Evaluating the production and efficacy of bacteriocins by potential probiotic bacteria isolated from chicken gut using dynamic in vitro gastrointestinal tract models

• Grant number: 21/13413-8
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: April 01, 2022
• End date: March 31, 2023
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Ricardo Pinheiro de Souza Oliveira
• Grantee: Carlos Miguel Nóbrega Mendonça
• Supervisor: Koen Venema
• Host Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Maastricht University, Venlo (UM), Netherlands
• Associated to the scholarship: 20/13271-6 - Production of bacteriocin-producing probiotic bacteria, BP.DD

Abstract

Demanded by the urgent need of a global public health response to the long-term threat from infectious diseases, the agrarian industry has been implementing a set of alternative, sustainable sanitation, hygienic and infection preventive measures to the use of non-therapeutic antimicrobial agents. Within these new methods stands the supplementation of animal feed with probiotics and functional as well as bioactive ingredients. Given the lack of a complete understanding of the potential of bacteriocinogenic probiotics in the poultry gastrointestinal tract, the extension of their use by agrarian industry at intensive livestock farming activities has been limited worldwide. Thus, a deep evaluation of their potential application on poultry feeding formulations is proposed in the present project. From a general point of view, the proposal aims to evaluate the production of antimicrobial compounds, such as bacteriocins and lactate, by newly isolated bacteriocinogenic bacteria under conditions analogues to the gastrointestinal tract (GIT) of chicken. Moreover, it intends to evaluate the ability of the isolated strains to reduce GIT pH of chicken. In that sense the effects of different potent acidifiers, low pH tolerant as well as bacteriocins producer Lactic Acid Bacteria strains will be evaluated using sophisticated in vitro GIT models. Four strains will be selected according to the best bacteriocinogenic, probiotic and acidification profile, and tests evaluating its supplementation either individually or as mixed-strain culture(s) will be performed. The probiotic growth will be evaluated along the different section of the in vitro GIT models by viable counts enumeration (pure culture assays) and PCR analysis of 16S rRNA (mixed strain). The bacteriocin production will be also evaluated along the different section of the GIT in vitro models by the analysis of its transcripts. The evaluation of synergistic and antagonistic effects regarding the production of bacteriocins in the mixed strain assays will be taken in consideration. If effective, the studied bacteriocinogenic strains will be used in future in vivo experiments. Based on the obtained data it is expected to contribute to the understanding of the potential of bacteriocinogenic probiotics on new dietary practices and poultry diet formulations with the ultimate goal of providing new selection criteria for the formulation of poultry feed supplements. (AU)