Study of the animal variability on the numbers of different microbial groups in the goats' rumen

The use of classical culture and, more recently, modern molecular techniques such as real-time PCR to quantify microbial groups in the rumen show a high animal to animal variability and, sometimes, a contradictory diurnal variation pattern. This work aimed to study the animal variation in the numbers of some microbial groups in the rumen within an established flock. In a first period (I), three adult goats cannulated in the rumen were fed alfalfa hay and samples of rumen contents collected at 0, 2 and 4 hours after the morning feeding in two non consecutive days. In two following periods (II and III) rumen contents was transferred between animals to evaluate the consistency of the differences between animals observed in Period I. The concentration of total bacteria, methanogenic archaea, protozoa, Fibrobacter succinogenes and Ruminococcus flavefaciens were determined by real time PCR. The animal to animal variability was higher before than after the morning feeding and lower with regards to bacteria, protozoa and archaea than to F. succinogenes and R. flavefaciens. The high variability in these two bacterial species was reduced after the rumen contents were exchanged between animals