妊娠日粮中可溶性纤维对母猪妊娠期饱感和泌乳期采食量的影响及其作用机理研究

发布时间：2018-05-06 08:39

  本文选题：日粮纤维 + 水合特性　； 参考：《华中农业大学》2016年博士论文

【摘要】：优化母猪泌乳期采食量是保证高效的母猪繁殖效率和提高猪场盈利水平的关键。母猪繁殖周期是一个相互联系,相互制约的整体过程。妊娠期营养摄入水平不仅影响仔猪初生窝重,而且影响泌乳期的采食量;而泌乳期营养摄入不足,则会影响母猪泌乳性能和母猪的再繁殖性能。由于母猪妊娠期能量摄入过高会降低泌乳期采食量。因此,妊娠期限饲是降低母猪能量摄入的有效途径,但是母猪限饲后饱感得不到满足,也会对繁殖性能产生负面影响。已有研究表明,妊娠日粮添加纤维性原料不仅可以促进限饲母猪的饱感,还能提高泌乳期采食量,但不同来源的纤维原料添加效果很不一致,这可能与日粮纤维的理化特性和发酵性密切相关,但需要进一步证实。此外,日粮纤维调控母猪泌乳期采食量及繁殖性能的作用机理并不清楚。基于已有研究,在保持效果的基础上,研究廉价的纤维组合十分必要。本研究围绕妊娠日粮中可溶性纤维促进母猪妊娠期饱感和提高泌乳期采食量的核心问题,结合体外发酵技术,研究了日粮纤维的发酵特性对母猪泌乳期采食量的影响。应用16S r DNA测序技术,以肠道菌群作为靶点,寻找日粮引起的肠道菌群结构变化与母猪胰岛素敏感性之间的关联,进一步阐明了日粮纤维调控母猪泌乳期采食量的机理。运用纤维原料协同增效的原理,筛选出与魔芋粉理化特性和发酵性一致的纤维组合,在大鼠模型中验证了其促进饱感和提高泌乳期采食量的效果。主要研究内容及结果如下:第一部分主要研究了妊娠日粮中不同来源纤维性原料的发酵特性对母猪泌乳期采食量和繁殖性能的影响。配种后,选取90头经产长白母猪随机分为三组,即对照组,魔芋粉组和甜菜渣组。三种日粮等能等氮且不溶性纤维含量相同。其中两个试验组与对照组的可溶性纤维含量不同,但魔芋粉组和甜菜渣组可溶性纤维含量相同。母猪妊娠期限饲,泌乳期自由采食,试验周期为两个繁殖周期。妊娠日粮酶解后残渣,用体外发酵方法检测发酵过程中的产气量和短链脂肪酸的含量。记录或度量母猪采食量,繁殖性能及仔猪性能。主要结果如下:1.日粮酶解后得到的残渣,通过体外发酵,显示魔芋粉组和甜菜渣组产气量显著高于对照组(P0.05),魔芋粉组主要属于快速发酵部分,而甜菜渣组则属于慢速发酵部分。魔芋粉组产气过程中的(FRD0)1显著低于对照组和甜菜渣组(P0.05)。在快速发酵部分,魔芋粉组发酵所用(T1/2)1显著低于甜菜渣组(P0.05),而对照组与甜菜渣组没有差异。魔芋粉组体外发酵产生的乙酸、丁酸和总短链脂肪酸显著地高于其它两组(P0.01)。2.与对照组相比,在妊娠90天时,魔芋粉组母猪显著地提高了采食后4h血浆中乙酸、丙酸、丁酸及总酸的浓度(P0.05);同时显著地降低了血浆中游离脂肪酸的浓度。此外,魔芋粉组母猪显著地提高了胰岛素敏感指数(homestasis model assessment-insulin sensitivity,HOMA-IS);显著地降低了胰岛素抵抗指数(HOMA-IR)(P0.05)。甜菜渣组和对照组差异不显著。3.与对照组相比,魔芋粉组母猪显著地提高了整个泌乳期的采食量,相应地,显著地提高了仔猪平均日增重及断奶窝重(P0.05),而甜菜渣组并未出现同样的效果。第二部分进一步研究了魔芋粉日粮对母猪肠道微生物、便秘、乳成分、泌乳期采食量及繁殖性能的影响。配种后,选取72头经产大白母猪随机分为两个组,即对照组和魔芋粉组。两种日粮等能等氮,不溶性纤维含量相同,而可溶性纤维含量不同。试验周期为连续两个繁殖周期。妊娠期限饲,泌乳期自由采食。分娩前后5天,记录母猪粪便形态并评分,同时记录母猪每天便秘情况。记录或度量母猪采食量,繁殖性能及仔猪性能。主要结果如下:1.日粮处理对母猪体重、背膘、断奶至发情间隔、粪便含水量、初乳和常乳的乳脂、乳糖及总干物质以及免疫球蛋白没有影响。魔芋粉组母猪提高了分娩前1天,分娩后4天,5天的粪便评分(P0.05),有降低便秘发生率的趋势(87.1%vs 69.2%,P=0.09)。魔芋粉日粮显著地提高了母猪初乳中的乳蛋白和去脂干物质(P0.05)。此外,魔芋粉组极显著提高了泌乳母猪产后4天粪便中乳酸杆菌(P0.001)的数量,并降低了产气荚膜梭菌的数量(P0.001)。2.魔芋粉日粮显著地提高了母猪泌乳期采食量和仔猪平均日增重及断奶窝重(P0.05)。第三部分应用16S r DNA测序技术探讨了魔芋粉日粮调控母猪肠道菌群对其泌乳期采食量及繁殖性能的机理。该研究的试验样品来源于第二部分的试验。于妊娠10天、60天、90天、109天、分娩当天、泌乳3天、7天、21天采食后2 h采集血液测定氧化应激标志物,并在妊娠10天、109天、泌乳3天及7天餐前和采食后4 h采集血液测定HOMA值、短链脂肪酸、游离脂肪酸及促炎因子。在妊娠109天和泌乳21天收集粪便并提取DNA进行16S r DNA测序,结合生物信息学分析,主要结果如下:1.相对于妊娠前期,母猪血清中硫代巴比妥酸(thiobarbituric acid reactive substances,TBARS),活性氧(reactive oxygen species,ROS)及8-羟基脱氧鸟苷(8-hydroxy-deoxyguanosine,8-OHd G)水平在妊娠后期,分娩当天,泌乳期显著上升(P0.05)。在分娩当天,魔芋粉组母猪显著地提高了血清中谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)的浓度,降低了ROS,8-OHd G的水平(P0.05),有降低泌乳21天GSH-Px,泌乳3天ROS水平的趋势(P0.1)。2.在妊娠109天采食后4 h,魔芋粉组母猪显著地提高了血浆中乙酸、丁酸及总酸的浓度(P0.05),相反地,显著地降低了血浆中游离脂肪酸的浓度(P0.05)。同时,魔芋粉组降低了母猪妊娠109天血清中TNF-α的水平(P0.05)。相对于妊娠前期,泌乳期母猪胰岛素敏感性降低(P0.05)。饲喂魔芋粉日粮母猪降低了HOMA-IR值,升高了HOMA-IS值(P0.05)。