Isolation and Characterization of Bacterial Probiotic Candidates from Chicken Gut with Bacteriocinogenic Properties

Abstract

Exposure to chicken and other poultry products has been identified as both a common source of campylobacteriosis and salmonellosis outbreaks and as a risk factor for sporadic infection with these pathogens. With the recent ban on the use of antibiotics as growth promoters and for prophylaxis, producers will have to change the way the industry raises broilers by trying to mitigate the spread of poultry pathogens while maintaining the productivity of the past. The main objective of this research project was to isolate and characterize bacterial strains from broiler chicken gastrointestinal tract with inhibitory activity against Salmonella and Clostridium perfringens. Several isolates from the caecal mucosa have been identified and their activity characterized. Of 290 active colonies pre-selected using a double-layer technique, a total of 31 colonies were able to produce a supernatant inhibiting Salmonella Abony and Clostridium perfringens and were identified as Ligilactobacillus salivarius, Ligilactobacillus agilis, Lactobacillus johnsonii, Lactobacillus. kitasatonis, Lactobacillus sp., and a new uncultured bacterium. Five most potent strains were further characterized for their probiotic potential (i.e., sensitivity to antibiotics and tolerance to gastrointestinal physicochemical conditions). Importantly, all five strains harbor bacteriocin genes, as evidenced by performing whole-genome sequencing.