The restriction in the time of access to forage in ovine fed a high quality pasture affect groups of ruminal microorganisms

The effects of restricting the time of access to forage and of the time from the beginning of the intake on different groups of ruminal microbes were studied. Six fistulized wethers, allocated in individual cages, consuming only fresh forage (88% legumes) were separated in 2 groups: 24h and 6h (forage available during all the day and 6 h/d, respectively). After 30 days of adaptation, ruminal content samples (fluid + solid) were extracted to evaluate the microbiota of each group (24h vs. 6h). In animals with restricted access to forage (6h group) the microbiota was also compared among 0, 4 and 8 hours from the beginning of the meal. The samples were analyzed by FISH (Fluorescence in situ hybridization), using probes targeting the Domain Bacteria (Eubacteria), fibrolytic (Ruminococcus albus and flavefaciens, lactate-producing (Streptococcus spp.) and lactate-consuming (Megasphaera elsdenii, Propionibacterium spp., Selenomona ruminantium) bacterias. The ruminal pH was not affected by the restriction, but R. albus, R. flavefaciens and S. ruminantum were more abundant for the 24h group. Within the animals under restriction the number of Eubacterias tended to be lower al hours 4 and 8, when ruminal pH was lower too, regarding to the hour 0, possibly due to the entry of fresh food. There were not differences between bacteria groups due to the sampling time were not observed.