Protein signatures of feed restriction and spontaneous lipolysis in skimmed ewe milk

Milk lipolysis refers to the breakdown of triacylglycerols by lipoprotein lipase. Our aim was to identify the drivers of spontaneous lipolysis in skimmed ewe milk. To achieve this, feed restriction was used as a lever to generate contrasting samples with respect to lipolysis. We combined multivariate statistical methods to identify the effects of feed restriction on ewes, the molecular composition of skim milk, and the drivers of spontaneous lipolysis in milk. The high spontaneous lipolysis in skimmed ewe milk was driven by a combination of variables consisting of 12 milk proteins (ANGPT1, FN1, COL14A1, W5PDQ9, W5QH04, CLSTN1, PPIB, PLIN3, ITIH2, ASAH1, SMPD1 and FST), 7 milk fatty acids (C6:0, C14:0, C14:1 cis9, C10:1 cis9, C10:0, C11:0 and C12:0), milk urea, plasma acetate, plasma urea, plasma IGF1, milk yield, and NEL. In particular, the proteins ANGPT1, SMPD1, and ASAH1 were identified as participants in the lipolytic process in milk, whatever the level of nutrition, which could be considered in future tools to manage milk lipolysis.