You are probably not chasing the correct problem but you do not provide enough context to really help you put things in perspective.
You can secure zone file transmission between different hosts, in various ways. First the master can restrict AXFR/IXFR queries to come only from its slaves and the slaves can restrict NOTIFY queries (the slaves pull the data from the master, so it is the initiator).
For stronger authentication you have TSIG. See this for Bind9: ftp://ftp.isc.org/isc/bind9/cur/9.9/doc/arm/Bv9ARM.ch04.html#tsig
Also nowadays many nameservers constellation are configured from a single source and/or provisioned out-of-band. For example, content can be in a database, generated in some place then distributed using
rsync or equivalent to all nameservers. There are no DNS messages between the nameservers to update them one from another.
In a separate way you often have an "hidden" master: a nameserver where all zonefile changes appear to feed all public nameservers. There is no MITM possible there since you do not even know there is an hidden master and even less where it is and its IP (except if you were already able to get control of one the nameservers, in which case this is a completely different problem).
And like I said in another comment, you now have DNSSEC. If your zone is correctly configured with DNSSEC, even if someone manages to change its content either on the nameserver or in transit, then any validating recursive nameserver will detect the change as the new answer will either not be signed at all or incorrectly signed.