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Metabolomic profiling in cattle experimentally infected with Mycobacterium avium subsp. paratuberculosis.

De Buck J, Shaykhutdinov R, Barkema HW, Vogel HJ - PLoS ONE (2014)

Bottom Line: In a monthly follow-up for 17 months, calves infected at 2 weeks of age were compared with aged-matched controls.Differences in acetone, citrate, glycerol and iso-butyrate concentrations indicated energy shortages and increased fat metabolism in infected cattle, whereas changes in urea and several amino acids (AA), including the branched chain AA, indicated increased protein turnover.In conclusion, metabolomics was a sensitive method for detecting MAP infection much sooner than with current diagnostic methods, with individual metabolites significantly distinguishing infected from non-infected cattle.

View Article: PubMed Central - PubMed

Affiliation: Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada.

ABSTRACT
The sensitivity of current diagnostics for Johne's disease, a slow, progressing enteritis in ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP), is too low to reliably detect all infected animals in the subclinical stage. The objective was to identify individual metabolites or metabolite profiles that could be used as biomarkers of early MAP infection in ruminants. In a monthly follow-up for 17 months, calves infected at 2 weeks of age were compared with aged-matched controls. Sera from all animals were analyzed by 1H nuclear magnetic resonance spectrometry. Spectra were acquired, processed, and quantified for analysis. The concentration of many metabolites changed over time in all calves, but some metabolites only changed over time in either infected or non-infected groups and the change in others was impacted by the infection. Hierarchical multivariate statistical analysis achieved best separation between groups between 300 and 400 days after infection. Therefore, a cross-sectional comparison between 1-year-old calves experimentally infected at various ages with either a high- or a low-dose and age-matched non-infected controls was performed. Orthogonal Projection to Latent Structures Discriminant Analysis (OPLS DA) yielded distinct separation of non-infected from infected cattle, regardless of dose and time (3, 6, 9 or 12 months) after infection. Receiver Operating Curves demonstrated that constructed models were high quality. Increased isobutyrate in the infected cattle was the most important agreement between the longitudinal and cross-sectional analysis. In general, high- and low-dose cattle responded similarly to infection. Differences in acetone, citrate, glycerol and iso-butyrate concentrations indicated energy shortages and increased fat metabolism in infected cattle, whereas changes in urea and several amino acids (AA), including the branched chain AA, indicated increased protein turnover. In conclusion, metabolomics was a sensitive method for detecting MAP infection much sooner than with current diagnostic methods, with individual metabolites significantly distinguishing infected from non-infected cattle.

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Related in: MedlinePlus

Boxplots of selected metabolites (acetone, asparagine, aspartate, betaine, glycerol, isobutyrate, isoleucine, leucine, mannose, threonine, tyrosine) for MAP-infected animals (n = 35) and non-infected age matched controls (n = 16).Significant differences with the control group by posthoc testing (Scheffe) after ANOVA are indicated by * (P<0.05).
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pone-0111872-g007: Boxplots of selected metabolites (acetone, asparagine, aspartate, betaine, glycerol, isobutyrate, isoleucine, leucine, mannose, threonine, tyrosine) for MAP-infected animals (n = 35) and non-infected age matched controls (n = 16).Significant differences with the control group by posthoc testing (Scheffe) after ANOVA are indicated by * (P<0.05).

Mentions: Most of the metabolites incorporated in the final OPLS-DA model between all infected and non-infected cattle (Fig. 3 and 4) matched the set identified by the Student's t-test, without correcting for multiple testing between infected and non-infected cattle and also in one-way ANOVA between the non-infected animals and the dose groups. Boxplots of those metabolites are shown (Fig. 7). Betaine was missing from the metabolites which were lower in infected cattle and the amino acids leucine, isoleucine, threonine that significantly discriminated HD from control (Fig. 5 and 7) were also not represented in the final model as metabolites which were higher in infected cattle. Interestingly citrate, urea, dimethylamine and myo-inositol were part of the OPLS-DA model, whereas individually they did not significantly differentiate between groups.


