Abstract
This study evaluated the effects of dietary Bixa orellana leaf meal on the growth performance and haemato-biochemical responses of Amur carp (Cyprinus carpio haematopterus) against Edwardsiella tarda infection. A total of 180 fish (9.23 ± 0.82 g) were equally distributed into four groups: control (0%), T1 (1%), T2 (3%), and T3 (5%) B. orellana supplementation for 90 days. Edwardsiella tarda was injected intraperitoneally into fish for 14 days after the feeding trial; RPS and histopathological changes was recorded. The result revealed a considerable improvement (P < 0.05) in growth performance (Weight gain, SGR, PER and survival rate) and a decreased feed conversion ratio with increasing BoLM supplementation. However, hematological indices differed significantly among treatments, with T3 showing higher TEC, TLC, hemoglobin, and hematocrit values. Fish Serum biochemical response showed a significant increase, as indicated by total protein, globulin, and albumin in T3 and T2, whereas glucose and cortisol levels were highest in the control group. Histopathological examination revealed distinct tissue alterations in the gills, liver, and intestine among the experimental groups following E. tarda challenge. Furthermore, the treatment group significantly reduced mortality rate following challenges with E. tarda challenge. In conclusion, 5% B. orellana supplementation enhanced growth performance, haemato-biochemical (health) status, and disease resistance in Amur carp.