Serum protein significantly increased in fish fed 14% lipid diets but was not affected by supplemental levels of vitamin E.
Lysozyme activity was not affected by dietary lipid levels but significantly increased in fish fed 200 mg vitamin E diets.
Alternative complement activity significantly decreased in fish fed 10 or 14% dietary lipids but increased when dietary vitamin E levels was increased to 100 or 200 mg. Dietary lipid and vitamin E levels had no effect on the resistance of Nile tilapia to S. iniae infection and on antibody titer against that bacterium.