Beneficial Effects of Fermented Blueberry Pomace Supplementation on Carcass Traits, Meat Quality, and Antioxidant Capacity of Spent Hens

This study aimed to evaluate the effects of fermented blueberry pomace (FBP) supplementation on carcass traits, meat quality, and antioxidant capacity in spent hens and further investigated underlying mechanisms using network pharmacology and molecular docking analyses. A total of 320 Yukou Jingfen No. 8 spent hens (345 days old) were fed a basal diet supplemented with 0, 0.25, 0.5, or 1.0% FBP for 56 days. Each group contained eight replicates with ten hens per replicate. Results showed that 0.25% FBP reduced the percentage of thigh muscle, whereas 0.5% FBP reduced drip loss at 24 h post-mortem in the breast muscle compared to the control group (<i>p</i> < 0.05). Additionally, 0.5% FBP enhanced the total antioxidant capacity compared to the 0.25% group and increased superoxide dismutase activity compared to the control and 0.25% FBP groups (<i>p</i> < 0.05). In the breast muscle, 0.25 and 0.5% FBP reduced drip loss compared to the control group at 48 h post-mortem, while 0.25% FBP upregulated glutathione peroxidase 1 expression more than the other groups (<i>p</i> < 0.05). Network pharmacology analysis identified 302 targets related to the potential bioactive compounds in FBP and 401 targets associated with meat quality, such as core targets of insulin, protein kinase cAMP-activated catalytic subunit beta, steroid receptor coactivator, etc. The identified key signaling pathways included JAK-STAT and PI3K-Akt signaling pathways, which were related to protein synthesis and muscle growth. Molecular docking analysis confirmed strong binding activity between bioactive compounds of FBP and meat quality. In conclusion, dietary FBP supplementation enhances the breast muscle quality of spent hens through the potential bioactive compounds targeting insulin and modulating JAK-STAT and PI3K-Akt signaling pathways, without affecting carcass traits. Moreover, 0.5% FBP exhibited better effects than other treatment groups in spent hens.