Toxicological Effects of Crude Oil on the Histopathology of Selected Organs in African Catfish (Clarias Gariepinus Burchell, 1822) (Published)
A twenty-eight (28) day study investigated the toxicological effects of crude oil on the histopathology of selected organs in African catfish (Clarias gariepinus Burchell, 1822) as a bioindicator organism. The research was conducted to evaluate the impact of varying concentrations of crude oil on water quality parameters, swimming and feeding behaviour, mortality rate, and histopathological changes in vital organs of the fish. A laboratory-based experimental design was adopted, where fish were exposed to different concentrations of crude oil (10 ml, 20 ml, 40 ml, 80 ml, and 160 ml) alongside zero (00 ml) control. Physicochemical parameters such as temperature, pH, dissolved oxygen (DO), and water hardness were measured. Results showed a progressive increase in water temperature and hardness with increasing crude oil concentration, while pH and DO levels decreased significantly, indicating deterioration in water quality. Mortality rates increased with both concentration and exposure time, with the highest mortality recorded at 160 ml. The histopathological examination revealed severe tissue damage in exposed fish with increased concentration of crude oil. Observed alterations included lamellae damage, epithelial lifting, and mucus accumulation in the gills; cellular degeneration, vacuolation, and necrosis in the liver; and tubular degeneration and shrinkage of glomeruli in the kidney. These changes demonstrate that crude oil exposure significantly impairs respiratory, metabolic, and excretory functions in fish. The study concludes that crude oil pollution poses serious threats to aquatic organisms and ecosystems by degrading water quality, increasing mortality, and causing structural damage to vital organs. It is therefore recommended that stricter environmental regulations and effective oil spill management strategies be implemented to protect aquatic biodiversity and sustain the community’s livelihood.
Keywords: Bioindicator, Clarias Gariepinus, Toxicity, crude oil, histopathology
Haematological Responses and Growth Performance of Clarias gariepinus (Burchell, 1822) Fingerlings exposed to a Cypermethrin, Deltamethrin and Cyhalothrin Insecticide (Published)
The fingerlings of Clarias gariepinus of 2.620 ± 0.370g and 6.480 ± 0.598cm weight and length were exposed to a Cypermethrin, Deltamethrin and Cyhalothrin insecticide at 0.0045, 0.0085, 0.0110, 0.0125 and 0.015ml/L in triplicates with a control (0ml/L) for 96hours. Some haematological parameters and blood performance (BP) were assessed to determine the ‘health status’ of the fish. The growth performance of the survivor fish from the exposure concentrations two weeks after exposure were also evaluated based on some growth parameters- mean weight gain (WG), specific growth rate (SGR%), relative growth rate (RGR%), and condition factor (K). The means ± SD of data obtained were determined and analyzed using One-way ANOVA. Results showed that the variations (at p<0.05) in the values of the parameters analyzed were concentration-dependent. The red blood cells, haemocrit, haemoglobin, mean corposular haemoglobin counts reduced with increase in concentration while the white blood cells, lymphocytes, eosinophils counts, and mean corposular haemoglobin concentration reduced with increased concentration, the basophils and monocytes counts were also affected. The BP values reflected the negatively impacted physiological condition and ‘health status’ of the fish. The growth performance premised on the WG (1.20±2.580 – 6.02±4.820g), SGR (11.06 – 22.68%), and RGR (54.9 – 217.46%) gave values that were comparatively better with increased concentration, than the control (2.29±2.772g, 14.96% and 109.56% respectively) which implied good recovery of the survivor fish. The K value, indication of the state of well-being of the fish had values from 0.69 – 1.60 from the concentrations while the control was 0.50, indicative of better well-being in the survivors with the removal of the toxicant.
Keywords: Clarias Gariepinus, Pyrethroid insecticide, blood parameters
ACUTE TOXIC EFFECT OF QUA IBOE LIGHT CRUDE OIL ON THE GILLS OF CLARIAS GARIEPINUS JUVENILES (Published)
The effect of the water soluble fraction of Qua Iboe Light crude oil on the survival of the Juveniles of African freshwater catfish (Clarias gariepinus) was investigated under laboratory conditions for 96 hours. A total of ten (10) juveniles of C. gariepinus each were grouped into twelve (12) test aquaria and held for 24, 48, 72 and 96 hours in six (6) different concentrations of Qua Iboe Light Crude oil (0, 10, 20, 30, 40 and 50mg/l) . The experiment were conducted in two batches (A and B). No mortality was recorded in the 0-20mg/l of toxicant, 40% mortality was recorded in the 30mg/l of toxicant giving 60% survival at the end of the 96 hours of test. In the 40mg/l of toxicant 90% mortality was recorded, giving 10% of the organism surviving at the end of the 96 hours test, while in the 50mg/l of toxicant, 100% mortality was recorded leaving 0% survivor at the end of the 96 hours bioassay. The 96 hours LC50 for both batches was 30.12mg/l. Toxicant exposure induced behavioural changes such as abnormal and uncoordinated swimming movement. It was observed that mortality was concentration – dependent: the higher the concentration, the higher the mortality. There was no significant differences in mortalities between the two batches (P>0.05) leading to the conclusion that the WSF of Qua Iboe Light Crude oil in the Nigerian coastal waters may have adverse effects on aquatic fauna and flora. However, it was observed that the WSF of Qua Iboe Light Crude oil had severe impacts on the gills of the test organisms resulting in gill lamellae disintegration and erosion which may be attributed to the cause of the mortality in the test organisms
Keywords: Acute Toxicity, Clarias Gariepinus, Gills, Juveniles, Qua Iboe Light Crude Oil
Acute Toxic Effect of Qua Iboe Light Crude Oil on The Gills of Clarias gariepinus Juveniles (Review Completed - Accepted)
The effect of the water soluble fraction of Qua Iboe Light crude oil on the survival of the Juveniles of African freshwater catfish (Clarias gariepinus) was investigated under laboratory conditions for 96 hours. A total of ten (10) juveniles of C. gariepinus each were grouped into twelve (12) test aquaria and held for 24, 48, 72 and 96 hours in six (6) different concentrations of Qua Iboe Light Crude oil (0, 10, 20, 30, 40 and 50mg/l) . The experiment were conducted in two batches (A and B).. No mortality was recorded in the 0-20mg/l of toxicant, 40% mortality was recorded in the 30mg/l of toxicant giving 60% survival at the end of the 96 hours of test. In the 40mg/l of toxicant 90% mortality was recorded, giving 10% of the organism surviving at the end of the 96 hours test, while in the 50mg/l of toxicant, 100% mortality was recorded leaving 0% survivor at the end of the 96 hours bioassay. The 96 hours LC50 for both batches was 30.12mg/l. Toxicant exposure induced behavioural changes such as abnormal and uncoordinated swimming movement. It was observed that mortality was concentration – dependent: the higher the concentration, the higher the mortality. There was no significant differences in mortalities between the two batches (P>0.05) leading to the conclusion that the WSF of Qua Iboe Light Crude oil in the Nigerian coastal waters may have adverse effects on aquatic fauna and flora. However, it was observed that the WSF of Qua Iboe Light Crude oil had severe impacts on the gills of the test organisms resulting in gill lamellae disintegration and erosion which may be attributed to the cause of the mortality in the test organisms
Keywords: Acute Toxicity, Clarias Gariepinus, Gills, Juveniles, Qua Iboe Light Crude Oil