Jersey Zoo has (or had, when this was suggested) no staff experienced in keeping big cats, and does not have the space to accommodate them in ideal conditions. The expense would be very high, to build a secure enclosure - they haven't even finished the Gorilla House yet! There would be increased insurance premiums, given that someone previously burned down the visitor centre in protest at the feeding of calves to ... I think it was Asian lions, or maybe the Snow leopards. The zoo is very near inhabited areas, so if a tiger escaped, people would be in danger, not only from the tiger, but from any stray bullets used to kill or bring down the tiger. Then there would be an uproar about the killing of the tiger.
In any case, I don't think the States of Jersey would issue a permit for the import of tigers.