  In this work we study mesonic excitations in a Quantum Field Theory dual to
the non Abelian T-dual of $AdS_5\times S^5$, using a D6 brane probe on the
Sfetsos-Thompson background. Before and after the duality, we observe
interesting differences between the spectra and interpret them. The spectrum of
masses and the interactions among mesonic excitations teach valuable lessons
about the character of non-Abelian T-duality and its implications for
Holography. The case of Abelian T-duality is also studied.
