L. acidophilus/L. johnsonii ratio affects slow transit constipation in rats.

Slow Transit Constipation (STC) is characterized by impaired colonic motility, but its relationship with gut microbiota remains unclear. This study investigated the correlation between specific gut microbial populations and STC, focusing on the Lactobacillus acidophilus to Lactobacillus johnsonii (A/J) ratio. We used four rat groups: Control (CON), Loperamide-induced STC (LOP), antibiotic-treated (ABX), and antibiotic plus Loperamide (ABX + LOP). Fecal samples were analyzed using 16S rRNA gene sequencing, and serum metabolites were examined through LC-MS. The LOP group showed an increased A/J ratio, while ABX and ABX + LOP groups had decreased ratios. Notably, the ABX + LOP group did not develop STC symptoms. Metabolomic analysis revealed alterations in key metabolites across groups, including changes in levels of guanidinoacetate, glycine, L-glutamine, nicotine, and nicotinate D-ribonucleotide in the LOP group, and variations in L-glutamine, L-phenylalanine, L-tyrosine, histamine, D-ornithine, and lecithin in the ABX and ABX + LOP groups. Our findings suggest a correlation between the A/J ratio and STC development, offering insights into STC pathophysiology and potential microbiome-targeted therapies.