The ability of rumen ciliates, Eudiplodinium maggii, Diploplastron affine, and Entodinium caudatum, to use the murein saccharides

Abstract

Murein polysaccharides may contribute to a considerable part of the dry matter of bacterial cells. Their utilization by protozoa inhabiting the rumen is, however, poorly recognized. The objective of this study was to examine the ability of three species of ciliates, i.e., Eudiplodinium maggii, Diploplastron affine, and Entodinium caudatum of digest, and ferment these saccharides. The cultivation experiments showed that the enrichment of growth medium with bacterial cell wall β-glycans increased the ciliate number (p < 0.05). A statistically significant increase (p < 0.01) was followed by a continuous decrease (p < 0.01) in the percentage of individuals containing β-glycans particles after 4- and 24-h incubation of ciliates with this substrate, respectively. The enzymatic experiments confirmed the ability of the examined protozoa to digest murein. E. caudatum exhibited the highest activity (8.2 unit (U)/mg protein per min), and E. maggii, the lowest (3.0 U/mg protein per min). The production rates of volatile fatty acids by starved and fed ciliate species were 0.7 and 1.6 (E. caudatum) pmol/ciliate cell per h, 30.5 and 42.5 (E. maggii) pmol/ciliate cell per h, and 8.3 and 19.2 (D. affine) pmol/ciliate cell per h (p < 0.05). © 2013 The Author(s).