Fig. 4: Dietary serine supplementation reduces deoxysphingolipid content and slows down peripheral neuropathy.

a, Plasma amino acid levels in the fed state in BKS-db/db mice fed with either a control (n = 8) or serine-supplemented diet (n = 9) for 8 weeks. b, Liver amino acid content in the fed state in BKS-db/db mice fed with either a control or serine-supplemented diet for 8 weeks (n = 8 per group). c, Thermal latency time course in BKS-db/db mice fed with either a control (n = 8) or serine-supplemented diet (n = 9). d, Tactile sensing 8 weeks after feeding BKS-db/db mice with either a control (n = 8) or serine-supplemented diet (n = 9). e, Levels of deoxyDHCer in the liver in BKS-db/db mice fed with either a control or serine-supplemented diet for 8 weeks (n = 8 per group). f, Levels of deoxyDHCer in the paw skin of BKS-db/db mice fed with either a control or serine-supplemented diet for 8 weeks (n = 8 per group). Data are mean ± s.e.m., and were analysed using a two-sided independent t-test (a,b,d–f) or two-way ANOVA with Fisher’s least significant difference post hoc test (c). Statistical analyses in e,f were performed using summed deoxyDHCer abundances.