ponds of Khuzestan province were examined. For this purpose 30 fish from several ponds were sampled. Lactic acid bacteria were isolated using specific culture media and identified by biochemical and molecular tests. Definite identification was performed by the PCR method and sequencing. The isolated probiotic bacteria identified as Enterococcus gallinarum, Enterococcus casseliflavus, Lactococcus lactis, and Staphylococcus hominis. The bacteria isolated in this study were able to grow in the temperature range of 25-45 ° C, pH renge of 3 to 9, media salinity containing 1-4% NaCl, and most of them in different bile doses of 7.5-2.5%. Assessing the antagonistic activity of these isolates showed that they have a relative ability when compared with a model bacteria (Aeromonas hydrophila). However, the results showed that the isolated bacteria were sensitive to the commonly used antibiotics in aquatic animals. The bacteria were appeared genetically similar to the bacteria that isolated from commercial products and aquatic organisms of Indonesia, China, Japan, The United States and India. This study is the first report of isolation and identification of Enterococcus spp with probiotic capabilities in common carp in Iran as Iranian strain. [ABSTRACT FROM AUTHOR]

Aeromonas hydrophila is a bacterium associated with many diseases and disorders such as fin rot, skin ulcers and lethal hemorrhagic septicemia in fish. It bears several virulence factors including type III secretion system (T3SS), aerolysin, cytolytic enterotoxin and enzymes (e.g., hemolysins, lipase) that seem to play an important role in its pathogenesis. Detection of virulence markers by polymerase chain reaction (PCR) is a key procedure in defining the pathogenic ability of pathogenic bacteria and preparing a vaccine for its treatment. In this sense, this study was aimed to determine the frequency of virulence genes in isolates obtained from infected cultured carps in Khuzestan province. Out of 200 moribund carps with septicemic symptoms, 125 isolates were belonged to the motile aeromonads and 59 isolates were identified as A. hydrophila by biochemical methods. Finally, using PCR analysis, 31 isolates were identified as A. hydrophila. Five virulence genes were detected in these isolates including hemolysin, aerolysin, cytolytic enterotoxin and T3SS (aopB and ascV) by specific primers. Results showed that 23 (74.19%), 18 (58.06%), 16 (51.61%), 13 (41.63%) and 10 (32.25%) isolates possessed cytolytic enterotoxin, hemolysin, aerolysin, and T3SS genes, respectively. The results of the present study showed that among 31 isolates, only five isolates had all of dominant virulence genes. Thirteen other isolates had genotypes including hlyA+, aerA+, and act+. The remaining isolates had at least one virulence gene. This study showed that determination of the virulence genes by PCR can be a reliable method to identify a potential pathogenic Aeromonad strain. [ABSTRACT FROM AUTHOR]

BACKGROUND: Tilapia, Oreochromis niloticus, is an omnivorous and important breeding species in the world. Over the recent years, tilapia breeding has begun in Iran. In aquaculture, it is very important to regulate a balanced diet in terms of nutrients needed for growth, which would be also economically appropriate. OBJECTIVES: The main objective of this study was to investigate the effect of substituting chicken waste powder in the diet of fish at levels of 0, 25, 50, 75, and 100 % on the tissue structure of different parts of the intestine of Nile tilapia. METHODS: 75 fish (three frequency per treatment) were fed with chicken waste powder instead of fish meal in their diet for eight weeks at 0, 25, 50, 75, and 100 % levels. At the end of the treatment, separate samples were taken from the initial, middle, and end parts of the intestine. After passing the usual histological steps, the slides were assessed by hematoxylin-eosin staining and TUNEL immunohistochemistry technique. RESULTS: In histometric studies, the highest villi height, thickness, muscle layer, and number of goblet cells were reported in the control group and the lowest in the 100 % group. In immunohistochemical studies, the number of apoptotic cells in groups 75 and 100 % was higher than that in the other groups. CONCLUSIONS: According to the results of the present study, it could be suggested that the replacement of chicken waste powder instead of a fish meal up to 50 % for indigo tilapia is tolerable. However, higher levels of chicken waste powder will reduce absorption, and acceptance of food and have adverse effects on growth. [ABSTRACT FROM AUTHOR]

