In the present study, helminth infection in grass carp fed with HFD resulted in a modest elevation of CPT1 expression, and caused a significantly reduction in the expression levels of PPAR-γ and LPL, while significantly increased the expression level of ApoE. These results indicated that helminth mainly regulate the expression of these lipid metabolism genes to inhibit the absorption of fatty acids, thereby reducing the deposition of lipid in the liver. This evidence concerns the gene PPARG and helminthiasis.