We investigate mean-field effects in two-component trapped Fermi gases in the superfluidphase, in the vicinity of s-wave Feshbach resonances. Within the resonance superfluidityapproach (Holland et al 2001 Phys. Rev. Lett. 87 120406) we calculate the ground stateenergy and the heat capacity as functions of temperature. Heat capacity is analysed fordifferent trap aspect ratios. We find that trap anisotropy is an important factor indetermining both the value of heat capacity near the transition temperature and thetransition temperature itself.