日粮营养水平对滩羊瘤胃细菌区系及pH和VFA的影响

发布时间：2018-06-21 16:02

本文选题：滩羊 + 瘤胃细菌　；参考：《西北农林科技大学》2017年硕士论文

【摘要】：宁夏滩羊以其优质的二毛裘皮以及鲜嫩的肉品质而闻名,近些年来,由于生态环境的压力,养殖方式由放牧转变为舍饲,饲料类型也随之变化。目前,有关滩羊瘤胃微生物发酵的研究较少,特别是日粮营养水平(能量和蛋白质水平)对滩羊瘤胃细菌区系的研究更少。因此,本试验的目的是研究不同日龄和不同营养水平的日粮对滩羊瘤胃细菌多样性、pH和VFA所占比例的影响。在本试验中共挑选平均体重为(29±1.25)kg健康的宁夏滩羊112只(其中公羊、母羊各一半,105日龄)。完全随机的分到4个不同日粮营养水平的处理组(组I,II,III和IV),每个处理组中包含4个重复,每个重复中有7只羊(每个处理组总共有28只羊)。从处理组I到IV,日粮能量分别为7.08 MJ·kg-1、8.09 MJ·kg-1、9.10 MJ·kg-1和10.11 MJ·kg-1;蛋白质水平分别为8.04%、9.19%、10.34%和11.49%。饲料中能量、蛋白质的比值相同(约为0.88)。试验期共75 d,其中预试期15 d。分别在每个试验期结束当天(即150日龄和180日龄),从每个处理组的每个重复中随机选取1只羊屠宰(即每个处理组共选取4只羊),采集瘤胃内容物并测定其pH和VFA的含量;提取瘤胃液基因组DNA,一部分基因组DNA样品通过绝对实时荧光定量PCR对相关微生物的含量进行测定,另一部分通过第二代测序技术对滩羊瘤胃细菌群落结构进行测定并进行相关功能的预测。试验结果表明:1、在150和180日龄时,仅S.ruminantium的数量有显著差异(P0.05);P.ruminicola、R.flavefaciens和S.dextrinisolvens的数量随着日粮营养水平的提高均显著增加(P0.05)。另外,通过相关分析发现,不同瘤胃细菌间(种分类水平)存在相互促进作用。2、滩羊瘤胃液pH不受日龄和日粮营养水平的影响(P0.05);但不同日粮营养水平对VFA所占比例有显著影响。其中,乙酸的含量随着日粮营养水平的增加呈显著降低趋势(P0.05),而丁酸、异丁酸、戊酸、异戊酸所占TVFA的比例呈明显上升趋势(P0.05)。丙酸所占比例与V.parvula的数量呈显著正相关关系(r=0.42,P0.05),而戊酸与V.parvula的数量呈极显著负相关关系(r=-0.53,P0.01)。3、本试验共获得了滩羊瘤胃细菌的16个门分类和133个属分类。其中,Firmicutes门、Bacteroidetes门和Proteobacteria门的数量最多,且随着日粮营养水平的提高,Bacteroidetes门和Proteobacteria门的数量均呈线性增加的趋势(P0.05),而Firmicutes门的数量呈线性降低的趋势(P0.05)。Butyrivibrio属、Saccharofermentans属和Pseudobutyrivibrio属的含量随着日粮营养水平的提高均呈线性降低趋势(P0.05),而Prevotella属、Prevotellaceae_uncultured属和Succinivibrio属的含量均呈线性增加的趋势(P0.05)。通过功能预测发现,参与碳水化合物代谢的基因家族所占比例较大,且随着日粮营养水平的提高,与氨基酸代谢相关的基因家族所占的比例呈线性增长趋势(P0.05)。综上所述,与日龄相比,不同营养水平的日粮显著影响瘤胃微生物数量及VFA含量。瘤胃中细菌(门、属、种分类水平)的数量均随日粮营养水平的提高而改变。另外,本试验还预测了瘤胃细菌相关基因家族的潜在功能。本试验实现对滩羊瘤胃细菌组成的首次研究并为提高滩羊日粮中能量和蛋白质的利用效率提供依据。
[Abstract]:Ningxia beach sheep is famous for its high quality 20 Fen fur and fresh meat quality. In recent years, because of the pressure of ecological environment, the breeding mode has changed from grazing to forage, and the type of feed has changed accordingly. At present, there are few studies on the microbial fermentation of the rumen of the beach sheep, especially the dietary nutrition level (energy and protein level) to the beach sheep. The study of rumen bacterial flora was less. Therefore, the purpose of this experiment was to study the effects of diet on rumen diversity, pH and VFA ratio of pH and VFA in different days of age and different nutritional levels. In this experiment, 112 sheep of Ningxia beach sheep (including rams, ewes, 105 days of age) were selected in this experiment. The machine was divided into 4 different diets (group I, II, III and IV), with 4 repetitions in each treatment group, 7 sheep in each repeat (28 sheep in each treatment group). From the treated group I to IV, the diet energy was 7.08 MJ. Kg-1,8.09 MJ kg-1,9.10 MJ, kg-1 and 10.11 respectively; protein levels were 8.04%, 9.19 respectively. The ratio of energy and protein in 10.34% and 11.49%. feed was the same (about 0.88). The test period was 75 D, in which the pre trial period 15 D. was at the end of each trial period (i.e. 150 days and 180 days of age), and 1 sheep were randomly selected from each treatment group (4 sheep in each treatment group), and the contents of