Quantification by real‐time PCR of cellulolytic bacteria in the rumen of sheep after supplementation of a forage diet with readily fermentable carbohydrates: effect of a yeast additive

• Published in: Journal of applied microbiology Vol. 103; no. 6; pp. 2676 - 2685
• Main Authors: Mosoni, P., Chaucheyras‐Durand, F., Béra‐Maillet, C., Forano, E.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.12.2007; Blackwell Science; Wiley
• Subjects: Animal Feed; Animals; Biological and medical sciences; Carbohydrate Metabolism; cellulolytic bacteria; Cellulose - metabolism; Colony Count, Microbial; diet; Dietary Supplements; DNA, Bacterial - analysis; Fermentation; Fibrobacter - genetics; Fibrobacter - isolation & purification; Fibrobacter - metabolism; Fibrobacter succinogenes; Fundamental and applied biological sciences. Psychology; Gram-Positive Bacteria - isolation & purification; Gram-Positive Bacteria - metabolism; Life Sciences; Male; Microbiology; Microbiology and Parasitology; Oligonucleotide Probes - genetics; real‐time PCR; Reverse Transcriptase Polymerase Chain Reaction - methods; rumen; Rumen - metabolism; Rumen - microbiology; Ruminococcus - genetics; Ruminococcus - isolation & purification; Ruminococcus - metabolism; Ruminococcus albus; Ruminococcus flavefaciens; Sheep, Domestic - metabolism; Sheep, Domestic - microbiology; yeast; Yeasts; Yeast; Applied microbiology; cellulolytic bacteria; Rumen; real-time PCR; Real time; Polymerase chain reaction; Vertebrata; Mammalia; Diet; Bacteria; Sheep; Carbohydrate; Artiodactyla; Ungulata; Quantitative analysis; TEMPS REEL PCR; REGIME; CELLULOLYTIQUE
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/j.1365-2672.2007.03517.x

Aim:  To examine the effect of concentrate and yeast additive on the number of cellulolytic bacteria in the rumen of sheep. Methods and Results:  Fibrobacter succinogenes, Ruminococcus albus and Ruminococcus flavefaciens were quantified using real‐time PCR (targeting 16S rDNA) in parallel to cellulolytic flora enumeration with cultural techniques. Whatever the conditions tested, R. flavefaciens was slightly more abundant than F. succinogenes, with both species outnumbering R. albus. Before feeding, the shift from hay to hay plus concentrate diet had no effect on rumen pH and on the number of the three specie; while after feeding, the concentrate‐supplemented diet induced a decrease (−1 log) of the number of the three species concomitant with the rumen acidification. Overall, the presence of the live yeast resulted in a significant increase (two‐ to fourfold) of the Ruminococci. Conclusion:  The use of real‐time PCR allowed us to show changes in the number of cellulolytic bacterial species in vivo in response to diet shift and additives that could not be as easily evidenced by classical microbial methods. Significance and Impact of the Study:  This study contributes to the understanding of the negative impact of readily fermentable carbohydrates on rumen cellulolysis and the beneficial effect of yeast on rumen fermentation.