Table 3.

The experimental groups for animal trials.

Groups	Treatment	Vaccine	Challenge Strain	Serum Collected
1	Negative control	PBS	PBS	Yes
2	Group A	S. iniae P3SAB	S. iniae P3SAB	Yes
3	Group A positive control	PBS	S. iniae P3SAB	-
4	Group B	S. iniae P3SAB	S. iniae Si 6-21	Yes
5	Group B positive control	PBS	S. iniae Si 6-21	-
6	Group C	S. iniae P3SAB	S. iniae CB Si-1	Yes
7	Group C positive control	PBS	S. iniae CB Si-1	Yes

Challenge inoculum was prepared by culturing S. iniae strains in 50 mL TSB up to an optical density of 0.5 at 600 nm. Cells were washed twice and resuspended in PBS to an OD600 = 1, which corresponds to 1 × 10⁸ CFU/mL.