Prophet Muhammad divided the food between the slaves and the free:
Let us look at the following narration:
Narrated Aisha, Ummul Mu'minin: "The Prophet (peace_be_upon_him) was brought a pouch containing bread and divided it among free women and slave women. Aisha said: My father used to divide things between free men and slave. (Translation of Sunan Abu-Dawud, Tribute, Spoils, and Rulership (Kitab Al-Kharaj, Wal-Fai' Wal-Imarah), Book 19, Number 2946)"
As we clearly see from this saying, our beloved Prophet Muhammad peace be upon him did honor slaves and their human dignity and value. Islam is a religion that honors humans. If it wasn't for the Judeo-Christian and Pagan slavery that was brutally practiced in the Middle East, then Islam would not have dealt at all with slavery.
Islam is a religion that did not come to enslave people, but to free slaves! Please visit Human rights and equality in Islam V.S. Christianity to see how much Islam honors humans and how much the Bible in both the New and Old Testaments disgraces humans.