Physiological Variation in Ruminal Microbiota under Altered Energy Levels in Starter Ration of Suckling Angus Calves.

The present study aim was to see the effects of different starter rations energy levels in the diet on ruminal microbial diversity, bacterial community structure and microbial diversity indices of rumen bacterial communities in Angus calves. For this, 18 suckling Angus calves were distributed into 3 different treatment groups. Dietary treatments were: Low metabolizable energy ration (LME); Medium metabolizable energy ration (MME) and High metabolizable energy ration (HME). Results of bacterial community revealed that most abundant phylum was Firmicute. At phyla level, TM7 and Fibrobacteres showed significant higher relative abundance in LME group than HME group. Under different dietary energy, 59 genera showed significant correlation with physiological production parameters. These results provide new information for the understanding of the dietary energy level effect on ruminal microbial community interactions and are of great importance for optimizing energy supply strategy for suckling calves. [ABSTRACT FROM AUTHOR]