RESUMEN
Edwardsiellosis is a serious bacterial disease affecting Nile tilapia (Oreochromis niloticus), causing septicemia and mortalities. Edwardsiella tarda and Edwardsiella anguillarum were isolated from Nile tilapia summer mortality events in Egypt. Diseased fish showed hemorrhagic septicemia, skin erosions, and eye opacity. A total of 24 Edwardsiella spp. isolates were retrieved from the investigated fish specimens. Phenotypic and biochemical characteristics grouped isolates into typical Ed. tarda (n = 14 strains) and atypical Ed. tarda (n = 10 strains). The BLAST analysis of sodB gene sequencing confirmed the conventional identification of typical Ed. tarda strains (n = 14) and reidentified all the atypical strains (n = 10) as Ed. anguillarum. Isolates showed a combination of virulence factors, including biofilm formation (66.6%), hemolysis (100%), chondroitinase (50%), and proteolytic activity (20.8%). The major part of isolates showed high resistance to ampicillin, amoxicillin, gentamycin antibiotics and harbored tetA, blaCTX-M, and aadA1 resistance genes. Pathogenicity testing of isolates in O. niloticus confirmed their virulence. Challenged fish exhibited septicemic signs similar to naturally diseased fish. Infections in naturally infected tilapia triggered acute and chronic histopathological alterations. Degenerative and necrotic changes were noticed in hematopoietic organs. Granulomas were noticed in between the hepatic parenchyma. The data extracted from the study confirm that accurate identification of the causative agents of edwardsiellosis should be reliant on genetic-based approaches. Analysis of the bacterium virulence properties offers insights into establishing novel therapeutics for edwardsiellosis control. The findings refer to the need for antimicrobial sensitivity testing to minimize antimicrobial resistance and increase therapy efficacy.
Asunto(s)
Cíclidos , Enfermedades de los Peces , Tilapia , Animales , Antibacterianos/farmacología , Cíclidos/microbiología , Edwardsiella tarda , Enfermedades de los Peces/microbiología , VirulenciaRESUMEN
This study aimed to prepare and characterize enzymatic modified chitosan nanoparticles (CSNPs) with gallic acid (GA) or octyl gallate (OG) to optimize its potential in human application and to evaluate their protective role against ochrtoxin A (OTA) toxicity in catfish. The modified CSNPs have average size around 90 nm with positive charge and high scavenging activity especially GA-CSNPs. In the in vivo study, catfish were divided into 8 groups and treated for 3 weeks as follow: the control group, OTA-treated group (1 mg/kg b.w.), the groups treated with CSNPs, GA-CSNPs or OG-CSNPs (280 mg/kg b.w.) anole or in combination with OTA. Blood, liver and kidney samples were collected for different analyses. OTA induced a significant biochemical disturbances accompanied with oxidative stress in liver and kidney, histological changes and increase DNA fragmentation in the kidney. Co-treatment with OTA plus the different CSNPs resulted in a significant improvement in all tested parameters and histological picture of the kidney. This improvement was more pronounced in the group treated with GA-CSNPs. It could be concluded that grafting of GA or its ester improved the properties of CSNPs. Moreover, GA-CSNPs showed strong scavenging properties than OG-CSNPs due to the blocking of carboxyl groups responsible of the scavenging activity in OG.
Asunto(s)
Antioxidantes/farmacología , Bagres/fisiología , Quitosano/química , Ácido Gálico/farmacología , Nanopartículas/química , Ocratoxinas/toxicidad , Animales , Antioxidantes/química , Quitosano/farmacología , Ácido Gálico/análogos & derivados , Ácido Gálico/química , Técnicas In Vitro , Riñón/efectos de los fármacos , Hígado/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Tamaño de la PartículaRESUMEN
The effects of cyanide, used in illegal fishing, on one of the most economically important Nile fishes, the African catfish (Clarias gariepinus), were studied. Cyanide impacts were evaluated in terms of biochemical, molecular and histopathological characteristics. After exposure to sublethal concentration (0.05mg/l) of potassium cyanide (KCN) for two and four weeks, GOT (glutamate oxaloacetate transaminase) was significantly increased in both male and female, while GPT (glutamate pyruvate transaminase), total plasma protein, phosphoprotein phosphorus (Vgt) in serum, vitellogenin gene expression (Vtg mRNA) and estrogen receptors (ER mRNA) were significantly decreased in female. On the other hand, male C. gariepinus showed a significant increase in Vtg and Vtg mRNA. Liver, testis and ovaries showed distinct histopathological changes. It was concluded that, cyanide caused damaging effects to fish and can cause serious disturbance in the natural reproduction and a drastic decline in fish population. Therefore, it is recommended that, the use of cyanide compounds must be prohibited to conserve the fisheries resources.
