Poultry gut health without antibiotic growth promoters and colistin — competitive exclusion cultures, Bacillus probiotics and bacteriophages

Replaces: in-feed antibiotic growth promoters (AGPs), prophylactic colistin and fluoroquinolones · Species: poultry · Evidence: high

The chemical problem#

• AGPs (low-dose antibiotics in feed to “improve growth”) select for resistant bacteria that pass to people via meat, manure and workers. The EU banned all AGPs in 2006 (Reg. (EC) 1831/2003). Many countries in Asia, Africa and the CIS still use them, or use therapeutic antibiotics routinely in drinking water.
• Colistin is a last-resort antibiotic for human multidrug-resistant infections. In 2015 the transferable resistance gene mcr-1 was discovered in pigs and chickens in China. After China banned colistin as a growth promoter (2017), mcr-1 prevalence in animals and humans fell significantly.
• Fluoroquinolones (enrofloxacin) in poultry → resistant Campylobacter in humans. The USA withdrew enrofloxacin approval for poultry in 2005 for this reason.

Product overview#

Three proven biological tools protect the chick gut:

1. Competitive exclusion (CE) cultures — the “Nurmi concept” (Finland, 1973): day-old chicks receive a defined or undefined culture of adult chicken gut microbiota. It colonizes the empty gut of the hatchling and blocks Salmonella. Products: Aviguard, Broilact, PoultryStar (defined multi-strain), and in RU domestic analogues from probiotic producers.
2. Bacillus-based direct-fed microbials (DFM): spores of Bacillus subtilis (e.g. PB6, DSM 32315), B. amyloliquefaciens, B. licheniformis (e.g. DSM 17236) in feed. They reduce Clostridium perfringens (necrotic enteritis) and improve feed conversion. Thermostable spores survive pelleting.
3. Bacteriophages against Salmonella (feed, water or carcass): phage cocktails are authorized as food-processing aids (USA: GRAS) and as feed additives in some countries.

Supporting measures: vaccination against Salmonella (live attenuated S. Enteritidis/Typhimurium vaccines), coccidiosis vaccines (V10), organic acids, dietary fibre, and hygiene and biosecurity.

Active ingredient / Composition#

• CE: defined consortia (Lactobacillus, Bifidobacterium, Enterococcus, Pediococcus, anaerobes) or undefined caecal culture from specific-pathogen-free (SPF) birds.
• Bacillus DFM: typically 1×10⁸–1×10⁹ CFU/kg feed (per EU authorization for each strain).
• Phages: lytic Salmonella-specific phage cocktails.

Key facts#

Advantages#

• Salmonella colonization reduced by 1–5 log in challenge studies after CE treatment. It is a key tool in the Nordic Salmonella-control programs (Sweden and Finland have very low Salmonella prevalence in poultry).
• Bacillus DFMs improve FCR by about 2–4 %, which is similar to the historic effect of AGPs.
• No residues and no withdrawal period, so they suit antibiotic-free (“raised without antibiotics”) and export markets.
• Helps meet AMR policy targets (WHO/WOAH/FAO One Health).

Mode of action#

• CE: occupies attachment sites, produces short-chain fatty acids (lower pH, toxic to Salmonella), competes for nutrients, stimulates gut immunity.
• Bacillus: secretes enzymes and antimicrobial peptides, suppresses C. perfringens and its toxins (NetB), strengthens tight junctions, modulates immunity.
• Phages: infect and lyse specific Salmonella serovars only.

Application#

Limitations#

• Necrotic enteritis outbreaks may still require therapeutic antibiotic treatment prescribed by a veterinarian. The goal is to eliminate routine and prophylactic use.
• CE efficacy is lower if the chick is exposed to Salmonella before treatment. Hatchery hygiene still matters.
• Phages are serovar-specific, and resistance can develop, so they are used as a partial and rotating tool.

Evidence of displacement — D2: measurable displacement (minority share)#

Assessment (hand-reviewed): Old practice ended by law: EU-wide ban on antibiotic growth promoters (2006); Belgian sales of antibiotic-containing feed down 89% since 2011 (AMCRA); EU food-animal antimicrobials down 24% vs 2018 (EEA). The share replaced by probiotics/enzymes is not shown.

