Gut Microbiota Modulation after the Administration of an Antihypertensive Milk Fermented with <i>Lactococcus lactis</i> NRRL B-50571

The aim of this study was to determine the effect of milk fermented with Lactococcus lactis NRRL B-50571 (FM-571) on gut microbiota (GM) of spontaneously hypertensive rats (SHRs), and its correlation with blood pressure (BP) short-chain-fatty acids (SCFAs) in feces, and antioxidant status in the plasma. Results showed that FM-571 increased (p < 0.05) diversity and reduced Firmicutes/Bacteroidetes ratio in GM. Moreover, FM-571 increased abundance (p < 0.05) of SCFA-producing bacteria Prevotellaceae (6.66 ± 3.29% and 7.29 ± 3.67%), Lachnospiraceae (21.38 ± 2.81% and 24.01 ± 12.32%), and Ruminococcaceae (21.82 ± 1.35 and 5.85 ± 0.3%) in feces and gut microbiota, respectively. Also, SCFAs in feces were higher (p < 0.05) in SHR treated with FM-571 and were negatively correlated to BP (p < 0.05). Additionally, Verrucomicrobiota, Acidoaminococcaceae, and Akkermansiaceae showed negative correlations with BP and oxidative stress index (p < 0.05) and positive correlations with the activity of antioxidant enzymes (p < 0.05). Overall, these results may suggest that the antihypertensive effect of FM-571 was linked to an improvement in the antioxidant status and SCFA production related to GM modulation.