Aims: To determine abundance of potential pathogenic microorganisms in pangasius and tilapia farms in five major fish-producing areas in Bangladesh by PCR approaches. Methodology and results: Important microbial water quality indicators were studied in water of 38 fish farms producing pangasius (Pangasianodon hypophthalmus) and tilapia (Oreochromis niloticus) in five major fish-producing areas of Bangladesh. The parameters included physicochemical data and PCR detection of total coliforms and E. coli, species of potentially pathogenic Vibrio, and cyanobacterial genes encoding the toxins microcystin and saxitoxin. Quantitative PCR showed that coliform bacteria occurred in all fish farms with densities from one to 2.2 × 105 per mL, while E. coli ranged from none to 5.0 × 104 per mL. Numbers of total coliforms and E. coli were higher in pangasius farms than in tilapia farms, and when high abundances occurred, coliform bacteria and E. coli bacteria co-varied. Detection of Vibrio-specific genes indicated presence of Vibrio species in 76% of the farms and included V. vulnificus and V. cholerae. The human pathogen type of V. cholerae (carrying the ctxA gene) and the fish pathogen V. parahaemolyticus were not detected. The microcystin-encoding mcyE gene ranged from undetectable to 2.6 × 105 copies per mL and tended to be highest in pangasius farms. The saxitoxin-encoding gene sxtA was not found in any of the farms. Conclusion, significance and impact of study Based on the high abundance of especially coliform bacteria and E. coli, we recommend more efficient water quality monitoring systems to improve detection and control of fecal coliforms and to reduce presence of microcystin-producing cyanobacteria in aquaculture farms in Bangladesh
Water Quality ; Tilapia ; Catfishes

The study aimed to assess the single and joint lethal toxicity, type of interaction and the extent to which simple mathematical model of concentration addition (CA), independent action (IA) and generalized concentration addition (GCA) could predict the joint toxicity of copper hydroxide and glyphosate mixture in Clarias gariepinus. Static bioassay were setup to determine the individual and combined (based on ratio 1:2) lethal concentrations (LCx) of the pesticides. Data from the static bioassays were then fitted into the synergistic ratio (SR), concentration-addition (toxicity unit; TU) and isobologram model to determine the type of interaction between the different classes of pesticides, while the CA, IA and GCA models were used to predicted the observed mixture effects. The estimated 24 h, 48 h, 72 h and 96 h LC50 for copper hydroxide were 198.66 mg/L, 167.51 mg/L, 138.64 mg/L, and 104.82 mg/L; glyphosate were 162.92 mg/L, 103.88 mg/L, 61.95 mg/L, and 52.6l mg/L; while the mixtures were 63.18 mg/L, 59.06 mg/L, 56.42 mg/L, and 50.67 mg/L, respectively. Glyphosate was 2 times more toxic than copper hydroxide to C. gariepinus when acting singly. The SR and RTU was <1 indicate that the interaction between the pesticides was synergistic. Synergism was also corroborated by the isobologram model. The interaction of the mixture of copper hydroxide and glyphosate followed the IA model while the CA and GCA model underestimated the observed mixture effects. The study showed that copper hydroxide was practically non-toxic, while glyphosate and the mixture were slightly toxic to C. gariepinus
Biological Assay ; Catfishes ; Copper ; Joints ; Models, Theoretical ; Pesticides

The study aimed to assess the single and joint lethal toxicity, type of interaction and the extent to which simple mathematical model of concentration addition (CA), independent action (IA) and generalized concentration addition (GCA) could predict the joint toxicity of copper hydroxide and glyphosate mixture in Clarias gariepinus. Static bioassay were setup to determine the individual and combined (based on ratio 1:2) lethal concentrations (LCx) of the pesticides. Data from the static bioassays were then fitted into the synergistic ratio (SR), concentration-addition (toxicity unit; TU) and isobologram model to determine the type of interaction between the different classes of pesticides, while the CA, IA and GCA models were used to predicted the observed mixture effects. The estimated 24 h, 48 h, 72 h and 96 h LC50 for copper hydroxide were 198.66 mg/L, 167.51 mg/L, 138.64 mg/L, and 104.82 mg/L; glyphosate were 162.92 mg/L, 103.88 mg/L, 61.95 mg/L, and 52.6l mg/L; while the mixtures were 63.18 mg/L, 59.06 mg/L, 56.42 mg/L, and 50.67 mg/L, respectively. Glyphosate was 2 times more toxic than copper hydroxide to C. gariepinus when acting singly. The SR and RTU was <1 indicate that the interaction between the pesticides was synergistic. Synergism was also corroborated by the isobologram model. The interaction of the mixture of copper hydroxide and glyphosate followed the IA model while the CA and GCA model underestimated the observed mixture effects. The study showed that copper hydroxide was practically non-toxic, while glyphosate and the mixture were slightly toxic to C. gariepinus
Biological Assay ; Catfishes ; Copper ; Joints ; Models, Theoretical ; Pesticides

