Feed and experimental design
Normal balanced feed composed of 42% fish meal, 20% groundnut oil cake, 15% tapioca powder, 15% wheat flour,
5% blood meal and 3% mineral-vitamin mixture was used as control diet (protein: 39%, carbohydrate: 24%, lipid:
11% and ash: 9%). E. alba aqueous leaf extract along with vitamins and minerals were mixed with the cooled steam
cooked diet (giving final concentration of 0.01, 0.01 or 1% of the leaf extract) before pelletization.
Fish were randomly divided into six sets of four groups each (n ¼ 6 per group) and fed with 0, 0.01, 0.1 or 1%
E. alba aqueous extract-supplemented diet at the rate of 2% of the body weight per day for 3 weeks. After the end
of every week, blood was collected from each set for assaying a particular immunological parameter.