Perturbative treatments of both the Kondo-boson and the magnetic fluctuations in the simple-cubic-lattice Coqblin-Schrieffer model lead to a possible coexistence of attractive-pairing interactions and antiferromagnetic correlations in the heavy-fermion system. Doping impurities which increase quasiparticle filling tend to suppress the even-parity pairing and enhance the antiferromagnetic correlations in agreement with the trends of the doped U compounds.