3.收集40个母猪粪样通过RDP数据库共比对到28个门,其中占总操作分类单元(operational taxonomic unit,OTU)1%的有9个门。厚壁菌门为第一优势门(38.69%),依次为蛋白菌门(17.12%)拟杆菌门(16.95%)。母猪饲喂魔芋粉日粮显著地提高了厚壁菌门,降低了拟杆菌门的丰度(P0.0001)。母猪饲喂魔芋粉日粮显著地提高了罗氏菌属(Roseburia),瘤胃球菌属(Ruminococcus),乳酸杆菌(Lactobacillus)及Akkermansia(P0.0001)的丰度;显著地降低了普氏菌属(Prevotella),拟杆菌属(Bacteroides)和绿弯菌属(Chloroflexi)的丰度(P0.0001)。4.主坐标分析显示泌乳期母猪聚集较好,个体间离散程度较小;而妊娠母猪分布较散,个体间离散程度大,这提示着妊娠母猪微生物菌群结构差异大,意味着妊娠日粮处理对母猪肠道微生物群落结构有显著影响。5.将关键肠道菌群与母猪代谢指标进行相关性分析发现结果显示Akkermansia丰度与HOMA-IR呈显著负相关(r=-0.61,P0.05),与HOMA-IS(r=0.63,P0.05)和乙酸(r=0.62,P0.05)呈显著正相关。Clostridium-Ⅺ与8-OHd G呈显著负相关(r=-0.74,P0.05)。Bacteroides与丁酸(r=0.64,P0.05)和总SCFA(r=0.73,P0.05)呈显著正相关,与FFA呈显著负相关(r=-0.64,P0.05)。初乳中Ig G分别与Roseburia(r=0.80,P0.05)和Blautia(r=0.84,P0.05)呈显著正相关。第四部分应用纤维原料协同增效原理,筛选出与魔芋粉理化特性和发酵性一致的纤维组合添加到大鼠日粮,研究了纤维的水合特性和发酵性调控饱感的效果及其可能作用机理。32只SD大鼠随机分到四个日粮处理:分别为对照组,魔芋粉组,纤维组合1及纤维组合2。日粮的水结合力和吸水膨胀力依次为纤维组合1魔芋粉组纤维组合2对照组。测定了胃肠道食糜的理化性质以及盲肠内容物的发酵性,通过饱感行为学,餐模式分析评估了纤维对大鼠饱腹感和饱感的影响。主要研究结果如下:1.日粮处理对大鼠体重及体增重没有影响。纤维组合1和魔芋粉组显著地降低了大鼠平均日采食量和累积采食量(P0.05)。2.通过饱感行为学观察发现,与对照组相比,纤维组合1和魔芋粉组显著地降低了采食时间(P0.05),促进了饱感转折点的出现,降低了1 h累积采食量(P0.05)。在餐模式分析中,与对照组相比,尽管日粮处理对采食速率,每餐采食量及每餐采食持续时间没有影响,纤维组合1和魔芋粉组通过显著地降低采食次数,延长采食间隔(P0.05),从而降低了全天采食量(P0.05)。3.尽管结肠重量在四个组之间没有差异。但与对照组相比,纤维组合1和魔芋粉组显著地提高了盲肠内容物含水量(P0.05),从而显著提高盲肠新鲜食糜重量(P0.05)。此外,与对照组相比,纤维组合1和魔芋粉组显著提高了胃食糜水结合力及吸水膨胀力(P0.05)。值得注意的是,胃食糜水结合力(r=-0.44,P0.05)和吸水膨胀力(r=-0.37,P0.05)分别与大鼠平均日采食量呈显著负相关。与对照组相比,纤维组合1和魔芋粉组有降低胃食糜滞留时间的趋势(P=0.09)。纤维组合1、魔芋粉组及纤维组合2组显著地提高了丙酸的浓度(P0.05),魔芋粉组显著地提高了总酸的浓度(P0.05)。日粮处理对血液中饱感激素(GLP-1,PYY)及回肠末端组织饱感基因(GLP-1,PYY)表达量没有影响。第五部分研究了母鼠妊娠日粮中纤维组合的水合特性和发酵性对泌乳期采食量的影响及其可能作用机理。48只SD雌鼠随机分配到四个日粮处理:分别为对照组,魔芋粉组,纤维组合1及纤维组合2。日粮的水结合力和吸水膨胀力依次为纤维组合1魔芋粉组纤维组合2对照组。通过葡萄糖耐受试验(Glucose tolerance test,GTT)和胰岛素耐受试验(Insulin tolerance test,ITT)评估了日粮纤维对妊娠母鼠胰岛素敏感性的影响。主要研究结果如下:1.日粮处理对母鼠体重没有影响。与对照组相比,纤维组合1显著提高了泌乳13、15、16、17和18天的采食量(P0.05),相应地,纤维组合1显著提高了仔鼠1-21天平均日增重及21天窝重(P0.05)。魔芋粉组和纤维组合2提高了仔鼠平均日增重,但差异不显著。2.尽管血糖浓度在ITT没有变化,然而在GTT中,与对照组相比,魔芋粉组和纤维组合1有降低葡萄糖注射后15min(P=0.05),30min(P=0.06),60min(P=0.14),90min(P=0.11)及120min(P=0.11)的血糖浓度的趋势,并且显著降低了血糖AUC的面积(P0.05)。相对于对照组,尽管空腹血糖,胰岛素水平没有变化,但魔芋粉组和纤维组合1显著地降低了HOMA-IR值。本研究的主要结论为:1.妊娠日粮添加魔芋粉提高了母猪泌乳期采食量,改善了仔猪生长性能。其可能机理是:一方面,快速发酵的魔芋粉日粮升高了母猪血液中SCFAs的浓度,降低了FFA的浓度,从而改善了母猪妊娠后期和泌乳前期的胰岛素敏感性;另一方面,魔芋粉日粮的发酵特性改变了母猪肠道菌群的结构,提高了与胰岛素敏感性相关的菌群的丰度,降低了氧化应激及促炎因子水平,进而改善了母猪胰岛素敏感性。2.体外筛选与魔芋粉具有类似性质的纤维组合,通过改变大鼠食糜水合特性,促进盲肠发酵产生SCFAs,降低了采食行为时间,促进了大鼠饱感。
