Epimural bacterial community structure in the rumen of Holstein cows with different responses to a long-term subacute ruminal acidosis diet challenge

Abstract

Subacute ruminal acidosis (SARA) is a prevalent metabolic disorder in cattle, characterized by intermittent drops in ruminal pH. This study investigated the effect of a gradual adaptation and continuously induced long-term SARA challenge diet on the epimural bacterial community structure in the rumen of cows. Eight rumen-cannulated nonlactating Holstein cows were transitioned over 1 wk from a forage-based baseline feeding diet (grass silage-hay mix) to a SARA challenge diet, which they were fed for 4 wk. The SARA challenge diet consisted of 60% concentrates (dry matter basis) and 40% grass silage-hay mix. Rumen papillae biopsies were taken at the baseline, on the last day of the 1-wk adaptation, and on the last day of the 4-wk SARA challenge period; ruminal pH was measured using wireless sensors. We isolated DNA from papillae samples for 16S rRNA gene amplicon sequencing using Illumina MiSeq. Sequencing results of most abundant key phylotypes were confirmed by quantitative PCR. Although they were fed similar amounts of concentrate, cows responded differently in terms of ruminal pH during the SARA feeding challenge. Cows were therefore classified as responders (n = 4) and nonresponders (n = 4): only responders met the SARA criterion of a ruminal pH drop below 5.8 for longer than 330 min/d. Data showed that Proteobacteria, Firmicutes, and Bacteroidetes were the most abundant phyla, and at genus level, Campylobacter and Kingella showed highest relative abundance, at 15.5 and 7.8%, respectively. Diversity analyses revealed a significant increase of diversity after the 1-wk adaptation but a decrease of diversity and species richness after the 4-wk SARA feeding challenge, although without distinction between responders and nonresponders. At the level of the operational taxonomic unit, we detected diet-specific shifts in epimural community structure, but in the overall epimural bacterial community structure, we found no differences between responders and nonresponders. Correlation analysis revealed significant associations between grain intake and operational taxonomic unit abundance. The study revealed major shifts in the 3 dominating phyla and, most importantly, a loss of diversity in the epimural bacterial communities during a long-term SARA diet challenge, in which 60% concentrate supply for 4 wk was instrumental rather than the magnitude of the drop of ruminal pH below 5.8.

Impact of high‐grain diet feeding on mucosa‐associated bacterial community and gene expression of tight junction proteins in the small intestine of goats

“…Previous studies showed that a long‐term HG diet appeared to disrupt the balance of the ruminal microbiota and affect the rumen health of dairy cattle and goats (Hua et al, ; Wetzels, et al, ). In the present study, the HG diet increased the richness of bacterial communities of jejunal mucosa, but it seemed to have no apparent effect on the richness of bacterial communities of ileal mucosa, with no significant between‐group difference observed.…”

The Signature Microbiota Driving Rumen Function Shifts in Goat Kids Introduced Solid Diet Regimes

“…The representative OTU5 associated with unclassified Sphingobacteriaceae as MRO predictors were negatively with macronutrients intake and VFA production. OTU5 classified as Olivibacter sitiensis function is not clear, but it decreased with pH reduction when intake high concentrate diet (25). The species affiliated with Prevotella (OTU2, OTU3, OTU6 and OTU13) in top 30 increased in solid supplementary regimes.…”

Utilization of Rumen Mechanical Stimulator as Pseudo Fiber in Ruminant to Minimize Metabolic Problem

“…Some research reported that high concentrate feeding induces the incidence of sub-acute ruminal acidosis (Mickdam et al 2016;Wetzels et al 2016;Sato 2016). Mickdam et al (2016) studied the effects of feeding 60:40% grain and forage ratio with NDF content of 31.8% and Wetzels et al (2016) investigated feeding 65:35% grain and forage ratio with NDF content of 256 g/kg and Sato (2016) investigated 80:20% of grain and forage ratio.…”

“…Different from SARA, acidosis is characterized by a prolong period of pH decrease below these thresholds (pH <5.0) (Nagaraja & Lechtenberg 2007). It is worth noting that there are quite a lot of pH thresholds have been used to illustrate SARA (Plaizier et al 2008;Zebeli et al 2008;Gimeno et al 2015a;Wetzels et al 2016). Most of the studies mentioned that ruminal pH dropped between 5.6 and 5.8 for three hours to 5.4 hours per day (Plaizer et al 2008;Zebeli et al 2008;Wetzels et al 2016).…”

“…It is worth noting that there are quite a lot of pH thresholds have been used to illustrate SARA (Plaizier et al 2008;Zebeli et al 2008;Gimeno et al 2015a;Wetzels et al 2016). Most of the studies mentioned that ruminal pH dropped between 5.6 and 5.8 for three hours to 5.4 hours per day (Plaizer et al 2008;Zebeli et al 2008;Wetzels et al 2016). Report on various pH levels of cattle with symptoms of SARA were due to methods and sites of ruminal fluid collection (Duffield et al 2004;Bramley et al 2008;AlZahal et al 2007).…”