Asunto(s)
Bagres/fisiología , Cianuros/toxicidad , Regulación de la Expresión Génica/efectos de los fármacos , Gónadas/efectos de los fármacos , Hígado/efectos de los fármacos , Vitelogeninas/metabolismo , Contaminantes Químicos del Agua/toxicidad , Animales , Conducta Animal/efectos de los fármacos , Bagres/metabolismo , Cianuros/metabolismo , Activación Enzimática/efectos de los fármacos , Enzimas/metabolismo , Femenino , Explotaciones Pesqueras , Agua Dulce , Masculino , Contaminantes Químicos del Agua/metabolismoRESUMEN
The current study was conducted to evaluate the ability of Egyptian bentonite (EB) and montmorillonite (EM) for the prevention of genotoxicity, histochemical and biochemical changes induced by aflatoxin B(1) (AFB(1)) using the micronucleus (MN) assay, chromosomal aberrations and DNA fragmentation analysis in Tilapia fish. Six groups of fish were treated for 3 weeks and included the control group, AFB(1)-treated group and the groups treated with EB or EM alone or in combination with AFB(1). At the end of experiment period, blood samples were collected for MN, testosterone and biochemical assays. Chromosomal aberrations were determined in kidney tissues, DNA fragmentation test was determined in liver and testis, whereas histochemical study was carried out on liver, testis and gills. The results indicated that a significant decrease in total protein, albumin, globulin, testosterone and DNA content in liver, gills and testis accompanied with a significant increase in number of micronucleated erythrocytes (MnRBCs), total chromosomal aberrations in kidney and DNA fragmentation in testis and liver of fish received AFB(1) alone. Fish treated with EB or EM alone were comparable to the control regarding the biochemical parameters except testosterone in EB-treated group which was significantly decreased. Both clays did not induce any significant differences in number of MnRBCs, chromosomal aberrations in the kidney, DNA fragmentation in testis, but not in liver of EB-treated group. The combined treatment with AFB(1) and EB or EM succeeded to improve all the tested parameters towards the control values although it did not normalize them. Moreover, the improvement was pronounced in the group received EM plus AFB(1). It could be concluded that EB and EM have the ability to tightly bind AFB(1) in the gastrointestinal tract of fish resulting in decreasing its bioavailability. Moreover, the two tested clays were safe and can be used as potential aflatoxin binders in animal feed.
Asunto(s)
Anomalías Inducidas por Medicamentos/prevención & control , Antídotos/uso terapéutico , Cíclidos/metabolismo , Suplementos Dietéticos , Eritrocitos/efectos de los fármacos , Riñón/efectos de los fármacos , Hígado/efectos de los fármacos , Aflatoxina B1/toxicidad , Alimentación Animal , Animales , Antídotos/administración & dosificación , Bentonita/administración & dosificación , Bentonita/uso terapéutico , Aberraciones Cromosómicas/efectos de los fármacos , Cíclidos/anomalías , Cíclidos/crecimiento & desarrollo , Fragmentación del ADN/efectos de los fármacos , Eritrocitos/metabolismo , Eritrocitos/patología , Branquias/efectos de los fármacos , Branquias/metabolismo , Branquias/patología , Riñón/metabolismo , Riñón/patología , Hígado/metabolismo , Hígado/patología , Masculino , Pruebas de Micronúcleos , Desintoxicación por Sorción/métodos , Testículo/efectos de los fármacos , Testículo/metabolismo , Testículo/patología , Testosterona/metabolismoRESUMEN
The present study was carried out in El-Bahria Oasis desert (Giza-Egypt) for 8 months (March-October) as a new study to assess the culture of tilapia spp. in underground well water. The obtained results showed a significant increase (P<0.01) in the values of plasma total protein, glucose, AST (aspartate aminotransferase), ALT (alanine aminotransferase), creatinine, uric acid, sodium, potassium and magnesium as well as a significant decrease (P<0.01) in plasma total lipids and calcium concentration. Furthermore, iron content in some selected vital organs was increased gradually with time, the studied organs are arranged according to their iron content in the following order: spleen > liver > kidney > gills > muscle. Remarkable changes were observed in the chemical muscle composition where the results showed a significant increase (P<0.01) in muscle water content, total lipids and ash. However, a significant decrease (P<0.01) in muscle total protein at the end of the study was observed. The growth of all male farmed tilapia in well water with a 3.2 mg/l iron concentration was unexpected; despite the presence of this high concentration of iron, the weight gain of cultured fish was 250 +/- 14.5 g. Molecular techniques are used nowadays as a good indicator for assessing the alteration in the genomes. RAPD-PCR technique indicated appearance of some changes in polymorphism band patterns. There also exists a distinct distance between the band patterns of cultured fish (T) and control fish (C). Histopathlogical sections showed pathological alterations in liver, kidney gills and spleen and the obtained results were discussed.