stanley iheanacho

Fisheries and Aquaculture, Federal University Ndufu Alike Ikwo Nigeria
{{numberWithCommas(11)}} Publications

Oxidative stress, biochemical, lipid peroxidation, and antioxidant responses in Clarias gariepinus exposed to acute concentrations of ivermectin

Abstract

The short-term effects of ivermectin (IVMT) on the oxidative stress and biochemical parameters of Clarias gariepinus juvenile was assessed under semi-static conditions at concentrations of 9 to 25 μg L−1 for up to 4 days. Juveniles were highly sensitive to ivermectin, with an LC50 of 15 μg L−1.The antioxidant enzyme profile assessed included glutathione reductase (GR), superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT). General stress biomarkers such as serum glucose, protein, alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were also determined at 24-h, 48-h, 72-h, and 96-h exposure durations. Lipid peroxidation showed significant (p < 0.05) decreases in higher concentrations (21 μg L−1and 25 μg L−1) and durations of exposure (72 h and 96 h). Significant concentration-dependent increases (p < 0.05) were recorded in the liver function enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR) when compared to the control. GPx decreased significantly (p < 0.05) in higher concentrations (21 μg L−1and 25 μg L−1) and durations of exposure (48–96 h). Protein showed significant concentration-dependent decreases, while glucose recorded a mixed trend. The changes in the hepatic antioxidant enzyme activities and serum metabolites were indicative of oxidative stress induced by IVMT. This showed that IVMT is toxic to fish and should be used with utmost caution.

Neurotoxicity, oxidative stress biomarkers and haematological responses in African catfish (Clarias gariepinus) exposed to polyvinyl chloride microparticles

Abstract

The aquatic environment is outrageously littered with resin pellets and particles of plastic origin which can jeopardise the health of aquatic organisms. The present study investigated the effect of polyvinyl chloride (PVC) microparticles on blood parameters, leucocytes, lipid peroxidation and antioxidant system (brain and gill) of Clarias gariepinus. C. gariepinus is a fresh water indicator species often used as model for ecotoxicological assay. Fish specimens were exposed to diets spiked with PVC microparticles (95.41 ± 4.23 μm) at the following concentrations; 0.50%, 1.50% and 3.0% and control diet for 45 days, followed by a depuration trial which lasted for 30 days. Blood and tissues (brain and gill) were sampled every 15 days interval for haematology, antioxidant enzymes and lipid peroxidation assay. The result obtained revealed that PVC orchestrated the marked alterations in haematological indices. Mean cell volume and mean cell haemoglobin values reduced significantly in all concentration treated groups and were time-dependent. Neutrophil counts decreased with a corresponding increase in PVC exposure time while lymphocytes and monocytes values showed no significant difference between the control and exposed fish groups. Glutathione peroxidase activity was altered substantially in the brain and gill of the exposed groups compared to the control. Superoxide dismutase activity was inhibited in the brain and gill of the exposed groups compared to the control, as well as the different exposed periods. Catalase activity reduced significantly in the brain of 0.5% PVC exposed groups, and also decreased in a time-dependent manner while its activity in the gill did not change significantly among the exposed groups relative to the control. Lipid peroxidation levels in the brain of PVC exposed groups increased significantly in a dose and time-dependent manner. However, PVC caused no significantly change in the gill lipid peroxidation level of the exposed fish, but elevated the lipid peroxidation levels as the exposure time increased. Acetylcholinesterase activity in the brain and gill of the exposed fish reduced substantially with increase in the exposure time. Variations in haematology, antioxidant enzymes, lipid peroxidation and acetylcholinesterase activities are indicative of oxidative stress and neurotoxicity in fish. C. gariepinus is an indispensable bioindicator to measure environmental impact of PVC microparticles.

