Please forgive me if this topic has already been discussed. Not got PD but have learnt so much from you all, as have an issue with, I believe, an overlapping contributory factor, dsybiosis.
I used Tributyrin (not ordinary butyrate) as a postbiotic. A lack of bifidobacteria and lactobacilli contributed to my dysbiosis and so a likely shortage of short chain fatty acids (SCFA). Using 500mg three times daily to 'treat' formless stools worked well, but I've needed to gradually decrease to just 500mg every three days to avoid total cessation of bowel movements.
So if you're thinking of trying it, a caution to those tending towards constipation would be to go very slowly/cautiously. And you would not need extra SCFA at all if you are on a ketogenic diet (can find relevant information if interested/relevant to you).
jnm.snmjournals.org/content...
And this study proposal gives more info re mechanism.
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/cdn.clinicaltrials.gov/larg...