Nanoemulsified chive (Allium schoenoprasum L.) essential oil in drinking water improves growth and gut health of broilers under cold-humid stress

This study evaluated whether supplementing drinking water with a nanoemulsion of chive (Allium schoenoprasum L.) essential oil could improve growth performance and intestinal health of broiler chickens reared under cold and humid stress conditions. One hundred and eighty one-day-old colored Rilai male broiler chicks were brooded for four weeks and then allocated to five treatments (four replicates, nine birds/replicate) for an eight-week trial: an unsupplemented negative control, a positive control receiving tetracycline (50 ppm), and three nanoemulsion doses (25, 50, and 100 µL/L). Chicks were housed on wet litter during a cold-humid period (approximately 12-15°C; 68-75% relative humidity). Compared with the negative control, supplementation at 50 µL/L improved final body weight and weight gain and reduced feed conversion ratio (P < 0.05), while feed intake, water consumption, and mortality were unchanged (P > 0.05). Nanoemulsion supplementation increased lactic acid bacteria counts in ileocecal digesta and reduced Salmonella spp., with no detectable colonies in supplemented groups. Jejunum histomorphology results showed greater villus height and villus width and deeper crypts in the 50 µL/L group (P < 0.01). These findings indicate that nanoemulsified chive essential oil supplied via drinking water, particularly at 50 µL/L, can support performance and intestinal health in broilers under cold-humid stress and may help reduce reliance on antibiotic growth promoters. Further studies are required to evaluate safety, dose tolerance, and possible adverse effects before broad field application.