A preliminary study on ulcerative skin lesions in sea - caged grouper (Epinephelus coioides)

A low incidence mortality (15%) was observed in sea-caged grouper (Epinephlus coioides) in the Persian Gulf (Mahshahr, Khouzestan) following introducing the fishes to the cages in December 1993. Clinically, the affected fish showed multiple-round Skin lesions, penetrating to the underlying muscles, ulceration of jaws, fin and tail rot and opacity of eyes. Results of bacteriological study indicated that the organism isolated from the lesion belonged to the genera Pasteurella, Aeromonas and Streptococcus. Treatment of infected fishes with Halamid (N.sodium-N-chloroparatoluene sulphonamide) at 8 mg/lit for one hour of tank water as bath, together with topical cleaning of lesions by Betadin solution resulted in improving of the condition. Mechanical damage and improper water exchange suspected to be the predisposing factors for occurrence of the condition

Determination of isolated Aeromonas hydrophila antibiotic resistance profile from farmed common carp (Cyprinus carpio) in Khuzestan Province

Aeromonas are an example of emerging bacterial pathogens. Even though they have been recognized as primary fish and human pathogens. Aeromonas hydrophila are opportunistic pathogens that are at the same time infectious and enterotoxigenic and multiple antibiotic resistances (MAR) among Aeromonas hydrophila strains has been reported from many parts of the world. Under these circumstances, it will be worthwhile to find out the prevalence of antibiotic resistance of the Aeromonas hydrophila strains. The one hundred pieces of fish samples were collected from 4 common carp training pool in Khuzestan province. The part of intestine was collected in sterile plate and was homogenized. The samples were cultured in blood agar and incubated in 37centigrade degree temperature. Three to five Aeomonas hydrophila suspected colony, were selected from any plate and purified in blood agar. After initial evaluation of each colony by catalase, oxidase and gram staining, suspected strains DNA was extracted by boiling. Aeromonas hydrophila strains were confirmed by PCR assay and using of genus and species specific primers. Finally, multiple antibiotic resistance (MAR) of confirmed Aeromonas hydrophila isolates was evaluated by Kirby-Bauer disc diffusion method. Twenty Aeromonas hydrophila strains of Aeromonas suspected colonies were confirmed by PCR assay and the most of isolates had a multiple resistance. The least and the most resistance was observed regarding to cefotaxim and ciprofloxacin (<25%), vancomycin and clindamycin (90%), respectively. Compared with results of other studies, antibiotic resistance pattern of these bacterial strains is variable in different geographical areas; therefore resistant pattern of each group of bacteria must be determined in each area

Short communication: Occurrence of squamous cell carcinoma in a platy fish (Xiphophorus maculatus): A case report

According to prior reports, similar to mammals, fish are frequently affected by neoplastic proliferations. These neoplasms are classified according to the mammalian tumor classification System (Rahmati-Holasoo et al., 2010). Squamous cell carcinoma (SCC) is one of the most common forms of skin neoplasm in which cells in the epithelial layer of the skin develop into a malignant tumor. SCC has been reported in both fresh and marine water fish (Mawdesley-Thomas and Bucke, 1967). Squamous cell carcinoma has been reported in a number of species, for example, Atlantic salmon, Salmo salar L. (Roberts, 1972); oscar, Astronotus ocellatus (Rahmati-Holasoo et al., 2010); rudd, Scardinius erythrophthalmus (Hanjavanit and Mulcahy, 2004); gudgeon, Gobio gobio (Mawdesley-Thomas and Bucke, 1967); gulf menhaden, Brevoortia patronus Goode (Fournie et al., 1987); and the hybrid sunfish (Fitzgerald et al., 1991). In spite of the fact that reports have been previously published on SCC in various species of fish, to the best of the author’s knowledge, this is the first report on SCC in platy fish (Xiphophorus maculatus) in the world

The effects of brown algae Sargassum angustifolium extract on growth performance, survival and Vibriosis resistance in shrimp Litopenaeus vannamei

In this study, the effect of ethanolic extracts of Sargassum angustifolium on growth and survival of shrimp Litopenaeus vannamei juvenile was investigated under challenge with shrimp pathogen bacteria Vibrio harveyi. Powder form of the extract was bioencapsulated in Artemia and fed to L. vannamei juvenile reared as 5 groups inclouding C- (unenriched Artemia, without bacteria), C+ (unenriched Artemia, with bacteria), T1 (enriched Artemia with 200 mg l-1 SA extract, with bacteria), T2 (enriched Artemia with 400 mg l-1 SA extract, with bacteria), T3 (enriched Artemia with 600 mg l-1 SA extract, with bacteria). One week after culture all groups except C- were inoculated with V. harveyi at the rate of 1.5 × 108 CFU ml-1 for 15 minutes then after every water exchange 10 ml of V. harveyi at the rate of 1.5 × 107 CFU ml-1 was added to aquaria. Shrimps at group C- showed maximum survival (86.6%), specific growth rate (SGR, 11.33%) and less bacterial load (0.5 ± 0.03× 102 CFU g-1 tissue). While (C2) exhibited lowest survival (33.3%), SGR (9.90%) and more bacterial load (3.4 ± 0.05× 105 CFU g-1 tissue) and the difference was significant (p<0.05). In treatment groups survival and SGR were significantly (p< 0.05) more than C+ and less than C-, also bacterial load were less than C+ and more than C-. Among treatment groups T2 that fed with enriched artemia with 400 mg l-1 SA extract gave better results than the other treatments

