Effects of some ionophore antibiotics and polyoxins on the growth of anaerobic rumen fungi

I. K.O. Cann, Y. Kobayashi, A. Onoda, M. Wakita, S. Hoshino

Research output: Contribution to journalReview articlepeer-review


The growth of mixed rumen fungi in vitro was suppressed by both ionophore antibiotics (salinomycin, monensin and portmicin) and polyoxins (polyoxin B and D: inhibitors of chitin synthesis). The fungistatic effect of the ionophores on a Piromonas spp. was more pronounced than on a Neocallimastix spp. The polyoxins, however, were more potent fungistatically against the Neocallimastix spp. than the Piromonas spp. Higher concentrations of the polyoxins were required to elicit the same effect as that observed with the ionophores. Salinomycin administration decreased fungal count in the rumen of sheep, but fungal count increased after the cessation of the feeding of the antibiotic. Polyoxin D also suppressed the growth of fungi in vivo, but the effect was short‐lived. Nevertheless, both bacterial and protozoal counts tended to increase during and after the administration of polyoxin D. Total volatile fatty acid concentrations in the rumen tended to increase during the period of polyoxin D administration. This increasing tendency was maintained for 10 d after the cessation of antibiotic administration. Offering polyoxin D to sheep increased production of propionate (P < 0·05), while decreasing that of acetate. The results indicate that the rumen fungi are sensitive to chitin synthesis inhibitors as well as ionophores, and are essential members of microbes in the rumen ecosystem.

Original languageEnglish (US)
Pages (from-to)127-133
Number of pages7
JournalJournal of Applied Bacteriology
Issue number2
StatePublished - Feb 1993
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Applied Microbiology and Biotechnology


Dive into the research topics of 'Effects of some ionophore antibiotics and polyoxins on the growth of anaerobic rumen fungi'. Together they form a unique fingerprint.

Cite this