Dataset Information

Rumen Bacteria Communities and Performances of Fattening Lambs with a Lower or Greater Subacute Ruminal Acidosis Risk.

ABSTRACT: Several ruminal cellulolytic bacteria species are sensitive to pH and could therefore be used as biomarkers to determine the risk of sub-acute ruminal acidosis (SARA) in finishing lambs. This study compared a 2-4 h post feeding ruminal pH measurement to abundances of the ruminal pH-sensitive bacteria to evaluate the risk of SARA in a herd of 120 finishing lambs. The lambs were reared in individual units for 50 days. Ruminal fluid was collected by use of an orogastric tube on day 51 2-4 h after feeding. Although the lambs were fed an identical diet, they responded differently in the abundances of four ruminal pH sensitive cellulolytic bacteria (Ruminococcus albus, Ruminococcus flavefaciens and Fibrobacter succinogenes and Butyrivibrio fibrisolvens). Lambs with the most or the least cellulolytic bacteria were then classified as either lower SARA risk (LSR, n = 10) or higher SARA risk group (HSR, n = 10), respectively. Data showed that the ruminal pH and VFA profiles were uncorrelated with the number of cellulolytic bacteria (P > 0.050). Lambs with the HSR showed lower ruminal pH (P = 0.013) and acetate to propionate ratio (P = 0.018), higher concentrations of lactate (P = 0.035) and proportion of propionate (P = 0.033) compared to those with the LSR. The DMI and ADG did not differ in LSR and HSR lambs (P > 0.050). A diversity analysis revealed significantly lower diversity in HSR lambs than in LSR (Simpson index, P = 0.004). The relative abundances of the phyla Bacteroidetes, Fibrobacteres, Verruomicrobia, and Proteobacteria were higher in LSR lambs than in HSR (P < 0.050). The abundances of several phyla including Firmicutes, Tenericutes and Actinobacteria were higher in the HSR than in the LSR group (P < 0.050). The bacterial communities of the LSR and HSR clustered separately in rumen based on the Unifrac distances, indicating distinct bacteria communities at OTU level between the LSR and HSR lambs. Overall, there was no correlation between 2 and 4 h post-feeding ruminal pH and the abundance of pH-sensitive bacteria and the amount of these bacteria could be used as a potential biomarker of SARA in lamb herd.

SUBMITTER: Li F

PROVIDER: S-EPMC5733016 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Rumen Bacteria Communities and Performances of Fattening Lambs with a Lower or Greater Subacute Ruminal Acidosis Risk.

Li Fei F Wang Zhilan Z Dong Chunxiao C Li Fadi F Wang Weimin W Yuan Zehu Z Mo Futao F Weng Xiuxiu X

Frontiers in microbiology 20171212

Several ruminal cellulolytic bacteria species are sensitive to pH and could therefore be used as biomarkers to determine the risk of sub-acute ruminal acidosis (SARA) in finishing lambs. This study compared a 2-4 h post feeding ruminal pH measurement to abundances of the ruminal pH-sensitive bacteria to evaluate the risk of SARA in a herd of 120 finishing lambs. The lambs were reared in individual units for 50 days. Ruminal fluid was collected by use of an orogastric tube on day 51 2-4 h after f ...[more]

