SORGHUM BURGERS WITH AND WITHOUT TANNINS IMPROVE INTESTINAL MORPHOLOGY IN WISTAR RATS.

Abstract: The high prevalence of iron deficiency, one of the most common nutritional deficiencies worldwide, has stimulated the search for plant-based foods that can improve mineral intake and nutritional quality. Sorghum has attracted attention due to its nutritional and functional properties, including the presence of condensed tannins. Although tannins are often associated with reduced iron bioavailability, they may also benefit gut health by modulating the intestinal environment and microbial activity. This study evaluated the effects of plant-based burgers formulated with tannin-containing sorghum (CMSXS 3019) and tannin-free sorghum (BRS 310), combined with cowpea protein isolate, on duodenal histomorphometric parameters in Wistar rats. Twenty-one newly weaned male Wistar rats were assigned to three groups (n = 7): ferrous sulfate control (FS), tannin-containing burger (TCB), and tannin-free burger (TFB). Cecal pH was measured from collected cecal contents, and duodenal histomorphometry was assessed using hematoxylin and eosin-stained sections. Villus thickness, crypt depth, and villus-to-crypt ratio were determined as indicators of intestinal integrity and absorptive capacity. Data were analyzed by one-way ANOVA followed by the Newman–Keuls test (p < 0.05). The study was approved by the Animal Ethics Committee of the Federal University of Viçosa (No. 34/2024). Both burger groups showed lower cecal pH values than the FS group (TFB: 7.21 ± 0.30; TCB: 6.59 ± 0.35; FS: 7.79 ± 0.30; p < 0.05). Histomorphometric analysis revealed greater villus thickness in TFB (58.96 ± 6.00 µm) and TCB (57.85 ± 11.05 µm) compared with FS (48.71 ± 6.69 µm). Crypt depth was lower in TFB (104.05 ± 9.03 µm) and TCB (103.43 ± 11.22 µm) than in FS (134.23 ± 11.27 µm). The villus-to-crypt ratio was higher in TFB (5.04 ± 0.41) and TCB (4.94 ± 0.32) than in FS (3.48 ± 1.10). No significant differences were observed between TFB and TCB. The lower cecal pH suggests enhanced fermentative activity and a more favorable intestinal environment. Improved villus thickness, reduced crypt depth, and higher villus-to-crypt ratios indicate better intestinal integrity and absorptive potential. Reduced crypt depth may also reflect lower mucosal turnover and tissue stress. Despite concerns regarding iron bioavailability, tannins did not negatively affect intestinal morphology. Sorghum- and cowpea-based burgers improved intestinal morphology and mucosal integrity, and the absence of differences between tannin-containing and tannin-free formulations suggests that tannins did not impair these beneficial effects. These findings highlight the potential of sorghum-based plant products as functional foods that support intestinal health. Acknowledgments: CNPq, CAPES, and FAPEMIG.