The Response of Ruminal Microbiota and Metabolites to Different Dietary Protein Levels in Tibetan Sheep on the Qinghai-Tibetan Plateau

Abstract

Ruminal microbiota and metabolites play crucial roles in animal health and productivity. Exploring the dynamic changes and interactions between microbial community composition and metabolites is important for understanding ruminal nutrition and metabolism. Tibetan sheep (Ovis aries) are an important livestock resource on the Qinghai-Tibetan Plateau (QTP), and the effects of various dietary protein levels on ruminal microbiota and metabolites are still unknown. The aim of this study was to investigate the response of ruminal microbiota and metabolites to different levels of dietary protein in Tibetan sheep. Three diets with different protein levels (low protein 10.1%, medium protein 12.1%, and high protein 14.1%) were fed to Tibetan sheep. 16S rRNA gene sequencing and gas chromatography coupled with time-of-flight mass spectrometry (GC-TOF-MS) were used to study the profile changes in each group of ruminal microbes and metabolites, as well as the potential interaction between them. The rumen microbiota in all groups was dominated by the phyla Bacteroidetes and Firmicutes regardless of the dietary protein level. At the genus level, Prevotella_1, Rikenellaceae_RC9_gut_group and Prevotellaceae_UCG-001 were dominant. Under the same forage-to-concentrate ratio condition, the difference in the dietary protein levels had no significant impact on the bacterial alpha diversity index and relative abundance of the major phyla and genera in Tibetan sheep. Rumen metabolomics analysis revealed that dietary protein levels altered the concentrations of ruminal amino acids, carbohydrates and organic acids, and significantly affected tryptophan metabolism (p < 0.05). Correlation analysis of the microbiota and metabolites revealed positive and negative regulatory mechanisms. Overall, this study provides detailed information on rumen microorganisms and ruminal metabolites under different levels of dietary protein, which could be helpful in subsequent research for regulating animal nutrition and metabolism through nutritional interventions.

Effects of dietary crude protein levels in the concentrate supplement after grazing on rumen microbiota and metabolites by using metagenomics and metabolomics in Jersey-yak

“…In recent years, researches on the effect of dietary nutrition level on the growth performance of ruminants showed that the type and nutrition level of diet will have a significant impact on the daily gain and weight of ruminants ( Xu et al, 2017 ; Estrada-Angulo et al, 2018 ; Wang et al, 2022b ). Protein is one of the most important nutrients in ruminants’ diets.…”

“…( Zhang et al, 2019 ; Li et al, 2020 ; Huang et al, 2021 ). 16S rRNA and metabonomics were used to study the bacterial composition in the rumen, and it was found that the nutritional level of diet could significantly change the relative abundance of dominant bacteria and metabolites in the rumen ( Granja-Salcedo et al, 2016 ; Wang et al, 2020a , 2022b ; Yi et al, 2022a ). The level of protein in the diet will not only affect the composition of microorganisms and metabolites in the rumen but also affect the rumen fermentation indexes and serum biochemical indexes of the host ( Wang et al, 2020b , 2022b ).…”

Dietary Palygorskite-Based Antibacterial Agent Supplementation as an Alternative to Antibiotics Improves Growth Performance, Blood Parameters, and Rumen Microbiota in Sheep

“…Thus, the rumen microbiota and rumen microbial fermentation are closely related to host productivity, health, and well-being [45]. Some studies have shown that different diets and feed additives can affect rumen fermentation and microbiota [46,47]. Previous research reported that thermally modified attapulgite and Zn-loaded attapulgite can improve rumen microbial fermentation and promote VFA formation and nitrogen utilization [14,48].…”

Effects of Dietary Protein Levels on Sheep Gut Metabolite Profiles during the Lactating Stage

“…In our recently published work, we evaluated how dietary protein levels (same diets as used in this experiment) change the fecal bacterial composition and found that changes in dietary protein contents altered rumen microbiota composition [ 17 ] and consequently influenced the growth performance, milk production, and blood biochemical indices [ 18 ] of the nursing ewes. Further, it is well established that dietary protein levels influence growth performance by altering the microbial and enzymatic function of sheep and cattle [ 5 , 21 ]. In the current experiment, the composition of the fecal metabolites significantly differed among groups based on PLS-DA analysis, suggesting that the dietary protein levels alter the rumen metabolomic profiles of lactating ewes.…”

“…Changes in dietary constituents like protein contents can alter the gut microbial community and subsequently impact the metabolites produced by gut bacteria [ 4 ]. Studies showed that dietary changes regarding protein quality and quantity have an impact on the rumen ecology and ruminal metabolites of dairy cattle and sheep [ 4 , 5 , 6 ]. The dietary protein supplies essential amino acids for the growth of fiber-digesting bacteria, which results in changes in metabolite profiling [ 7 ].…”