Figure 1. Changes of the liver (a) and changes of the growth index (GI, b) of liver at 21 and 42 days of experiment.

Livers are smaller in the three NaF-treated groups than those in the control group. Hepatic growth index is decreased in the 24 and 48 mg/kg groups. CG: Control group; GI: 12mg/kg group; GII: 24mg/kg group; GIII: 48mg/kg group. b changes of the growth index (GI) in liver, *P<0.05, compared with the control group **P<0.01, compared with the control group.