The Effect of Feeding Lactic Acid to Salmonella Typhimurium Experimentally Infected Swine

Abstract

Antimicrobial resistant Salmonella are becoming more prevalent. Therefore, alternative methods to control swine Salmonella infection must be explored. We examined whether lactic acid feeding is an effective way to control clinical and subclinical Salmonella Typhimurium infection in swine. In this experiment, swine were inoculated 5.6×10⁷CFU (hi-ST) or 5.6×10⁵CFU (lo-ST) S. Typhimurium per swine to reproduce the clinical and subclinical infection. And swine were fed 2.8% lactic acid was (LA) or was not (C) added commercial feed to examine the effect of feeding lactic acid. Twenty 21- and 22-day-old swine were divided into 4 groups, LA-hiST, C-hiST, LA-loST and C-loST, and began to eat respectively feed. Swine were inoculated S. Typhimurium at 51- and 52-day-old. Clinical symptoms and the number of S. Typhimurium shed in feces were evaluated. The LA-hiST group did not show obvious clinical symptoms, such as diarrhea or febrile response, but the C-hiST group did show clinical symptoms. The number of S. Typhimurium shed in feces of the LA-hiST group were lower than in that of the C-hiST group and in that of LA-loST was lower than in that of C-loST. Our data suggest that dietary supplementation with 2.8% lactic acid can be an effective way to control clinical and subclinical infections of S. Typhimurium in swine.