Fructooligosaccharides modulate intestinal fermentation and immune response during Giardia lamblia infection in Meriones unguiculatus.

Giardia lamblia infection alters gut physiology and microbiota interactions, but the impact of prebiotic supplementation in this context remains unclear. This study investigated how fructooligosaccharide (FOS) treatment affects microbial fermentation, intestinal function, inflammation, and hepatic bile acid synthesis in G. lamblia-infected gerbils. Gerbils were divided into four groups: uninfected control, infected control, uninfected and FOS-treated, and infected and FOS-treated. Cecal short-chain fatty acids (SCFAs), intestinal disaccharidase activities, serum and intestinal cytokines, and hepatic expression of Cyp7a1 and Cyp8b1 were analysed. Giardia infection increased cecal acetate, reduced butyrate, elevated serum TNF-α, and increased hepatic Cyp7a1 expression. FOS supplementation increased cecal propionate and other SCFAs and elevated IL-10 levels in serum and intestinal tissue. Notably, FOS reduced intestinal maltase activity regardless of infection status, without affecting lactase activity. Together, these data indicate that giardiasis alters microbial fermentation and inflammatory responses, whereas FOS supplementation primarily promotes a more regulatory immune profile, characterized by increased IL-10 levels, alongside shifts in microbial fermentation, without directly modifying hepatic bile acid-related gene expression. These findings highlight complex diet-microbiota-host interactions during intestinal parasitic infection and support further mechanistic studies.