The use of H-nuclear magnetic resonance (H-NMR) in ewes suffering milk fat depression: Could blood metabolomic differences explain the individual variations?

Póster presentado al: 2017 ADSA Annual Meeting #M240. Pittsburgh, Pennsylvania (Estados Unidos), 25-28 de junio de 2017.Dietary supplementation of dairy ewes with marine lipids improves milkfatty acid (FA) profile, but causes milk fat depression (MFD). A largeindividual variation in the MFD response has been observed, and factorscausing this variation are not clear. This study was conducted in dairy sheepto test whether differences in the blood metabolomic profile would clarifycauses of individual variations in terms of MFD when marine lipids wereadded to the diet. Assaf dairy ewes (n = 15) received a total mixed rationsupplemented with 0 (control; n = 5) or 20 g of fish-oil/kg DM [n = 10; withanimals divided in those showing a strong (RESPO+, n = 5) or slight(RESPO-) MFD]. Blood samples collected before (d 0) and after (d 36) oilsupplementation were analyzed by H-NMR spectroscopy operating at 600MHz. For better metabolite detection, spectral editing was done based onspin-spin relaxation time (CPMG filter) and molecular diffusion (DOSY filter).Multivariate analyses of data were carried out by the ChemoSpec package ofR program and the web-based MetaboAnalyst program. Principal componentand partial least square–discriminant analyses were used to detectmetabolite differences among treatment groups. Both RESPO- and RESPO+ewes supplemented with fish oil had lower concentrations of proline, valine,isoleucine, keratin, lactate and β-glucose. The reductions in amino acidconcentrations were in accordance with lower (P < 0.05) milk proteincontent in lipid-supplemented ewes (4.75%) compared with control ewes(5.03%). Additionally, some monounsaturated FA increased in RESPO- andRESPO+ ewes, which could include some potential antilipogenic FA that aresupposed to be able to induce MFD. However, there was no cleardiscrimination between RESPO+ and RESPO- ewes. In conclusion, lipidsupplementation caused significant differences in blood H-NMRmetabolomics, but no clear discrimination was observed between animalsshowing slight and strong MFD.Study funded by Project AGL2014–54587(Plan Nacional, MINECO, Spain)Peer reviewe