the rumen were collected and measured. The content of pH and VFA, genomic DNA extracted from the tumor gastric juice, and some genomic DNA samples were measured by absolute real-time fluorescence quantitative PCR, and the other was determined by second generation sequencing technology to determine the structure of the bacterial community in the rumen of the beach sheep and predict the related functions. The results showed that 1, in 150 and 180. At the age of age, the number of only S.ruminantium was significantly different (P0.05); the number of P.ruminicola, R.flavefaciens and S.dextrinisolvens increased significantly with the increase of dietary nutrition level (P0.05). In addition, the correlation analysis showed that there was a mutual promotion of.2 between different rumen bacteria (species classification level), and the pH of the gastric juice of the Tan sheep was not affected by the age of day and age. The effect of dietary nutrition level (P0.05), but the proportion of different dietary nutrition levels had a significant influence on the proportion of VFA. Among them, the content of acetic acid decreased significantly with the increase of dietary nutrition level (P0.05), while the proportion of butyric acid, isobutyric acid, valerate and isovaleric acid accounted for a significant upward trend (P0.05). The proportion of propionic acid and V.parvula The number showed a significant positive correlation (r=0.42, P0.05), while the number of valerate and V.parvula was significantly negative correlation (r=-0.53, P0.01).3. The 16 gate taxonomy and 133 taxonomy of the rumen bacteria of the beach sheep were obtained. Among them, the number of Firmicutes gate, Bacteroidetes gate and Proteobacteria gate was the most, and with the nutrition level of the diet. The number of Bacteroidetes gates and Proteobacteria doors increased linearly (P0.05), while the number of Firmicutes gates decreased linearly (P0.05).Butyrivibrio, and the content of Saccharofermentans and Pseudobutyrivibrio genera linearly decreased with the increase of dietary nutrition level (P0.05), while Prevotella, Pre, Pre. The content of votellaceae_uncultured and Succinivibrio genera showed a linear increase (P0.05). Through functional prediction, it was found that the proportion of genes involved in carbohydrate metabolism was larger, and the proportion of genes related to amino acid metabolism increased linearly with the increase of dietary nutrition level (P0.05). Compared with day age, the number of rumen microbes and the VFA content were significantly affected by the diet of different nutrition levels. The number of bacteria in the rumen (gate, genus, species and species) changed with the increase of dietary nutrition level. In addition, this experiment also predicted the potential function of the rumen bacteria related basis family. The first study of bacterial composition provides the basis for improving the efficiency of energy and protein utilization in Tan sheep diets.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S826.5

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