Studies on the physico-chemical parameters of Omi water body of Ago-Iwoye, Nigeria

In Omi water body, the physico-chemical parameters such as dissolved oxygen ranged from 1.4 to 4.8 mg/L; pH, 6.7 to 7.2; temperature, 26.5 to 31.5°C; alkalinity, 24.2 to 25.4 ppm; conductivity, 23.0 to 28.3 Ohms/cm; turbidity 0.11 to 0.15 m; and free carbon dioxide from 3.5 to 4.5 mg/L. Dissolved oxygen, pH and water temperature serve as variables since the fluctuation of one affects the values of others. The investigation shows that Omi water is safe for drinking when purified

Histopathology of the gill and liver tissues of the African catfish Clarias gariepinus exposed to lead

An investigation on the effect of the heavy metal, lead (Pb) on the gill and liver of the African catfish Clarias gariepinus was carried out in the laboratory. One hundred and sixty (160) fingerlings of the fish were exposed to continuous exposure to sub-lethal concentrations (0.006 mg/l and 0.008 mg/l) of lead for a period of three weeks. The liver and gill of fish were removed every 9 days for histological examination. The results showed that the degree of distortion of the gills and liver was proportional to the exposure periods and concentration of the metals was found to be dose and time dependent. Key Words: Lead, Clarias gariepinus, histopathology, gill, liver. African Journal of Biotechnology Vol.4(1) 2005: 117-12

Use of palm oil in the diet of the African mudfish, Clarias gariepinus

This study was conducted to investigate the effect of the substitution of fish oil with palm oil in the diet of Clarias gariepinus fingerlings over a 49 day period. Four diets were prepared with fish oil substituted with palm oil at 0% (control Diet 1), 25% (Diet 2), 50% (Diet 3) and 100% (Diet-4), using a completely randomised block design. Mortality was observed in all the treatments, while fish fed with 100% palm oil were most sluggish in accepting their feeds. Average weight gained, specific growth rate and feed conversion efficiency were not significantly affected by diet. It was concluded that palm oil can be substituted for fish oil in the diet of C. gariepinus. Key Words: African mudfish, diet, palm oil, growth. African Journal of Biotechnology Vol.3(8) 2004: 418-42

Short communication - use of palm oil in the diet of the African mudfish, Clarias gariepinus

This study was conducted to investigate the effect of the substitution of fish oil with palm oil in the diet of Clarias gariepinus fingerlings over a 49 day period. Four diets were prepared with fish oil substituted with palm oil at 0% (control Diet 1), 25% (Diet 2), 50% (Diet 3) and 100% (Diet-4), using a completely randomised block design. Mortality was observed in all the treatments, while fish fed with 100% palm oil were most sluggish in accepting their feeds. Average weight gained, specific growth rate and feed conversion efficiency were not significantly affected by diet. It was concluded that palm oil can be substituted for fish oil in the diet of C. gariepinus

On the occurrence of three non-native cichlid species including the first record of a feral population of Pelmatolapia (Tilapia) mariae (Boulenger, 1899) in Europe

Thermally influenced freshwater systems provide suitable conditions for non-native species of tropical and subtropical origin to survive and form proliferating populations beyond their native ranges. In Germany, non-native convict cichlids (Amatitlania nigrofasciata) and tilapia (Oreochromis sp.) have established populations in the Gillbach, a small stream that receives warm water discharge from a local power plant. Here, we report on the discovery of spotted tilapia (Pelmatolapia mariae) in the Gillbach, the first record of a reproducing population of this species in Europe. It has been hypothesized that Oreochromis sp. in the Gillbach are descendants of aquaculture escapees and our mtDNA analysis found both O. mossambicus and O. niloticus maternal lineages, which are commonly used for hybrids in aquaculture. Convict cichlids and spotted tilapia were most probably introduced into the Gillbach by aquarium hobbyists. Despite their high invasiveness worldwide, we argue that all three cichlid species are unlikely to spread and persist permanently beyond the thermally influenced range of the Gillbach river system. However, convict cichlids from the Gillbach are known to host both native and non-native fish parasites and thus, non-native cichlids may constitute threats to the native fish fauna. We therefore strongly recommend continuous monitoring of the Gillbach and similar systems

Histopathological alterations observed in the liver of Poecilia vivipara (Cyprinodontiformes: Poeciliidae) as a tool for the environmental quality assessment of the Cachoeira River, BA

Histopathological alterations in liver have been widely used as a tool in studies for monitoring environmental quality. To evaluate the environmental quality in the Cachoeira river, five spots were monitored between the municipal districts of Itapé and Ilhéus, using liver histological analysis. The species chosen for analysis was Poecilia vivipara due to the fact that it is one of the most abundant in the sampling. The routine technique of inclusion and impregnation in paraffin was used, and the cuts were stained with Hematoxylin and Eosin (H & E). Histopathological alterations in the liver were evaluated semi-quantitatively and based on the severity of the lesions. The results of the histopathological alteration frequency together with the average taken from the Histopathological Alteration Index from points 1 (Vila de Itapé) and 2 (Fazenda Santa Amélia) showed that in this area the environment is more threatened because of some stressor agent, possibly contaminants that seem to be acting in the environment and endangering the health of fish. The statistic results demonstrated that there were no significant differences among points 1, 2 and 4, which means they are very similar to one another, and are ecologically endangered