Microencapsulated inulin as a prebiotic: Enhancing growth, digestive enzyme activity, and immune response in striped catfish (Pangasianodon hypophthalmus)

This study assessed the influence of dietary microencapsulated inulin on the physiological performance, enzymatic activity, immune modulation, antioxidant status, and tissue morphology of striped catfish ( Pangasianodon hypophthalmus ). Juvenile fish (initial weight: 5.06 ± 0.12 g; length: 6.93 ± 0.14 cm) were reared under controlled conditions and fed diets containing 0 %, 0.4 %, 0.8 %, and 1.2 % inulin for eight weeks. Feeding was conducted thrice daily to apparent satiation. The 0.8 % inulin treatment yielded the most pronounced improvements in final body weight, and feed conversion ratio (p < 0.05), while survival and viscerosomatic index were unaffected. Hepatosomatic index increased significantly in fish receiving 0.8 % and 1.2 % inulin-based diets. Enhanced cellulase activity was observed with inulin inclusion (p < 0.05), whereas protease and amylase activities remained unchanged. Blood parameters, including erythrocyte, leukocyte, and hemoglobin levels, showed no notable variation; however, total plasma protein, immunoglobulin, lysozyme, and antioxidant enzymes (Superoxide dismutase and Glutathione peroxidase) increased significantly. Morphological enhancements in intestinal tissues such as villi architecture and goblet cell density were observed, along with improved liver histoarchitecture in inulin-fed groups. These results support the use of microencapsulated inulin, particularly at 0.8 %, as an effective functional feed additive to enhance growth, immune defense, and tissue integrity in striped catfish culture. • Dietary microencapsulated inulin (0.8 %) improved growth performance and feed efficiency in striped catfish. • Inulin enhanced intestinal villi, goblet cell density, and liver histology for improved nutrient absorption. • Inulin increased cellulase activity and antioxidant enzymes (SOD and GPx), enhancing digestive function. • Plasma protein, immunoglobulin, and lysozyme levels were significantly elevated by inulin. • Microencapsulated inulin is a heat-stable, sustainable additive for responsible aquaculture practices.