Siamese Crocodile (Crocodylus siamensis) Meat Protein Hydrolysate Enhances Antioxidant Activity and Attenuates Airway Lesions in Ovalbumin-Induced Asthmatic Rats

Allergic asthma involves airway inflammation, oxidative imbalance, and structural injury. This study evaluated the effects of Siamese crocodile (Crocodylus siamensis) meat protein hydrolysate on serum antioxidant enzyme activities, hematological and biochemical parameters, and airway histopathology in an ovalbumin-induced rat model of allergic asthma. Forty-two Sprague-Dawley rats were allocated to six groups: healthy control, untreated asthma, and asthma treated with crocodile meat protein hydrolysate (100 or 200 mg/kg), commercial chicken essence (100 mg/kg), and dexamethasone (2.5 mg/kg). Treatments were administered for 14 days. Food intake, body weight, hematological indices, serum biochemical parameters, and superoxide dismutase (SOD) and catalase (CAT) activities were measured, and tracheal and pulmonary histopathological findings were evaluated qualitatively, without inferential statistical comparison. Food intake did not differ significantly among groups. Neither hydrolysate dose significantly altered body weight or most measured hematological and biochemical parameters relative to the healthy control or untreated asthma group. Dexamethasone was associated with lower body weight and platelet counts, neutrophilia, lymphopenia, increased alanine and aspartate aminotransferase activities, and altered serum protein and lipid profiles. SOD activity was higher in both hydrolysate-treated asthma groups than in the untreated asthma group, whereas CAT was higher in the hydrolysate-treated asthma groups than in the dexamethasone group. Existing histopathological descriptions and representative sections suggested less pronounced epithelial injury, inflammatory, infiltration, hemorrhage and vascular changes in the hydrolysate groups than in untreated asthma. These qualitative observations did not establish statistically significant histological differences or dose dependence. Hydrolysate administration was associated with higher serum SOD activity than untreated asthma, while qualitative histopathological observations suggested less pronounced airway lesions. These findings support further preclinical investigation of the hydrolysate as a potential food-derived bioactive ingredient. However, they do not confirm efficacy against asthma, establish that antioxidant responses mediated the histopathological observations, or demonstrate long-term safety.