Inulin dietary supplementation attenuates the stress induced by pursuit/capture/atmospheric exposure and improves innate immune response in hybrid catfish (Pseudoplatystoma reticulatum & FEMALE; x Leiarius marmoratus & MALE;) after exposure to Aeromonas hydrophila

The aim of the study was to evaluate the effects of inulin on stress and innate immunity of hybrid catfish (P. reticulatum x L. marmoratus). A total of 208 juvenile surubim, with initial average weight and length 37.91 & PLUSMN; 5.58 g and 18.51 & PLUSMN; 0.69 cm, were randomly distributed in 16 tanks (100 L) in a 4 x 5 factorial scheme. Inulin was used at four inclusion levels (0% - control, 0.25%, 0.50%, and 0.75%) for 31 days. At the end of period, blood aliquots were collected to characterize time zero. Then, the fish were exposed to pursuit/capture/atmospheric exposure stress for a new blood collection after 0.5 h. Soon after, the fish were exposed to A. hydrophila, and new blood samples were obtained at 3, 6, and 24 h post-challenge. There was a significant interaction on plasma cortisol in 0.50% inulin group. There was a significant reduction in hemoglobin and hematocrit at 24 and 3 h, respectively, after stress management + bacterial challenge. For glucose, a significant increase was observed after stress management (0.5 h) as well as a significant decrease at 6 h after stress management + bacterial challenge. A significant increase in total leukocytes and lymphocytes was observed at 6 h, while thrombocytes increased significantly at 6 and 24 h. No significant interaction was observed in leukocyte respiratory activity. Fish supplemented with 0.50% inulin showed a significant increase in serum lysozyme. The inclusions of inulin at 0.25% and 0.75% provide greater hormone cortisol homeostasis, while inulin at 0.50% improved the immune system of hybrid surubim.

Automated summary

The aim of the study was to evaluate the effects of inulin on stress and innate immunity of hybrid catfish. The fish were given inulin at four inclusion levels for 31 days. The results showed that inulin supplementation at 0.50% improved the immune system of the hybrid catfish.