Fig. 7. Representative ultra-thin pathological photos of the small intestine of female mice after 270 days consecutive zinc dietary supplementation. (A) Control group; (B) Zn ion group; (C) ZnO-NP group; (D) ZnO-MP group. The scale bar is 2.5 μm. N: nucleus; EN: enterocyte; GC: goblet cell; MV: microvilli.