Kemono no Gochisou, Hijoushoku

When he was young, a herbivore named Hakka was caught in a trap and was unable to move. A carnivore named Daiya picked him up and decided to keep him as "emergency food," but as they spent time together, they began to feel as if they were family.

Ten years pass and the two become adults. Daiya still thinks of Hakka as family, but he realizes that Hakka's feelings are different from his own.

(Source: Sankosha, translated)