The affix viṭ comes after the verb ad 'to eat' when in composition with a case-inflected word other than anna 'food'.,
The anuvritti of the word 'Chhandasi' does not extend to this sutra.
Thus आममत्ति =आमात् 'eating raw food'; शस्यात् 'granivorous'.
But with अन्न as an upapada, we have अन्नादः 'eating food', which is formed by the general affix अण् (III 2. 1).,