Effect of dietary NaBT supplementation on hepatic lipid accumulation of common carp. Lipid droplets and nuclei are dyed in red and blue by oil red staining, respectively (200× magnification). A, the control diet; B, the high-fat diet; C, the high-fat diet added with 0.1% sodium butyrate. D. lipid accumulation was quantified by measuring the intensity of the stained oil droplets. Bars marked with different letters are significantly different (P<0.05).