No. Slavery is an immoral and unethical concept. The Naruto series promotes values like friendship, hard work, and equality. Owning slaves goes against these positive values. In Naruto, characters strive for a better world where everyone is treated fairly, not one with such a dehumanizing practice as slavery.
It is completely inappropriate. The Naruto universe is built on a foundation of honor among ninjas, loyalty, and respect for others. Slavery is a dark and inhumane concept that is the antithesis of what Naruto stands for. A fanfic with such a concept would be a misrepresentation of the Naruto world and would likely be rejected by the majority of fans who expect the fanfic to stay true to the spirit of the original series.