| In livestock and poultry production and breeding,antibiotics have been added to feed as growth promoters for nearly 50 years,bringing huge economic profits for producers and low costs for consumers.However,the irrational use of antibiotics have caused the problems of bacterial drug resistance and drug residue,which has posed a serious threat to human health,public health safety and the development of aquaculture industry.In recent years,adding traditional Chinese medicine and its active ingredients to feed to replace traditional antibiotics has become the focus of industry attention.In this study,the effects of Lotus Leaf Extract(LLE)supplementation on growth performance,immune stimulation and intestinal microbial composition of one-day-old broilers were studied.The main results are as follows:Results showed that in the LLE5 group,ADG was higher than that of the antibiotics and blank control groups(P <0.05)from age of 7 to 21,the thymus index at d14,spleen index at age of 21,and bursa index at age of 14 anage of 21 were increased markedly(P < 0.05).In the LLE5 and LLE7.5 groups,serum total Ig G and s Ig A concentrations were higher than those of the antibiotics and blank control groups(P<0.05)at age of 7 and higher than those of the antibiotics group(P <0.05)at age of14.No significant effect was observed for interferon gamma concentrations between the antibiotics and LLE5 or LLE7.5 groups;compared with the antibiotics group,IL2 concentrations were increased in the LLE5 group at age of 7 and in the LLE7.5 group at age of 21(P <0.05).Antioxidant assay results showed that the SOD content in all experimental groups was higher than that in the antibiotic group at age of 21(P <0.05);The MDA content in the LLE1,LLE2.5,LLE7.5,and LLE10 groups was higher than that in the blank group and antibiotic group versus at age of 7(P <0.05);The GSH content in the LLE5 group at age of 21 was higher than that in the blank group(P < 0.05)but had no significant effect compared with the antibiotic group.16 s r RNA sequencing analysis revealed that there were 1,704,232,and 4,814 OTU in the blank control group,antibiotics group,and LLE groups,respectively.The intestinal microbiota consisted mainly of Firmicutes,Proteobacteria,Actinobacteria,and Bacteroidetes(>95%)at the phylum level;at the family level,the abundance of Clostridiaceae and Bacteroidales S24-7 was increased,whereas that of Peptostreptococcaceae was reduced in LLE5 group(P <0.05).This study shows that LLE may be a good source of prebiotics,helping to modulate the immune response and boost the levels of beneficial bacteria. |
