The laboratory acclimatized Clarias gariepinus (80 ± 10 g) were divided into six groups and five subgroups each containing 10 fish. A fish feed was reconstituted by adding 33% powder of Leucaena leucocephala seed in place of fish trash. Group B, C and E were fed on reconstituted feed and group A, D and F were fed on artificial feed containing animal protein for 7 days prior to start of experiments. Then Group B was challenged with BSA while other groups were challenged with Vibrio harveyi (Group C, D) and Pseudomonas aeruginosa (Group E, F). Group A was used as negative control (not challenged with antigen). The fish were challenged on weekly intervals till 28th day. Blood was collected from one subgroup of each group on day 7, 14, 21 & 28 and finally sacrificed on day 35. Change in body weight, liver function tests (SGOT, SGPT) and serum ALP levels were monitored. The phagocytic index, percentage phagocytosis and nitric oxide levels were measured in macrophages isolated from spleen and head kidney. The levels of total fish immunoglobulin were also measured following indirect ELISA. The results showed improved immune response in fish fed on 33% L. leucocephala pod seed reconstituted feed; however their specific growth rate was low.