TDK conference 2022

Swine dysentery causing pathogen Brachyspira hyodysenteriae becomes increasingly difficult to eliminate from the herd due to widespread antimicrobial resistance. Due to restrictions on the use of antimicrobial drugs all over the world, functional feed additives have been applied to protect the health of the animals. Phytogenic feed additives have been found to act as antioxidant, antimicrobial, anti-inflammatory, and they directly influence the host immune system. However, the exact mechanism of action of certain herbal feed additive products is unknown, therefore our goal is to determine the mechanism of action of a natural plant-based feed additive on B. hyodysenteriae bacteria.

To explore the possible mechanism of action, the B. hyodysenteriae cultures were treated with three different concentrations of a plant-based feed additive. Then the control and treated bacterial suspensions were centrifuged, and RNA was isolated from each sample. After the reverse transcription step, the flagellum-coding targets of B. hyodysenteriae were measured via quantitative polymerase chain reaction (qPCR) method.

The expressions of certain flagellar assembly genes and flagellar hook protein-coding genes were resulted in concentration-dependent decrease following the treatment with the plant-based feed additive test material.

Flagellum is an important virulence factor of pathogen bacteria through chemotaxis, adhesion and invasion of host surfaces; therefore, inhibition of flagellum-formation may be an important target for the different substances to prevent pathogens from entering the host. Further studies are required to determine the efficacy of the treatment substance in live animals.