serotonin is a neurotransmitter. It should have an effect on anything with a brain or digestive system.
It should not be viable to consume it. Most things that are consumed are broken down into their basic parts and the energy derived is used to drive the building of new proteins, etc. (which is why eating brains doesn't make you smarter, and eating jellyfish doesn't make you glow)
...Maybe that's just for protein and some chemicals remain intact or promote the production of chemicals similar to themselves.
hoonoes.