There was a recent small scale study[1] that suggested taking probiotics could increase the time for the gut microbiota to return to normal. The biggest bang might have been a fecal transplant of cultures taken from your own gut before you started on antibiotics. The study is more suggestive than conclusive because of limited sample size.

[1]https://www.sciencedaily.com/releases/2018/09/180906141640.h...