Most are hybrids, but it's complicated since a recent taxonomic revision has shown that some lion "types" are the same subspecies (Asiatic lions and the now likely-extinct Barbary lions are both considered the same subspecies along with some other Northern African lion populations). It's pretty complicated, but I did find a studbook for P. leo krugeri in AZA zoos (though P. l. krugeri is now considered a part of P. l. melanochaita). Some zoos in Europe, as far as I know, keep Asiatic lions, and American zoos also formerly carried Asiatic lions (until they were phased out due to being mixed with African lions and poor record keeping).