No, I would say that any for or against slavery that is rooted in arguments about the presence of absence of consciousness is meaningless pseudoscience. It is the modern equivalent of Phrenology. If you want to make those arguments you need a genuine science of consciousness. Or you need to base your morality in something other than the presence of consciousness.
Thanks for the reply!
I'm not sure I agree that consciousness (or sentience if we're making that distinction) is worthless when considering the morality of exploiting something/someone. I do agree there are more angles than that but they seem on top of something's ability to perceive not instead/despite of it.
Do you have some examples of other things that go into your own moral opinions about slavery?