"The question: Did God recreate these animals [carnivores] and change their digestive tracts after the Noachian flood so that they could eat meat [other creatures] as the jw's believe that these animals only ate straw [herbivores] before the flood and that he will restore their original herbivore digestive tract after Armageddon?"
Watchtower has sent mixed signals on this issue.
You might find the following two blog articles helpful. One contains a little recognized teaching coming from Watchtower. The other contains multiple references to scholarly information that most JWs are woefully unfamiliar with because Watchtower has meticulously avoided them. See: