Digestion Of Intestinal Bacterial Genome Diversity And Biosafety Assessment On Large-scale Pig Farms

In this study,large-scale pig farms with three-way cross fattening pigs and two-way cross breeding pigs were used as research objects to compare the effects of microbial diversity,microbial structure changes,nutrition and environmental factors on different groups.The use of pig intestinal microflora genome as a molecular marker for monitoring pig health breeding level will provide a scientific basis for a reasonable assessment of pig production capacity.The test includes the following five parts:Test 1:the change of pig microbial flora at different growth stages.Fresh feces from suckling piglets to fattening pigs at 19 weeks of age were selected for 16S rDNA sequencing.The fattening pigs from 1 to 19 weeks of age were divided into 6 groups according to the feed.There were lactating piglets ZZ,weaning piglets YF1,suckling pig YF2,piglets YF3,fattening pig YF4,fattening pig YF5.The results show that the total number of OTUs in 60 samples is 32,695,with an average of 545 OTUs per sample.60 sample OTUs were annotated to 14 Phylum,23 Class,32 Order,55 Family,126 Genus.Observed species index and Chao1 index were the lowest in suckling piglets ZZ,significantly lower than other groups(P ?0.05),and significantly higher in fattening pig YF5(P ?0.05).As the age of the week increases,the Shannon and Simpson indexes also increase,and the microbial diversity of weaned piglets YF1 and rearing pigs is rich.There was no significant difference between weaning piglet YF1 and fattening pig YF4(P?0.05).The microbial flora of fattening pig manure is mainly composed of five phylums,Firmicutes,Bacteroidetes,Proteobacteria,Actinobacteria and Spirochaetes.Firmicutes and Bacteroidetes are the two dominant phylums of fattening pigs,and Firmicutes are significantly different in the groups(P ?0.05).The content of Fusobacteria in ZZ feces of suckling piglets was significantly higher than that of other groups(P ?0.05).As the age increases,Bacteroidetes decrease and Firmicutes increase.Test 2:The change of microbial flora of pigs in different physiological cycles.The feces of pregnant sows,farrowing sows,weaning sows and gilts were selected for 16S rDNA sequencing.The results show that the total number of OTUs in 45 samples is 32,814,with an average of 729 OTUs per sample.45 sample OTUs were annotated to 14 Phylum,24 Class,33 Order,56 Family,120 Genus.Compared with other breeding pigs,the HY of pregnant sows has lower microbial diversity and significant differences in bacterial group structure(P?0.05).The microbial abundance and species diversity are arranged in order,and they tend to grow from pregnant sows-farrowing sows-weaning sows-gilts.Firmicutes and Bacteroidetes are the two dominant phylums in the fecal microflora of breeding pigs,accounting for more than 85%,and the third dominant bacteria are Spirochaetes.There was no significant difference between Firmicutes and Bacteroidetes groups separately(P?0.05);there was a significant difference between Spirochaetes groups(P ?0.05).Test 3:Correlation between pig manure microorganisms and fecal nutrients.The fattening pig and breeding pig manure samples were selected to use ICP-AES internal standard method and GB/T 6433-2006 to determine the nutrient composition.The microorganisms and nutrient composition of pig manure at different growth stages are divided into There are 4 modules,and the predominant bacteria in the intestinal tract of younger pigs are positively correlated with nutrients,and most of the genus of bacteria interact with crude fat,Cu,Zn,Se and other substances.Microbial and environmental indicators of pig feces in different physiological periods are divided into 6 Module,the intestinal flora of adult sows is at the genus level,and the nutritional composition is positively related to the genus of Firmicutes,and negatively related to the genus of Bacteroidetes.Correlation analysis on the entire large-scale pig farm found that it is divided into 4 modules.The flora structure is divided into two categories,which are significantly positively correlated with crude fat,Cu,and Se;and significantly positively correlated with Ca,Co,Mn,and Fe.Test 4:Correlation of pig manure microorganisms and environmental indicators.When collecting fattening pig and breeding pig manure samples,the environmental indicators were copied on the environmental control system in the housing area.The pig manure microorganisms and environmental indicators at different growth stages are divided into 4 modules,age Dominant bacteria and ventilation in the intestine of smaller pigs.The amount is negatively correlated,and most of the bacteria with less content are positively correlated with the amount of ventilation.Microbial and environmental indicators of pig feces in different physiological periods are divided into 6 modules.The intestinal flora of adult sows is at the genus level and is related to temperature.The microbial flora is negatively correlated with humidity,CO2 and ventilation.A correlation analysis of the entire large-scale pig farm found that it is divided into 4 modules,and the module genus has a positive correlation with humidity and ventilation,and a negative correlation with temperature and CO2.The genus of bacteria that are positively related to humidity and ventilation are:Firmicutes,Bacteroidetes,Spirochaetes,Verrucomicrobia.Test 5:Differences between the microbiological system of pig manure on large-scale and free-range pig farms.26 samples from free-range pig farms and 96 sample samples from large-scale pig farms were compared and analyzed.,Bacteroidetes,Spirochaetes,Proteobacteria Proteobacteria,consistent with the analysis of large-scale pig farms.The dominant bacteria are Firmicutes and Bacteroidetes,the relative content is different.The fattening pigs on the free-range pig farm also detected a little Fusobacteria 0.09%,which was Diarrhea in pig farm fattening pig YF2 group.Compared with fattening pigs in large-scale pig farms,Firmicutes and Bacteroidetes are dominant bacteria at the gate level.In the past,Bacteroidetes increased,while the content of bacteria in Firmicutes,Spirochaetes,Proteobacteria and Actinobacteria was relatively reduced.Compared with large-scale farms,Bacteroidetes increased,while Firmicutes.The relative bacterial populations of Spirochaetes,Proteobacteria and Actinobacteria are reduced.There is no significant difference in the microbial structure of free-range pig farms and large-scale pig farms,and the microbial diversity of large-scale pig farms is relatively rich.