Effect of Entodinium caudatum on starch intake and glycogen formation by Eudiplodinium maggii in the rumen and reticulum

This study aimed to quantify the engulfed starch and reserve alpha-glucans (glycogen) in the cells of the ciliates Eudiplodinium maggii, as well the alpha-glucans in defaunated and selectively faunated sheep. The content of starch inside the cell of ciliates varied from 21 to 183 mg/g protozoal DM relative to the rumen fauna composition whereas, the glycogen fluctuated between 17 and 126 mg/g dry matter (DM) of this ciliate species. Establishment of the population Entodinium caudatum in the rumen of sheep already faunated with E. maggii caused a drop in both types of quantified carbohydrates. The content of alpha-glucans in the rumen of defaunated sheep varied from 4.4 to 19.9 mg/g DM and increased to 7.4-29.9 or 11.8-33.9 mg/g DM of rumen contents in the presence of only E. maggii or E. maggii and E. caudatum, respectively. The lowest content of the carbohydrates was always found just before feeding and the highest at 4 h thereafter. The alpha-glucans in the reticulum varied 7.5-40.1, 14.3-76.8 or 21.9-106.1 mg/g DM of reticulum content for defaunated, monofaunated or bifaunated sheep, respectively. The results indicated that both ciliate species engulf starch granules and convert the digestion products to the glycogen, diminishing the pool of starch available for amylolytic bacteria. (C) 2016 Elsevier GmbH. All rights reserved.