Benefits of a next generation probiotic in poultry
In recent years, the use of probiotics has emerged as a sustainable and scientifically supported strategy to enhance poultry gut health and performance, particularly in the context of reducing antibiotic use.
Probiotics are live microorganisms which, when administered in adequate amounts, confer health benefits to the host. In poultry, the gastrointestinal tract is central to nutrient absorption, immunity, and disease resistance, making gut health a critical area of focus.
Among various probiotic candidates, spore-forming Bacillus subtilis strains, like DSM 29784 (commercially known as Alterion, named Bs29784), stand out for their stability, consistent performance, and multiple mechanisms of action. Bs29784 has been shown to improve gut microbial balance, maintain intestinal barrier integrity, regulate immune responses, and effectively germinate in vivo to exert its beneficial effects.
A healthy and diverse microbiota is essential for robust gut function. Bs29784 enhances microbial balance by increasing the relative abundance of beneficial bacterial taxa while limiting the presence of pathogenic organisms.
In a 42-day study conducted at Southern Poultry Research (US), broilers supplemented with Bs29784 (1×10⁸ CFU/kg feed) exhibited a significant increase in beneficial genera such as Ruminococcus (6.99% vs. 3.74% in control) and Lachnoclostridium (0.94% vs. 0.47%). These bacteria contribute to the breakdown of complex carbohydrates into short-chain fatty acids, especially butyrate, which fuels enterocytes and inhibits inflammation.
Moreover, under necrotic enteritis challenge conditions, Bs29784 supplementation significantly increased microbial alpha-diversity and enhanced the prevalence of Faecalibacterium prausnitzii by +13.4%, a species strongly associated with intestinal health and inflammation control. Such modulation limits the colonisation and proliferation of pathogenic bacteria like Clostridium perfringens and Salmonella, creating a more stable and protective microbial environment.
The intestinal barrier is composed of epithelial cells and tight junctions that prevent the translocation of harmful substances from the gut lumen into systemic circulation. Disruption of this barrier leads to increased permeability, inflammation, and impaired nutrient absorption. Bs29784 strengthens this barrier through multiple mechanisms. In vivo, Bs29784 supplementation led to significantly longer microvilli in the ileum (+18%) and cecum (+17%), supporting increased nutrient absorption. Gene expression analyses from jejunal tissue showed upregulation of key tight junction proteins, including CLDN1, JAM2, and TJP1, indicating improved junctional integrity.
In an in vitro model using Caco-2 cells challenged with TNF-α (a pro-inflammatory cytokine), Bs29784 restored transepithelial electrical resistance (TEER) to levels close to non-stimulated controls (from 1,287 Ω·cm² to 1,723 Ω·cm²) and significantly reduced D-mannitol permeability (from 22.19 to 14.11 fmol/cm²), demonstrating its protective role in maintaining epithelial cohesion under stress conditions.
An overactive inflammatory response diverts energy from growth to immune activity. Thus, regulating inflammation is key to optimising performance. Bs29784 modulates the immune system by reducing the production of pro-inflammatory mediators and supporting anti-inflammatory pathways. In an in vitro Caco-2 cell model exposed to IL-1β, a strong inducer of inflammation, Bs29784 significantly decreased IL-8 secretion to levels comparable with non-stressed controls and the polyphenol epigallocatechin gallate (EGCG), known for its anti-inflammatory effects. In contrast, other commercial Bacillus strains (Bs A and Bs B) not only failed to reduce IL-8 production but in some cases exacerbated the inflammatory response when combined with mycotoxins like deoxynivalenol.
Bs29784 also indirectly contributes to immune balance by increasing gut microbial production of SCFAs like butyrate, which promotes the secretion of antimicrobial host defense peptides (HDPs) and suppresses the expression of Salmonella pathogenicity genes (SPI-1), further reinforcing gut homeostasis.
Finally, the ability of Alterion to germinate in the gut is a prerequisite for exerting its beneficial effects. Its spores are metabolically dormant but highly resistant to environmental stresses such as heat and acidity. Upon ingestion, they must germinate into vegetative cells to become active. Bs29784’s germination has been uniquely confirmed in vivo using a dual-fluorescence reporter system. This innovative technique tags spores with green fluorescence and vegetative cells with red fluorescence (dsRed).
In a 13-day broiler study, intestinal samples from Bs29784-supplemented birds showed predominant red fluorescence in the ileum, indicating successful germination and activation of spores within 72 hours.
In a field trial done in Thailand (2 cycles of production, 4 farms involved), intestinal contents (ileum, cecum) of broiler chickens were collected over the 35 days of life and the presence of Bs29784 was assessed by quantitative digital-PCR (Figure 1). This showed in commercial conditions the efficacy of the germination process of Bs 29784. Additionally, in vivo quantification of specific metabolites – niacin, pantothenate, and hypoxanthine – confirmed that their intestinal concentrations were tightly correlated with Alterion-derived Bacillus counts, highlighting the metabolic activity and efficacy of the strain post-germination.
Alterion exemplifies a next-generation probiotic tailored to poultry needs. Through targeted modulation of microbiota, reinforcement of the gut barrier, immune regulation, and demonstrated in vivo germination, it consistently improves bird performance and supports a sustainable, antibiotic-free production system.
References available on request.
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