PMID: 29312208

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Project description:Effects of subacute ruminal acidosis (SARA) challenges on the bacteria in rumen fluid, cecal digesta, and feces of dairy cows were determined using 16S rRNA gene pyrosequencing and real-time quantitative PCR. Six non-lactating Holstein cows with cannulas in the rumen and cecum were used in a 3 × 3 Latin square arrangement of treatments. During the first 3 wk of each experimental period, cows received a control diet containing 70% forages on a dry matter (DM) basis. In wk 4 of each period, cows received one of three diets: (1) the control diet; (2) a diet in which 34% of the dietary DM was replaced with pellets of ground wheat and barley (GBSC); or (3) a diet in which 37% of dietary DM was replaced with pellets of ground alfalfa (APSC). Rumen fluid, cecal digesta and feces were collected on d 5 of wk 4 of each period and the composition of the bacterial community was studied. Rumen fermentation responses were reported in a companion study. Both SARA-inducing challenges resulted in similar digesta pH depressions (as shown by the companion study), and reduced bacterial richness and diversity in rumen fluid, but GBSC had the larger effect. None of the challenges affected these measures in cecal digesta, and only GBSC reduced bacterial richness and diversity in feces. Only GBSC reduced the abundance of Bacteroidetes in rumen fluid. Abundances of limited number of bacterial genera identified by 16S rRNA gene sequencing in the rumen, cecum and feces were affected by the GBSC. The APSC did not affect any of these abundances. Both challenges increased the abundances of several starch, pectin, xylan, dextrin, lactate, succinate, and sugar fermenting bacterial species in the rumen, cecum, and feces as determined by qPCR. Only GBSC increased that of Megasphaera elsdenii in the rumen. Both challenges decreased the abundance of Streptococcus bovis, and increased that of Escherichia coli, in cecal digesta and feces, with GBSC having the larger effect. These results showed that the SARA challenges caused moderate and reversible changes of the composition of the bacteria in the foregut and hindgut, with the greater changes observed during GBSC.

Project description:Subacute ruminal acidosis (SARA) negatively impacts the dairy industry by decreasing dry matter intake, milk production, profitability, and increasing culling rate and death loss. Six ruminally cannulated, lactating Holstein cows were used in a replicated incomplete Latin square design to determine the effects of SARA induction on the ruminal microbiome and epithelium. Experimental periods were 10 days with days 1-3 for ad libitum intake of control diet, followed by 50% feed restriction on day 4, and ad libitum access on day 5 to the basal diet or the basal diet with an additional 10% of a 50:50 wheat/barley pellet. Based on subsequent ruminal pH, cows were grouped (SARA grouping; SG) as Non-SARA or SARA based on time <5.6 pH (0 and 3.4 h, respectively). Ruminal samples were collected on days 1 and 6 of each period prior to feeding and separated into liquid and solid fractions. Microbial DNA was extracted for bacterial analysis using 16S rRNA gene paired-end sequencing on the MiSeq Illumina platform and quantitative PCR (qPCR). Ruminal epithelium biopsies were taken on days 1 and 6 before feeding. Quantitative RT-PCR was used to determine gene expression in rumen epithelium. Bray-Curtis similarity indicated samples within the liquid fraction separated by day and coincided with an increased relative abundance of genera Prevotella, Ruminococcus, Streptococcus, and Lactobacillus on day 6 (P < 0.06). Although Firmicutes was the predominant phyla in the solid fraction, a SG × day interaction (P < 0.01) indicated a decrease on day 6 for SARA cows. In contrast, phylum Bacteroidetes increased on day 6 (P < 0.01) for SARA cows driven by greater genera Prevotella and YRC22 (P < 0.01). Streptococcus bovis and Succinivibrio dextrinosolvens populations tended to increase on day 6 but were not affected by SG. In ruminal epithelium, CLDN1 and CLDN4 expression increased on day 6 (P < 0.03) 24 h after SARA induction and a tendency for a SG × day interaction (P < 0.10) was observed for CLDN4. Overall, results indicate more rapid adaptation to an induced bout of SARA in the solid fraction ruminal microbiome compared with ruminal epithelium.