Climate change adaptation actions by fish farmers: evidence from the Niger Delta Region of Nigeria

This paper examined climate change adaptation strategies in fish farming and the effect of such methods on the profit of fish farmers in the Niger Delta region of Nigeria, Africa’s most populous country. Using cross‐sectional data obtained from 420 fish farmers from the region and applying multivariate probit and instrumental variable regressions, the study found that fish farmers have adopted a broad range of strategies to address climate risk and that these have significantly increased farmers’ profit. Our findings indicated important relationships between certain farm, socio‐economic and institutional characteristics and the adaptation actions. The study provides useful insight into factors that potentially encourage the adoption of livelihood‐enhancing climate risk adaptation strategies by fish farmers in the Niger Delta region and similar contexts.

Indian Journal of Fisheries

Suitability of discarded cashewnut (Anacardium occidentale) meal as replacement of soybean meal (Glycine max) in the diet of juvenile African catfish Clarias gariepinus (Burchell, 1822)

The search for alternative protein sources in aquaculture nutrition is still trending as the use of costly traditional feed stuffs in aquaculture diet formulation is no longer sustainable. The present study investigated the effects of partial and total dietary inclusion of cashewnut meal on growth, haematology, carcass composition, serum biochemistry and intestinal histology of juvenile African catfish Clarias gariepinus (Burchell, 1822). Soybean meal (SBM) was substituted with cashewnut meal (CM) at 0, 50 and 100% in formulated fish diets. A total of 135 juveniles of C. gariepinus (30.25± 1.02 g; 16.08±0.34 cm) were randomly assigned to three dietary treatments (0, 50 and 100% CM based diets) at a stocking density of 45 fish per treatment and further randomised into triplicates of 15 fish per replicate. The feeding trial lasted for 56 days and fish were fed twice daily at 5% body weight. Statistical analysis was carried out for all the parameters evaluated in this study. Fish group fed 50% CM based diet had the best growth performance and haematological profile when compared to 100% CM fish group and the control group. Insignificant changes in serum biochemical parameters were observed in CM fed fish groups when compared to the control. Histological examination of fish intestinal morphology revealed no adverse changes in the cellular structure of mucosal layer and villi in 50% CM fed fish, while mild histo-morphological changes were observed in 100% CM fed fish group. Significant increases in villi length and weight were observed in fish group fed CM based diets when compared to the control. The findings of the present study revealed that partial replacement (50%) of soybean with cashewnut meal improved growth performance and haematological profile of C. gariepinus.

Indian Journal of Fisheries

Suitability of discarded cashewnut (Anacardium occidentale) meal as replacement of soybean meal (Glycine max) in the diet of juvenile African catfish Clarias gariepinus (Burchell, 1822)

The search for alternative protein sources in aquaculture nutrition is still trending as the use of costly traditional feed stuffs in aquaculture diet formulation is no longer sustainable. The present study investigated the effects of partial and total dietary inclusion of cashewnut meal on growth, haematology, carcass composition, serum biochemistry and intestinal histology of juvenile African catfish Clarias gariepinus (Burchell, 1822). Soybean meal (SBM) was substituted with cashewnut meal (CM) at 0, 50 and 100% in formulated fish diets. A total of 135 juveniles of C. gariepinus (30.25± 1.02 g; 16.08±0.34 cm) were randomly assigned to three dietary treatments (0, 50 and 100% CM based diets) at a stocking density of 45 fish per treatment and further randomised into triplicates of 15 fish per replicate. The feeding trial lasted for 56 days and fish were fed twice daily at 5% body weight. Statistical analysis was carried out for all the parameters evaluated in this study. Fish group fed 50% CM based diet had the best growth performance and haematological profile when compared to 100% CM fish group and the control group. Insignificant changes in serum biochemical parameters were observed in CM fed fish groups when compared to the control. Histological examination of fish intestinal morphology revealed no adverse changes in the cellular structure of mucosal layer and villi in 50% CM fed fish, while mild histo-morphological changes were observed in 100% CM fed fish group. Significant increases in villi length and weight were observed in fish group fed CM based diets when compared to the control. The findings of the present study revealed that partial replacement (50%) of soybean with cashewnut meal improved growth performance and haematological profile of C. gariepinus.

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