  We consider defects in 5d field theories corresponding to higher-rank
generalizations of the $E_{N_f+1}$ theories; holographically dual to the
Brandhuber-Oz background in type I' String Theory. We concentrate on
codimension 2 and 1 defects, corresponding, respectively, to 3d and 4d defect
Quantum Field Theories. We study holographically such defect theories by
considering supersymmetric probe D4- and D6-branes in the $AdS_6$, whose
fluctuations allow us to study the spectrum of mesonic operators of the defect
theories. In the case of D4-branes, we also consider wrappings in the internal
space which can be regarded as generalizations of the configurations capturing
the antisymmetric Wilson loop.
