According to the KB 1038827 “Enabling Jumbo Frames for VMkernel ports in a virtual distributed switch”, VMware says that you have to recreate the vmkernel port to set the MTU for jumbo frames. This is not true if you use powerCLI, I do not know exactly how it is done beneath the hood but it is very easy to configure using quite a few lines scripting..  By the way, there is no way in the GUI to edit this.

$cred = Get-Credential
Connect-VIServer ESXhost.test.loc -credential $cred

Get-VMHostNetworkadapter -name vmk2 | Set-VMHostnetworkadapter -Mtu 9000

Get-VMHostnetworkadapter -name vmk2 | ft Mtu

Setting the Mtu on the vmkernel port is basically not different using a standard vSwitch or a distributed vSwitch.

Of course you can connect to a vcenter and add a foreach loop to set the Mtu for more than one host vmkernel port.