is there any broth available on the cruise?
The only broth I have seen available is many ships have a build your own miso soup station and there was broth there.
I would imagine if there is soup available you could ask if they could strain it if you only wanted the broth.
If you are looking to have broth in the Main Dining room, I would discuss it with the Head waiter and see if it can be arranged for future nights of your cruise. As far as getting it in the Windjammer (buffet) I would ask when you get on board who you need to speak to about it.
If there is a medical need for broth, I would email the special needs department to see what can be done in advance. That email is firstname.lastname@example.org. Make sure to include your name, reservation number,ship and sail date.