The effect of arginine on the growth of probiotics

Abstract

<h3>Objective(s)</h3><p>The study objective was to examine the effect of arginine (Arg) supplementation on the growth of probiotics.</p><h3>Methods</h3><p><em>Lacticaseibacillus rhamnosus</em> GG, <em>Lactiplantibacillus plantarum</em>, and <em>Lactobacillus acidophilus</em> were identified as potential probiotics. <em>L. rhamnosus</em> GG and <em>L. plantarum</em> were selected for further experimentation. The probiotics were co-treated with 0.9 % NaCl (negative control), 0.5 % Arg, and 1.0 % Arg in a 1:1 ratio for 24 h at 5 % CO₂, 37 °C. The probiotics were tested for growth profiles, spectroscopic turbidity assay, metabolic assays (XTT and WST-8), live/dead cell assessment using confocal laser scanning microscopy (CLSM), and colony forming units (CFU).</p><h3>Results</h3><p>The growth profiles of <em>L. rhamnosus GG</em> and <em>L. plantarum</em> were found to be similar, whereas <em>L. acidophilus</em> showed minimal or no transition from the initial lag phase. In the turbidity assay, the end-point absorbance for <em>L. rhamnosus</em> GG with 1.0 % Arg was significantly lower than 0.9 % NaCl and 0.5 % Arg (<em>p</em> < 0.05). For metabolic assays and CFU, increasing concentrations of Arg increased the viable cells for <em>L. rhamnosus</em> GG (<em>p</em> < 0.05), but decreased viability for <em>L. plantarum</em> (<em>p</em> < 0.05). Metabolic assays with dual-species bacterial suspensions indicated that Arg co-treatment inhibited viable proportions compared to control (<em>p</em> < 0.05). The dead cell proportion was significantly lower than live cell proportion for all tested interventions and probiotics (<em>p</em> < 0.05).</p><h3>Conclusion</h3><p>Increasing concentrations of Arg promote the growth of <em>L. rhamnosus</em> GG, while conversely inhibiting the growth of <em>L. plantarum</em>. Therefore, the effect of prebiotic Arg on probiotics is concentration-dependent, leading to a selective promotion or inhibition of growth.</p><h3>Clinical significance</h3><p>The present study results show that Arg supplementation can selectively enhance the growth of <em>L. rhamnosus GG</em> while inhibit the growth of <em>L. plantarum</em>. This underscores the need to consider strain-specific responses in probiotic formulations when developing Arg-based synbiotics for modulating biofilms and creating ecologically homeostatic biofilm microenvironments.</p>