Integrated multi-omics to elucidate the interplay between rumen microorganisms and host metabolism in Hu sheep supplemented with herbal preparations.

Abstract

The aim of this experiment was to study the effects of herbal preparations on serum metabolites, rumen microorganisms, and their metabolites, and the relationship between them. Hu sheep ram lambs with an average initial weight of (19.57 ± 1.56 kg) at 3 months of age were selected and randomly divided into three groups of six lambs each. The groups were as follows: the control group (Con), which was fed the basic diet; Test I, which was fed a diet with 0.5% herbal preparations added to the concentrate; and Test II, which was fed a diet with 1% herbal preparations added to the concentrate. Also, the main component of herbal medicine is polysaccharide. The pre-experimental period was 10 days and the experimental period was 90 days. The results of the study showed that the addition of herbal preparations resulted in differences in species, abundance, and metabolic functions of rumen microorganisms. The abundance of rumen-dominant bacteria, such as Firmicutes and Proteobacteria, increased after the addition of herbal preparation, which was more conducive to rumen development. In addition, after the addition of 0.5% herbal preparation, there was an increase in the abundance of fermenting carbohydrate (CHO) and fiber-degrading bacteria (e.g., Ruminococcus and Prevotella). Herbal preparations significantly altered rumen microorganisms and serum metabolite compositions. Metabolites such as bile acids, L-glutamine, cytosine, and choline, which contribute to the antiviral and anti-inflammatory effects, nutrient metabolism, and immune responses, and increased rumen microbial activity, were increased in the rumen of the experimental group with the addition of the herbal preparations. The increase in serum metabolites, such as L-tryptophan, and the pathways of tryptophan metabolism and glutathione metabolism in animals were also significantly higher than those in Con. Prevotella and Ruminococcus were significantly positively correlated with histamine and L-arginine. The uncultured_rumen_bacterium was significantly negatively correlated with serum metabolites testosterone and guanine, but Prevotella and Ruminococcus were significantly positively correlated with both metabolite testosterone and guanine.

Importance: In this study, we investigated the changes in rumen microbes after supplementation with herbal preparations. We used 16S sequencing and metabolomics approaches to explore changes in rumen contents and serum metabolites and their interrelationships. Our findings revealed marked changes in rumen microbial profiles, including changes in species composition, abundance levels, and metabolic activities induced by herbal supplementation. The increased abundance of beneficial bacteria (e.g., fixative and proteobacteria) in the rumen was more favorable for their survival and colonization of the rumen. In addition, a surge in the abundance of fermenting carbohydrate and fiber-degrading bacteria was observed. It was also found that the addition of herbal preparations enhanced antiviral and anti-inflammatory responses, nutrient metabolism, immune function, and stimulation of rumen microbial activity as well as facilitated the acceleration of body metabolism in Hu sheep.