Chemical Composition of Some Conventional Fishes Obtained in Asejire Dam, Egbeda Local Government Area of Oyo State, Nigeria (Published)
Freshly caught freshwater fish samples of three conventional fishes Clarias gariepinus (Burchell, 1822), Chrysichthys nigrodigitatus (Lacepede, 1803) and Parachanna obscura (Gunther, 1861) were purchased from Asejire Dam in Egbeda Local Government Area of Oyo State Nigeria in April 2017. Fishes were degutted, washed and processed using steam-cooking, oven-drying, kiln-drying and raw as control. Samples were divided into four equal portions of 500g each and transported in ice to the Central Research Laboratory, Federal University of Technology, Akure for Proximate analysis. Free Fatty Acid was also determined according to the methods of AOAC, 2005. Crude fat estimation was done using the Folch Method. Minerals were obtained by Dry–ashing the fish samples at 550oC and determined using Atomic Absorption Spectrophotometer (Perkin–Elmer Model 403, Norwalk CT). Potassium was determined by flame photometer (Corning, UK Model 405), [AOAC, 1980] and Phosphorus by the vanadomolybdate calorimetric method. Descriptive statistics (mean and standard deviation) were conducted while statistical significance (P < 0.05) was determined by Analysis of Variance (ANOVA) with SPSS version 10. Ducan multiple range test was used to determine significant differences between the means. The results showed that the moisture contents were highest (72.43%) in raw C. gariepinus and lowest (7.23%) in kiln-smoked C. gariepinus. Ash content was highest (9.26%) in kiln-smoked C. gariepinus and lowest (0.89%) in steamed-cooked C. gariepinus. Kiln-smoked C. gariepinus had the highest fat content (29.72%) and raw C. gariepinus recorded the lowest (0.86%) fat. The crude fiber was present in P. obscura and conspicuously absent in other species. Crude protein content ranged from 73.40% in kiln-smoked P. obscura to 17.31% in raw C. nigrodigitatus. Carbohydrate was highest (12.82%) in steamed-cooked C. gariepinus and lowest (0.45%) kiln-smoked C. nigrodigitatus. Free Fatty Acid was highest (1.90%) in steamed-cooked P. obscura but lowest (0.92%) in kiln-smoked C. gariepinus and steamed-cooked C. nigrodigitatus respectively. fiber content was absent in all the species except P. obscura that has low fiber content. the above reveals that moisture, ash, crude protein, fat, fiber, Carbohydrate, and Free Fatty Acid were not significantly (p>0.05) affected by the treatment. Minerals contents of all the species subjected to different processing methods were within tolerable levels needed for optimal growth and development. Cadmium was not detected in all the fishes irrespective of the processing method. The above reveals that Cu, Fe, Zn, Mg, Ca, and K were not significantly (p<0.05) affected by the processing methods. The Mean value of treatment in C. gariepinus is similar to C. nigrodigitatus but significantly (p<0.05) lesser than P. obscura. Based on the findings of this study, Kiln-smoking is the best processing method and P. obscura has the highest protein content. Its culture could be initiated through research efforts to boosts its availability at an affordable price. The finding of this research will be useful to the consumers in choosing fish based on their nutritional values rather than taste, appearance, norms and other physical features.
Using EF, PLI and Igeo for the Assessment of Heavy Metal Pollution and Sediment Quality of Asejire Reservoir, Southwest Nigeria (Published)
Asejire Reservoir is the largest lake in Southwest Nigeria, supplying domestic and industrial water to more than two million inhabitants of Ibadan and adjoining villages and towns in Oyo and Osun States. A study on the characteristic of sediment quality was conducted to evaluate the heavy metal content of the reservoir. Twenty stations were selected, sampled and analyzed using standard methods.Standard pollution indices such as Igeo, Enrichment Factor, Contamination Factor and Pollution Load Index were deployed to assess the level of heavy metals contamination in the reservoir. The result showed that the sediment was slightly acidic across the study stations, with low conductivity and organic matter content. The heavy metals order of dominance was: Fe>Pb>Cu>Zn>Mn>Ba>Ni>Cr. The mean concentration levels of all the heavy metals were lower than mean background value except Fe and Pb. Analysed data shows that the sediments in the area are rich in Fe with Igeo values > 6, high enrichment and contamination factor. Igeo and CF levels of Pb indicate moderate to no pollution, while other heavy metals indicated low calculated Igeo, EF and CF respectively. The calculated PLI values for all the heavy metals in all the location were < 1, indicating low anthropogenic contamination by these elements and suggesting that the heavy metals were derived mainly from natural sources such as bedrock materials and weathering processes.