Protective effects of synbiotic soymilk fortified with whey protein concentrate and zinc sulfate against bile duct ligated-induced hepatic encephalopathy

This study aimed to compare the effects of synbiotic soymilk fortified with whey protein concentrate and zinc sulfate with lactulose on bile duct ligated-induced HE. Background: Hepatic encephalopathy (HE) is seriously associated with neuromuscular and cognitive alterations. Methods: Eighty-two Sprague Dawley rats were randomly assigned into seven groups (sham, bile duct ligation (BDL), BDL + lactulose, BDL + soymilk (SM), BDL + Synbiotic soymilk (SSM), BDL + SSM + whey protein concentrate (WPC), BDL + SSM + WPC + ZnSO4). Different SM products, lactulose, and normal saline were administered via oral gavage (2 mL/rat/day). The serum and liver markers as well as liver histopathology were assessed after 28 days. Results: The SM products significantly reduced the serum alanine aminotransferase, albumin, and ammonia (P < 0.05). The levels of aspartate aminotransferase, endotoxin, and liver interleukin-6 improved significantly in all treatments, except for those receiving SM. SSM and SSM + WPC + ZnSO4 were the only effective products in reducing serum alkaline phosphatase (P < 0.05). Furthermore, the liver total antioxidant capacity was greater (P<0.05) in the SSM + WPC and SSM + WPC + ZnSO4 groups. The histopathological examinations confirmed the efficiency of all SM products in reducing liver fibrosis. Liver bile duct proliferation diminished only in the SSM + WPC and SSM + WPC+ ZnSO4 groups (P<0.05). Conclusion: This study showed the positive effects of different SM products, especially SSM + WPC and SSM + WPC + ZnSO4, on HE. Further studies are required to confirm our findings.