Nope. The brown of shit is dead blood cells filtered out by the liver. Those are a potent source of Death energy, and so are drawn up into the new vampire’s body as part of the conversion process. What’s left in the new vampire’s colon is a nearly odorless, dusty gray substance — emptied of both Life and Death energy — that is typically farted out during the vampire’s first few feedings.
As a wise man once said — everybody must get stoned.