@GiratinaIsGod since the zoo is based in the UK, where muntjacs are an invasive species. I would assume that the lion’s victim was sourced from the latter.
It is a culled invasive muntjac - the zoo have confirmed that they source the muntjacs used to feed their Komodo dragons from local gamekeepers, so I imagine this one came from the same source: Komodo dragon eating muntjac - ZooChat
@GiratinaIsGod I guess there is some risk, but I also imagine the carcasses are checked during preparation - although the photo does not show it at all, this carcass had been cut in half and only the front bit offered to the lion. That would theoretically stop a lot of the intestinal types of parasite.