Evaluation of stirring time through a rumen simulation technique: Influences on rumen fermentation and bacterial community

Zuo Wang; Quan Li; Xinyi Lan; Weijun Shen; Fachun Wan; Jianhua He; Shaoxun Tang; Zhiliang Tan

doi:10.3389/fmicb.2023.1103222

Evaluation of stirring time through a rumen simulation technique: Influences on rumen fermentation and bacterial community

Front Microbiol. 2023 Mar 3:14:1103222. doi: 10.3389/fmicb.2023.1103222. eCollection 2023.

Authors

Zuo Wang¹, Quan Li¹, Xinyi Lan¹, Weijun Shen¹, Fachun Wan¹, Jianhua He¹, Shaoxun Tang², Zhiliang Tan²

Affiliations

¹ College of Animal Science and Technology, Hunan Agricultural University, Changsha, Hunan, China.
² Key Laboratory of Agro-Ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.

Abstract

Introduction: Rumen motility is a key element that influences ruminant nutrition, whereas little is known about the effects of rumen contraction duration on rumen fermentation and ruminal microbiome. We previously reported that proper rotation speed of a rumen simulation technique (RUSITEC) system enhanced rumen fermentation and microbial protein (MCP) production. In the present study, different contraction durations and intervals were simulated by setting different stirring times and intervals of the stirrers in a RUSITEC system. The objective of this trial was to evaluate the influences of stirring time on rumen fermentation characteristics, nutrient degradation, and ruminal bacterial microbiota in vitro.

Methods: This experiment was performed in a 3 × 3 Latin square design, with each experimental period comprising 4 d for adjustment and 3 d for sample collection. Three stirring time treatments were set: the constant stir (CS), the intermittent stir 1 (each stir for 5 min with an interval of 2 min, IS1), and the intermittent stir 2 (each stir for 4 min with an interval of 3 min, IS2).

Results: The total volatile fatty acid (TVFA) concentration, valerate molar proportion, ammonia nitrogen level, MCP density, protozoa count, disappearance rates of dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber, emissions of total gas and methane, and the richness index Chao 1 for the bacterial community were higher (p < 0.05) in the IS1 when compared to those in the CS. The greatest TVFA, MCP, protozoa count, nutrient disappearance rates, gas productions, and bacterial richness indices of Ace and Chao 1 amongst all treatments were observed in the IS2. The relative abundance of the genus Treponema was enriched (p < 0.05) in CS, while the enrichment (p < 0.05) of Agathobacter ruminis and another two less known bacterial genera were identified in IS2.

Discussion: It could be concluded that the proper reduction in the stirring time might help to enhance the feed fermentation, MCP synthesis, gas production, and the relative abundances of specific bacterial taxa.

Keywords: full-length 16S rRNA gene sequencing; rumen fermentation; rumen simulation technique; ruminal microbiota; stirring time.