Curcumin- and capsaicin-loaded nanoemulsions improve oxidative stress, intestinal morphology, and feed efficiency in slow-growing Korat chickens under high stocking density.

This study investigated the effects of curcumin (CUR)- and capsaicin (CAP)- loaded nanoemulsion on blood biochemical changes, oxidative status, jejunal morphology, inflammatory parameters, and performance of slow-growing Korat chickens (KRC) raised under high stocking density (HSD). A total of 480 male KRC (21 d of age) were allocated into four groups: (1) HSD without supplementation, (2) normal stocking density (NSD) without supplementation, (3) HSD supplemented with CUR and CAP in powdered form (P-CUR+CAP), and (4) HSD supplemented with CUR- and CAP-loaded nanoemulsions (NE-CUR+CAP). Chickens receiving NE-CUR+CAP showed no adverse changes in liver or kidney function compared with other groups. The heterophil-to-lymphocyte ratio was reduced in NE-CUR+CAP group relative to HSD group and was comparable with NSD and P-CUR+CAP groups (P < 0.05). NE-CUR+CAP also lowered levels of TBA in the liver and jejunum while enhancing hepatic superoxide dismutase activity compared with HSD group (P < 0.05). Villus height, villus height-to-crypt depth ratio, anti-inflammatory response, and cecal Lactobacillus counts were improved, whereas crypt depth and cecal Escherichia coli were reduced in the NE-CUR+CAP group (P < 0.05). Although feed intake, BW, and body weight gain were not affected, the feed conversion ratio was significantly lower in NE-CUR+CAP compared with HSD group (P < 0.05). In conclusion, NE-CUR+CAP mitigated oxidative stress and inflammation, improved intestinal health, and enhanced feed efficiency in slow-growing chickens raised under HSD.