Project description:Subacute ruminal acidosis (SARA) represents one of the most important digestive disorders in intensive dairy farms, and dairy cows are individually different in the severity of SARA risk. The objectives of the current study were to investigate differences in the ruminal bacterial community and metabolome in dairy cattle with different susceptibility to SARA. In the present study, 12 cows were initially enrolled in the experiment. Based on average ruminal pH, 4 cows with the lowest ruminal pH were assigned to the susceptible group (SUS, pH = 5.76, n = 4) and 4 cows with the highest ruminal pH assigned to the tolerant group (TOL, pH = 6.10, n = 4). Rumen contents from susceptible (SUS, n = 4) and tolerant (TOL, n = 4) dairy cows were collected through rumen fistula to systematically reveal the rumen microbial and metabolic alterations of dairy cows with different susceptibility to SARA using multi-omics approaches (16S and 18S rRNA gene sequencing and metabolome). The results showed that despite being fed the same diet, SUS cows had lower ruminal pH and higher concentrations of total volatile fatty acids (VFA) and propionate than TOL cows (P < 0.05). No significant differences were observed in dry matter intake, milk yield, and other milk compositions between the SUS and TOL groups (P > 0.05). The principal coordinates analysis based on the analysis of molecular variance indicated a significant difference in bacterial composition between the two groups (P = 0.01). More specifically, the relative abundance of starch-degrading bacteria (Prevotella spp.) was greater (P < 0.05), while the proportion of fiber-degrading bacteria (unclassified Ruminococcaceae spp., Ruminococcus spp., Papillibacter, and unclassified Family_XIII) was lower in the rumen of SUS cows compared with TOL cows (P < 0.05). Community analysis of protozoa showed that there were no significant differences in the diversity, richness, and community structure (P > 0.05). Metabolomics analysis revealed that the concentrations of organic acids (such as lactic acid), biogenic amines (such as histamine), and bacterial degradation products (such as hypoxanthine) were significantly higher in the SUS group compared to the TOL group (P < 0.05). These findings revealed that the higher proportion of starch-degrading bacteria/lower fiber-degrading bacteria in the rumen of SUS cows resulted in higher VFA-producing capacity, in particular propionate. This caused a disruption in metabolic homeostasis in the rumen which might be the reason for the higher susceptibility to SARA. Overall, these findings enhanced our understanding of the ruminal microbiome and metabolic changes in cows susceptible to SARA.

Project description:The demand for economic benefits has led to an increase in the proportion of high-concentrate (HC) feed in the ruminant diet, resulting in an increased incidence of subacute ruminal acidosis (SARA). During SARA, a high concentration of lipopolysaccharide (LPS) translocated in the rumen induces a systemic inflammatory response. Inflammatory diseases, such as endometritis and mastitis, are often associated with SARA; however, in sheep, the mechanism of the effect of SARA on the endometrium has rarely been reported. Therefore, the aim of this study was to investigate, for the first time, the influence of LPS translocation on endometrial tight junctions (TJs) during SARA in sheep. The results showed that LPS and TNFα levels in the ruminal fluid, serum, and endometrial tissue supernatant during SARA increased, transcription levels of TLR4, NFκB, and TNFα in the endometrium increased, the protein expression level of claudin-1 in the endometrium increased, and the protein expression level of occludin decreased. 17β-estradiol (E2) inhibits claudin-1 protein expression and promotes occludin expression, and progesterone (P4) promotes claudin-1 protein expression and inhibits occludin protein expression. E2 and P4 regulate claudin-1 and occludin protein expression through their receptor pathways. Here, we found that LPS hindered the regulatory effect of E2 and P4 on endometrial TJs by inhibiting their receptor expression. The results of this study indicate that HC feeding can cause SARA-induced LPS translocation in sheep, increase susceptibility to systemic inflammation, induce the endometrial inflammatory response, and cause endometrial epithelial TJ damage directly and/or by obstructing E2 and P4 function. LPS translocation caused by SARA has also been suggested to induce an endometrial inflammatory response, resulting in endometrial epithelial barrier damage and physiological dysfunction, which seriously affects ruminant production. Therefore, this study provides new evidence that SARA is a potential factor that induces systemic inflammation in ruminants. It provides theoretical support for research on the prevention of endometritis in ruminants.

Dataset Information

Rumen Bacteria Communities and Performances of Fattening Lambs with a Lower or Greater Subacute Ruminal Acidosis Risk.

Publications

Rumen Bacteria Communities and Performances of Fattening Lambs with a Lower or Greater Subacute Ruminal Acidosis Risk.

Similar Datasets

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