饲粮NDF水平对山羊营养物质表观消化率及瘤胃古菌结构与组成的影响研究

Effects of Dietary NDF Levels on Apparent Digestibility of Nutrients and the Composition of Rumen Archaea in Goats

【目的】旨在采用代谢试验和高通量测序技术,研究饲粮中性洗涤纤维(NDF)水平对山羊营养物质表观消化率及瘤胃古菌结构与组成的影响。【方法】选用6只8月龄健康雄性山羊进行3×3拉丁方试验,依据饲粮NDF水平设低(LN组)、中(MN组)和高(HN组)NDF水平共3个处理组进行代谢试验。代谢试验共分3期进行,每期试验结束后采集瘤胃内容物,提取瘤胃微生物总DNA后,用古菌通用引物进行PCR扩增,扩增产物用Illumina平台进行高通量测序后进行生物信息学分析。【结果】结果表明:(1)处理组间山羊日粮DM、OM、CP表观消化率差异均不显著(P>0.05);LN组EE的表观消化率显著高于MN组和HN组(P<0.05),HN组NDF的表观消化率显著高于LN组和MN组(P<0.05)。(2)LN组古菌Chao1、Shannon和Observed_species指数均显著高于其他两组(P<0.05),其他两组间的差异不显著(P>0.05)。(3)在门水平上,3个处理组间所有古菌的相对丰度差异均不显著(P>0.05),优势门均为广古菌门(Euryarchaeota)。(4)在属水平上,Methanobrevibacter,Candidatus_Methanomethylophilus和Candidatus_Methanoplasma均为3个处理组的优势属。LN组Methanobrevibacter的相对丰度极显著低于其他两组(P<0.01),但Candidatus_Methanomethylophilus和Candidatus_Methanoplasma的相对丰度显著高于其他两组(P<0.05),其余各菌属的相对丰度在3个处理组间差异均不显著(P>0.05)。【结论】研究结论:饲粮NDF水平在35%~45%之间变化时,显著影响山羊对日粮中EE、NDF的表观消化率,显著影响瘤胃Methanobrevibacter、Candidatus_Methanomethylophilus和Candidatus_Methanoplasma等古菌属的相对丰度。

【Objective】This study was conducted to examine the effects of dietary NDF levels on appar-ent digestibility of nutrients and the composition of rumen archaea in goats by using metabolic trial and high throughput sequencing techniques.【Method】Six eight-month-old healthy male goats were used in a 3×3 Latin square experiment.Three experimental treatments were set for the metabolic trial as follows:low dietary NDF level group(LN),middle dietary NDF level group(MN)and high dietary NDF level group(HN).The whole experiment contained three phases,and the rumen contents of each goat were collected after each phase.The total DNA of rumen microorganism in the rumen contents was extracted.Primers specific for archaea were used to amplified the V3-V4 high variable regions of 16S rRNA gene.Bioinformatics analysis of PCR products were performed by high-throughput sequencing using Illumina platform.【Result】①There were no significant differences in the apparent digestibility of DM,OM and CP between the three groups(P>0.05).The apparent digestibility of EE in LN group was significantly higher than that in MN and HN group(P<0.05).The apparent digestibility of NDF in HN group was significantly higher than that in LN and MN group(P<0.05).②The Chao1,Shannon and Observed species indices of LN group were significantly higher than those of the other two groups(P<0.05),no significant difference was found between the other two groups(P>0.05).③At phylum level,the relative abundance of all taxonomy in the three treatment groups had no significant different(P>0.05),and the dominant phylum group was Euryarchaeota.④At genus level,Methanobrevibacter,Candidatus_Methanomethylophilus and Candidatus_Methanoplasma were the dominant genera groups in all of the three treatment groups.The relative abundance of Methanobrevibacter in LN group was remarkablely lower than that in the other two groups(P<0.01),but the relative abundances of Candidatus_Methanomethylophilus and Candidatus_Methanoplasma were significantly higher than those of the other two groups(P<0.05),and these archaea had no significant difference between the other two groups.The other archaeal genera had no significant difference between the three treatment groups(P>0.05).【Conclusion】The change of the NDF level(from 35%to 45%)significantly affected the apparent digestibility of EE and NDF,as well as the relative abundances of major ruminal archaea such as Methanobrevibacter in goats.