Combining chicory root pulp with yeast selenium: a novel strategy for improving egg quality, enhancing immune function, and promoting gut health in laying hens

Against the backdrop of ban on antibiotic used in animal feed, the effects of non-antibiotic feed chicory root pulp and yeast selenium on egg quality, immune function, and intestinal health of laying hens were investigated. 96 Hy-Line Sonia laying hens were randomly divided into 6 groups, including groups control, 0, 5, 10, 15, and 20 fed with basic diet, yeast selenium and various content of chicory root pulp, respectively. The experiment lasted 56 days, which were detected at the end of 4 weeks and 8 weeks. The results showed that the eggshell strength and Haugh units of group 5-Week 8 was significantly higher than that of group control-Week 8 (P < 0.05). The protein, phosphorus, calcium, and selenium content of eggs in group 5 was significantly higher than in group control (P < 0.05) during the whole experiment pierid. Immunoglobulin M (IgM) and interleukin-2 (IL-2) levels in groups 5-Week 8 and 10-Week 8 were significantly elevated compared to group control-Week 8 (P < 0.05). The relative abundance of phylum Bacillota in groups 0-Week 8 and 5-Week 8 (39.86 % and 39.22 %) was significantly higher than in group control-Week 8 (31.35 %) (P < 0.05). Groups 5-Week 8 had higher relative abundance of genus Mediterraneibacter (5.00 %) and Prevotella (2.74 %) compared with group control-Week 8 (2.79 % and 1.13 %) (P < 0.05). The relative abundance of gene cps4L in groups 0-Week 8, 5-Week 8, 10-Week 8, 15-Week 8, and 20-Week 8 (77.02 %, 71.57 %, 75.69 %, 76.89 % and 77.30 %) was significantly lower than in group control-Week 8 (84.60 %) (P < 0.05). Besides, immune function of the hens was closely related to gut microbiota composition, especially phyla Bacillota, genera Prevotella and Mediterraneibacte, induced by chicory root pulp and yeast selenium. In short, long-term combined feeding of 5 % chicory root pulp and yeast selenium improved egg quality, increased the nutritional content of eggs, enhanced immune function by optimizing the gut microbiota, and reduced harm to laying hens caused by virulence factor.