Edwardsiella (E.) ictaluri is a major bacterial pathogen that affects commercially farmed striped catfish (Pangasius hypothalamus) in Vietnam. In a previous study, 19 strains of E. ictaluri collected from striped catfish were biochemically identified with an API-20E system. Here, the same 19 strains were used to assess the ability of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS; applied using a MALDI Biotyper) to conduct rapid, easy and accurate identification of E. ictaluri. MALDI-TOF MS could directly detect the specific peptide patterns of cultured E. ictaluri colonies with high (> 2.0, indicating species-level identification) scores. MALDI Biotyper 3.0 software revealed that all of the strains examined in this study possessed highly similar peptide peak patterns. In addition, electrophoresis (SDS-PAGE) and subsequent immuno-blotting using a specific chicken antibody (IgY) against E. ictaluri revealed that the isolates had highly similar protein profiles and antigenic banding profiles. The results of this study suggest that E. ictaluri isolated from striped catfish in Vietnam have homologous protein compositions. This is important, because it indicates that MALDI-TOF MS analysis could potentially outperform the conventional methods of identifying E. ictaluri.
Agriculture ; Asian Continental Ancestry Group* ; Catfishes* ; Chickens ; Edwardsiella ictaluri* ; Edwardsiella* ; Electrophoresis ; Humans ; Mass Spectrometry* ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Vietnam

The advantages of monounsaturated fatty acids (MUFAs) on insulin resistance and type 2 diabetes mellitus (T2DM) have been well established. However, the molecular mechanisms of the anti-diabetic action of MUFAs remain unclear. This study examined the anti-hyperglycemic effect and explored the molecular mechanisms involved in the actions of fish oil- rich in MUFAs that had been acquired from hybrid catfish (Pangasius larnaudii×Pangasianodon hypophthalmus) among experimental type 2 diabetic rats. Diabetic rats that were fed with fish oil (500 and 1,000 mg/kg BW) for 12 weeks significantly reduced the fasting plasma glucose levels without increasing the plasma insulin levels. The diminishing levels of plasma lipids and the muscle triglyceride accumulation as well as the plasma leptin levels were identified in T2DM rats, which had been administrated with fish oil. Notably, the plasma adiponectin levels increased among these rats. The fish oil supplementation also improved glucose tolerance, insulin sensitivity and pancreatic histological changes. Moreover, the supplementation of fish oil improved insulin signaling (p-Akt(Ser473) and p-PKC-ζ/λ(Thr410/403)), p-AMPK(Thr172) and membrane GLUT4 protein expressions, whereas the protein expressions of pro-inflammatory cytokines (TNF-α and nuclear NF-κB) as well as p-PKC-θ(Thr538) were down regulated in the skeletal muscle. These data indicate that the effects of fish oil-rich in MUFAs in these T2DM rats were partly due to the attenuation of insulin resistance and an improvement in the adipokine imbalance. The mechanisms of the anti-hyperglycemic effect are involved in the improvement of insulin signaling, AMPK activation, GLUT4 translocation and suppression of pro-inflammatory cytokine protein expressions.
Adipokines ; Adiponectin ; AMP-Activated Protein Kinases ; Animals ; Blood Glucose ; Catfishes ; Cytokines ; Diabetes Mellitus, Type 2 ; Fasting ; Fatty Acids, Monounsaturated ; Fish Oils ; Glucose ; Glucose Transporter Type 4 ; Insulin ; Insulin Resistance ; Leptin ; Membranes ; Muscle, Skeletal ; Plasma ; Rats* ; Triglycerides

OBJECTIVES: This study aimed to estimate the effects of 4-nonylphenol (NP), a ubiquitously present surfactant in aquatic environments, on the anti-oxidant systems of the liver in the Far Eastern catfish Silurus asotus. METHODS: Changes in biochemical parameters involved in glutathione (GSH)-related and other anti-oxidant systems were analyzed following 4 weeks of 4-NP administration (0.1 and 1.0 mg/kg diet) via a formulated diet to catfish. RESULTS: 4-NP exposure induced an elevation in hepatic lipid peroxide levels and an accompanying decrease in reduced state GSH after 2 weeks, suggesting pro-oxidant effects of the chemical in catfish. This oxidative stress was associated with an inhibition of the GSH-utilizing enzyme glutathione peroxidase at the same time point. This inhibition was restored after 4 weeks. The activities of other anti-oxidant enzymes, i.e., glutathione reductase, superoxide dismutase and catalase were increased after 4 weeks. These enzyme increases occurred more strongly at the higher 4-NP concentration (1.0 mg/kg diet). CONCLUSIONS: 4-NP given to catfish at 0.1 to 1.0 mg/kg diet, concentrations relevant to environmental levels, depletes the endogenous anti-oxidant molecule GSH and temporarily inhibits GSH-related anti-oxidant enzymes. Such declines in anti-oxidant capacity and elevated oxidative stress seem to be compensated eventually by subsequent activation of various anti-oxidant enzyme systems.
Catalase ; Catfishes* ; Detergents* ; Diet ; Glutathione ; Glutathione Peroxidase ; Glutathione Reductase ; Liver ; Oxidative Stress ; Superoxide Dismutase

