Natural alternatives to in-feed antibiotics: Screening compounds to combat necrotic enteritis

To combat the growing issue of antimicrobial resistance, the U.S. has restricted the use of in-feed antibiotics in poultry production since 2017. This has resulted in diseases such as necrotic enteritis (NE), which is caused by Clostridium perfringens, to become more widespread, necessitating more effective mitigation strategies. This study aimed to investigate the potential of using natural products as a preventative for NE. Thirteen natural compounds were selected from a previous screening for further evaluation for their antimicrobial activity. Several antibacterial tests such as agar well diffusion assay, minimum inhibitory concentration, minimum bactericidal concentration and time-kill assays were performed to evaluate the relative potency of these compounds. Further, to evaluate the impact on host immunity, the effect of selected compounds on regulating host defense peptide (HDP) gene expression was investigated in vitro. The results of this study demonstrate the potential of ursolic acid and celastrol to prevent NE through inhibition of C. perfringens and stimulation of host immunity.