Gills Of Clarias Gariepinus Research Articles

Assessment of Some Selected Heavy Metals Concentration in the Organs of Two Different Fish Species (Clarias gariepinus and Mormyrus rume) of River Gidin Dorowa

This study was aimed to assess selected heavy metals concentration in the organs of Clarias gariepinus and Mormyrus rume from River Gidin Dorowa, Wukari, Taraba State, Nigeria. The liver, muscles and Gills of the fish species and water were collected. During dry (September, October and November,) and wet (December, January and February) seasons. Cadmium, Lead, Zinc and Copper were analyzed using Atomic Absorption Spectrometer. Sampling of fish was carried out monthly for six (6) months. The results showed that heavy metals mean were high in the muscles followed by the liver and low in the gills of Clarias gariepinus, while heavy metals were highest in the gills followed by the liver and lowest in the muscles of Mormyrus rume. High heavy metals concentration (1.900mg/kg) was recorded for Zinc (Zn) in the gills follow by copper (Cu) with a mean of (0.00917mg/kg) recorded in the liver of Mormyrus rume, Pb recorded the high mean of (0.2932mg/kg) in the liver while low lead (Pb) mean (0.1855mg/kg) was recorded in the muscle. However, Zn (1.6250mg.kg) and Pb (0.2882mg/kg) was high in the muscle than in other tissues of C. gariepinus. In other to avoid serious health hazards, there is need to institute effective fisheries pollution control measures and management of River Gidin Dorowa fisheries resources. Continuous monitoring of the pollution levels of the River Gidin Dorowa using fish species as bioindicators can provide adequate information necessary for its effective management.

Integrative Morphological and Genetic Characterisation of the Fish Parasitic Copepod Ergasilus mirabilis Oldewage & van As, 1987: Insights into Host Specificity and Distribution in Southern Africa

Ergasilids are external parasites typically found on the gills and fins of their hosts. In Africa, 19 species of Ergasilus von Nordmann, 1832 are reported. Of those, Ergasilus mirabilis Oldewage & van As, 1987 is one of the least host-specific, with a wide distribution range in southern Africa. As with most species in the genus, genetic data are not available to support the morphological placement of this species within the genus. Specimens representing E. mirabilis were obtained from the gills of Clarias gariepinus (Burchell, 1822) collected from several localities in South Africa and Zambia. Fish were dissected and gills screened using standard techniques. Following a comprehensive morphological study using light and scanning electron microscopy, additional morphological characters are reported. Furthermore, novel data on partial 18S, 28S (rRNA), and COI (mtDNA) gene regions are presented. This is the first integrative study on the morphology of E. mirabilis with supporting genetic data, as well as new distribution records from the KuShokwe Pan in the Phongolo River floodplain and the Vaal River in South Africa, and from the Barotse floodplain in Zambezi River, Zambia. An updated overview is provided for the species of Ergasilus from Africa, including hosts, distribution, and genetic information.

Biomineralisation and metal sequestration in a crustacean ectoparasite infecting the gills of a freshwater fish

It has been suggested that parasites are effective bioindicators as they are sensitive to environmental changes and, in some cases, accumulate trace elements in higher concentrations than their hosts. Accumulated elements sequester in different organs. In monogenean and crustacean ectoparasites, sclerotised structures and egg yolk appear to be the preferred site for element sequestration. In this study, the sequestration of trace elements; Mg, Al, Ca, Fe, Cu, and Zn in Lamproglena clariae was studied from two rivers. Adult L. clariae were collected from the gills of Clarias gariepinus from Lake Heritage in the Crocodile River and in the Vaal River below the Vaal Dam, South Africa. Collected parasites were flash frozen in liquid nitrogen and sectioned with a cryomicrotome. Sections were treated with Phen-Green to observe fluorescent signals. Trace elements in the parasite were analysed using a scanning electron microscope with an energy-dispersive spectroscope (SEM–EDS). Results showed more intense fluorescence signals in the exoskeleton compared to tissues, and in the egg yolk. Analysis by SEM–EDS confirmed the presence of elements in the parasite from both sites. Levels of Al were higher in L. clariae from the Vaal River than those from Lake Heritage, and Fe was higher in L. clariae from Lake Heritage. Element distribution patterns in the parasite matched those in the water from the sites. Unlike other crustaceans, regulation of metals in adult females of L. clariae does not occur through moulting, but high levels occurred in the yolk.

Histopathological and cholinesterase changes in the gills of Clarias gariepinus as a result of cadmium exposure

Histopathological and cholinesterase changes in the gills of Clarias gariepinus as a result of cadmium exposure

Induction of oxidative stress in Clarias gariepinus from Eleyele River in Nigeria

This study evaluated some markers of oxidative stress in the organs of African Catfish, Clarias gariepinus from Eleyele River in Oyo State, Nigeria. Clarias gariepinus (250 g-400 g) were collected from Eleyele River (a suspected polluted River) and Clarias gariepinus from a clean fish farm (Durantee fisheries) were used as the control. Levels of Malondialdehyde (index of lipid peroxidation), Glutathione (GSH) and activities of antioxidant enzymes- Superoxide dismutase (SOD), Catalase and Glutathione-STransferase (GST) were evaluated in the liver, kidney and gills of the fish. From the results, there were significant (p<0.001) increases in malondialdehyde and GSH levels in the liver, kidney and gills of Clarias gariepinus from Eleyele River compared with control. The activity of GST increased significantly (p<0.05; p<0.001) in the liver and kidney of fish from Eleyele River compared with control. There was a significant decrease (p<0.05; p<0.001) in SOD activity in all the organs of Clarias gariepinus from Eleyele River compared with conrol and also a significant (p<0.001) decrease in catalase activity in the gills and kidney of the fish but catalase activity increased in the liver. Increase in lipid peroxidation and alterations in antioxidant status in Clarias gariepinus from Eleyele River show that the fish were under oxidative stress. These suggest that the River is polluted probably as a result of various wastes frequently discharged into the River. This could pose serious health risks to consumers of water and aquatic organisms from the River.

