| The balance of the rumen microbial system is an important guarantee for maintaining the normal function of the rumen.In the era of anti-inhibition and anti-inhibition,antibiotic substitutes with broad functions such as antimicrobial peptides are more and more popular in the industry and outside.In this paper,high-throughput sequencing technology was used to analyze and compare the diversity of rumen bacteria and community structure of high-precision fat goats after adding compound antibacterial peptide or/and monensin,and the use of q RT-PCR technology to compare and compare the number of functional bacteria in the rumen.To explore the effect of compound antimicrobial peptides on rumen flora of high-precision fattening goats,and to provide a theoretical basis for the development and utilization of compound antimicrobial peptides.The experiment selected 25 healthy and similar-weight（23.69±0.42 kg）6-month-old Chengdu grey goats randomly divided into 5 groups.GroupⅠ（normal control group）was fed with a hay-to-concentrate ratios of 40:60.GroupⅡ（high-precision control group）,GroupⅢ（antibacterial peptide group）,GroupⅣ（monensin group）,and GroupⅤ（mixed group）goats were divided into 3 Feeding in stages,20 d in each stage,the ratio of hay-to-concentrate is 60:40,70:30,80:20,and add AMPs 2 g·d-1·goat-1or/and monensin 50 mg·kg-1.Before the morning feeding on the0 d,20 d,40 d and 60 d of the experimental period,3 goats were randomly selected from each group to collect rumen fluid（the sample group is indicated by A～E,and the four time points are indicated by 1～4）.The total DNA of rumen bacteria was extracted,and the 16S r DNA V3-V4 region was amplified.The amplified products were sequenced by Mi Seq platform,and the quantitative changes of different functional bacteria were compared by q RT-PCR.The results showed that:（1）High concentrate can reduce the richness of rumen bacterial species in fattening goats;the addition of compound antibacterial peptides or rumen can increase the Chao1index and ACE index of high precision fattening goats,and increase the richness of rumen bacterial species at 40 d When the ratio is 70:30),it is significantly different from the groupⅡandⅣ（P<0.05）,but it has no significant effect on Shannon index and Simpson index（P>0.05）.（2）Among all samples,the relative abundance of Bacteroidetes is the highest（accounting for 40.13%～66.00%of the total sequence）,followed by Firmicutes（22.31%～49.41%）.Prevotella is the dominant genus of all samples（27.11%～50.94%）.（3）At the phylum level,Group II reduced the relative abundance of Bacteroides and increased the relative abundance of Firmicutes,compared with groupⅠ,indicating that high concentrates can reduce the relative abundance of Bacteroides and increase the Relative abundance of Firmicutes.The relative content of Bacteroidetes and Proteobacteria increased in GroupⅢcompared with Group II,Group IV and Group V,while the relative contents of Firmicutes,Actinomycetes,and Euryarchaeota were reduced,indicating that the addition of compound antibacterial peptides could increase The relative abundance of Bacteroides and Proteobacteria reduces the relative abundance of Firmicutes,Actinomycetes,and Euryarchaeota,and the effect is better than the addition of rumen and mixed addition.At the genus level,the relative content of Prevotella in groupⅡwas lower than that in groupⅠ,and the relative content of genus Ornatilinea and Treponema was higher.Compared with groupⅡ,groupⅢincreased the relative content of Prevotella and Ruminococcus,and decreased the relative content of Ornatilinea and Treponema,and it was larger than that of groupⅣand groupⅤ.Relative abundance of Prevotella.Increases the relative abundance of Ornatilinea and Treponema.Adding compound antimicrobial peptides can increase the relative abundance of Prevotella and Ruminococcus,and the effect is better than that of adding monensin and mix.（4）Compared with groupⅠ,groupⅡincreased the number of Fibrobacter succinogene,Anaerovibrio lipolytica,Streptococcus bovis,Lactobacillus and Megasphaera elsdenii at 40 and 60 d.It shows that high concentrate can increase the number of the above five kinds of bacteria.Compared with groupⅡ,groupⅢcan increase the number of rumen Fibrobacter succinogene and Butyrivibrio fibrisolvens at40 d and 60 d,and significantly reduce the number of Lactobacillus（P<0.01）.The number of Selenomonas ruminantium,and Megasphaera elsdenii.Throughout the test period,the number of bacteria showed an upward trend and then a downward trend.And it is larger than that of GroupsⅣandⅤ.It shows that the addition of compound antibacterial peptides can increase the number of rumen Fibrobacter succinogene and Butyrivibrio fibrisolvens at the ratio of 70:30 and 80:20,and reduce the number of Lactobacillus.The number of Anaerovibrio lipolytica,Selenomonas ruminantium,and Megasphaera elsdenii,and the effect is better than the addition of monensin and mixed addition.Conclusions:The highest rumen abundance of Chengdu grey goat is Bacteroides and Prevotella.The relative abundance of Bacteroides and Prevotella decreased and that of Firmicutes increased under high-concentrate condition.When the ratio of hay-to-concentrate is70:30,the abundance of rumen bacteria species,the relative abundance of Bacteroides and Proteobacteria,the relative abundance of Prevotella,Succiniclasticum,Ruminococcus and Butyrivibrio,the relative abundance of Succiniclasticum,Butyrivibrio,Anaerovibrio lipolytica,and so on can be increased In addition,the addition of compound antimicrobial peptide was better than that of monensin and mixture.The results showed that the compound antimicrobial peptide could regulate the structure of rumen flora,promote the growth of some fiber degradation bacteria,protein degradation bacteria,starch degradation bacteria,fat degradation bacteria and lactic acid utilization bacteria,enhance the rumen decomposition and utilization of fiber,protein,starch,fat and lactic acid,and improve the growth performance of goats. |
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