Effects of the antimicrobial peptide cecropin AD on performance and intestinal health in weaned piglets challenged with Escherichia coli

► Twenty-four weaned barrows were used to determine the effects of a dietary antimicrobial peptide in weaned pigs challenged with E. coli. ► We checked changes in growth performance, diarrhea, intestinal health and immune response pre and post-chanllenge. ► Antimicrobial peptides cecropin AD appeared to mediate immune status to improve the performance and reduce diarrhea incidence after E. coli challenge. ► Antimicrobial peptides have potential for use as alternatives to antibiotics in diets fed to weaned piglets. This study was conducted to determine the effects of the antimicrobial peptide cecropin on performance and intestinal health in piglets. Newly weaned barrows were randomly assigned to one of three treatments (n=8), including a corn-soybean basal diet or similar diets supplemented with antibiotics (100mg/kg kitasamycin plus 800mg/kg colistin sulfate) or 400mg/kg cecropin AD. On day 13, all piglets were orally challenged with 109CFU/mL of Escherichia coli K88. On day 19, all piglets were euthanized and sampled. Before challenge, piglets fed antibiotics had greater weight gain, feed efficiency, nitrogen and energy retention than the control (P