[Abstract]:Optimizing the milk production of sows during lactation is the key to ensure efficient sow reproductive efficiency and raise the profit level of the pig farm. The sow reproductive cycle is a whole process of interrelated and mutual restriction. The level of nutrition intake in pregnancy not only affects the newborn piglets' primary nest weight, but also affects the intake of milk during lactation period, while the nutrition intake is insufficient in lactation period. It will affect the lactation performance of sows and the rebreeding performance of sows. Due to the excessive intake of energy in the sows during pregnancy, the period of pregnancy is an effective way to reduce the energy intake of sows. However, the sow's satiety is not satisfied after the sow's limited feeding, and it will also have a negative effect on the reproductive ability. The addition of fibrous raw materials can not only promote the satiety of sows but also increase the feed intake of the lactation period, but the effect of fiber raw materials from different sources is not consistent, which may be closely related to the physical and chemical properties and fermentation of the dietary fiber, but it needs further confirmation. In addition, dietary fiber regulates the feeding and reproduction of sows during lactation period. The mechanism of the performance is not clear. Based on the existing research, it is necessary to study the cheap fiber combination on the basis of maintaining the effect. This study focuses on the core problem of the soluble fiber in gestation to promote sow's pregnancy satiety and the increase of milk production intake, and studies the fermentation characteristics of the dietary fiber in vitro. The effect of 16S R DNA sequencing technology, using the intestinal microflora as the target, was used to find the relationship between the structural changes of the intestinal flora and the sensibility of the sow's insulin, and further clarified the mechanism of dietary fiber regulating the feed intake of the sows during the lactation period. A combination of the physicochemical properties and fermentative properties of konjac powder was used to verify the effect of promoting satiety and increasing the feed intake of lactation in the rat model. The main contents and results were as follows: the first part mainly studied the feeding and reproduction of different sources of fibrous raw materials from different sources of pregnancy on the lactation period of the sows. After mating, 90 sows were randomly divided into three groups, namely the control group, the konjac powder group and the beet residue group. The content of the nitrogen and insoluble fibers in the three kinds of diet was the same. The soluble fiber content of the two test groups was different from the control group, but the content of