Probiotic Bacillus Strains Enhance T Cell Responses in Chicken

Abstract

Banning antibiotic growth promotors and other antimicrobials in poultry production due to the increasing antimicrobial resistance leads to increased feeding of potential alternatives such as probiotics. However, the modes of action of those feed additives are not entirely understood. They could act even with a direct effect on the immune system. A previously established animal-related in vitro system using primary cultured peripheral blood mononuclear cells (PBMCs) was applied to investigate the effects of immune-modulating feed additives. Here, the immunomodulation of different preparations of two probiotic Bacillus strains, B. subtilis DSM 32315 (BS), and B. amyloliquefaciens CECT 5940 (BA) was evaluated. The count of T-helper cells and activated T-helper cells increased after treatment in a ratio of 1:3 (PBMCs: Bacillus) with vital BS (CD4+: p < 0.05; CD4+CD25+: p < 0.01). Furthermore, vital BS enhanced the proliferation and activation of cytotoxic T cells (CD8+: p < 0.05; CD8+CD25+: p < 0.05). Cell-free probiotic culture supernatants of BS increased the count of activated T-helper cells (CD4+CD25+: p < 0.1). UV-inactivated BS increased the proportion of cytotoxic T cells significantly (CD8+: p < 0.01). Our results point towards a possible involvement of secreted factors of BS in T-helper cell activation and proliferation, whereas it stimulates cytotoxic T cells presumably through surface contact. We could not observe any effect on B cells after treatment with different preparations of BS. After treatment with vital BA in a ratio of 1:3 (PBMCs:Bacillus), the count of T-helper cells and activated T-helper cells increased (CD4+: p < 0.01; CD4+CD25+: p < 0.05). Cell-free probiotic culture supernatants of BA as well as UV-inactivated BA had no effect on T cell proliferation and activation. Furthermore, we found no effect of BA preparations on B cells. Overall, we demonstrate that the two different Bacillus strains enhanced T cell activation and proliferation, which points towards an immune-modulating effect of both strains on chicken immune cells in vitro. Therefore, we suggest that administering these probiotics can improve the cellular adaptive immune defense in chickens, thereby enabling the prevention and reduction of antimicrobials in chicken farming.

Association of Bacillus subtilis and Bacillus amyloliquefaciens: minimizes the adverse effects of necrotic enteritis in the gastrointestinal tract and improves zootechnical performance in broiler chickens

“…However, there are reports that these effects are substantial and do not show improvements in zootechnical performance and necrotic enteritis in broiler chickens ( Jerzsele et al, 2012 ; Geeraerts et al, 2016 ). These results are in line with existing literature, as the positive effects of combining Bacillus subtilis and Bacillus amyloliquefaciens are better than when administered individually ( Sandvang et al, 2021 ; Khalid et al, 2022 ; Zhang et al, 2022 ; Larsberg et al, 2023 ).…”

Characteristics of gut microbiota in chicken early life

“…The most common bacteria found in the gut microbiota of commercial broiler chickens include the genera Lactobacillus, Bifidobacterium, and Escherichia (Bolton, 1965;Wielen et al, 2002;Yeoman et al, 2012;Saxena et al, 2016). Bacillus is recognized for its role in promoting gut health, increasing the growth rate and body weight of poultry, and enhancing the immune system, and thus resistance to bacterial infections (Additives et al, 2019;Bilal et al, 2021;Larsberg et al, 2023). Ligilactobacillus is believed to contribute to maintaining gut microbiota balance, enhancing intestinal mucosal barrier function, alleviating inflammation, and supporting the immune system (Moretti et al, 2022).…”

Bacillus subtilis PM5 from Camel Milk Boosts Chicken Immunity and Abrogates Salmonella entertitidis Infections

“…The website (https://lpsn.dsmz.de/search?word=Bacillus, accessed on accessed on 15 April 2023) provides a comprehensive list of Bacillus species. Species of Bacillus displayed remarkable positive impacts, including enhancing T-cell responses in chickens [17], alleviating colitis [7], and attenuating neurodegenerative symptoms in mouse models [8].…”