The experiment was carried out to evaluate the prophylactic efficiency of dietary powdered Persea americana leaves on the organosomatic indices, disease resistance, and liver histopathology of Clarias gariepinus exposed to Klebsiella pneumoniae. Five (5) different isonitrogenous diets with varying percentages of P. americana powered leaves inclusion were formulated as follows: Do(0%); D1(3%); D3 (6%); D3 (9%) and D4 (12%). One hundred and fifty (150) C. gariepinus were distributed in five groups in triplicates of ten (10), and fed diets Do-D4 accordingly. After eight (8) weeks of feeding, they were injected intraperitoneally with klebsiella pneumoniae at days 1, 7, 14 and 21. After twenty eight (28) days post-infection period, three fish from each of the triplicate were sacrificed for evaluation of the Hepatosomatic index (HSI); Cistosomatic index (CSI), and Spleenosomatic index (SSI), and the liver was taken to the laboratory for histopathological analysis. The survival rate was calculated in each of the groups and the disease resistance was determined. At the end of the experiment, serious ulcerations were observed on the fish fed Do and infected with K. pneumonia, while the fish fed D1 – D4 were ulcer- free. The result reveals that the SSI and CSI were similar in all the groups (Do-D4), but the HSI was higher (P>0.05) in the group fed Do (control) compared to the group fed D1-D4. The survival rate and the diseases were Lower (<0.5) in the group Do compared to the group fed D1-D4, though it was not dose dependant. The result of the histopathology shows that the liver of the fish fed Do has bloodstain in the portal vein and sinusoid, while the liver of the fish fed D1-D4 have no bloodstain. The experiment reveals that Persea americana powdered leaves as applied is an anti-liver inflammatory herb, disease resistant and anti-bacterial.

The effect of three extraction methods which include soxhlet, gas and charcoal powered smoking kiln on extraction of oil from Trachurus trachurus were investigated. Chemical analyses of the oil was carried out to determine its quantity and quality in terms of fatty acid composition by using standard laboratory methods. The results obtained indicated that the highest oil yield (14.0%) was recorded in oil extracted with soxhlet method, while the lowest (0.93%) in oil extracted with charcoal powered kiln extraction method. Based on the fatty acid profile of the oils, there are sixteen fatty acids in all the extraction methods with stearic acid (53.62%) as the highest saturated fatty acid (SFA); oleic acid (7.05%) as the foremost monounsaturated (MUFA) and linolenic acid (23.31%) as the major polyunsaturated fatty acid (PUFA). The Soxhlet methods consistently recorded the highest oil yield, and can be used to extract oil for industrial use. While, the gas powered kiln can be used to extract oil for consumption purpose.