The relationship between rumen microbiota and animal performance of lambs fed polyherbal additives

The relationship between lamb productive parameters and changes in the ruminal microbial community in response to different polyherbal mixtures in the feed was analyzed. Ruminal fluid samples were collected from finishing lambs fed polyherbal diets and their control groups in four independent experiments. The microbial community analysis of ruminal microbiota, based on sequencing of partial 16S rRNA genes, showed no differences in richness and diversity caused by polyherbals. Relative abundance analysis of microbial families showed that polyherbals increased the abundance of Succinivibrionaceae (P < 0.05) and reduced that of Ruminococcaceae (P < 0.10). Microbial biomass estimated with the National Research Council model allowed us to identify some relationships with productive parameters with multiple regression. Rikenellaceae and Coriobacteriaceae were negatively related with average daily gain (ADG) in all lambs. The feed efficiency was negatively associated with methanogenic Archaea in lambs fed polyherbals, whereas in control lambs, it was negatively related to Succinivibrionaceae. Feed intake showed a positive association with the biomass of methanogenic Archaea in all lambs, and Methanobacteriaceae biomass was also associated with the consumption of neutral detergent fiber (NDF) and acid detergent fiber (ADF) fractions. Polyherbals increased the abundance of Succinivibrionaceae and reduced that of Ruminococcaceae, without affecting richness and diversity. Methanogenic Archaea seem to play an important role in lamb performance.