Curcumin alleviates the effects of heat stress on broiler pectoral muscle via decorin (DCN) -mediated TGF-β Signaling pathway

This study investigates the molecular mechanism by which curcumin (CUR) alleviates oxidative damage and developmental inhibition in pectoral muscles of white-feather broiler chickens under heat stress by regulating the decorin (DCN)-mediated TGF-β signaling pathway. 1-day-old Arbor Acres white-feathered broilers (n = 108) were randomly divided into 3 groups: control (normal temperature, 22 ± 1°C), heat stress (HS, 34 ± 1°C, 8 h/d), and HS + curcumin (300 mg/kg diet). After 21 days of treatment, pectoral muscle tissues were collected for TMT proteomics analysis. Primary chicken embryonic myoblasts were isolated and subjected to heat stress (45°C, 4 h) under DCN knockdown. Data were analyzed using one-way ANOVA, and P < 0.05 was considered statistically significant. Results showed that heat stress significantly increased the levels of malondialdehyde (MDA) and protein carbonyl (PC) in broiler pectoral muscles, decreased the activity of total superoxide dismutase (T-SOD), and downregulated the expression of antioxidant genes (Nrf2, NQO1, CAT, etc.) (P < 0.05). Meanwhile, heat stress inhibited key muscle development genes (Myf5, MyoG, IGF-1) and upregulated myostatin (MSTN) (P < 0.05). After curcumin supplementation, T-SOD activity and expression of some antioxidant genes were significantly restored, PC levels were reduced, expression of muscle development genes was improved, and DCN protein was significantly upregulated (P < 0.05). In vitro experiments showed that DCN knockdown exacerbated the inhibition of myoblast differentiation genes (MyoG, Myf6) by heat stress and activated the TGF-β/Smad pathway (upregulation of TGF-β1 and p-SMAD2/3) (P < 0.05). Mechanistically, curcumin inhibits the TGF-β signaling pathway by upregulating DCN, reduces oxidative damage, and promotes myoblast differentiation, ultimately alleviating the negative impact of heat stress on pectoral muscle development. This study provides a theoretical basis for the application of curcumin in poultry to resist heat stress and promote pectoral muscle development.