# Safety and efficacy of a feed additive consisting of Bacillus velezensis NRRL B‐67647, Bacillus pumilus NRRL B‐67648 and Bacillus licheniformis NRRL B‐67649 (Microsaf®) for chickens for fattening, other poultry for fattening and ornamental birds (S.I. Lesaffre)

**Authors:** Roberto Edoardo Villa, Giovanna Azimonti, Eleftherios Bonos, Henrik Christensen, Mojca Durjava, Birgit Dusemund, Ronette Gehring, Boet Glandorf, Maryline Kouba, Marta López‐Alonso, Francesca Marcon, Carlo Nebbia, Alena Pechová, Miguel Prieto‐Maradona, Ilen Röhe, Katerina Theodoridou, Baltasar Mayo, Montserrat Anguita, Nicole Bozzi Cionci, Rosella Brozzi, Matteo L. Innocenti, Jordi Ortuño, Piera Valeri, Yolanda García‐Cazorla

PMC · DOI: 10.2903/j.efsa.2025.9465 · EFSA Journal · 2025-06-10

## TL;DR

This study evaluates the safety and effectiveness of a feed additive containing three Bacillus species for poultry and ornamental birds.

## Contribution

The study confirms the safety and efficacy of Microsaf® for poultry and ornamental birds using a qualified presumption of safety approach.

## Key findings

- Microsaf® is safe for target species, consumers, and the environment.
- The additive improves zootechnical performance in chickens for fattening.
- It is compatible with several commonly used feed additives.

## Abstract

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of Microsaf® when used as a feed additive for chickens for fattening, other poultry for fattening and ornamental birds. The product under assessment is based on viable cells/spores of Bacillus velezensis NRRL B‐67647, Bacillus pumilus NRRL B‐67648 and Bacillus licheniformis NRRL B‐67649. The three bacterial species are considered by EFSA to be suitable for the qualified presumption of safety approach to safety assessment. As the identity of the strains was clearly established, no acquired antimicrobial resistance determinants of concern were detected and the lack of toxigenic potential was corroborated, the FEEDAP Panel considered the use of the active agents safe for the target species, consumers and the environment. Since no concerns are expected from the other components of the additive, the Panel concluded that Microsaf® is also considered safe for the target species, consumers and the environment. Regarding user safety, the additive is not irritant to the skin or eyes provided it is formulated with only calcium carbonate. The additive should be considered skin and respiratory sensitisers, and any exposure via skin or respiratory tract is considered a risk. The FEEDAP Panel concludes that the additive has the potential to improve the zootechnical performance of chickens for fattening at a proposed minimum inclusion level of 3 × 107 total CFU/kg of complete feedingstuffs. These results are extrapolable to other poultry for fattening and ornamental birds. Microsaf® is compatible with diclazuril, narasin, maduramicin ammonium, salinomycin sodium, monensin sodium, robenidine hydrochloride and the combination narasin/nicarbazin, lasalocid and halofuginone.

## Linked entities

- **Chemicals:** calcium carbonate (PubChem CID 10112), diclazuril (PubChem CID 456389), narasin (PubChem CID 65452), maduramicin ammonium (PubChem CID 68595), salinomycin sodium (PubChem CID 6602450), monensin sodium (PubChem CID 23667299), robenidine hydrochloride (PubChem CID 16212175), lasalocid (PubChem CID 5360807), halofuginone (PubChem CID 400772)

## Full-text entities

- **Chemicals:** halofuginone (MESH:C010176), narasin (MESH:C013612), robenidine hydrochloride (MESH:D012370), monensin sodium (MESH:D008985), maduramicin ammonium (MESH:C018091), diclazuril (MESH:C057884), nicarbazin (MESH:D009528), Microsaf (-), lasalocid (MESH:D007832), calcium carbonate (MESH:D002119)
- **Species:** Bacillus pumilus (species) [taxon 1408], Bacillus licheniformis (species) [taxon 1402], Gallus gallus (bantam, species) [taxon 9031]
- **Cell lines:** NRRL B-67647 — Opodiphthera eucalypti (Emperor gum moth), Spontaneously immortalized cell line (CVCL_C2VY)

## Full text

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## References

10 references — full list in the complete paper: https://tomesphere.com/paper/PMC12149980/full.md

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Source: https://tomesphere.com/paper/PMC12149980