Phytogenic feed additive mitigates necrotic enteritis-associated gut damage and performance loss in broilers

Necrotic enteritis (NE) remains a major challenge in broiler production following the withdrawal of antibiotic growth promoters. In response, phytogenic feed additives (PFA) have emerged as promising alternatives. This study investigated the efficacy of a phytogenic blend (PHB) containing thymol, oleic acid, capric acid, and refined sunflower fat in mitigating NE-associated compromise in performance, gut health, liveability, oxidative stress, and excreta biomarkers of intestinal inflammation in broilers. A total of 450 Cobb 500 D-old chicks were randomly allocated to three dietary groups: NC (non-challenged control), CC (NE-challenged control), and PHB (NE-challenged birds fed 0.01% phytogenic blend), with 10 replicates of 15 birds each. Birds in the CC and PHB groups were orally inoculated with Eimeria spp. on d9 and Clostridium perfringens at d14 to induce NE. Birds were fed starter (d0-10), grower (d10-24), and finisher (d24-35) diets. During the starter phase (d0-10), birds fed PHB had significantly lower body weight gain (BWG) (P < 0.05) and higher FCR (P < 0.05) compared to the controls. NE challenge significantly (P < 0.05) reduced BWG, feed intake (FI), and increased FCR during d10-24, d10-35, and d0-35. During d10-35, PHB supplementation significantly improved BWG and FI and reduced FCR (P < 0.05) compared with the CC group. While NE challenge impaired gut morphology by reducing villus height (VH), VH/crypt depth (CD), and increasing intestinal lesion scores (P < 0.05), birds in the PHB group showed reduced duodenal lesions and increased VH/CD (P < 0.05) compared to CC birds. Furthermore, NE-related mortality and inflammation markers in excreta, such as calprotectin, fibronectin, and lipocalin-2, were significantly higher (P < 0.05) in NE-challenged birds compared to the NC group. Supplementation with PHB shifted liveability, and excreta calprotectin and fibronectin values towards the NC group (P > 0.05). These findings suggest that PHB supplementation improves intestinal histomorphology and liveability, reduces NE-related mortality, and alleviates inflammation, which together may contribute to the enhanced performance of the PHB-supplemented birds.