Scientific Opinion on the safety and efficacy of Miya-Gold (Clostridium butyricum) for chickens for fattening, chickens reared for laying and minor avian species

zootechnical additive, Clostridium butyricum, efficacy, safety, chickens for fattening, chickens reared for laying, minor avian species
First published in the EFSA Journal
8 January 2013
11 December 2012
Scientific Opinion


Miya-Gold is an additive containing viable spores of a single strain of Clostridium butyricum as the active agent. It is presently authorised for use in diets for weaned piglets, minor weaned porcine species, chickens for fattening and minor avian species for fattening. The applicant is now seeking to reduce the minimum authorised dose from 5 x 108 CFU/kg feed to 2.5 x 108 CFU/kg feed when used with chickens for fattening and all minor avian species (except laying birds) and to extend this authorisation to chickens reared for laying. The safety for the consumers, users of the product and the environment has been previously assessed by EFSA and found that it did not raise concerns. In a previous opinion the FEEDAP Panel concluded that the additive is safe for chickens for fattening when used at the then recommended dose. The Panel considers that this conclusion can be extended to chickens reared for laying. This conclusion can be taken to apply to the revised dose for all of species under application. The data from three trials made with chickens for fattening confirmed the effectiveness of the additive when used at the currently authorised dose of 5 x 108 CFU/kg feed. Effects with the reduced dose of 2.5 x 108 CFU/kg feed were less clear and showed significantly positive results in only two of the five trials in which this dose was tested. However, a meta-analysis made by pooling results from the five trials showed significant gains in final body weight and improved feed conversion indicating that the additive had some potential to improve performance of chickens for fattening at the lower dose. This conclusion can be extended to chickens reared for laying and extrapolated to minor avian species (other than those used for laying).

Panel members at the time of adoption

Gabriele Aquilina, Alex Bach, Vasileios Bampidis, Maria De Lourdes Bastos, Gerhard Flachowsky, Josep Gasa-Gasó, Mikolaj Antoni Gralak, Christer Hogstrand, Lubomir Leng, Secundino López-Puente, Giovanna Martelli, Baltasar Mayo, Derek Renshaw, Guido Rychen, Maria Saarela, Kristen Sejrsen, Patrick Van Beelen, Robert John Wallace and Johannes Westendorf.
Panel on Additives and Products or Substances used in Animal Feed
EFSA Journal 2013;11(1):3040
Question Number
On request from
European Commission