Protective effects of ferulic acid on embryonic development by improving antioxidant function in broilers embryo of thermal manipulation

This study aimed to elucidate the effects of broiler embryos soaked in ferulic acid (FA) solution on alleviating the negative impact of thermal manipulation (TM) on chicken embryo development and to provide a theoretical and experimental basis for applying TM and FA in the poultry feeding industry. A total of 120 broiler fertilized eggs were randomly divided into three groups: control group, TM group, and comprehensive group (TM + FA), with 40 eggs in each group. The TM group and the comprehensive group from the 7th embryonic age to the 16th embryonic age received TM for ten days, treated with a temperature of 39.5 °C and relative humidity of 65% for 18 h a day. In the comprehensive group, broiler embryos were immersed in FA solution at a concentration of 80 mg/L for 6 min at 16:00 every day from the 6th to the 8th embryo age. They were incubated continuously after being soaked until the chicks hatched. The results showed that the rates of dead embryos and weak chicks in the TM group were significantly higher than those in the control group and comprehensive group. Chick body temperatures of the TM group and comprehensive group were significantly lower than those of the control group. The heart weights of the TM group and comprehensive group were significantly lower than those of the control group, and the leg weights of the TM group were significantly decreased compared with those of the control group and comprehensive group. The SOD activity of serum in the comprehensive group was significantly higher than that in the control group and TM group, while the CAT activity of serum in the comprehensive group and control group was significantly higher than that in the TM group; however, there was no difference between the comprehensive group and control group. The activities of SOD and CAT in the liver were significantly higher than those of the TM group; however, the MDA content of the liver in the comprehensive group and control group was significantly lower than that of the TM group. The gene expression of Nrf2 and SOD in the comprehensive group and TM group was significantly higher than that in the control group; however, there was no significant difference between the comprehensive group and TM group. Soaking broiler embryonic eggs in an FA solution can improve the antioxidant capacity of the liver by upregulating Nrf2-Keap1 signal pathway-related gene expression. FA can effectively alleviate the side effects of TM on chicken embryos and does not impact the effects of TM.