bind named error: zone NS has no address records A or AAAA

Today I have found bind named error on one of my Linux servers in main server log file /var/log/messages

Aug 12 19:39:53 shkodenko named: zone shkodenko.com/IN: NS 'ns.shkodenko.com' has no address records (A or AAAA)
Aug 12 19:39:53 shkodenko named: zone shkodenko.com/IN: not loaded due to errors.
Aug 12 19:39:53 shkodenko named: _default/shkodenko.com/IN: bad zone

Command to start bind named service:

# /sbin/service named start

has failed with errors listed above.

To fix this error I have added NS and A records to zone file /var/named/chroot/var/shkodenko.com:

shkodenko.com.               IN NS   ns.shkodenko.com.
ns.shkodenko.com.            IN A    217.20.163.193

Also, I have changed zone serial number.
I have started bind named service using command:

# /sbin/service named start

Error messages has disappeared.