Effects of Fermented and Unfermented Chinese Herbal Formulations on Laying Performance, Intestinal Health and Cecal Microbiota in Late-Phase Laying Hens

The intestinal structure and function of laying hens undergo age-related degeneration, which can impair nutrient absorption and reduce production performance. Chinese herbal additives have been investigated for their potential benefits in supporting intestinal health and physiological function. In this study, a compound seven-herb formula was evaluated for its potential to support intestinal health in late-phase laying hens. The study aimed to compare the effects of unfermented and fermented herbal formulations on laying performance, egg quality, and intestinal health in late-phase laying hens. A total of 540 hens were randomly assigned to three groups (six replicates per group, 30 hens per replicate) and fed either a basal diet (Control), a diet supplemented with Chinese herbal medicine (CHM), or a diet supplemented with fermented Chinese herbal medicine (FHM) for 12 consecutive weeks. During weeks 9–12, egg production rate was significantly higher in the CHM and FHM groups than in the control group (p < 0.05). Over the entire experimental period, average egg weight was significantly higher in the FHM group than in the control and CHM groups (p < 0.05). Both treatments also improved selected indices of intestinal morphology, including villus height and the villus height-to-crypt depth ratio (p < 0.05). Additionally, serum concentrations of immunoglobulin A (IgA), the immunoglobulin reported as IgG, and immunoglobulin M (IgM) were significantly increased, whereas intestinal concentrations of interleukin-1β (IL-1β), interleukin-8 (IL-8), and transforming growth factor-β (TGF-β) were reduced in both treatment groups (p < 0.05). Both CHM and FHM supplementation reduced serum malondialdehyde (MDA) concentrations and increased superoxide dismutase (SOD) activity, although serum glutathione peroxidase (GSH-Px) activity was decreased (p < 0.05). Furthermore, FHM altered the cecal microbial composition and increased the concentrations of acetate, butyrate, and isovalerate. In conclusion, dietary herbal supplementation, particularly in fermented form, may improve selected production-performance traits and intestinal health in aged laying hens.