FIGURE 2 | Relation between lipids, acyl chain properties, and the pHu lines. The total number of carbons and unsaturation in the acyl chains of the lipids were plottedwiththeVIPsandthecontributionsextractedfromtheinitialOPLS-DAmodelincludingthe185lipids( SupplementaryTableS2 )identi fi edbytargetedlipidomics inthe serum ofbroilers from thepHulines (trainingdataset; n =100foreach line).Theimportanceofthelipids(VIP) intheOPLS-DAmodel(M1a)wasrepresentedbythe sizeofthecircleandthecontributiontothepHu − orpHu+lineswerevisualizedbyagradientgoingfromred(pHu − )toblue(pHu+).ThecharacteristicsofthisOPLS-