To investigate the interaction between the Activin or the BMP branch of the TGF-β signaling and the metabolism of stored lipids in the context of parasitic nematode infection, we determined the levels of TAG and free cholesterol in daw and dpp loss-of-function mutant larvae 24 h after infection with axenic or symbiotic H. bacteriophora. This evidence concerns the gene TGFB1 and infection.