WGHPE alleviates FLHS in hens

Extracts from walnut green husk exhibit various beneficial properties, including antiinflammatory, immune regulating, growth promoting, and antioxidant effects and the enhancement of intestinal microecology. However, their role in mitigating fatty liver and hemorrhagic syndrome in laying hens and the underlying mechanisms remain unclear. This study investigated the effects of walnut green husk polyphenol extracts on FLHS indicators, antioxidant performance, and cecal microbiota regulation, following the establishment of an FLHS model in laying hens using estradiol and corn oil.A total of 350 43 week old Hy Line Brown laying hens were randomly assigned to five groups. The FLHS model was induced via intramuscular injection of estradiol and corn oil. The control and FLHS model groups received a basal diet, while three treatment groups were established based on the FLHS model and received the basal diet supplemented with 0.5%, 1.0%, or 1.5% WGHPE, respectively. All laying hens had unrestricted access to food and water throughout the 8 week experimental period. Additionally, chicken houses were routinely cleaned and disinfected weekly to maintain a clean and hygienic environment.Liver weight, liver coefficient, abdominal adipose weight, and abdominal adipose coefficient were significantly reduced in WGHPE supplemented hens compared with the FLHS group. WGHPE alleviated vacuolar degeneration and lipid droplet accumulation in hepatocytes of laying hens, indicating its potential to ameliorate the characteristic pathological features of fatty liver syndrome. Following supplementation with WGHPE in the diet of the FLHS model group, the elevated serum levels of total cholesterol, aspartate aminotransferase, alanine aminotransferase, and low density lipoprotein cholesterol induced by FLHS were significantly reduced. Additionally, WGHPE significantly increased the serum activities of catalase and total superoxide dismutase in FLHS induced laying hens, while decreasing malondialdehyde levels. Dietary inclusion of WGHPE also significantly increased villus height in both the jejunum and ileum and enhanced the villus to crypt ratio. Furthermore, in the WGHPE treatment group, the relative abundance of beneficial bacterial taxa, including Rikenellaceae RC9 gut group, Phascolarctobacterium, unclassified Lachnospiraceae, and unclassified Muribaculaceae, was increased. Campylobacter and Parasutterella exhibited significant positive correlations with body weight, abdominal adipose weight, and abdominal adipose coefficient in FLHS laying hens, whereas Desulfovibrio and unclassified Oscillospiraceae showed significant negative correlations with these parameters. Moreover, Campylobacter, unclassified Oscillospiraceae, unclassified Ruminococcaceae, Megasphaera, and Phascolarctobacterium were significantly negatively correlated with antioxidant markers CAT and glutathione peroxidase. These findings collectively suggest that dietary supplementation with WGHPE exerts beneficial effects on intestinal microbiota composition and overall health status in laying hens with FLHS.Dietary WGHPE supplementation mitigates FLHS induced liver injury, enhances antioxidant capacity, and improves intestinal morphology and microbial composition. A supplementation level of 1.5% WGHPE is recommended for optimal efficacy.