Effect of in-water administration of quorum system inhibitors in broilers' productive performance and intestinal microbiome in a mild necrotic enteritis challenge.

Abstract

The poultry industry has been facing the impact of necrotic enteritis (NE), a disease caused by the bacteriumproducing the haemolytic toxin NetB. NE severity may vary from mild clinical to prominent enteric signs causing reduced growth rates and affecting feed conversion ratio. NetB production is controlled by the Agr-like quorum-sensing (QS) system, which coordinates virulence gene expression in response to bacterial cell density. In this study, the peptide-containing cell-free spent media (CFSM) fromwas tested in NE challenged broilers in two battery cage and one floor pen studies. Results showed a significant reduction of NE mortality. Metagenomic sequencing of the jejunum microbiome revealed no impact of the CFSM on the microbial community, and growth ofwas unaffected by CFSM. The expression of QS-controlled virulence genesandwas found to be significantly repressed by CFSM during the mid-logarithmic stage ofgrowth and this corresponded with a significant decrease in haemolytic activity. Purified fractions of CFSM containing bioactive peptides were found to cause reduced haemolysis. These results showed that bioactive peptides reduce NE mortality in broilers by interfering with the QS system ofand reducing bacterial virulenceFurthermore, the microbiome of-challenged broilers is not affected by quorum sensing inhibitor containing CFSM.