Growth and Biochmical Studies of Mrigal Fish (Cirrhinus mrigala) Fed Graded Levels of Oil

A 45-day experiment was carried out to evaluate the growth performance,digestive enzymes activity and biochemical response of Cirrhinus mrigala fed graded levels of oil.Three isonitrogenous purified diets (6％,8％ and 10％ of oil) were formulated.A total of 108 juveniles of Cirrhinus rarigala (5.95±0.25) g were equally distributed in triplicate groups in nine plastic tanks of 100 L capacity and fed under natural light cycle.Growth performance of the fish significantly reflected the effect of inclusion levels of oil tested but the diet with 8％ lipid had the best significant growth performance ％ weight gain,Feed Conversion Ratio (FCR) and Specific Growth Rate (SGR)],across different experimental groups.Levels of secretion of digestive enzymes in the fish fed different experimental diets resulted in significant values of (p＜0.05) amylase and lipase,while Aspartate transaminase (AST),Alanine transaminase (ALT),Lactate dehydrogenase (LDH) and Malate dehydrogenase (MDH) values in the muscle and liver decreased significantly (p＜0.05) as the levels of oil in the diet increased.However,serum biochemical parameters did not record any significant difference (p＞0.05) with the exception of the total lipid across diets.The study confirmed the inclusion effect of graded levels ofoil in juvenile Mrigal diet,but the inclusion should not be more than 8％ to avert growth depression.