Effects of Mixed Fruits and Berries on Ameliorating Gut Microbiota and Hepatic Alterations Induced by Cafeteria Diet

<b>Background/Objectives:</b> The study investigated the potential of mixed fruits and berries (MFB) as a dietary intervention to mitigate cafeteria (CAF) diet-induced gut microbiome dysbiosis and hepatic dysfunction associated with metabolic syndrome and steatohepatitis (MASH) in an adolescent rat model. <b>Methods:</b> Forty-eight adolescent male Sprague-Dawley rats (<i>n</i> = 3 cages per group (two rats per cage)) were divided into eight experimental groups, where NC received the normal AIN-93G basal diet, PC received the CAF diet and normal AIN-93G basal diet, T₁ and T₂ received MFB supplementation (3% and 6% levels) without CAF exposure, P₁ and P₂ received a MFB (3% and 6% levels) supplementation initiated at the onset of CAF feeding, and I₁ and I₂ received MFB supplementation initiated 2 weeks after CAF feeding. After 6 weeks, cecal 16S rRNA, hepatic histopathology, Oil Red O staining, and metabolic dysfunction-associated steatotic liver disease (MASLD)-related biomarkers (liver enzymes, alanine aminotransferase (ALT), and aspartate aminotransferase (AST)) were analyzed. <b>Results:</b> AST: ALT ratio was the highest in the PC group (3.63, <i>p</i> < 0.05) compared to the MFB groups. Oil Red O staining showed lower hepatic lipid accumulation, and histological analysis demonstrated a marked reduction in portal inflammatory cell infiltration in MFB. Alpha diversity (Simpson Index) decreased in PC (Kruskal-Wallis, <i>p</i> = 0.043). CAF increased <i>Lactobacillus johnsonii</i> (+75%, <i>p</i> < 0.05), while reducing <i>L. murinus</i> and <i>L. intestinalis</i> (~90%, <i>p</i> < 0.05). MFB supplementation restored <i>Bifidobacterium Pseudolongum</i> and increased <i>Akkermansia muciniphila</i> levels in the P₂, I₁, and I₂ groups (~20-fold, <i>p</i> < 0.05). <i>Bacteroides dorei</i> was present in all groups except the PC group. These bacteria presented a positive correlation with key SCFAs. <b>Conclusions:</b> The results from this study indicated that MFB supplementation modulated gut microbiota composition and enhanced SCFA production, thereby strengthening intestinal barrier integrity and reducing gut-derived inflammation. Collectively, these effects attenuated hepatic lipid accumulation and inflammation, highlighting the potential of MFB to restore gut-liver axis homeostasis disrupted by CAF-induced dysbiosis in adolescent rats.