Effects of Aibellin, a Novel Peptide Antibiotic, on Rumen Fermentation In Vitro

Abstract

A new icosapeptide, aibellin, markedly modified rumen fermentation in vitro. Batch culture experiments with mixed rumen microorganisms showed that 12.5 to 25 mg/L of aibellin enhanced propionate production and reduced methanogenesis without significantly affecting production of total VFA, protozoal survival, or cellulose digestion. Aibellin had essentially the same effects in continuous culture with hay powder and concentrate. Monensin (5 mg/L) had similar effects on propionate production and methanogenesis, but total VFA, protozoa, and cellulolysis were decreased even by this low concentration of monensin. Commercially available peptide antibiotics also were compared with aibellin. Of the antibiotics examined, only graminicidin D (7.5 to 15 mg/L) enhanced propionate production and reduced methanogenesis. However, gramicidin D decreased total VFA, protozoa, and cellulolysis even at 7.5 mg/L. Alamethicin (7.5 to 15 mg/L), which resembles aibellin in its structure, did not increase propionate production but raised the percentage of propionate because of reduced production of total VFA. Alamethicin depressed methanogenesis but also decreased protozoal survival and cellulose digestion. These in vitro experiments indicate that aibellin could be a useful and potent modifier of rumen fermentation.

Comparison of nisin and monensin effects on ciliate and selected bacterial populations in artificial rumen

“…On the other hand, less competition from bacteria on which CILs feed cannot be excluded. Under in vitro conditions MON is toxic to rumen CILs (Dennis and Nagaraja 1986;Gyulai and Hudousková 1987;Hino et al 1993), which is consistent with our results. MON showed also a dominant effect in the application with NIS.…”

Effects of Cordyceps militaris on the growth of rumen microorganisms and in vitro rumen fermentation with respect to methane emissions

“…However, the modes of action of C. militaris appear similar to those of monensin and secondary plant metabolites (saponins) because the reduction of methane production in response to the addition of C. militaris was accompanied by a decrease in live protozoan population ( Figure 2) and abundance of ciliate protozoa ( Figure 3). It has been reported that monensin and saponin affect methanogens indirectly by suppressing ciliate protozoa (Hino et al, 1993;Lila et al, 2003). Rumen ciliate are known to provide hydrogen as a substrate for methanogens (Stumm and Zwart, 1986;Ushida et al, 1997), and methanogenic archaea are metabolically correlated with ciliate protozoa (Stumm et al, 1982;Newbold et al, 1995).…”

Factors affecting rumen methanogens and methane mitigation strategies

“…The ionophore affects methanogens indirectly by inhibiting protozoa and cellulolytic bacteria (Hino et al 1993), which in turn changes the dominant product of sugar fermentation from acetate to propionate (Chen and Wolin 1979;Newbold et al 1995). However, the protozoan population can adapt to ionophores present in low or high concentrate diets.…”