Fig. 1

Effect of Lp. plantarum FRT4 on the antioxidant capacity in the liver of laying hens. A The biochemical parameters of antioxidant enzymes in the liver. B The relative mRNA expression levels of antioxidant-related factors in the liver. The results were expressed as mean ± SEM, n = 6 hens per group. * indicates significant difference between the HELP group and CT groups, and * indicates P < 0.05, ** indicates P < 0.01, *** indicates P < 0.001. # indicates the significant difference between the FRT4L, FRT4M, and FRT4H groups and the HELP group, and # indicates P < 0.05, ## indicates P < 0.01, ### indicates P < 0.001. CT: control group, hens fed with normal diet. HELP: model group, hens fed with high-energy low-protein diet. FRT4L, FRT4M, and FRT4H: experimental groups, hens fed with high-energy low-protein diet with 109 CFU/kg, 1010 CFU/kg, and 1011 CFU/kg Lp. plantarum FRT4, respectively