Inulin and multispecies probiotic effects on blood, liver and kidney biochemistry and metabolic and stress-related gene expression in pigs

Dietary supplementation with probiotics, prebiotics, and their combination (synbiotics) can improve pig health through direct and indirect mechanisms. This study evaluated the effects of probiotics, inulin, and their combination on: (1) blood biochemistry parameters reflecting lipid metabolism, liver function, oxidative stress, and immune status; (2) liver and kidney gene expression and biochemical markers related to energy and reactive oxygen species metabolism; and (3) mineral profiles in blood plasma, liver, and kidneys, including renal aquaporin gene expression. Inulin increased total protein, while raising total and LDL-cholesterol but lowering hepatic cholesterol and triglyceride levels, and upregulating apolipoprotein A1 expression. Probiotics lowered AST and ALT activity and enhanced the expression of energy metabolism genes in the liver and kidneys, similarly to the combined treatment. Inulin increased plasma sodium and phosphorus but reduced liver magnesium and copper contents; probiotics elevated selenium, iron, and phosphorus concentrations in the blood and kidneys. Both supplements improved antioxidant capacity and anti-inflammatory responses, although their combination unexpectedly elevated renal interleukin-6 expression. Overall, probiotics, inulin, and their combination positively affected lipid metabolism, liver function, oxidative balance, and immune status, supporting their potential as natural alternatives to antibiotics in pig nutrition.