NAMPT overexpression alleviates defective phenotypes of oocytes from obese mice. (a) Immunoblotting showing the overexpression of exogenous NAMPT protein in oocytes (200 oocytes per lane). (b) Quantitative analysis of NAD+ content in oocytes of ND, HFD, and HFD + NAMPT (n = 150 for each group). (c) ND, HFD, and HFD + NAMPT oocytes were stained with α‐tubulin antibody to visualize spindle (green) and counterstained with propidium iodide to visualize chromosomes (red). Arrowheads denote the disorganized spindle and misaligned chromosomes. Scale bar: 30 µm. (d) Quantification of ND (n = 102), HFD (n = 119), and HFD + NAMPT (n = 114) oocytes with spindle/chromosome defects. (e) Representative images of CM‐H2DCFDA fluorescence (green) in oocytes from ND, HFD, and HFD + NAMPT oocytes. Scale bars: 50 µm. (f) Quantification of the levels of ROS in oocytes. Each data point represents an oocyte (n = 15 for each group). Data are expressed as the mean ± SD from three independent experiments. Statistical analyses were performed with one‐way ANOVA with Tukey's post hoc test. **p < 0.01, ***p < 0.001. HFD, high‐fat diet; NAMPT, nicotinamide phosphoribosyl transferase; ND, normal diet