A Tribble Called Quest

The crew hunts for bosonite on a planet overrun by genetically modified giant tribbles. Zero breaks their leg and learns that their body is breaking down and won't last much longer. Rok works with the Klingon scientist who accidentally created the creatures to successfully reverse the change, but Rok inadvertently creates a bribble hybrid in the process whom she adopts as a pet. With the bosonite, the crew manages to create a new proto-core and sets course for Voyager 3,000 light years away.

Summary from Wikipedia, CC BY-SA 4.0.