Search

The concentrations of Iron (Fe), Copper (Cu), Zinc (Zn), Lead (Pb), Cadmium (Cd), Chromium (Cr) and Manganese (Mn) in water, sediment and selected fish samples from Ureje water reservoir, Ado Ekiti, were determined using Atomic Absorption Spectrophotometer (AAS). A total of three samples each of water, sediment, fishes (Hemichromis fasciatus and Hepsetus odoe) were collected and analyzed for heavy metals. Data obtained were subjected to analysis of variance (ANOVA) test at 0.05%. The results showed higher levels of Zn (13.08 ± 0.45 mg/g) and Fe (2.10 ± 0.56 mg/g) in fish in comparison with other heavy metals examined. Chromium has exceeded the toxicity threshold in the muscle of the fishes in line with W.H.O standards in food. Cadmium was not detected in soil, while other elements detected were in trace amount below the Environmental Protection Agency allowable limits in soil. In water, except for Fe (1.25 ± 0.02) mg/l, other metals were below allowable limit in water with reference to the World Health Organization’s recommendation. This finding indicates that the water is safe for both aquatic life and man.

A 70 day feeding trial was conducted to evaluate the utilization of all plant- protein diets supplemented with L-lysine and L-methionine by Hybrid catfish (Hetero-clarias) juveniles. At the start of the experiment, fifteen (15) glass aquaria tanks (70 cm × 45 cm × 40 cm)/each, filled with borehole water up to 70 L of its capacity were stocked with one hundred (150) Hetero-clarias juveniles (Av. Wt. 16.49 ± 0.02 g)/one at 30 fish per treatment in three replicates in a complete randomized design. Five diets (D1-D5) isonitrogenous (40% Crude Protein) and isocaloric (12.1kcal/kg) were formulated. Except the control (D1), varying levels of Corn Gluten Meal (CGM) of 60% crude protein (CP) as main plant protein source were added to other plant protein materials such as Soya bean meal and Groundnut cake to formulate diets (D2-D5). Fish were fed at 5% body weight twice daily (8.00 and 10:00) for 10 weeks. Water quality parameters were monitored daily. Mean Weight Gain (MWG), Specific Growth Rate (SGR), Feed Conversion Ratio (FCR), Protein Efficiency Ratio (PER) and Net Protein Utilization (NPU) were determined. Proximate and mineral composition of the diets and fish were determined using AOAC methods. Fish fed D1 (control) significantly (PE‚0.05) had the best growth performance in terms of final mean weight gain (44.54 ± 0.02)g; Specific Growth Rate (1.86 ± 0.06) and Protein Efficiency Ratio (1.11 ± 0.04). The mean value for Feed Conversion Ratio (FCR) was significantly (PE‚0.05) highest (1.4 ± 0.04) in fish fed. Least mean value (8.00 ± 0.03) for Net Protein Utilization (NPU) was also recorded in fish fed D5. Fish fed D2 with minimal plant materials exhibited feed utilization close to D1 (100%FM) as reflected in the growth performance. Fish growth was significantly impaired from (D3-D5) despite supplementation with amino acids, suggesting that inclusion of all-plant protein materials in the diets of Hetero-clarias at this stage of growth should not be encouraged.

The viscosity, shear stress and shear rate of African star apple juice (Chrysophyllum albidium) at different concentrations of 8 % to 32% total solid concentration and temperature range of 20°C to 70°C were obtained in order to determine the effect of changes in concentration and temperature on the rheological properties of the juice. Also, the physico-chemical analyses of the sample were carried out. Plot of shear stress against shear rate showed that at all concentrations, African star apple juice behaved as a non-Newtonian fluid at temperature below 60°C. At 70°C, however, lower concentration (8% and 12%) behaves non-Newtonian while higher concentrations behave Newtonian. Increase temperature decreases the viscosity of the juice. The knowledge of rheological properties of African star apple juice is essential for the design and optimization of energy process and heat transfer.

Eleven diets (D1-D11), designated as treatments (T1-T11), supplemented with different levels of inorganic phosphorus (P) (Ca2PO4) were fed to Heterobranchus bidorsalis (10.8 ±0.02 g) to determine the optimum P requirement. D1 - D11 contained total P of 10.2, 10.4, 11.0, 11.9, 12.3, 12.6, 13.4, 13.9, 14.2 14.7 and 15.4 g kg-1 respectively. After 84 days of feeding trial, there was increase in fish growth up to T5 with 12.3g P kg-1 diet, followed by consistent decline in growth towards T11 with the highest P content. However, fish in T5 had the best (P