Ie Naki Ko
English name: Nobody's Boy Remi
Genres: Adventure, Drama, Slice of Life
Type: TV, Episodes: 51
Aired: Oct 2, 1977 to Oct 1, 1978
Studio: Madhouse, TMS Entertainment
Source: Novel
Rating: G - All Ages
Synopsis:
Remi is a boy living happily with his mother in the French countryside. But everything changes when his estranged father comes home and, in desperate need of money, reveals that Remi is adopted, and sells him. Heartbroken, Remi ends up with Vitalis, a traveling musician, and his troupe of animal entertainers. Together, they travel the country in search for Remi's real parents, along the way learning the harsh lessons of life. A deeply moving story about friendship, loss and the pursuit of happiness. 

(Source: AniDB)