IFNG and tuberculosis: Plasma ELISA revealed that compared with the control group (without TB supplementation, 0%), the group with 0.06% TB supplementation in feed exhibited significantly higher levels of IFN-γ, IgM and IgG (P<0.05), and the groups with 0.06% and 0.09% TB supplementation in feed exhibited significantly higher content of C3 (P<0.05) (Figure 2).