Determine of appropriate concentration of propofol anesthetic drug in Benni (Barbus sharpeyi)

The propofol anesthetic drug was used on 60 farmed Benny fish (Barbus sharpeyi) with mean (±SD) weight and length 99±30g and 208±19.2cm, respectively. The fish were divided into 6 treatments of 10 fish. The treatment 1(control group) was not exposed to any type of anesthesia material. Five treatments were exposed to propofol anesthetic drug with 2, 4, 6, 8 and 10mg/l concentration by immersion method. The mean time of initial anesthesia, mean time of total anesthesia, mean recovery time from anesthesia and survival rate were investigated in treatments. Results showed that increasing of propofol dose had reduced with time of initial anesthesia. Treatment 2 and 3 with 2 and 4mg/l of propofol were significantly different with treatment 5 and 6 with 8 and 10mg/l of propofol material. The mean time of total anesthesia in treatments 5 and 6 with 8 and 10mg/l of propofol material were significantly different with treatments 2, 3 and 4 with 2, 4 and 6mg/l of propofol material, respectively. The mean (±SD) recovery time from anesthesia in Benny fish in treatment 5(8mg/l) was highest amount (428±33S) compared to other treatments. Survival rate in all treatment except treatment 6 (70%) was 100%. Overall, it appears that propofol material was as an anesthetic drug that present experiment showed safety. In 4-6mg/l concentration had the best performance in total anesthesia and recovery to initial condition

The interactive effect of water-borne cadmium and environmental hypoxia on common carp (Cyprinus carpio) metabolism

Regarding to the tight association between aquatic hypoxia and heavy metal contaminations in one hand and the role of both parameters on fish respiration, metabolism of carp could be assessed under single and mutual exposures to hypoxia and cadmium. Following measuring LC50-96h of cadmium (43.679 mg/l) for this species, 80 common carp were exposed to 10 different treatments, including control, acute (43.68 mg/l), sub-lethal (21.84 mg/l) and chronic (4.37 mg/l) cadmium as well as hypoxia for immediately (20% of saturation), 24h (40%) and 7 days (60%), and joint exposure of each similar treatment. By using of respirometer technique, we measured oxygen consumption rate in different time spans to calculate each individual standard metabolic rate (SMR), maximum metabolic rate (MMR), aerobic scope (AS), factorial aerobic scope (FAS) and critical oxygen tension (PCrit). Obtained data show that acute and sub-lethal cadmium treatments led to significant (P<0.05) increases in all metabolic indices in comparison with control group whilst the MMR and AS have been reduced (P<0.05) following hypoxia treatments. Combined treatments of hypoxia and cadmium led to reduce SMR and PCrit in all treatments and MMR, AS and FAS only in acute and sub-lethal treatments. In overall, hypoxia can act as a limiting stressor in carp while cadmium can account as a loading stressor

Detection and distribution of virulence genes in Aeromonas hydrophila isolates causing infection in cultured carps

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

Phylogenetic relationships of Iranian Infectious Pancreatic Necrosis Virus (IPNV) based on deduced amino acid sequences of genome segment A and B cDNA

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 important diseases of farmed rainbow trout, Oncorhynchus mykiss, in Iran which is often associated with the transmission of pathogens from European resources. In this study, moribund rainbow trout fry were collected during an outbreak of IPNV in three different fish farms in one northern province (Mazandaran), and two west provinces (Chaharmahal and Bakhtiari, and Kohgiluyeh and Boyer Ahmad) of Iran. We investigated full genome sequence of Iranian IPNV and compared it with previously identified IPNV sequences. The sequences of different structural and non-structural protein genes were compared with other aquatic birnaviruses sequenced to date. Our results showed that the Iranian isolate fall 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

Isolation and expression of recombinant viral protein (VP2) from Iranian isolates of Infectious Pancreatic Necrosis Virus (IPNV) in Escherichia coli

Infectious Pancreatic Necrosis Virus (IPNV) is a member of the family Birnaviridae that has been linked to high mortalities in salmonids. Bacterial based systems as live vectors for the delivery of heterologous antigens offer a number of advantages as vaccination strategies. VP2 is a structural viral protein of IPNV with immunogenicity effects. In this study IPNV was isolated from diseased fry of rainbow trout Oncorhynchus mykiss (Walbaum) using CHSE-214. Then an expression vector was constructed for expression of viral protein VP2. The designed vector was constructed based upon pET-26b (+) with T7 promoter. A fragment containing the full length of the VP2 gene of Iranian Sp strain was amplified by PCR using genomic RNA of IPNV as template and cloned inpET-26b(+) plasmid. Recombinant structural viral protein VP2 was expressed as a soluble, N-terminal PelB fusion protein and secreted into the periplasmic space of Escherichia coli BL21(DE3) and Rosetta (DE3). The glucose, Isopropyl-β-D-thiogalactopyranoside (IPTG) was used as a chemical inducer for rVP2 production in 37º C. The rVP2 was extracted from the periplasm by osmotic shock treatment. The presence of gene in bacterial system of E. coli was confirmed by gel electrophoresis technique. The constructed vector could efficiently express the rVP2 into the periplasmic space of E. coli. The successful cloning and expression of the structural viral protein gene into E. coli can be used for developing a useful and safe vaccine to control IPNV infection in Iranian fish industry