OBJECTIVES: This study aimed to estimate the effects of 4-nonylphenol (NP), a ubiquitously present surfactant in aquatic environments, on the anti-oxidant systems of the liver in the Far Eastern catfish Silurus asotus. METHODS: Changes in biochemical parameters involved in glutathione (GSH)-related and other anti-oxidant systems were analyzed following 4 weeks of 4-NP administration (0.1 and 1.0 mg/kg diet) via a formulated diet to catfish. RESULTS: 4-NP exposure induced an elevation in hepatic lipid peroxide levels and an accompanying decrease in reduced state GSH after 2 weeks, suggesting pro-oxidant effects of the chemical in catfish. This oxidative stress was associated with an inhibition of the GSH-utilizing enzyme glutathione peroxidase at the same time point. This inhibition was restored after 4 weeks. The activities of other anti-oxidant enzymes, i.e., glutathione reductase, superoxide dismutase and catalase were increased after 4 weeks. These enzyme increases occurred more strongly at the higher 4-NP concentration (1.0 mg/kg diet). CONCLUSIONS: 4-NP given to catfish at 0.1 to 1.0 mg/kg diet, concentrations relevant to environmental levels, depletes the endogenous anti-oxidant molecule GSH and temporarily inhibits GSH-related anti-oxidant enzymes. Such declines in anti-oxidant capacity and elevated oxidative stress seem to be compensated eventually by subsequent activation of various anti-oxidant enzyme systems.
Catalase ; Catfishes* ; Detergents* ; Diet ; Glutathione ; Glutathione Peroxidase ; Glutathione Reductase ; Liver ; Oxidative Stress ; Superoxide Dismutase

OBJECTIVE: The main objective of this study is to provide an assessment of the risks to human health associated with the exposure to heavy metal bioaccumulation in Manila Catfish (Arius dispar) from Laguna Lake.

METHODS: Manila Catfish (common name Kanduli) samples were collected in eight sampling stations in three major areas of the lake during the dry and wet seasons. Dry season samples were collected from May to June 2010 and wet season samples from September to November 2010. Coordinates of sampling locations were recorded using Global Positioning System to facilitate re-sampling activities and ensured that subsequent samples for the wet season were collected in the area as that of the wet season samples. Heavy metals analyses for cadmium, lead, arsenic, and chromium were conducted using Atomic Absorption Spectrophotometer and Mercury Analyzer for mercury. Estimates of health risks associated with Kanduli consumption were estimated based on non-carcinogenic health effects of heavy metals.

RESULTS: Non-carcinogenic Health Quotient (NHQ) values of the five heavy metals showed that lead is the most significant pollutant of concern in terms of adverse health effects from risks associated with Kanduli consumption from the lake.

CONCLUSION: From the point of view of disease prevention and control, long term consumption of Kanduli from Laguna Lake is expected to increase health risk due to lead contamination.

.humans ; Arsenic ; Mercury ; Cadmium ; Lakes ; Chromium ; Catfishes ; Seasons ; Geographic Information Systems ; Metals, Heavy ; Spectrophotometry, Atomic

By using cell culture and virus infection methods, a new reovirus had been isolated from channel catfish (Ictalurus punctatus) suffered with severe hemorrhage and had been identified as channel catfish reovirus (CCRV) after artificial infection in fish, electron microscopy observation, physical-chemical tests, genomic SDS-PAGE analysis and sequencing. In artificial infection test, the typical symptoms of channel catfish hemorrhage as naturally occurred could be reproduced. The isolated virus could cause typical cytopathic effect in CCO and CCK cell lines. Electron microscopy observation of ultra-thin section samples of CCRV infected CCO and CCK cells revealed that the virus replicated in cytoplasm, arrayed in crystalline, and had a non-enveloped double capsid with a diameter of 60-70 nm. Frozen-thawed, 56 degrees C 1 h, chloroform and ether had no significant effects on CCRV titer, 65 degrees C 1 h could significantly inactivated the viral infectivity. The CCRV genome SDS-PAGE analysis and nuclease sensitivity test showed that the virus genome was the same as that of viruses in Aquareovirudae and consisted of 11 segments of dsRNA assigned into three classes L1, L2, L3; M1, M2, M3 and S1, S2, S3, S4, S5 with a range of size from 0.9 to 4.4 kb. The Cloning and sequencing of the CCRV S4 segment indicated the nucleic acid number of CCRV S4 was 909 bp in length, which was exactly the same as that of GCRV S4 (AF403396) and GSRV S4 (AF403407) segments. The BLAST of CCRV S4 sequence in NCBI GenBank showed that it had a 99% and 90% similarity in sequence to the GCRV S4 and GSRV S4 segments, respectively.
Animals ; Base Sequence ; Catfishes ; Cell Line ; Fish Diseases ; virology ; Molecular Sequence Data ; Reoviridae ; classification ; genetics ; isolation & purification ; ultrastructure ; Reoviridae Infections ; veterinary ; virology

Adolescent ; Adult ; Aged ; Animals ; Catfishes ; Ciguatera Poisoning ; Eggs ; adverse effects ; Female ; Humans ; Male ; Middle Aged ; Young Adult