Effects of Taraxacum mongolicum Hand.-Mazz. (dandelion) on growth performance, expression of genes coding for tight junction protein and mucin, microbiota composition and short chain fatty acids in ileum of broiler chickens

BACKGROUND: Dandelion is becoming an exploitable alternative to the widely prohibited antibiotics in the poultry production. This research aimed to investigate the effects of dandelion on the growth performance and intestinal barrier function of broiler chickens maintained under standard condition of management. One-hundred and sixty 1-day-old Arbor Acres (AA) male broiler chickens were randomly divided into four groups, with five replicates of eight birds each. The birds were fed a basal diet supplemented without (control group, [CON]) or with 500 (low dose [LD]) or 1000 (high dose [HD]) mg/kg dandelion or with 250 mg/kg chlortetracycline 20% premix (CTC) for 42 days, including the starter phase (d 1 to 21) and the grower phase (d 22 to 42). Body weight (BW) of each bird and feed consumption of each replicate were measured at d 21 and d 42. The ileal tissues were collected on day 21 and 42 to determine expression of genes coding for tight junction protein and mucin as well as ELISA analysis for immune factor. The ileal digesta was collected for microbiota and short chain fatty acids analysis. RESULTS: Compared with CON group, during day 1–21, the average daily feed intake (ADFI) and feed/gain ratio (F/G) of LD group were lower (P < 0.05); during day 22–42, the F/G of LD and CTC group tended to be lower (P = 0.07); during the overall phase, the ADFI of HD and CTC groups were decreased (P < 0.05), and the F/G of dandelion and CTC groups tended to be decreased (P = 0.07). On day 21, the relative mRNA expression of claudin, occludin-1 and mucin1 in dandelion groups were up-regulated (P < 0.05), and the ZO-1 mRNA expression in CTC group was increased (P < 0.05); on day 42, the claudin and mucin1 transcripts in LD group and ZO-1 transcripts in HD and CTC group were up-regulated (P < 0.05), while the occludin-1 and mucin1 transcripts in CTC group was significantly down-regulated (P < 0.05). In addition, the contents of TNF-α in dandelion groups were lower than that in CTC group (P < 0.05). In the analysis of ileal microbiota, on day 21, decreased α-diversity was observed in HD and CTC groups (P < 0.05). Meanwhile, on day 21, the relative abundance of Firmicutes in dandelion groups tended to be higher (P = 0.09), the relative abundance of Lactobacillus in LD and CTC group were increased (P < 0.05), while Bacteroidete, Bacteroides, and Alistipes relative abundance in dandelion and CTC groups were decreased (P < 0.05). On day 42, the Actinobacteriota relative abundance in CTC group tended to be higher (P = 0.05), and Lysinibacillus relative abundance of CTC group was higher (P = 0.02). Compared with CON group, on day 21, the propionic acid and butyric acid content in CTC group were higher, the butyric acid content in HD group was lower (P < 0.10). CONCLUSION: In summary, dietary dandelion supplementation at 500 mg/kg of diet enhanced growth performance of broilers by improving the intestinal barrier function. Dandelion can be supplemented in the diet as an antibiotics alternative to enhance production in poultry industry.