A study on fungal defensin against multidrug-resistant Clostridium perfringens and its treatment on infected poultry.

In the present study, we aimed to investigate the antibacterial activity and mechanisms of plectasin-derived peptide NZ2114 in vitro and its therapeutic effects in vivo on broilers challenged with Clostridium perfringens. In vitro assay showed that NZ2114 had potent (minimal inhibitory concentration, 0.91 μM) and rapid antibacterial activity (99.9% reduction within 2 h), and the dual antibacterial mechanisms (including interfering with the cell membrane and intracellular DNA) against C. perfringens CVCC 2030. In vivo study, NZ2114 tended to increase linearly and quadratically the average daily gain as NZ2114 level increased and was the highest at 20 mg/L. NZ2114 at 10 ~ 40 mg/L dramatically reduced jejunal lesion score. Besides, the levels of IL-6, TNF-α, and IL-1β tended to downregulate linearly and quadratically as the NZ2114 level increased and were all the lowest at the dose of 20 mg/L. NZ2114 significantly upregulated those levels of IgA, IgG, IgM, and sIgA with a linear and quadratic dose effect, with the highest IgA, IgG, IgM, and sIgA at 20 mg/L. Finally, NZ2114 tended to linearly and quadratically increase the numerical value of crypt depth, with the lowest value at 40 mg/L. Lincomycin only dramatically reduced the jejunal lesion score and increased the numerical value of crypt depth. These results indicate that NZ2114 has the potential as a new alternative to antibiotics for the treatment of C. perfringens-induced necrotic enteritis infection.Key points• NZ2114 could kill C. perfringens by dual antibacterial mechanisms• Broiler necrotic enteritis model induced by C. perfringens was established• NZ2114 treatment could ameliorate C. perfringens-induced necrotic enteritis.