Metabolomic profiling in cattle experimentally infected with Mycobacterium avium subsp. paratuberculosis.

De Buck J, Shaykhutdinov R, Barkema HW, Vogel HJ - PLoS ONE (2014)

Boxplots of selected metabolites (acetone, asparagine, aspartate, betaine, glycerol, isobutyrate, isoleucine, leucine, mannose, threonine, tyrosine) for MAP-infected animals (n = 35) and non-infected age matched controls (n = 16).Significant differences with the control group by posthoc testing (Scheffe) after ANOVA are indicated by * (P<0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4221196&req=5

pone-0111872-g007: Boxplots of selected metabolites (acetone, asparagine, aspartate, betaine, glycerol, isobutyrate, isoleucine, leucine, mannose, threonine, tyrosine) for MAP-infected animals (n = 35) and non-infected age matched controls (n = 16).Significant differences with the control group by posthoc testing (Scheffe) after ANOVA are indicated by * (P<0.05).
Mentions: Most of the metabolites incorporated in the final OPLS-DA model between all infected and non-infected cattle (Fig. 3 and 4) matched the set identified by the Student's t-test, without correcting for multiple testing between infected and non-infected cattle and also in one-way ANOVA between the non-infected animals and the dose groups. Boxplots of those metabolites are shown (Fig. 7). Betaine was missing from the metabolites which were lower in infected cattle and the amino acids leucine, isoleucine, threonine that significantly discriminated HD from control (Fig. 5 and 7) were also not represented in the final model as metabolites which were higher in infected cattle. Interestingly citrate, urea, dimethylamine and myo-inositol were part of the OPLS-DA model, whereas individually they did not significantly differentiate between groups.

Bottom Line: In a monthly follow-up for 17 months, calves infected at 2 weeks of age were compared with aged-matched controls.Differences in acetone, citrate, glycerol and iso-butyrate concentrations indicated energy shortages and increased fat metabolism in infected cattle, whereas changes in urea and several amino acids (AA), including the branched chain AA, indicated increased protein turnover.In conclusion, metabolomics was a sensitive method for detecting MAP infection much sooner than with current diagnostic methods, with individual metabolites significantly distinguishing infected from non-infected cattle.

View Article: PubMed Central - PubMed

Affiliation: Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada.

ABSTRACT
The sensitivity of current diagnostics for Johne's disease, a slow, progressing enteritis in ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP), is too low to reliably detect all infected animals in the subclinical stage. The objective was to identify individual metabolites or metabolite profiles that could be used as biomarkers of early MAP infection in ruminants. In a monthly follow-up for 17 months, calves infected at 2 weeks of age were compared with aged-matched controls. Sera from all animals were analyzed by 1H nuclear magnetic resonance spectrometry. Spectra were acquired, processed, and quantified for analysis. The concentration of many metabolites changed over time in all calves, but some metabolites only changed over time in either infected or non-infected groups and the change in others was impacted by the infection. Hierarchical multivariate statistical analysis achieved best separation between groups between 300 and 400 days after infection. Therefore, a cross-sectional comparison between 1-year-old calves experimentally infected at various ages with either a high- or a low-dose and age-matched non-infected controls was performed. Orthogonal Projection to Latent Structures Discriminant Analysis (OPLS DA) yielded distinct separation of non-infected from infected cattle, regardless of dose and time (3, 6, 9 or 12 months) after infection. Receiver Operating Curves demonstrated that constructed models were high quality. Increased isobutyrate in the infected cattle was the most important agreement between the longitudinal and cross-sectional analysis. In general, high- and low-dose cattle responded similarly to infection. Differences in acetone, citrate, glycerol and iso-butyrate concentrations indicated energy shortages and increased fat metabolism in infected cattle, whereas changes in urea and several amino acids (AA), including the branched chain AA, indicated increased protein turnover. In conclusion, metabolomics was a sensitive method for detecting MAP infection much sooner than with current diagnostic methods, with individual metabolites significantly distinguishing infected from non-infected cattle.

Show MeSH
Related in: MedlinePlus