Dietary Turmeric Enhances Physiological Resilience of African Catfish (Clarias gariepinus) Following Aeromonas hydrophila Challenge: An Integrated Physiological Assessment

Abstract

Improving physiological resilience to bacterial infection has become an important objective in sustainable aquaculture because disease outbreaks continue to compromise fish health, survival and production efficiency. Although dietary turmeric (Curcuma longa) has been reported to improve fish health, its effects on the integrated physiological responses associated with bacterial challenge remain poorly understood in African catfish (Clarias gariepinus). This study evaluated the effects of graded dietary turmeric supplementation on physiological resilience following experimental Aeromonas hydrophila challenge through an integrated assessment of post-challenge survival, haematological profile, platelet indices, serum biochemical profile, electrolyte balance, antioxidant status and cortisol response. Fish were fed diets containing 0% (control), 0.5%, 1.0% or 2.0% dietary turmeric for 16 weeks before bacterial challenge. Dietary turmeric significantly improved post-challenge survival (P < 0.001), with the highest survival (86.03 ± 2.95%) recorded in fish fed the 1.0% turmeric diet compared with the control (55.53 ± 1.40%). Turmeric supplementation also produced coordinated improvements in haematological characteristics, platelet indices, serum biochemical profile and electrolyte homeostasis, while enhancing tissue reduced glutathione concentrations and moderating the cortisol response following bacterial infection. These physiological responses collectively indicate an improved capacity to maintain homeostasis during bacterial stress. The present study demonstrates that the benefits of dietary turmeric extend beyond improved survival to encompass coordinated physiological adaptations that enhance resilience to A. hydrophila infection. These findings support further evaluation of dietary turmeric as a functional phytogenic feed additive for improving fish health and disease resilience in African catfish culture.