Table 2. Immunological parameters of olive flounder, Paralichthys olivaceus, fed three experimental diets for 12 weeks before and after challenge test

	NBT activity (OD)	Lysozyme activity (µg/mL)	Ig level (mg/mL)	AP activity (% inhibition)	SOD activity (% inhibition)	MPO activity (OD)	GPx activity (mU/mL)
Before challenge test
AP0	0.64 ± 0.10	56.0 ± 5.3	107 ± 20	23.7 ± 2.2	76.2 ± 2.1	1.86 ± 0.15	50.3 ± 9.5
AP25	0.65 ± 0.08	52.3 ± 5.1	104 ± 16	25.0 ± 2.4	80.1 ± 2.7	1.97 ± 0.17	60.1 ± 5.4
AP50	0.64 ± 0.02	46.9 ± 7.3	110 ± 19	23.4 ± 4.4	79.1 ± 1.4	2.14 ± 0.37	60.7 ± 3.8
After challenge test
AP0	0.30 ± 0.01	25.4 ± 5.9b	38.3 ± 0.7b	39.2 ± 3.1b	88.4 ± 6.3	1.18 ± 0.22	32.2 ± 0.2
AP25	0.32 ± 0.09	53.8 ± 11.4a	58.4 ± 6.2a	43.4 ± 2.2ab	85.6 ± 7.5	1.65 ± 0.55	35.2 ± 1.7
AP50	0.29 ± 0.07	47.8 ± 9.7a	45.8 ± 4.3ab	46.8 ± 1.9a	82.6 ± 3.0	1.64 ± 0.25	38.9 ± 4.0

Values are mean of quadruplicate groups and presented as mean ± SD.
Values in the same column having different superscript letters are significantly different (p ≤ 0.05). The diets were prepared by coating 0%, 0.25%, or 0.50% of Bacillus sp. SW1-1 mixture solution (designated as AP0, AP25, or AP50, respectively).
NBT, nitro blue tetrazolium; Ig, immunoglobulin; AP, antiprotease; SOD, superoxide dismutase; MPO, myeloperoxidase; GPx, glutathione peroxidase.