Abstract
The antimicrobial activity of the novel ionophore tetronasin (formerly ICI 139603) was compared with that of monensin for the growth of ruminal bacteria, protozoa, and an anaerobic fungus. The potency of tetronasin toward most bacteria and the fungus was an order of magnitude or more greater than that of monensin. Lactobacillus casei was 55 times more sensitive to tetronasin than to monensin, indicating a potential role for tetronasin in reversing lactic acidosis. Bacteria with a gram-positive ultrastructure were generally sensitive to the ionophores and unable to adapt to grow in their presence. The exception was the cellulolytic Ruminococcus flavefaciens, which adapted during successive cultivation on media with increasing ionophore concentrations to grow at 100-fold higher concentrations of tetronasin than were initially lethal to the organism. Gram-negative bacteria were more resistant and generally able to adapt to grow in the presence of both ionophores. An in vivo trial with cattle and in vitro growth experiments indicated that the effect of tetronasin on ciliate protozoa was minor. In vitro experiments measuring hydrogen production by Neocallimastix frontalis suggested that this fungus would be unable to survive in ruminants receiving tetronasin.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Chen M., Wolin M. J. Effect of monensin and lasalocid-sodium on the growth of methanogenic and rumen saccharolytic bacteria. Appl Environ Microbiol. 1979 Jul;38(1):72–77. doi: 10.1128/aem.38.1.72-77.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dennis S. M., Nagaraja T. G., Bartley E. E. Effects of lasalocid or monensin on lactate-producing or -using rumen bacteria. J Anim Sci. 1981 Feb;52(2):418–426. doi: 10.2527/jas1981.522418x. [DOI] [PubMed] [Google Scholar]
- Dennis S. M., Nagaraja T. G., Dayton A. D. Effect of lasalocid, monensin and thiopeptin on rumen protozoa. Res Vet Sci. 1986 Sep;41(2):251–256. [PubMed] [Google Scholar]
- Van Nevel C. J., Demeyer D. I. Effect of monensin on rumen metabolism in vitro. Appl Environ Microbiol. 1977 Sep;34(3):251–257. doi: 10.1128/aem.34.3.251-257.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]