In autumn of 2019 a three years old female parrot fish was referred to the veterinary hospital for diagnosis and treatment. The prominent symptom was inappetence and a large mass or unilateral distention in the abdominal cavity. Ultrasonography and radiology imaging with contrast media were done to evaluate the abdominal cavity. According to presumptive diagnosis by imaging, the fluid-filled mass was aspirated by a sterile syringe. No bacteria or other microorganisms were seen in the fluid using microscopy and culturing of the fluid on trypticase soy agar. The parrot fish died after three days because of imbalance and inappetence. Two fluid-filled masses were seen in necropsy. The ovarian structure of the cyst was proved based on the anatomical position, histopathology, ultrasonography and radiology of the cyst tissue. It could be concluded that prompt diagnosis and therapy of ovarian cyst may be necessary for saving the life of the fish. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of water temperature on the shrimp hepatopancreas of Litopenaeus vannamei by immunohistochemical method. In this research, a total of 50 shrimp with an average length of 23 ± 1 cm and an average weight of 28 ± 0.5 gr were accidentally caught from shrimp farms of the Choebdeh Abadan from Khuzestan province in two different seasons of the year. The shrimp were sampled for the histological and structural study of the hepatopancreas. After killing the shrimp by physical method, the hepatopancreas of each shrimp was transferred to Davidson's solution. The tissue samples were processed by routine histological procedure, using ascending ethanol for dehydration, xylene for clearing, and paraffin impregnation. 4-6 μm sections were taken and stained with hematoxylin-eosin and TUNEL immunohistochemistry technique. Finally, slides were studied by a light microscope equipped with a Dino-lite lens and Dino-capture software. The results indicated that the hepatopancreas structure is a tubular organ that can be affected by water temperature. In the warm season, the diameter of the tubules was smaller than in the cold season (p≤0.05). There was a significant difference in the percentage of apoptosis between the tubule-forming cells in the warm and cold seasons. [ABSTRACT FROM AUTHOR]

Viral haemorrhagic septicaemia (VHS) is one of the most important viral diseases in rainbow trout that has caused great losses to Iranian rainbow trout aquaculture industry in the last 3 years. Therefore, rapid and reliable diagnosis of VHS virus infections is of great importance. An enzyme linked immunosorbent assay (ELISA) method was performed to study serum antibodies against viral haemorrhagic septicaemia virus (VHSV) using recombinant fragments of their N protein. For this purpose, the virus was first isolated from an infected farm. A part of the nucleocapsid (1–505 bp) gene was amplified by RT‐PCR using specific primers. The amplified fragment was ligated to pMALc2x vector and transferred to DH5α strain of Escherichia coli. Then, recombinant plasmids were tested for protein expression in E. coli Rosetta strain. SDS‐PAGE analysis indicated the production of a recombinant protein with an expected molecular weight of 61 KDa. Analysis of trout serum samples from seven previously infected farms and two VHS free farms showed that the designed ELISA method was effective in diagnosing the infected fish. The results revealed that the developed serological assay using designed ELISA based on recombinant protein (N) has the potential to be used in monitoring studies and to determine the prevalence of VHS in rainbow trout farms. The present data allow evaluating the levels of nonneutralizing antibodies without crude virus preparations. [ABSTRACT FROM AUTHOR]

Saprolegniosis is one of the most frequent diseases in the ornamental fish industry that may cause by Achlya spp. There is no report of fungal infection caused by Achlya spp. in Oscar (Astronotus ocellatus) in Iran. An Oscar fish was referred to the Veterinary Hospital, Shahid Chamran University of Ahvaz, Ahvaz, Iran with saprolegniosis symptoms including loss of appetite and yellow to gray cottony mass on the skin of flank and caudal peduncle. The infected area of the fish body was investigated by wet smear. After observing broad aseptate hyphae (approximate width 10-15 µm), the infected skin was inoculated on Sabouraud dextrose agar and incubated at 30 °C for seven days. The large fungi colony was appeared on the agar and the isolated fungi were detected as Achlya spp. after examination by wet and stained dry smears according to the morphology of hypha, spores, and zoosporangium. It is the first report of cutaneous saprolegniosis in Oscar caused by Achlya spp. in Iran. [ABSTRACT FROM AUTHOR]

Background: Anisakid nematodes are common parasites of fish, mammals, fisheating birds, and reptiles with a worldwide distribution, causing diseases in human, fish and important economic losses. Methods: A preliminary epidemiological study was carried out on Anisakid nematodes larvae in some commercially important fish species to evaluate the anisakid nematode larvae from greater lizardfish, (Saurida tumbil), Japanese thread fin bream (Nemipterus japonicus), crocodile longtom (Tylosurus crocodilus crocodiles) and longfin trevally (Carangoides armatus) from the Persian Gulf of Iran. Result: The collected larvae were identified mainly as the third larval stage (L3) of Hysterothylacium larval type A, B and C, Anisakis sp., Raphidascaris sp., Pseudoterranova sp. and Philometra sp. (Nematoda: Philometridae). The prevalence of Anisakid larvae infection of examined fishes was 97.2% in N. japonicus, 90.3% in S. tumbil, 20.5% in crocodile longtom and 5.5% in longfin trevally. Anisakis type III for the first time was different from Anisakis type I and Anisakis type II. Discussion: Zoonotic anisakids by high prevalence in edible fish could be a health hazard for people. So health practices should be considered in these areas. [ABSTRACT FROM AUTHOR]

