Stability and iron affinity of Donkey-hide gelatin hydrolysates: Implications for improving iron bioavailability and gut microbiota modulation

Iron deficiency anemia (IDA) is a prevalent nutritional disorder primarily treated with inorganic iron supplements. However, these interventions are often limited by poor bioavailability and gastrointestinal side effects. Food-derived protein hydrolysates have emerged as promising dietary strategies to enhance iron absorption and mitigate adverse effects. This study evaluated the efficacy of dietary supplementation with Donkey-hide gelatin hydrolysates (DH) in alleviating IDA in a rat model. DH-Fe exhibited superior binding affinity and stability, retaining more soluble iron fraction under diverse conditions, confirming its role as a functional dietary iron carrier. In vivo, DH markedly enhanced hematopoiesis and iron homeostasis, elevating hemoglobin by 44% and normalizing serum ferritin (25.34 ng/mL). DH also enhanced antioxidant defenses, increasing SOD and hydroxyproline levels to 111% and 168% of the reference groups, respectively. Moreover, DH ameliorated IDA-induced liver injury and gut microbiota dysbiosis by promoting beneficial bacteria (e.g., Ruminococcus) and suppressing pathogenic bacteria (e.g., Escherichia-Shigella). Overall, these findings indicate that DH improves hematopoiesis and modulates gut microbiota composition, supporting its potential as a next-generation dietary iron supplement for IDA management.