Protective and therapeutic efficacy of phytogenic botanical blend and multi-strain probiotic in Avian Pathogenic Escherichia coli-challenged broilers.

OBJECTIVE: Avian pathogenic Escherichia coli (APEC)-induced colibacillosis is a challenge in broiler production, necessitating alternatives to antibiotics because of antimicrobial resistance. However, limited information is available on the efficacy of phytogenic botanical blend (PBB). Therefore, the study was conducted to evaluate the efficacy of a PBB, alone or in combination with a liquid formulation, in broiler chickens under an APEC challenge, in comparison with a multi-strain probiotic (MSP). METHODS: A total of 384 one-day-old male "Vencobb 430Y" broiler chicks were randomly allocated to eight treatments with four replicates of 12 birds each for 42 days. Treatments included negative and positive controls, PBB supplementation (with or without APEC challenge), PBB combined with liquid supplementation under prophylactic and therapeutic regimens, and MSP-based programs. APEC challenge was induced at 10th days of age (10⁸ CFU/bird). Growth performance parameters, mortality, and EPI were recorded. On day 14 (4 days post-infection), samples were collected for hematological, serum biochemical, and E. coli enumeration analyses, along with lesion scoring of visceral organs. RESULTS: Growth performance parameters were not significantly affected (p > 0.05) by either PBB or MSP supplementation under APEC challenge. Survival improved with PBB, with better outcomes in prophylactic than therapeutic use. Haematology remained unchanged, while serum biochemical markers (AST, ALP, bilirubin, TP) were significantly altered, indicating hepatic involvement, with reduced stress under prophylactic PBB. Birds in the PC+PBB (Ther) group showed 0 abdominal and thoracic lesion score. E. coli counts in fecal content at day 16 were significantly reduced (p < 0.05) in the groups PC+PBB, PC+MSP and PC+PBB (Ther) compared to PC. CONCLUSION: Overall, the powder based PBB, particularly when used prophylactically, showed promising potential to mitigate the adverse effects of APEC challenge. However, as most parameters did not reach statistical significance, these findings should be considered supportive rather than definitive.