Baicalein and Citric Acid Modulate Intestinal Morphology and Health Status in Laying Hens

This study aimed to investigate the effects of baicalin and citric acid on egg production performance, egg quality, and the intestinal morphology and function of laying hens. A total of 600 Hy-Line Brown laying hens, 59 weeks old, were randomly allocated to four dietary treatments, with 10 replicates per treatment and 15 hens per replicate. The control group was fed a basal diet, while the other three groups were fed the basal diet supplemented with 150 mg/kg baicalin (B), 2000 mg/kg citric acid (CA), or 150 mg/kg baicalin plus 2000 mg/kg citric acid (B + CA), respectively. The experimental period lasted for 12 weeks, and the results indicated that neither the individual addition nor the combined application of baicalin and citric acid had a significant impact on the laying performance. However, compared with the control group, the baicalin and/or citric acid supplementation significantly increased the eggshell strength and Haugh unit. Additionally, the combination of baicalin and citric acid significantly increased the villus height and the villus height/crypt depth ratio in the duodenum and jejunum. It also enhanced the population of beneficial bacteria, such as Lactobacillus and Bifidobacterium, in the cecum and improved the activity of intestinal digestive enzymes, primarily disaccharidases. Furthermore, the addition of baicalin to the diet significantly increased the content of Secretory Immunoglobulin A in the ileum and jejunum after 12 weeks of feeding. These results suggest that the combination of baicalin and citric acid had a synergistic effect on the improvement of egg quality and intestinal morphology and function in laying hens. Overall, our findings provide important insights into the potential benefits of supplementing baicalin and citric acid in the diet of laying hens and may have practical implications for improving egg quality and poultry health status.