Dietary capsaicin supplementation improves production performance and intestinal health of laying hens by regulating intestinal microbiota

Capsaicin exhibits diverse bioactivities, including anti-inflammatory, antioxidant, and modulation of the intestinal microbiota. The objective of this study was to investigate the effects of different doses of dietary capsaicin supplementation on the production performance, egg quality and intestinal health of laying hens. A total of 480 forty-week-old Hy-Line Brown laying hens with similar body condition and comparable egg production rates were randomly divided into four treatment groups with 6 replicates of 20 hens each, and each group was offered diets supplemented with 0, 120, 240 or 360 mg/kg capsaicin for 8 weeks. The results showed that dietary capsaicin supplementation increased laying rate (<i>P</i> = 0.033), serum and hepatic antioxidant enzyme activities and serum anti-inflammatory factor levels (<i>P</i> < 0.05) in a dose-dependent manner. Moreover, capsaicin improved intestinal digestive enzyme activities, intestinal morphology and secretory immunoglobulin A (sIgA) level (<i>P</i> < 0.05). 16S rRNA sequencing results showed that capsaicin reshaped intestinal microbiota, primarily increased the relative abundance of <i>g_CHKCI001</i> and <i>g_unclassified_Rikenellaceae</i> (<i>P</i> < 0.01), decreased <i>unclassified_Bacteroidales</i> (<i>P</i> < 0.05), which have a positive effect on improving antioxidant and anti-inflammatory capacity of laying hens. Overall, dietary capsaicin supplementation improved laying performance, anti-inflammatory properties, antioxidant capacity, and intestinal health of laying hens through regulating intestinal microbiota. Notably, the 360 mg/kg dietary capsaicin supplementation exhibited the most pronounced efficacy.