Mulberry leaves supplementation alters lipid metabolism and promotes fatty acid β oxidation in growing mutton sheep.

Mulberry leaves are an unconventional feed with fiber and various active ingredients, and acknowledged likely to regulate lipid metabolism, while the molecular mechanism remains undefined. Therefore, our objective was to define the role of mulberry leaves on the overall lipid metabolism. We conducted a feeding experiment of three groups on growing mutton sheep fed with dried mulberry leaves or with fermented mulberry leaves or without mulberry leaves (as control). Analyses of transcriptome and widely target lipids demonstrated the addition of mulberry leaves triggered big perturbations in genes and metabolites related to glycerolipid, phospholipid, ether lipid and sphingolipid metabolism. Additionally, the variations of above lipids in the treatment of mulberry leaves possibly facilitate immunity enhancement of growing mutton sheep via the activation of complement and coagulation cascades. Furthermore, treatments with mulberry leaves could expedite proceedings of lipid degradation and fatty acid β oxidation in mitochondria, thereby to achieve the effect of lipid reduction. Besides, added dried mulberry leaves also fuel fatty acid β-oxidation in peroxisomes and own much stronger lipolysis than added fermented mulberry leaves, possibly attributed to high fiber content in dried mulberry leaves. These findings establish the novel lipid-lowering role and immune protection of mulberry leaves, which lays the foundation for the medicinal application in mulberry leaves.