This study aimed to evaluate the effects of fermented corn–soybean meal mixed feed on intestinal barrier function and cecal microbiota in laying hens. A total of 360 Jingfen No.6 laying hens (22 wk-old) were assigned to 4 dietary treatments, which were offered basal diets (without antibiotics) containing 0, 4, 6 and 8% of fermented mixed feed respectively. The results showed that the pH value and anti-nutritional factor concentrations in fermented mixed feed were lower than those in unfermented feed (p < 0.05). Moreover, fermentation in the feed significantly increased the crude protein content (p < 0.05). Supplementation with fermented feed significantly reduced the crypt depth and increased the villi height:crypt depth ratio of duodenum and jejunum (p < 0.05). Meanwhile, fermented feed increased the secretory immunoglobulin A content and MUC2 mRNA expression of jejunum (p < 0.05). These beneficial effects were exhibited at the addition level ≥6% and microbial composition of caeca in the control, and so 6% fermented feed groups were analyzed. The structure of the gut microbiota was remarkably altered by additions, characterized by increased abundances of some health-promoting bacteria, such as Parasutterella, Butyricicoccus and Erysipelotrichaceae (p < 0.05). In summary, fermented mixed feed modulated cecal flora, subsequently contributing to improvements in intestinal morphology and barrier functions in laying hens.

This experiment was conducted to investigate the effects of different compound probiotics on the performance, cecal microflora, and intestinal immunity of laying hens. A total of 270 Jing Fen No.6 (22-week-old) were randomly divided into 3 groups: basal diet (CON); basal diet supplemented with 6% fermented feed A by Bacillussubtilis,Lactobacillus, and Yeast (FA); and with 6% fermented feed B by C. butyricum and L. salivarius (FB). Phytic acid, trypsin inhibitor, β-glucan concentrations, and pH value in fermented feed were lower than the CON group (p < 0.05). The feed conversion ratio (FCR) in the experimental groups was decreased, while albumen height and Haugh unit were increased, compared with the CON group (p < 0.05). Fermented feed could upregulate the expression of the signal pathway (TLR4/MyD88/NF-κB) to inhibit mRNA expression of pro-inflammatory cytokines (p < 0.05). Fermented feed promoted the level of Romboutsia (in the FA group) Butyricicoccus (in the FB group), and other beneficial bacteria, and reduced opportunistic pathogens, such as Enterocooccus (p < 0.05). Spearman’s correlations showed that the above bacteria were closely related to albumen height and intestinal immunity. In summary, fermented feed can decrease the feed conversion ratio, and improve the performance and intestinal immunity of laying hens, which may be related to the improvement of the cecal microflora structure.

This study aimed to investigate the effects of different levels of methionine hydroxyl analogue chelated zinc (MHA-Zn) on antioxidant capacity and liver metabolism of aged laying hens. A total of 960 57-week-old layers were fed a basal diet (Zn: 35.08 mg/kg) without extra zinc for two weeks, and then allocated to four treatments consisting of eight replicates of 30 birds each for 14 weeks. Four levels of Zn (zinc sulfate (ZnSO₄): 80 mg/kg; MHA-Zn: 20, 40, 80 mg/kg) were added to the diet. The results indicated that compared with inorganic zinc, organic zinc of 80 mg/kg has a significant advantage in improving the antioxidant capacity of aged hens, which increased the level of Cu/Zn-superoxide dismutase (SOD) and the total antioxidant capacity (T-AOC) in the serum and liver, and reduced the concentration of malondialdehyde (MDA) of laying hens. The serum albumen composition was significantly modified, meanwhile, the level of total protein, globulin, and urea increased remarkably, whereas serum glutamic-oxaloacetic transaminase decreased notably in 80 mg/kg MHA-Zn groups. Compared with the 20 mg/kg MHA-Zn group, the metabolic profile of 40 and 80 mg/kg MHA-Zn groups was higher than that of the inorganic zinc group. Furthermore, integrated key metabolic pathway analysis showed that 40 and 80 mg/kg MHA-Zn groups participated in the regulation of glutathione metabolism, glycine, serine, and threonine metabolism. Therefore, this study suggests that 40 and 80 mg/kg supplementation of MHA-Zn can increase the activity of Cu/Zn-SOD and T-AOC and decrease MDA; additionally the 80 mg/kg MHA-Zn group has better antioxidant capacity. Meanwhile, the enhanced MHA-Zn promoted methionine (Met) synthesis and protein metabolism.