if by "trub", you mean the material from the boil kettle that ends up in the fermenter after cooling, well there can't be any yeast in there yet since it hasnt been pitched.
i drain the cooled contents from the boil kettle into a carboy and let it settle an hour. then i rack into a fresh carboy and pitch yeast. there is no trub at all doing it this way. it saves the hassle of staining.