Interesting article about organic acids in monogastric animals. I have been brewing and using a probiotic in our pigs drinking water for close to a year. I can attest to the positive effect it has had on piglets through to the breeding herd. During that time we have not injected a pig with anything other than iron for new piglets. The whole herd is healthier, FCR is lower and growth faster. They seem to have less pest problem as well, even flies are gone.
There is another benefit that we have gained. There is almost no smell in the pigs excretions.
Our brew is primarily lactic acid bacteria, a strain that occurs naturally in the pigs. We also use it in composting manure and in concert with other organic substances as foliar sprays and soil drenches on the farm.