Effects of dietary histamine on gastrointestinal morphology, antioxidant capacity, and muscle quality in striped catfish (Pangasianodon hypophthalmus)

This study investigated the dose-dependent effects of increasing dietary histamine concentrations on gastrointestinal function, antioxidant status, and muscle quality in striped catfish ( Pangasianodon hypophthalmus ), to assess potential histamine-related health risks. An eight-week feeding trial was conducted using seven isonitrogenous and isolipidic diets supplemented with 0, 15, 30, 60, 120, 240, and 480 mg/kg histamine, respectively. The findings demonstrated that as the dietary histamine concentration increased, the activities of intestinal trypsin, lipase, and maltase displayed a linear decline. Histological examination of hematoxylin and eosin-stained gastric and intestinal sections showed that gastric villus width, gastric muscular thickness, and intestinal villus height were significantly reduced when dietary histamine inclusion exceeded 15, 60, and 480 mg/kg, respectively. The relative expressions of tight junction-related genes ( zonula occludens-2 , occludin , claudin 7a , and claudin 12 ) were progressively downregulated with increasing dietary histamine, accompanied by elevated intestinal permeability. This was supported by a significant increase in serum lipopolysaccharide level at histamine inclusions above 30 mg/kg. Compared with the H0 group, the H480 group exhibited significantly lower serum total antioxidant capacity and peroxidase and catalase activities. Muscle yellowness, elasticity, and chewability increased as dietary histamine increased, with significant elevations observed above 30, 240, and 480 mg/kg, respectively. Collectively, increasing dietary histamine concentrations were associated with pronounced impairments in striped catfish, highlighting the importance of controlling histamine concentrations in aquafeeds and providing evidence to support risk assessment and the development of safety guidelines. • Dietary histamine reduced intestinal digestive enzyme activities in striped catfish. • Excess histamine impaired gastric and intestinal morphology in striped catfish. • Histamine compromised intestinal barrier integrity via tight junction downregulation. • Dietary histamine deteriorated fillet color and texture quality in striped catfish.