Effect of an amalgamated antibiotic and its connection to cytogenotoxicity and histo-architectural malformations in stinging catfish

Intensive fish farming has an excessive prevalence of infection and is typically controlled by the administration of antibiotics.Although amalgamated antibiotics are a relatively novel therapeutic idea and more effective than traditional antibiotic monotherapy,they can also have a toxic effect on the fish body when it is administered abruptly.This study investigated the cyto-genotoxic effects on erythrocytes and histo-architectural malformations in the liver and kidneys of stinging catfish(Heteropneustes fossilis)in relation to Enrocip plus use as an amalgamated antibiotic agent.The experimental fish with an initial average weight of 17.38±1.94 g were divided into four treatment groups with antibiotic doses:according to the recommendation of the manufacturer 0.167 mg/ml Enrocip plus was used as a standard dose(x)and it was treated as T3,while 0%of the standard dose(0×mg/ml),1/2×(0.083 mg/ml),and 2×(0.333 mg/ml)were treated as T1,T2 and T4,respectively for a period of 30 days.The observed erythrocyte cellular deformities(ECD)were twin,tear-drop,serrated,tail budded and de-membranated cells,whereas the erythrocyte nuclear deformities(END)were a nuclear bridge,bi-nucleus,nuclear termination,karyopyknosis,and micronucleus at different concentrations of Enrocip plus.Both ECD and END percentages experienced the interaction of antibiotic dose and exposure time,and were significantly different(P<0.01).Significant changes in hepatocytes,mild to severe necrosis,vacuole formation,and hepatopancreas damage were also observed in the liver of the treated fish whereas highly degraded renal tubules and hematopoietic tissue,glomerular occlusion,and vacuolation were evident in the kidneys.The current investigation fully emphasizes the adverse effects of amalgamated antibiotics on the cytogenotoxicity and the histomorphology of the kidneys and liver of fish.Thus,the use of an amalgamated antibiotic in aquaculture must be carefully evaluated.

Assessment of genetic diversity, detection of strain-specific single nucleotide polymorphisms and identification of the Bangladesh and Vietnam strain of Channa striata by PCR-RFLP analysis of the mitochondrial COI gene fragment

Striped snakehead(Channa striata)has enormous fisheries and aquaculture importance due to its high market demand and food value.Recently,Vietnam strain of the species has been introduced to Bangladesh for aquaculture.Therefore,it is essential to develop a reliable molecular technique that can distinguish the Bangladesh strain from the Vietnam ones as biological invasion by feral exotic fish to the wild may cause enduring damage to ecosystem and species diversity.Fin clips from snakehead samples were collected from six locations and total DNA was extracted.The cytochrome oxidase c 1(COI)gene fragment was amplified by PCR using the Fish F1/R1 primer set and sequenced for analysis of intra-and inter-strain genetic diversity and detection of single nucleotide polymorphism to distinguish the Vietnam strain from Bangladesh ones.A total of 15 haplotypes were identified with an overall haplotype diversity of 0.888.The median-joining network created based on COI gene sequences clearly differentiated the Bangladesh strain from the strain of Vietnamese origin by a total of 18 single nucleotide polymorphisms.An In silico restriction analysis revealed AluI was the most suitable restriction enzyme that produced diagnostic restriction profiles of the two strains of C.striata.PCR-RFLP analysis by the restriction enzyme AluI created distinguishing restriction profile similar to that in the In silico analysis.This work illustrates a simple,reliable and inexpensive molecular tool for the identification of the Bangladesh and Vietnam strains of C.striata by one-step PCR and restriction of the COI gene fragment.