食粪行为对獭兔肠道菌群和生长发育的影响

发布时间：2018-06-04 20:14

本文选题：食粪行为 + 肠道菌群　；参考：《四川农业大学》2015年硕士论文

【摘要】：中小型草食性动物由于具有较高的代谢率和较小的消化道容积,食物在消化道的平均滞留时间较短,然而食物发酵所需要的时间远比食物的滞留时间要长。在长期的适应性进化过程中,中小型草食性动物从生理、行为等方面进化出了多种有效机制来提高其消化率,如结肠分离机制和食粪行为。食软粪行为是食粪行为的一种特殊形式。食软粪行为对中小型草食性动物的营养作用己被广泛研究。然而,软粪中除了含有较高的营养成分外,菌群含量也较硬粪高。食软粪行为是否有助于草食性动物肠道菌群的建立以及食软粪行为对草食性动物的促生长作用是否调节肠道菌群组成来实现,这些科学问题仍悬而未决。为了探究这一科学问题,我们以最具食软粪行为代表性的兔形目中的一个物种--獭兔作为模式动物。首先,我们选择10只高体重獭兔和10只低体重獭兔,分别采集其软粪和硬粪,针对16s rRNA的V4高变区利用Illumina MeSiq平台进行测序,探究了软粪和硬粪菌群组成差异以及体重不同的獭兔肠道菌群组成差异。随后,我们利用自行设计的禁食粪圈和食粪圈,探究了食软粪行为对獭兔肠道菌群和生长发育的影响。我们选择了 111只健康的40日龄断奶獭兔,将其随机分配成3组:戴禁食粪圈禁止食粪组(CP组,n=39)、戴食粪圈允许食粪组(CA组,n=38)、不戴圈空白组(CON组,n=34)。我们分别称量獭兔在40d、49d、56d、63d、70d、84d和98d的体重,并采集其粪便进行高通量测序。我们的研究结果如下:(1)软粪和硬粪菌群结构与组成存在差异,软粪含有较高水平的瘤胃菌科(Ruminococcaceae)、梭菌目(Clostridiales)矛口Adlercreutzia;(2)高体重獭兔和低体重獭兔肠道菌群也存在差异:与低体重獭兔硬粪相比,高体重獭兔硬类含有较高水平的乳球菌(Lactococcus)、乳酸菌(Lactobacillus)等;与低体重獭兔软粪比,高体重獭兔软粪含有较高水平的兄F32和α-变形菌（Alphaproteobacteria);(3)食粪组獭兔体重显著高于禁食粪组;(4)禁食粪后,獭兔肠道菌群组成发生明显改变:Blautia和真细菌(Eubacterium)含量增加,RF39目和Barnesiellaceae含量降低;(5)食粪行为对雌性濑兔和雄性獭兔肠道菌群的影响存在差异,对雌性獭兔影响更大。食粪行为对雌性獭兔影响最大的是梭菌目(Clostridiales)和拟杆菌属(Bacteroides);对雄性獭兔影响最大的是RF3外目和Blautia;(6)食粪组獭兔肠道中富含的RF39目、梭菌目(ClosCri价iales)和瘤胃菌科(Ruminococcaceae)与獭兔的体重呈正相关;(7)PICRUSt预测结果显示,食粪组雌性獭兔增加了对营养物质的代谢和免疫系统及消化系统通路水平;食粪组雄性獭兔增加了循环系统通路水平;同时食粪组雌性獭兔和雄性獭兔对有毒有害物质的降解水平较高。总的来说,我们的研究结果表明:食软粪行为能够调节肠道菌群稳态,并有可能通过调节肠道菌群来促进獭兔生长和健康。
[Abstract]:Due to the high metabolic rate and small digestive tract volume of small and medium-sized herbivores, the average residence time of food in the digestive tract is shorter, but the time of food fermentation is much longer than that of food. In the long-term adaptive evolution process, small and medium-sized herbivores have evolved a variety of physiological, behavioral and other effective mechanisms to improve their digestibility, such as colon separation mechanism and fece-eating behavior. Soft fecal eating behavior is a special form of fecal eating behavior. The nutritional effects of soft fecal feeding on small and medium herbivorous animals have been widely studied. However, in addition to higher nutrient content, the microflora content in soft feces is also higher than that in hard feces. Whether the soft fecal feeding behavior contributes to the establishment of intestinal flora of herbivorous animals and whether the promoting effect of soft fecal feeding behavior on the growth of herbivorous animals can regulate the composition of intestinal flora remains unanswered. In order to explore this scientific problem, we take the rex rabbit, one of the most representative species of the order Rabbit, which has the most representative behavior of eating soft feces, as a model animal. Firstly, we selected 10 high-weight rex rabbits and 10 low-weight rex rabbits, collected their soft and hard feces, and sequenced the V4 hypervariable region of 16s rRNA using Illumina MeSiq platform. The differences of composition between soft feces and hard feces and intestinal flora of rex rabbits with different body weight were investigated. Then, we studied the effects of soft fecal feeding behavior on intestinal flora and growth of Rex rabbits by using the self-designed fasting and fecal cycle. We selected 111 healthy 40-day-old weaned rex rabbits and divided them into 3 groups at random: no feeding fecal circle forbidding dung feeding group (CP) group (n ~ (39), dung feeding ring (CA) group (CA) group (n ~ (38), and no "ring" blank group (n ~ (3) (n ~ (3) group (n ~ (34). We measured the body weight of rex rabbits at 40d ~ 49d ~ 56d ~ (63) d ~ (70) d ~ (84) d and ~ (98) d, respectively, and collected their feces for high-throughput sequencing. Our results are as follows: (1) the structure and composition of soft feces and hard faeces are different. Soft feces contained higher levels of Ruminococcaceaeae (Clostridial diales2) spears (Adlercreutziae) and high weight Rex rabbits and low body weight Rex rabbits. Compared with low body weight Rex rabbits, the higher levels of Lactococcus lactococcus and Lactobacillus were found in high body weight Rex rabbits compared with low body weight Rex rabbits. Compared with low-weight rex rabbits, the soft feces of high-weight rex rabbits contained higher levels of F32 and Alphaproteobacteria amurensis than those of low-weight rex rabbits. The body weight of rex rabbits in defecal-eating group was significantly higher than that in non-diet faecal group (4) after fasting feces, the body weight of rex rabbits was significantly higher than that of low-weight rex rabbits. The composition of intestinal microflora of Rex rabbits was obviously changed. The contents of 1: Blautia and Eubacterium1) increased RF39 and decreased the content of Barnesiellaceae.) the effect of fecal feeding behavior on intestinal flora of female and male Rex rabbits was different, and the effect on female Rex rabbits was greater than that on female Rex rabbits. The effect of fecal eating behavior on female Rex rabbits was the greatest in Clostridiales and Bacteroidesus, and on male Rex rabbits in RF3 and Blautia (6) the RF39 order in the intestinal tract of faecal rex rabbits was the most significant. ClosCri value of Clostridium) and Ruminococcaceaes were positively correlated with the body weight of rex rabbits. The predicted results showed that the metabolism of nutrients and the level of immune system and digestive system pathway were increased in female rex rabbits in fecal feeding group. The level of circulatory pathway was increased in male Rex rabbits and the degradation level of toxic and harmful substances was higher in female Rex rabbits and male Rex rabbits. In general, our results show that soft fecal feeding can regulate the homeostasis of intestinal flora, and it is possible to promote the growth and health of Rex rabbits by regulating the intestinal flora.
【学位授予单位】：四川农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S829.1

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