Zoology-Scholarly Publications

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Browsing Zoology-Scholarly Publications by Subject "African sharptooth catfish"

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    Open Access
    Biomarkers of toxicity in Clarias gariepinus exposed to sublethal concentrations of polycyclic aromatic hydrocarbons
    (African Journal of Aquatic Science, 2018-08) Sogbanmu, Temitope O.; Osibona, Adesola O.; Oguntunde, Olubanji A.; Otitoloju, Adebayo A.
    Physiological, biochemical and histological indices in Clarias gariepinus broodstock, and teratogenic indices in embryos exposed to sublethal concentrations of naphthalene, phenanthrene and pyrene were investigated in 2014 using a static-renewal bioassay protocol. Phenanthrene (1.41 mg l−1) was the most toxic, followed by pyrene (1.53 mg l−1) and naphthalene (7.21 mg l−1), based on 96 h LC50 values. Hepatosomatic indices were significantly higher in naphthalene- and pyrene-treated males compared with solvent controls, whereas fecundity in females was significantly lower by factors of 2.4 (naphthalene), 2.8 (phenanthrene) and 2.4 (pyrene), compared with controls. Catalase levels were lower in female phenanthrene-treated fish compared with controls. Histological alterations observed in PAH-treated fish include oedema, inflammatory cells, epithelial lifting and hyperplasia in the gills, vacuolation, haemosiderin pigments and sinusoidal congestion in the liver, and degenerated zona radiata in the ovary. Teratogenic effects were not observed, as evidenced by the lack of histological alterations in embryos spawned from pre-exposed broodstock. Sex-specific responses and the utility of biomarkers at cellular and individual levels of organisation are therefore demonstrated for holistic evaluations of polycyclic aromatic hydrocarbons in ecotoxicological studies.
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    Open Access
    Biomonitoring, physico-chemical, and biomarker evaluations of abattoir effluent discharges into the Ogun River from Kara Market, Ogun State, Nigeria, using Clarias gariepinus
    (Environmental Monitoring and Assessment, 2019-01) Olaniran, Esther I.; Sogbanmu, Temitope O.; Saliu, Joseph K.
    The discharge of untreated effluents into aquatic ecosystems poses potential adverse effects to aquatic organisms. In this study, the physico-chemical characteristics of abattoir effluent from Kara Cow Market, Ogun State, Nigeria, surface water and sediments from the Ogun River were evaluated. Fish species and macrobenthic fauna diversity in the river were also examined. Acute toxicity and biochemical and histological studies were investigated in Clarias gariepinus exposed to sub-lethal concentrations of the effluent over a period of 28 days. Effluent physico-chemical parameters such as ammonia, conductivity, total dissolved solids, and total suspended solids were higher than set limits. Total polycyclic aromatic hydrocarbons (PAHs) in the effluent and sediment were 6.73 mg/L and 8.07 mg/kg, respectively. Tetracycline (an antibiotic administered to the cows at the market) levels in the effluent and surface water were 0.23 μg/mL and 0.85 μg/mL, respectively. Fish species diversity was lower at the test site compared to the reference site. Chironomus spp. and Tubifex tubifex dominated the benthic assemblage at the test site. There were significant changes (p < 0.05) in the biochemical indices but no histological alterations in exposed C. gariepinus after 28 days. The results demonstrate that the effluent poses potential risks to the aquatic organisms and ecosystem services provided by the river. We recommend that environmental regulatory agencies and stakeholders should establish effluent and solid wastes management systems at the market to prevent environmental and public health epidemics within the framework of the United Nations Sustainable Development Goals 6 (clean water and sanitation) and 14 (life below water).
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    Open Access
    Embryotoxic, Developmental and Genotoxic Evaluations of a Endosulfan and Deltamethrin Mixture on the African Sharptooth Catfish (Clarias gariepinus)
    (West African Journal of Applied Ecology, 2018-07) Mumuni, Abdulmujib A.; Sogbanmu, Temitope O.
    The evaluation of pesticides using early life stages of fish yields high throughput results that can inform one about the developmental effects of these toxicants. The effects of sublethal concentrations of a commercial mixture of endosulfan and deltamethrin (ratio 280:2) were evaluated in the embryos and juveniles of Clarias gariepinus. Embryotoxic and developmental evaluations were conducted in the embryos from 0 - 26 hours post fertilization. Genotoxic effects were assessed in the erythrocytes of the juveniles using the micronucleus assay over a period of 28 days. The acute toxicity studies revealed that the 24 hLC50 and 26 hEC50 (non-hatching) values for embryos were 25.25 μg/L and 12.96 μg/L respectively while the 96 hLC50 value for fingerlings was 12.67 μg/L. Hatching success was lower in the exposed embryos compared to the control. The percentage developmental abnormalities and number of heartbeats per minute were statistically higher (p<0.05) in the exposed embryos compared to the control. Developmental abnormalities observed included pericardial and yolk sac oedema, scoliosis and tail curvature. The genotoxicity studies showed that there was a significant increase (p<0.05) in micronuclei in the erythrocytes of the exposed juveniles by days 14 and 28 compared to the control animals. These results imply that the pesticide mixture can cause a decline in the population of non-target organisms such as fish at sub-lethal or environmentally realistic concentrations. A review of the use of this pesticide formulation and development of environmentally friendly methods for pest management are recommended to safeguard non-target organisms such as the African sharptooth catfish.