wow, I wasn't even trying to find this. Ok, I guess in the 90s there was an anime called Super Pig? I didn't know either until I heard a passing comment about it, so I youtubed it and came across the show, clicked the first link I saw cuz I was curious and it has a pig TF ala Sailor Moon, don't believe me? Well see for yourself. TF takes places almost right from the start
https://www.youtube.com/watch?v=FfruNQi6fAc