EFFECT OF ENVIRONMENTAL POLLUTION ON OXIDATIVE STRESS BIOMARKERS IN AFRICAN CAT FISH (CLARIAS GARIEPINUS) FROM ASEJIRE RIVER IN OYO STATE, NIGERIA

Background: Fishes are widely used as model organisms for the assessment of the quality of aquatic environment and can therefore serve as bioindicators of environmental pollution. In this study, the activities of Superoxide dismutase, Catalase , Glutathione S-transferase (GST), reduced glutathione (GSH) concentration and Malondialdehyde formation were determined in the organs of African Catfish, Clarias gariepinus from Asejire River in Ibadan, Oyo State, Nigeria. The River receives effluents discharged from various industries and it is suspected to be polluted. Materials and Methods: Clarias gariepinus weighing between 250g-400g were collected from Asejire River and Clarias gariepinus from a clean fish farm (Durantee fisheries) were used as the control. Results: A significant increase in malondialdehyde formation was observed in the liver, kidney and gills of Clarias gariepinus from Asejire River compared with control. Superoxide dismutase, Catalase and GST activities decreased in the organs of the fish. There was also a decrease in GSH concentration in the liver and kidney of Clarias gariepinus from Asejire River compared with control but GSH concentration increased in the gills of the fish. Conclusion: The results of this study show that there was induction of oxidative stress in the organs of Clarias gariepinus from Asejire River reflecting the pollution status of the River.

Parasite hybridization in African Macrogyrodactylus spp. (Monogenea, Platyhelminthes) signals historical host distribution

Macrogyrodactylus spp. from the gills of Clarias gariepinus in Zimbabwe and Kenya, and C. anguillaris in Senegal were identified using haptoral sclerite morphology and by sequencing the nuclear ribosomal DNA internal transcribed spacers (ITS) 1 and 2, partial 18S and the complete 5.8S rRNA gene. A molecular phylogeny was constructed using all sequenced Macrogyrodactylus species to date. Based on morphology, Macrogyrodactylus congolensis, M. heterobranchii, M. clarii, and M. karibae were identified, with one specimen from Zimbabwe displaying morphological features that were intermediate between M. heterobranchii and M. clarii. In the intermediate form, the partial 18S and ITS1 sequence was identical to that of M. clarii while the remaining ITS1 and complete ITS2 region was almost identical to M. heterobranchii as was the partial cox1 fragment, thus strongly suggesting a hybrid origin. At present, the catfish host of M. heterobranchii and M. clarii do not co-occur in southern Zimbabwe; this hybridization event is therefore proof of historical sympatry of both fish species.

Histological changes in the gills of Clarias gariepinus (Teleostei: Clariidae) from a polluted South African urban aquatic system

A semi-quantitative histological assessment was used to investigate histological changes in the gills of Clarias gariepinus from Marais Dam and Rietvlei Dam near Pretoria, which receive effluent from sewage treatment plants and industries, as well as runoff from informal settlements. Results were compared to those from a laboratory-bred reference group offish. Histological alterations were prevalent in fish from both impoundments, including circulatory disturbances such as telangiectasia and epithelial lifting, hyperplasia of mucous cells and epithelial cells between secondary lamellae, structural alterations in the form of fusion and branching of primary and secondary lamellae, and regressive changes in the form of intracellular alterations within gill epithelial cells. Significantly higher histological index values were calculated for fish from Marais Dam compared to those from Rietvlei Dam.

Aspects of the pathology of Lamproglena clariae (Copepoda: Lernaeidae) on gills of Clarias gariepinus from the Vaal River system, South Africa

Lamproglena clariae attaches to gill filaments of Clarias gariepinus, penetrates the gill tissue and consumes blood. Hence, the purpose of this study was to investigate the mechanical damage caused by this parasite on gill filaments of the host. Infestation intensity and haematocrit values of fish blood were determined and correlated. Fish were killed, gills dissected out and observed with a dissection microscope. Gill filaments with adult females in situ were fixed in a solution of alcohol, formaldehyde and acetic acid and preserved in 70% ethanol. Fixed specimens were studied by histological examination following staining with Heidenhein’s azan solution. Gross morphology revealed varying degrees of swelling of gill filaments near the attached specimens of L. clariae. Epithelial hyperplasia, resulting in fusion of gill lamellae and necrosis of the host tissue in the vicinity of the parasite were revealed through histological examination. No correlation was evident between the infestation intensity and fish haematocrit values. Although results showed that L. clariae causes localized infestation, high intensity of infestation may be detrimental to the fish. Hyperplasia of epithelial tissue resulting in fusion of lamellae would result in restriction of air passages and thus hinder the process of respiration of the host.