Hydrolysates of Chicken Byproducts and Their Effect on the Histological and Histopathological Analysis of Liver and Kidney in a Murine Model of Induced Metabolic Syndrome

This study investigated the potential of chicken byproduct hydrolysates (CBH) characterized by a mixture of low-molecular-weight peptides (<1.35 kDa) and larger peptides (<17.5 kDa) as a treatment for metabolic syndrome (MS), from a histological and histopathological point of view. This study aimed to evaluate the effects of CBH obtained using plant proteases (BP: B. pinguin, BK: B. karatas, BRO: bromelain) on the histological and histopathological analysis of the liver and kidney in an MS-induced murine model. Methods: Thirty adult male Wistar rats were randomly assigned to six groups (n = 5): (1) standard diet (STD); (2) MS with a hypercaloric diet (MS + HC); (3) CBH-BP (200 mg/kg of body weight); (4) CBH-BK (200 mg/kg of body weight); (5) CBH-BRO (200 mg/kg of body weight); (6) carnosine (CAR) 50 mg/kg of body weight. Liver and kidney samples were processed by conventional hematoxylin and eosin (H&E) histological techniques, Masson’s trichrome stain (MTS), and the periodic acid–Schiff (PAS) histochemical method. A scoring scale was used for the histopathological evaluation with scores ranging from 0 (normal tissue) to 4 (severe damage). Results: CBHs demonstrated a significant therapeutic effect (p < 0.05) on hepatic and renal morphological alterations induced by MS. Hepatic scores for lipid inclusions, vascular congestion, and cellular alteration were all reduced to below two. Similarly, renal scores for tubular degeneration, vascular congestion, and dilation of Bowman’s space were also decreased to less than two. The therapeutic efficacy of CBHs was comparable to that of the positive control, CAR (β-alanyl-L-histidine). Conclusions: CBH-BP, CBH-BK, and CBH-BRO treatments reduced morphological alterations observed in liver and kidney tissues, which is relevant since from a histological and histopathological point of view, it allows us to understand at the cellular and tissue level the effects that these treatments can have on a living organism, indicating a potential to improve organ health in people with MS.