Microbubbles (Rtextlesssubtextgreater0textless/subtextgreatertextequals100 $micro$m) are injected in fully developed turbulence (Retextlesssubtextgreater$łambda$textless/subtextgreatertextequals200) up to a volume concentration of 0.3textpercent. An enhancement of the energy on small scales and a reduction on the large scales is observed, confirming theoretical prediction by I. Mazzitelli, D. Lohse, and F. Toschi [Phys. Fluids 15, L5 (2003)]. The result is a (nonuniversal) less steep slope than –5/3 in the power spectrum.