Silver nitrate is commonly used as a glaze additive - for example in Raku. What effects might be expected from using small amounts of silver nitrate in the clay body itself!? Would this affect the vitrification temperature of the clay body? Is it safe?
Glaze additives aren't always appropriate for adding to a clay body, but sometimes they can be. I've never used silver nitrate or even heard of its use in glazes, but then I've never been a Raku artist. It sounds like a lot of fun, but I don't have the equipment or the community for doing it, so I've always stuck to plain mid-fire stoneware.
If you have silver nitrate on hand, why not experiment with adding a small amount to your Raku body and see what happens. That's kind of the spirit of Raku anyway; experimentation. Raku (as I'm sure you're aware) isn't typically intended to be used other than as a beautiful object of art. It isn't even necessarily expected to be durable (at least not for decades). Since the kiln set-up is so casual, you probably aren't going to do any damage to your equipment. Just be sure to take the usual Raku precautions, maybe protect your kiln shelf with a disk of bisqued clay and wear appropriate clothing, gloves, eye covering, etc.