  The main purpose of this paper is to treat semigroups properties, like norm
continuity, compactness and differentiability for perturbed semigroups in
Banach spaces. In particular, we investigate three large classes of
perturbations, Miyadera-Voigt, Desch-Schappacher and Staffans-Weiss
perturbations. Our approach is mainly based on feedback theory of Salamon-Weiss
systems. Our results are applied to abstract boundary integro-differential
equations in Banach spaces.
