Only one that I saw, and ISIS agrees. In fact, ISIS makes it clear how scarce these are in Europe - 0.1 at Howletts, 1.0 at Edinburgh and 2.2 in Prague, plus 5 animals in Israeli zoos. Zootierliste has nothing to add to this so it looks like only 11 animals in European zoos (and only 6 if we exclude the geographically-distant Israel).