Journal of Advances in Biology & Biotechnology

This study reveals how Delonix regia leaf meal influences the blood profile of Labeo rohita maintained under regulated aquaculture conditions over a 90-day period. Six diets with equal protein and energy content were prepared, containing 0, 10, 20, 30, 40, and 50% D. regia leaf meal, and were offered to the fish twice daily at a rate of 5% of body weight. At the conclusion of the feeding trial, blood parameters such as haemoglobin concentration, haematocrit level, red blood cell (RBC) count, and white blood cell (WBC) count were assessed. Both haemoglobin and haematocrit showed a steady rise with increasing levels of leaf meal, reaching maximum values at 50% inclusion (9.24 g/dL and 27.8%, respectively) compared with the control diet (8.28 g/dL and 22.8%). A similar upward trend was observed in RBC numbers, which increased from 2.39×10⁶/µl in the control group to 3.20×10⁶/µl at the highest inclusion level, while WBC counts exhibited a modest but uniform increase, reflecting enhanced immune responsiveness. Importantly, all measured parameters remained within the normal physiological limits for L. rohita, indicating no evidence of blood-related toxicity. The observed enhancement in haematological traits is likely linked to the therapeutic and antioxidant constituents of D. regia leaves and aligns with previous findings on the positive effects of plant-based additives on fish health and immunity. Overall, the results demonstrate that D. regia leaf meal can be incorporated safely up to 50% in the diet of L. rohita, improving oxygen-carrying capacity and immune-associated blood indices, and highlighting its suitability as an economical herbal feed ingredient in carp farming.