Brand Orego-Stim · Manufacturer Meriden Animal Health; distributed by Actifeed
↗ public sourceswww.actifeed.com/orego-stim.html· 5 studies, 4 independent/mixed
Evidence · moderate
The active substance is backed by 5 studies including meta-analyses; the verdict per claim below reflects what the literature actually shows, not the brochure. Strength reflects the active substance, not the brand.
What the manufacturer claims
Free
Captured from the product page, typed and attributed — the producer’s own statements, checked against the literature below.
Physiological
Acts on a broad microbial spectrum affecting the intestinal system of all animals (antimicrobial / gut health)
Performance
Improves performance and productivity
Safety
A natural alternative tool (organic-approved) effective in difficult/challenged production situations
Manufacturer’s own words — not independently verified. The ledger below gives the evidence verdict for each.
Claim ↔ evidence ledger
Verdict free · receipts in Power
Each claim against the studies on the active substance, with the funding split. Open a row for the studies behind the verdict.
Claim
Verdict
Evidence & funding
PhysiologicalActs on a broad microbial spectrum affecting the intestinal system of all animals (a…
Supported
2 studies · 100% indep
›
Read Antimicrobial/gut and anticoccidial effects are well supported by independent RCTs, including parity with an anticoccidial drug.
2015
Dietary oregano essential oil alleviates experimentally induced coccidiosis in broilers300-500 ppm oregano oil raised BW gain (P=0.039) and improved FCR (P=0.010); 500 ppm lowered intestinal lesion scores similarly to Diclazuril
Dietary benzoic acid and oregano essential oil as a substitute for an anticoccidial in Eimeria-challenged broilersOregano EO + benzoic acid matched salinomycin for coccidiosis control and improved growth, gut and immune responses
Read Performance improves especially under enteric/coccidial challenge; benefits in unchallenged or sow contexts are smaller.
2025
Essential oils alleviate coccidiosis impact in broiler chickens: a meta-analysisOregano-based EO improved final body weight under coccidia challenge (SMD = 2.51; 95% CI 0.32-4.69; P<0.05); EO also raised ADG in unchallenged birds
Evaluation of the phytogenic Orego-Stim in broilers during Eimeria maxima challenge (SPRG, PSA 2022)Greater body-weight gain and numerically improved FCR at 21 d vs infected control; lower late coccidia cycling
SafetyA natural alternative tool (organic-approved) effective in difficult/challenged prod…
Not addressed
no study
›
The 'natural alternative in difficult situations' framing is consistent with the challenge data but not separately tested as a claim.
IndependentMixedIndustryNone/undisclosed
Bottom line. Oregano essential oil (carvacrol/thymol) has strong independent support as a gut-health and anticoccidial phytogenic in poultry, including a meta-analysis and an RCT matching an anticoccidial drug on lesion scores.
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Evidence — on the active substance
Table free · full-text in Power
Why these studies The evidence for a proprietary product is the evidence for its active substance. These are the studies (meta-analyses first) behind the verdicts above, with funding labelled.
Year
Study & effect size
Funding
Type
Access
2025
Essential oils alleviate coccidiosis impact in broiler chickens: a meta-analysisOregano-based EO improved final body weight under coccidia challenge (SMD = 2.51; 95% CI 0.32-4.69; P<0.05); EO also raised ADG in unchallenged birds
Dietary benzoic acid and oregano essential oil as a substitute for an anticoccidial in Eimeria-challenged broilersOregano EO + benzoic acid matched salinomycin for coccidiosis control and improved growth, gut and immune responses
Evaluation of the phytogenic Orego-Stim in broilers during Eimeria maxima challenge (SPRG, PSA 2022)Greater body-weight gain and numerically improved FCR at 21 d vs infected control; lower late coccidia cycling
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Analysis & tools
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Open the analyst workbench
Dose benchmark, the independent-vs-sponsored split, the pooled meta-analysis effects, the contradictions and the gaps — all derived from the studies above.
Dose: label vs effective trial range vs EU max
Independence-of-evidence breakdown
Pooled meta-analysis effect sizes
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Dose benchmark
Label / recommendedNot numerically stated
Effective in trials~300-500 ppm oregano oil in feed
EU maximumAuthorised as a flavouring (no numeric maximum; use per good practice)
Also applied via water or as a post-pelleting coating.
broiler body weight under coccidiosis challenge Independentoregano EO improved BW (SMD = 2.51; 95% CI 0.32-4.69) (0.32 to 4.69)
Pooled estimates from the systematic reviews/meta-analyses above — the closest thing to a settled answer.
Discussion — grounded in the evidence
Oregano essential oil (carvacrol/thymol) has strong independent support as a gut-health and anticoccidial phytogenic in poultry, including a meta-analysis and an RCT matching an anticoccidial drug on lesion scores.
Performance benefits are largest under enteric or coccidial challenge; in healthy birds or for suckling-pig growth the effect is smaller.
The one product-specific (Orego-Stim) trial showing a benefit under E. maxima challenge is manufacturer-linked.
In the EU the product is authorised as a sensory additive (flavouring); it is not authorised as a coccidiostat or zootechnical additive despite the gut-health positioning.
Evidence is mostly for oregano oil as a class; the manufacturer's claimed patent could not be tied to a resolvable number.
Where studies disagree: Benefits are clearest under enteric/coccidial challenge; in unchallenged birds or for suckling-pig growth the effect is smaller or inconsistent. Marketed broadly for 'all animals', but the strong evidence is concentrated in poultry coccidiosis.
Gaps: The Actifeed page makes only general performance/antimicrobial claims; the best-evidenced use (anticoccidial) is not explicitly stated. Product-specific independent (non-manufacturer) data are limited. No resolvable patent identified despite the manufacturer's patent claim.
Manufacturer’s stated mechanism (their words): Carvacrol and thymol disrupt microbial and protozoal cell membranes, modulating gut microbiota and the host immune/antioxidant response, which lowers enteric challenge (incl. Eimeria) and supports feed intake and performance.
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Put this beside alternatives on the same active substance (e.g. HMBi / other rumen-protected methionine), and take the data with you.
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