Effects of Composite Probiotic Food on Urinary, Serum Biochemical and Oxidative Stress Parameters in a Urolithiatic Rat Model.

Research background: Prevention, management or cure of diseases through dietary approaches is becoming increasingly important. Research suggests that probiotic, oxalate-degrading Lactobacillus species administered via a milk and cereal food can prevent kidney stones while also addressing nutritional deficiencies and maintaining essential calcium levels. This study investigates the effect of a composite probiotic milk beverage on urolithiatic rats.

Experimental approach: Probiotic milk-barley beverage (PMBB) was prepared by fermentation of milk enriched with barley (Hordeum vulgare) flour using starter culture containing oxalate-degrading probiotic strains (Lacticaseibacillus rhamnosus strains MTCC5945 and MTCC25062, Lactobacillus helveticus MTCC5463 and Lactiplantibacillus plantarum M11). Cumin and common salt were used as flavourings. Unfermented milk-barley base (C) served as control. Wistar rats were divided in four groups (N=6). Normal control (NC) group received normal rat diet, and to induce kidney stones, ethylene glycol (0.75 %) and ammonium chloride (1 %) were administered to the disease control (DC) group, PMBB and control (C) groups for 28 days. PMBB and C groups received 1 mL of probiotic milk and barley beverage and unfermented milk-barley base from day 15 to day 28. Indicators of urolithiasis were studied.

Results and conclusions: PMBB significantly (p<0.05) increased urine output, decreased urine oxalate concentrations and increased creatinine, calcium and uric acid concentrations. Serum parameters such as concentrations of calcium, uric acid, urea and creatinine increased significantly (p<0.05) in DC rats, but decreased significantly (p<0.05) in the PMBB group. In addition, serum concentrations of magnesium and osteopontin decreased more significantly in DC rats than in the PMBB ones. The increase in malondialdehyde and decrease in reduced glutathione concentrations observed in the DC group were significantly lower in the PMBB group. The histomorphology of the kidney tissue of DC rats showed calcium oxalate crystal aggregates in the tubules, indicators of renal injury, tubular dilatation, enlarged urinary space and shrunken glomeruli. The PMBB group showed an improvement in the renal histological architecture. Analysis of the caecal digesta of the rats showed a significantly (p<0.05) higher mass fraction of fatty acids (acetic and propionic) in the treatment group. The results show the potential of PMBB in the dietary control of urolithiasis.

Novelty and scientific contribution: This study focuses on the antiurolithiatic prospect of a composite probiotic milk beverage produced with oxalate-degrading culture. It also points to a new functional food form that shows promising health benefits in nutrition of patients with urolithiasis.