Safety and efficacy of Monteban® G100 (narasin) for chickens for fattening

Abstract

The feed additive Monteban® G100, containing the active substance narasin, an ionophore anticoccidial, is intended to control coccidiosis in chickens for fattening at a dose of 60–70 mg/kg complete feed. Narasin is produced by fermentation. Limited data on the taxonomic identification of the production strain did not allow the proper identification of strain NRRL 8092 as Streptomyces aureofaciens. The FEEDAP Panel cannot conclude on the absence of genetic determinants for antimicrobial resistance in Streptomyces spp. under assessment. Based on the available data set, the FEEDAP Panel cannot conclude on the safety of Monteban® G100 for chickens for fattening. The simultaneous use of Monteban® G100 and certain antibiotic drugs (e.g. tiamulin) is contraindicated. Narasin is not genotoxic. No indication of carcinogenicity or developmental toxicity was found at the doses tested in the mouse, rat and rabbit. The lowest no observed effect level (NOEL) identified in the oral toxicity studies was 0.5 mg/kg body weight (bw) per day for the neuropathy seen in a one‐year dog study. The acceptable daily intake (ADI) derived from this NOEL is 0.005 mg narasin/kg bw applying a uncertainty factor of 100. Monteban® G100 is safe for the consumer. Maximum residue limits (MRLs) of 50 μg narasin/kg for all wet tissues ensure consumer safety. Monteban® G100 is irritatant to the eyes but not to the skin. It has the potential to induce skin sensitisation. Inhalation exposure would pose a risk to persons handling the additive. Narasin, when used as a feed additive for chickens for fattening at 70 mg/kg feed, is not expected to pose a risk to the environment. The risk for sediment compartment cannot be assessed. The FEEDAP Panel cannot conclude on the efficacy of Monteban® at the minimum applied dose of 60 mg narasin/kg complete feed for chickens for fattening.

Modification of the terms of authorisation regarding the maximum inclusion level of Maxiban® G160 (narasin and nicarbazin) for chickens for fattening

“…In its opinion on the safety and efficacy of Monteban ® G100 containing narasin produced by the same microorganism (EFSA FEEDAP Panel, ), the FEEDAP Panel concluded that: ‘Limited data on the taxonomic identification of the production strain did not allow the proper identification of strain NRRL 8092 as Streptomyces aureofaciens . The FEEDAP Panel cannot conclude on the absence of genetic determinants for antimicrobial resistance in Streptomyces spp.…”

“…The holder of the authorisation of Maxiban ® G160 and Monteban ® G100 is the same and narasin from Maxiban ® G160 is applied at the same maximum concentration as narasin from Monteban ® G100. The applicant submitted the same literature search on the tolerance of narasin in poultry covering the period 2000–2014 using several databases that has been assessed by the FEEDAP Panel in 2018 in its opinion on the safety and efficacy of Monteban ® G100 for chickens for fattening (EFSA FEEDAP Panel, ) . The applicant claimed that no papers relevant to the safety of the target species were identified…”

“…The applicant provided the same review of pharmacovigilance case data on narasin assessed by the FEEDAP Panel in 2018 (EFSA FEEDAP Panel, ): the database of the company was queried for the product family Monteban and all cases reported in Europe during the period from 30 June 2004 to 1 July 2014. The query returned a total of 14 cases (3 cases in the target species (chicken) and 11 cases in non‐target animal species).…”

“…Data on the interactions of narasin with feed materials, other approved additives or medicinal products have been assessed by the FEEDAP Panel in the past (EFSA, ; EFSA FEEDAP Panel, ). In its recent opinion on the re‐evaluation of Monteban ® G100 (containing narasin) for chickens for fattening (EFSA FEEDAP Panel, ) the FEEDAP Panel concluded that ‘the simultaneous use of Monteban ® G100 and certain antibiotic drugs (e.g. tiamulin) is contra‐indicated’.…”

“…The active substance narasin, as the only active substance of the product Monteban ® G100, was assessed by the FEEDAP Panel in 2004 (EFSA, ) and re‐evaluated in 2018 (EFSA FEEDAP Panel, ). Monteban ® G100 is intended to be used for chickens for fattening at a dose range of 60–70 mg narasin/kg complete feed .…”