Transcriptomics-Related Mechanisms of Supplementing Laying Broiler Breeder Hens with Dietary Daidzein to Improve the Immune Function and Growth Performance of Offspring.

Daidzein (DA) is an isoflavone that is primarily extracted from soy plants. This study evaluated the effects of supplementing laying broiler breeder hens with dietary DA on the immune function and growth performance of their offspring and the underlying mechanism. A total of 720 breeders were divided into three treatment groups that were fed either a control diet (CON), a DA-low-supplemented diet (DLS, CON+20 mg/kg DA), or a DA-high-supplemented diet (DHS, CON+100 mg/kg DA) for 8 weeks, and eggs were collected for hatching during the final week. The broiler offspring received a basal diet for 42 days, and blood, livers, and immune organs were collected at 21 and 42 days of age. DLS treatment promoted embryonic development and increased growth hormone levels, body weight, feed intake, and carcass traits on days 21 and 42 of broilers. Additionally, the IgA and IgG concentrations, antibody titers, and antioxidant capacity of broilers were increased at 21 days of age, and B lymphocyte differentiation was increased at 42 days. Besides, DLS treatment upregulated the expression of genes related to embryonic and muscle development in offspring and regulated mitogen-activated protein kinase (MAPK), transforming growth factor beta (TGF-β), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and Toll-like receptor signaling. DHS treatment decreased the percentage of abdominal fat in the broilers at 42 days, but it did not significantly affect embryonic development, growth performance, or IgA and IgG concentrations. In summary, providing dietary DA supplementation at 20 mg/kg to broiler breeders can improve their immune function and growth performance.