摘要
肠道是动物重要的消化和吸收的器官。为探究饲粮中不同氮硫比对藏羔羊空肠组织形态和空肠微生物区系的影响,试验选择初始条件相似的60日龄藏羔羊150只,随机分为5组,分别用氮硫质量比为10.5꞉1(A)、9꞉1(B)、7.5꞉1(C)、6꞉1(D)、4.5꞉1(E)的饲粮饲养至180日龄,试验期结束每组随机屠宰6只,采集空肠组织和内容物分析饲粮氮硫比对空肠组织形态和空肠微生物菌群结构及功能的影响。结果显示:1)B组和E组的空肠绒毛长度和绒毛宽度显著高于其余3组(P<0.05),并且A、D组的绒毛长度显著高于C组(P<0.05);D组的隐窝深度显著高于其他4组(P<0.05);B、E组的绒毛长度/隐窝深度显著高于A、C、D组(P<0.05);B组和E组的黏膜层厚度显著高于C、D组(P<0.05);B组的肌肉层厚度均显著高于其他组(P<0.05)。2)B、E两组的操作分类单元数(operational taxonomic units,OTU)、Chao1指数显著高于A、C组(P<0.05);B、E组的Shannon指数显著高于其他组(P<0.05);C、D两组的Simpson指数显著高于B、E组(P<0.05);B、D、E组的Ace指数显著高于A、C组(P<0.05)。3)从门和属水平上分析空肠微生物菌群结构:在门水平下5组的优势菌门均为厚壁菌门(Firmicutes)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)和变形菌门(Proteobacteria)。其中B组厚壁菌门的丰度显著高于C组(P<0.05);A、C组的放线菌门丰度显著高于B、E组(P<0.05);B组和E组拟杆菌门的丰度显著高于A、C两组(P<0.05);E组的变形菌门丰度显著高于B组和D组(P<0.05)。在属水平下:5组的优势菌属均为红球菌属(Rhodococcus)、短杆菌属(Brevibacterium)、克里斯滕森氏菌R7菌群(Christensenellaceae-R-7-group)、Quinella属和理研菌科RC9肠道菌群(Rikenellaceae-RC9-gutgroup)。A、C、D组红球菌属的丰度显著高于B、E组(P<0.05),B组的克里斯滕森氏菌R7菌群丰度显著高于其他组(P<0.05),A、B组的Quinella丰度显著高于D、E组(P<0.05)。4)16S rRNA基因组的PICRUSt功能预测结果显示,空肠微生物菌群功能主要集中在转录、碳水化合物运输与代谢、氨基酸的运输与代谢等方面,表明藏羔羊空肠细菌在提高宿主碳水化合物和蛋白质的代谢与吸收方面至关重要。综上,氮硫比在B和D水平下均有利于藏羔羊空肠组织形态的发育,并且可提高空肠微生物菌群多样性和丰富度,从经济效益上考虑,氮硫质量比为9꞉1时更符合藏羔羊的高效养殖。
The intestinal tract of animals is an important digestive and absorbing organ. To investigate the effects of different nitrogen to sulfur ratios on jejunal morphology, microbial diversity, and function in Tibetan lambs, 150 Tibetan lambs aged 60 days old with similar initial conditions were randomly divided into 5 equal groups. Lambs were fed until 180 days of age on diets containing similar energy, with nitrogen to sulfur mass ratios of 10.5:1(group A), 9:1(group B), 7.5:1(group C),6:1(group D), and 4.5:1(group E). At the end of the experiment, 6 animals from each group were randomly slaughtered and then examined. The jejunum tissues and contents were collected to analyze the effects of dietary nitrogen to sulfur ratios on jejunum tissue morphology, microbial community structure, and function. The following results were noted: 1) The length and width of jejunum villi in groups B and E were significantly higher than the other three groups(P < 0.05), and the lengths of villi in groups A and D were significantly higher than that in group C(P < 0.05). The depth of crypts in group D was significantly higher in the other four groups(P < 0.05). The villus-length/crypt-depth quotient in groups B and E was significantly higher than in groups A, C, and D(P < 0.05). The mucosal layer thicknesses in groups B and E were significantly higher than in groups C and D(P < 0.05). The muscle-layer thickness in group B was significantly higher than those of other groups(P < 0.05). 2) The OTU and Chao1 indexes of the B and E groups were significantly higher than those of the A and C groups(P < 0.05). The Shannon indexes of the B and E groups was significantly higher than those of other groups(P < 0.05). The Simpson indexes of the C and D groups were significantly higher than those of groups B and E(P <0.05). B, D, and E group Ace indexes were significantly higher than those of A and C groups(P < 0.05). 3) Analysis of community structure of the jejunal microbial flora at phylum and genus levels revealed that at the phylum level, the Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria predominate. Among them, the abundance of Firmicutes in group B was significantly higher than in group C(P < 0.05). The abundances of Actinobacteria in groups A and C were significantly higher than in groups B and E(P < 0.05). In groups B and E, the abundance of Bacteroidetes was significantly higher than in A and C groups(P < 0.05), and the abundance of Proteobacteria in group E was significantly higher than in groups B and D(P < 0.05). At the genus level, the four dominant bacterial genera were Rhodococcus, Brevibacterium,Christensenellaceae-R-7-group, Quinella, and Rikenellaceae-RC9-gut-group. The abundances of Rhodococcus in groups A,C, and D were significantly higher than in groups B and E(P < 0.05);the Christensenellaceae-R-7-group in group B was significantly higher than in all other groups(P < 0.05), and Quinella in groups A and B was significantly higher than in groups D and E(P < 0.05). 4) The PICRUSt function prediction results for the 16S rRNA genome show that the functions of the jejunal microbial flora mainly involve transcription and the transport and metabolism of carbohydrates and amino acids,indicating that Tibetan lamb jejunum bacteria can improve the host’s carbohydrate and protein metabolism and absorption. In summary, the nitrogen to sulfur ratio at B and D levels is beneficial to the development of jejunum tissue morphology in Tibetan lambs and increases the diversity and richness of the jejunum microbial flora. From an economic perspective, a nitrogen to sulfur ratio of 9:1 is most conducive to efficient raising of Tibetan lambs.
作者
闫小兰
侯生珍
李鹏翔
王志友
杨葆春
贾建磊
YAN Xiaolan;HOU Shengzhen;LI Pengxiang;WANG Zhiyou;YANG Baochun;JIA Jianlei(College of agriculture and animal husbandry,Qinghai University,Xining 810016,Qinghai,China)
出处
《草业科学》
CAS
CSCD
北大核心
2021年第4期758-768,共11页
Pratacultural Science
基金
青海省农牧科技创新羊产业科技研发平台(QNKP-2017-06-01)
国家自然科学基金(31660662)。
关键词
藏羔羊
氮硫比
空肠组织形态
微生物多样性
tibetan lamb
nitrogen sulfur ratio
jejunum morphology
microbial diversity