Differential Rumen Microbial Dynamics and Fermentation Parameters in Cattle Fed on High Fibre and High Concentrate Diets

In the present study, the effect of two diets containing varying level of fibre was evaluated on the rumen microbial dynamics and rumen fermentation characteristics at different intervals in Karan Fries crossbred cattle. Ruminal microbial groups were quantified using species specific primers using real-time PCR assays. A significant increase in copy numbers of fibrolytic bacteria viz. Ruminococcus albus, R. flavefaciens, Butyrivibrio fibrisolvens and Fibrobacter succinogens was observed on day 11 in rumen of cattle fed on high fibre diet (HFD). Similarly, the total bacterial and total anaerobic fungi population also increased by nearly 50% on day 11 in HFD group than day 0. However, the levels of acetate, propionate and butyrate as well as ammonia nitrogen (NH₃-N) were found significantly higher in cattle fed high concentrate diet (HCD) compared to HFD group. These findings indicate the importance of fibre content of the diet influencing microbial dynamics in rumen ecosystem.