RESUMEN
This study aimed to examine the side effects of selected neonicotinoids (Acetamiprid, Aceta, and Imidacloprid, Imid) on Oreochromis niloticus juveniles. The acute toxicity, Probit method, revealed an LC50 of 195.81 and 150.76 ppm for Aceta/96 h and Imid/72 h respectively. The fish were divided into three groups that were exposed, for 21 days (n = 5/replicate), to 1/10 of the LC50 of either neonicotinoids, however, the third was an unexposed control group. Results of erythrocytic micronucleus (MN), and nuclear abnormalities (NA) showed that Aceta and Imid exposure caused a significant (p < 0.05) increase in MN by ~ 2.2 and ~ 10 folds, respectively relative to control. NAs occurred at the order of kidney-shaped > budding > binucleated in Aceta, however, budding > binucleated > kidney-shaped was noticed in the Imid group. Histopathological changes in gills, liver, and muscles were observed significantly in both exposed groups with more severity in the Imid group. Collectively, Aceta and Imid have potential genotoxicity and histopathological alterations in O. niloticus.
Asunto(s)
Cíclidos , Contaminantes Químicos del Agua , Animales , Cíclidos/fisiología , Contaminantes Químicos del Agua/toxicidad , Branquias , Neonicotinoides/toxicidad , Daño del ADN , HígadoRESUMEN
Imidacloprid (Imid), a systemic neonicotinoid insecticide, is broadly used worldwide. It is reported to contaminate aquatic systems. This study was proposed to evaluate oxidative stress and genotoxicity of Imid on Nile tilapia (Oreochromis niloticus) and the protective effect of ascorbic acid (Asc). O. niloticus juveniles (30.4 ± 9.3 g, 11.9 ± 1.3 cm) were divided into six groups (n = 10/replicate). For 21 days, two groups were exposed to sub-lethal concentrations of Imid (8.75 ppm, 1/20 of 72 h-LC50 and 17.5 ppm, 1/10 of 72 h-LC50); other two groups were exposed to Asc (50 ppm) in combination with Imid (8.75 and 17.5 ppm); one group was exposed to Asc (50 ppm) in addition to a group of unexposed fish which served as controls. Oxidative stress was assessed in the liver where the level of enzymatic activities including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in addition to mRNA transcripts and, Lipid peroxidation (LPO) were evaluated. Moreover, mitotic index (MI) and comet assay were performed, in addition, the erythrocytic micronucleus (MN), and nuclear abnormalities (NA) were observed to assess genotoxicity in fish. Imid exposure induced significant (p Ë 0.05) changes in the antioxidant profile of the juveniles' liver by increasing the activities and gene expression of SOD, CAT and GPX as well as elevating the levels of LPO. DNA strand breaks in gill cells, erythrocytes and hepatocytes along with erythrocytic MN and NA were also significantly elevated in Imid-exposed groups. MI showed a significant (p Ë 0.05) decrease associated with Imid exposure. Asc administration induced a significant amelioration towards the Imid toxicity (8.75 and 17.5 ppm). A significant protective potency against the genotoxic effects of Imid was evidenced in Asc co-treated groups. Collectively, results highlight the importance of Asc as a protective agent against Imid-induced oxidative stress and genotoxicity in O. niloticus juveniles.
Asunto(s)
Ácido Ascórbico/farmacología , Cíclidos , Neonicotinoides/toxicidad , Nitrocompuestos/toxicidad , Animales , Antioxidantes/metabolismo , Cíclidos/genética , Citoprotección/efectos de los fármacos , Daño del ADN/efectos de los fármacos , Interacciones Farmacológicas , Exposición a Riesgos Ambientales , Dosificación Letal Mediana , Pruebas de Mutagenicidad , Estrés Oxidativo/efectos de los fármacos , Contaminantes Químicos del Agua/farmacologíaRESUMEN
Heavy metal residues in sediment and Oreochromis niloticus fish muscles, collected from a Nile River Canal (Bahr Shebeen Canal), Egypt, were investigated from September 2014 to December 2015. The spatial and seasonal distributions of Cd, Cu, Fe, Pb, and Zn are described and discussed. Relative abundance of these metals in sediment was found as follows: Fe > Zn > Cu > Pb > Cd. Indices of pollution were used to detect the degree of sediment contamination and indicated elevated concentrations likely to adversely affect benthic and benthic-associated organisms. Anthropogenic activities strongly influenced metal occurrence in sediments. Accumulation of heavy metals in fish muscular tissue was found to be nearly comparable to the sediment. Relative abundance of metals in fish tissue followed the trend of Fe > Zn > Pb > Cu > Cd. Fish can be used as a surrogate for heavy metals pollution. The bioaccumulation factor (BAF) in fish muscle showed the following trend: Pb > Zn > Cu > Fe > Cd. Levels of most selected heavy metals detected in muscular tissue of fish were below admissible limits set by different organizations. However, HI (hazard index) showed that the cumulative risk effects are of considerable concern, especially where fish consumption is high. Consequently, it is recommended that discharged water containing pollutants should be prioritized to include continuous monitoring, and adequate public awareness.
Asunto(s)
Cíclidos , Monitoreo del Ambiente , Contaminación de Alimentos/análisis , Metales Pesados/análisis , Ríos/química , Contaminantes Químicos del Agua/análisis , Animales , Egipto , Sedimentos Geológicos/química , Músculos/química , Medición de RiesgoRESUMEN
In the present investigation, length-weight relationship, condition factor, age, growth, mortality, gonadosomatic index (GSI) and fecundity of tilapias (Bolti in Arabic): Oreochromis niloticus, from Shanawan drainage canal (SDC), Al-Minufiya Province, Egypt, were studied. This was carried out on 162 fish samples collected during the period from April 1992 to May 1993. Oreochromis niloticus was found to attain sexual maturity early (8-9 cm), was more fecund (1,234-3,893) and has high mortality rates (91% for males and 94% for females). A comparison of the various parameters of O. niloticus from SDC with those of other authors in different localities and times in Egypt revealed year-to-year and geographically significant differences in relation to variation in weight with length, condition factor, fecundity, growth and mortality rates. These differences were discussed and were found to be attributed to the effect of eutrophication and pollution on the growth, age and other biological aspects of O. niloticius. Multiple regression analysis showed that only female GSI correlated significantly with pesticides and heavy metals contamination.