Figures found (verified as quoted, but the assessment above explains why they do not count as displacement evidence for this substitution):

• displacement — In Belgium, sales of feed containing antibiotics fell by 89.1% between 2011 and 2024. (Belgium, 2011-2024; government or intergovernmental: amcra.be)
• displacement — Sales of veterinary antimicrobials for food-producing animals in the EU fell by 24.3% between 2018 and 2024. (EU, 2018-2024; government or intergovernmental: eea.europa.eu)
• displacement — In January 2006, the European Union implemented a comprehensive ban on the use of all antibiotic growth promoters (AGPs) in animal diets. (EU, 2006; weak: jafs.com.pl)
• performance — In a commercial farm study, a combined probiotic-phage approach resulted in a 90% decrease in Salmonella presence, a 72% reduction in broiler mortality, and a 6.4% increase in broiler weight compared to standard conditions. (Italy, 2025; weak: cris.unibo.it)

Suppliers — real products and services (from the vendor index)#

Companies below are active vendors in the vendor index whose own card (profile / official website) shows this product or service — matched 2026-09-28 by keyword and checked by hand against the card text. Being listed is not an endorsement; open each card for evidence, contacts and status.

Government funding signals#

Public grants for a specific technology are a leading indicator: governments fund what regulators want to replace and what is close to practical adoption. Searched on 2026-09-27 in: EU CORDIS (FP7, Horizon 2020, Horizon Europe), US federal awards (USAspending: USDA NIFA/ARS/APHIS/Forest Service, EPA, DOE, NOAA, USAID; plus NSF and NIH), UK UKRI Gateway to Research, Australian Research Council. Each grant below was reviewed by hand for relevance. China, Brazil and India are covered in the subsection below (publication-acknowledged grants). Not covered: Russia (RSF, FASIE — not reachable from the research environment) and national agencies outside these databases. Amounts are the funder’s contribution as recorded (US NIH/UKRI: per award or fiscal year).

Signal: Strong. 5 relevant grant(s) · about €15.2M in total · jurisdictions: EU, UK.

China, Brazil, India — national research grants acknowledged in publications#

Chinese, Brazilian and Indian funders have no open grant databases reachable here, so this measures scientific papers published since 2015 that acknowledge national government grants, taken from the grant numbers publishers deposit with Crossref. Only papers whose title contains this article’s key terms are counted (a conservative lower bound; “100+” = search window full). It shows research-funding intensity, not budgets. Funders: China — NSFC, National Key R&D Program, China Agriculture Research System; Brazil — CNPq, CAPES, FAPESP, Embrapa, FAPEMIG; India — DBT, DST, ICAR, SERB, CSIR, BIRAC. Rating per country: Strong ≥50 papers · Moderate 10–49 · Weak 1–9.

Scientific evidence#

• Nurmi E, Rantala M (1973). New aspects of Salmonella infection in broiler production. Nature 241: 210–211.
• Schneitz C (2005). Competitive exclusion in poultry — 30 years of research. Food Control 16: 657–667.
• Castanon JIR (2007). History of the use of antibiotic as growth promoters in European poultry feeds. Poultry Science 86: 2466–2471.
• Liu YY, Wang Y, Walsh TR, et al. (2016). Emergence of plasmid-mediated colistin resistance mechanism MCR-1 in animals and human beings in China: a microbiological and molecular biological study. The Lancet Infectious Diseases 16: 161–168.
• Wang Y, Xu C, Zhang R, et al. (2020). Changes in colistin resistance and mcr-1 abundance in Escherichia coli of animal and human origins following the ban of colistin-positive additives in China: an epidemiological comparative study. The Lancet Infectious Diseases 20: 1161–1171.
• Jayaraman S, Thangavel G, Kurian H, Mani R, Mukkalil R, Chirakkal H (2013). Bacillus subtilis PB6 improves intestinal health of broiler chickens challenged with Clostridium perfringens-induced necrotic enteritis. Poultry Science 92: 370–374.
• Atterbury RJ, Van Bergen MAP, Ortiz F, et al. (2007). Bacteriophage therapy to reduce Salmonella colonization of broiler chickens. Applied and Environmental Microbiology 73: 4543–4549.

Bioeconomy value#

Fermentation-produced living additives replace antibiotics. This protects the effectiveness of human medicines (One Health) and opens antibiotic-free premium markets.