Effect of different amounts of Enterococcus faecium probiotic on some blood serum and skin mucus immune parameters in common carp (Cyprinus carpio) fry

The effect of different concentrations of dietary Enterococcus faecium on some immune parameters in common carp was carried out on 2019 in Ahmadabad farm. For this purpose, 600 fry with average weight 11.0 ± 0.5 g were reared in 12 plastic tanks (50 fish per tank) for 56 days and had been fed by 4 different concentration of E. faecium including [0 (control), 1×107 CFU/g (T1), 1×108 CFU/g (T2), and 1×109 CFU/g (T3)]. The results showed that the most amount of serum lysozyme (46.2±2.7 IU/ml), immunoglobulin M (IgM) (38 ± 0.9 mg/dl) and components complement system C3 (24.8 ± 0.6 mg/dl) and C4 (10.4 ± 0.4 mg/dl) obtained in T3 (P < 0.05). Among the experimental treatments, the highest lysozyme activity and mucus protease activity were measured in T3 (P < 0.05). However, there was no significant difference among the experimental treatments in alkaline phosphatase activity of the skin mucus samples (P > 0.05). Based on the obtained results, it seems that applying of E. faecium at the concentration of 1×109 CFU /g in common carp diet can provide positive effects on some serum and skin mucus immune responses.