Effects Of High Copper On Cecal Microbial Diversity In Broilers Based On High Throughput Sequencing

Copper is an essential trace element in organisms.The addition of copper to feed can promote the growth of livestock and poultry and is commonly used as a feed additive in agricultural production.However,excessive intake of copper can cause damage in the organism.Previous studies have shown that intake of high copper induces oxidative stress injury in broilers and various degrees of intestinal structural damage.Because the composition and diversity of the intestinal flora can reflect the nutritional and healthy levels of broilers to some extent,this experiment will focused on changes in the intestinal flora.This experiment aims to study the effect of high concentration of copper on cecal microbes and intestinal structure of broilers.240 1-day-old broilers were randomly selected and divided into 4 groups: control group,high copper group I,high copper group II and high copper group III.The experimental period is 49 days.The copper source is anhydrous copper sulfate,and the basal diet is configured according to the nutritional requirements of the poultry proposed in the NRC(1994)feeding standard.On this basis,the copper content of the control group is added to 11 mg/kg,and the copper content of the high copper group I,II and III is added.to 110 mg/kg,220mg/kg and 330 mg/kg respectively.All groups of broilers are free access to water.On the 49 th day of the experiment,12 broilers were randomly selected from each group and the cecal contents were collected.16S rDNA high-throughput sequencing was used to detect changes in microbial community structure,diversity,protein function and metabolic pathway function in the cecal contents.The duodenum,jejunum,ileum,cecum and rectum were taken for the observation of histological structure and the detection the contents of copper,zinc and iron in each intestine.The results are asfollows.(1)In the control group and high copper group III,6 cecal contents samples were randomly selected from each group.14,988 OTUs were obtained by microbial sequencing.Its microbial group has 10 bacteriophyta,12 bacteria families and 95 bacteriums.(2)Firmicutes and Bacteroidetes accounted for maximum in the dominant bacteria in the control group and the high copper group III.The proportion of Alistipes in the control group and the high copper group III was the largest,accounted for 10.82% and 21% respectively.(3)Compared to the control group,the abundance of Tenericutes in the high copper group III was significantly increased(P<0.05),and the abundance of Firmicutes was significantly decreased(P<0.05),the abundance of Rhodospirillaceae extremely significantly increased(P<0.01),the abundance of Enterobacteriaceaae increased significantly(P<0.05),and the abundance of Erysipelotrichaceae decreased significantly(P <0.05).The abundance of Alistipes increased significantly(P<0.05);the abundance of Anaerotruncus and Ruminiclostridium decreased significantly(P<0.05).(4)The cell motility,chromatin structure and dynamics protein function of the cecum microflora in the high copper group III were significantly reduced(P<0.05),and the function of replication,recombination and repair proteins was significantly increased(P<0.05).(5)The p53 signaling pathway associated with oxidative phosphorylation,and metabolic pathway factors such as Fatty acid metabolism related to nutrient metabolism were significantly elevated in the high copper group III(P<0.05).However,metabolic pathway factors such as mineral absorption related to nutrition metabolism and DNA repair and recombination proteins related to other physiological functions were significantly reduced(P<0.05).(6)High copper dietary decreased the ratio of villus height and crypt depth in the intestine of broilers.The high copper group III had a significant decrease compared to the control group(P<0.05).(7)With increase of the concentrations of copper in the diet,the content of copper in the intestinal tissues of the broilers increased.The content of copper in each intestinal segment was positively correlated with the content of dietary copper.Copper and iron are antagonistic in metabolism,and copper and zinc are antagonistic in duodenum,ileum and rectum.The experimental results showed that high copper dietary could cause changes in the composition,protein and metabolic pathways factor of the caecal flora.With the increase of copper content in the diet,the content of copper in the intestine increased,and the content of zinc and iron decreased to varying degrees,affecting the intestinal structure.