Infectious pancreatic necrosis virus (IPNV) is the causal agent of a highly contagious disease that affects many species of fish and shellfish. This virus causes economically significant diseases of farmed rainbow trout, Oncorhynchus mykiss (Walbaum), in Iran, which is often associated with the transmission of pathogens from European resources. In this study, moribund rainbow trout fry samples were collected during an outbreak of IPNV in three different fish farms in north and west provinces of Iran in 2012; and we investigated the full genome sequence of Iranian IPNV and compared it with previously identified IPNV sequences. The sequences of different structural and nonstructural-protein genes were compared to those of other aquatic birnaviruses sequenced to date. Our results show that the Iranian isolate falls within genogroup 5, serotype A2 strain SP, having 99 % identity with the strain 1146 from Spain. These results suggest that the Iranian isolate may have originated from Europe. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate pharmacokinetic profiles of florfenicol after a single dose of intravenous (5.00 mg kg -1 body weight) and oral (40.00 mg kg -1 body weight) administrations in common carp ( Cyprinus carpio ). The residue depletion of florfenicol was also investigated after oral administration (10.00 mg kg -1 body weight) and bath treatment (5.00 mg L -1 ) for 10 consecutive days. Pharmacokinetics of florfenicol in plasma after a single dose administration, at 10 time points (0.50, 1, 2, 4, 8, 12, 24, 72, 120 and 168 hr) and florfenicol concentrations in tissues (plasma, liver and muscle) at three time points (1, 7 and 14 days) after 10 consecutive days, were analyzed by high performance liquid chromatography. The peak concentration of florfenicol was 137.02 ng mL -1 and the time to reach peak concentration in plasma was two hr. The elimination half-lives, the volume of distribution at steady state and total body clearance were estimated as 21.40 hr, 0.30 and 0.03 L hr -1 , respectively. After drug administration for 10 days, it's concentration in plasma and muscle in oral treatment was significantly more than bath treatment in all days. Drug concentrations in the liver after bath treatment were significantly higher for a shorter period than the concentration in the oral treatment, indicating that higher levels of florfenicol for a longer period can be achieved in the tissues after oral drug administration. According to pharmacokinetic results, florfenicol may be a suitable candidate for the treatment of common bacterial infections in common carp farming.

In this study the effects of water salinity on serum total protein and its components in grass carp were investigated. The aim of this study was to determine the effect of salinity tolerance of fish on total serum protein level and its components as an indicator of liver and kidney activity. One hundred and twenty grass carp were divided into four groups, randomly. The first three groups were reared in concentration of 4, 8 and 12 g L(-1) of salt solution, respectively, and the fourth group was reared in freshwater and served as control. After 3 weeks, blood samples were collected and after harvesting the blood serum, serum total protein and protein components were measured with Biuret and electrophoresis methods, respectively. Results showed that mean value of serum total protein in the control and three salinities groups were 2.75, 3.28, 2.90 and 3.13 g dL(-1), respectively. Five fractions of serum protein were electrophoretically observed as: albumin (Alb), alpha-1 globulin (α1-glu), alpha-2 globulin (α2-glu), beta globulin (β-glu) and gamma globulin (γ-glu). There were not any significant differences between the average mean of serum total protein of experimental and control groups (p > 0.05). However, Alb, α1-glu and β-glu levels in the experimental groups were significantly higher than in the control group (p < 0.05). The average of α2-glu and γ-glu revealed no significant difference between the experimental groups (p > 0.05). In conclusion, our results showed that increasing water salinity could have a significant effect on Alb, α1-glu and β-glu levels but not on total serum protein in grass carp.

In this study the effects of salinity on the electrocardiogram and some of blood serum minerals in grass carp were investigated. For this purpose, grass carp were exposed to concentrations of 4, 8 and 12 g L(-1) salinities and electrocardiogram of all fish was recorded. Blood samples were also collected from all fish and serum minerals were measured. Our results indicated that mineral level in the studied groups was significantly different. The average of heart rate per minute in control group and 4, 8 and 12 g L(-1) were 10.15, 10.06, 12.17 and 7.79 beat per min, respectively. In 8 g L(-1) group only the average of QT and ST segment decreased significantly in comparison with the control group (p < 0.05). In 12 g L(-1) group the average of heart rate per minute decreased significantly in comparison with 8 g L(-1) group (p < 0.05) and no difference in the average of heart rate per minute was observed in all groups. The average of RR, PT and ST segment in the 12 g L(-1) group were significantly more than the other groups (p < 0.05). The results showed that water salinity level increased to concentrations above 8 g L(-1) can have significant effect on the electrocardiogram and mineral level of blood serum in grass carp. These changes are probably can be considered as one of the causes of impairment of health and death of this fish species in the salinities more than 8 g L(-1) due to ion imbalance and cardiovascular disorders.