Effects of esculetin on growth performance, carcass traits, intestinal morphology, digestive enzyme, barrier function...

This study investigated the effects of dietary esculetin supplementation on growth performance, carcass traits, intestinal morphology, digestive enzymes, barrier function and cecal microbiota in broiler chickens. A total of 960 one-day-old chickens were randomly divided into six groups and fed diets supplemented with different levels of esculetin (0, 10, 25, 50, 75 and 100 mg/kg) for 42 consecutive days. The results showed that esculetin supplementation linearly and quadratically increased average daily gain, and linearly decreased the ratio of feed to gain during d 22-42 and d 1-42. Evisceration rate increased quadratically, and semi-evisceration increased linearly and quadratically with esculetin supplementation. Additionally, esculetin supplementation induced linear and quadratic decreases in abdominal fat rate and thymus index. The ratio of villus height to crypt depth in the duodenal and jejunal increased linearly and quadratically, while duodenal crypt depth decreased linearly. Esculetin supplementation also caused linear and quadratic increases in jejunal villus height. Amylase activity in the duodenum and jejunum increased linearly and quadratically with esculetin supplementation. Jejunal occludin mRNA expression levels increased linearly and quadratically, and esculetin supplementation quadratically increased claudin-1 and trefoil factor 3 mRNA expression levels in both the jejunum and ileum. Dietary esculetin supplementation linearly and quadratically increased ileal immunoglobulin (Ig) M and IgG levels. Moreover, 16S rRNA sequencing revealed that esculetin supplementation modulated the diversity and composition of cecal microflora. Esculetin supplementation significantly increased the relative abundance of Christensenellaceae_R-7_group and decreased the relative abundance of Butyricimonas. Overall, esculetin supplementation enhances growth performance in broiler, probably by improving intestinal morphology, nutrient digestion, barrier function, immune response, and modulating cecal microbiota.