Do you recommend trying to support the microbiome with probiotic foods or supplements while one is taking a course of antibiotics? Or should one wait until after the course is done and then start? Are probiotic supplements better in that situation than eating lots of foods like yogurt and pickles etc (cheaper)?
Thank you.

Antibiotics MAY kill some good bacteria in your gut, so probiotics may help. Strains of different probiotics have been shown to be variously susceptible to or resistant to different antibiotics.

https://academic.oup.com/jac/article/59/5/900/728499

I would be somewhat cautious of most probiotic supplements as their supply and delivery chain is not as strict as for pharmaceutical medicines, so they may end up mostly killed off sitting in 40+ degree warehouses and delivery vans in the summer months. Shop bought yoghurt or yoghurt drinks aren’t though to be that effective in getting probiotics into the gut as they have relatively microbial count. Making your own yoghurt would be more effective (as Michael Mosley recommends), or Kefir (fermented milk) and Saeurkraut (fermented cabbage + garlic or ginger + other veg), or Kimchi (fermented cabbage, veg & fish). During hot months you may need to control the fermenting temperature with an icepack/coolbox setup.
Of the commercial probiotics, Symprove, a probiotic drink, and VSL#3 and its European version Vivomixx available in either pill or sachet form are the only ones that I am aware of that have proven survivability in the stomach and gut (UCL study). You can order VSL#3 in a cooled delivery box from the manufacturer
https://www.vsl3.co.uk/

you can get VSL#3 and Vivomixx from Lifestyle Labs in a slightly cheaper chilled delivery
https://www.lifestyle-labs.com/products/Vivomixx-Probiotic-450-Billion-30-Sachets

I would only order Symprove from the manufacturer
https://www.symprove.com/

You should also try and eat and drink more healthily, so cut out junk food & processed foods, cut down on things high in sugar, including chocolate (even high cocoa% as that can contain fairly high caffeine levels), and stimulants such as energy drinks, non de-caffeinated coffee, tea, and alcohol. Make sure you also include some prebiotics in your diet – you can see from the study below which foods contain the most and which the least – basically garlic (particularly dried), chicory root, and Jerusalem artichoke have very high levels, then leeks, onions, wheat bran and asparagus lower, chickpeas, oats, lentils and beans also. If you already eat those foods in decent amounts you probably don’t need to change anything. Eating a lot (10g+) of prebiotics can cause bloating & gas.
https://academic.oup.com/jn/article/129/7/1407S/4722578

Testing as it seemed to delete my reply!

Antibiotics MAY kill some good bacteria in your gut, so probiotics may help. Strains of different probiotics have been shown to be variously susceptible to or resistant to different antibiotics.

https://academic.oup.com/jac/article/59/5/900/728499

I would be somewhat cautious of most probiotic supplements as their supply and delivery chain is not as strict as for pharmaceutical medicines, so they may end up mostly killed off sitting in 40+ degree warehouses and delivery vans in the summer months. Shop bought yoghurt or yoghurt drinks aren’t though to be that effective in getting probiotics into the gut as they have relatively microbial count. Making your own yoghurt would be more effective (as Michael Mosley recommends), or Kefir (fermented milk) and Saeurkraut (fermented cabbage + garlic or ginger + other veg), or Kimchi (fermented cabbage, veg & fish). During hot months you may need to control the fermenting temperature with an icepack/coolbox setup.
Of the commercial probiotics, Symprove, a probiotic drink, and VSL#3 and its European version Vivomixx available in either pill or sachet form are the only ones that I am aware of that have proven survivability in the stomach and gut (UCL study). You can order VSL#3 in a cooled delivery box from the manufacturer
https://www.vsl3.co.uk/

you can get VSL#3 and Vivomixx from Lifestyle Labs in a slightly cheaper chilled delivery
https://www.lifestyle-labs.com/products/Vivomixx-Probiotic-450-Billion-30-Sachets

I would only order Symprove from the manufacturer
https://www.symprove.com/

You should also try and eat and drink more healthily, so cut out junk food & processed foods, cut down on things high in sugar, including chocolate (even high cocoa% as that can contain fairly high caffeine levels), and stimulants such as energy drinks, non de-caffeinated coffee, tea, and alcohol. Make sure you also include some prebiotics in your diet – basically garlic (particularly dried), chicory root, and Jerusalem artichoke have very high levels, then leeks, onions, wheat bran and asparagus lower, chickpeas, oats, lentils and beans also. If you already eat those foods in decent amounts you probably don’t need to change anything. Eating a lot (10g+) of prebiotics can cause bloating & gas.