soluble fiber in the konjac powder group and the beet residue group was the same. Feeding period, lactating period is free to feed, the test period is two reproductive cycles. The residue of enzymatic hydrolysis of pregnancy diet, in vitro fermentation method to detect the production of gas and the content of short chain fatty acids in the fermentation process, record or measure the feed intake, reproductive performance and piglet performance. The main fruits are as follows: residue after enzymatic hydrolysis of the 1. diet, through body The gas production of the konjac powder group and beet residue group was significantly higher than that of the control group (P0.05). The konjac powder group was mainly a fast fermenting part, while the sugar beet residue group was a slow fermentation part. (FRD0) 1 was significantly lower than the control group and the beet residue group (P0.05). In the rapid fermentation part, the fermenting of the konjac powder group was used (T1/2 ) 1 was significantly lower than the beet residue group (P0.05), but there was no difference between the control group and the beet residue group. The acetic acid, butyric acid and total short chain fatty acids produced in the konjac powder group were significantly higher than those of the other two groups (P0.01).2. compared with the control group. At 90 days of pregnancy, the sow significantly improved the acetic acid, propionic acid, butyric acid and total in 4H plasma after 90 days of pregnancy. The concentration of acid (P0.05) significantly decreased the concentration of free fatty acids in plasma. In addition, the sow significantly increased the insulin sensitivity index (homestasis model assessment-insulin sensitivity, HOMA-IS), significantly reduced the insulin resistance index (HOMA-IR) (P0.05). The difference between the beet residue group and the control group was not significant.3. Compared with the control group, the sow in the konjac powder group significantly increased the feed intake of the whole lactation period, and correspondingly increased the average daily weight gain and weaning litter weight (P0.05) of the piglets, while the beet residue group did not have the same effect. The second part further studied the intestinal microorganism, constipation, milk composition and lactation period of the sows. After breeding, 72 large white sows were randomly divided into two groups, namely the control group and the konjac powder group. The two kinds of diet were equal in nitrogen, the insoluble fiber content was the same, but the soluble fiber content was different. The test period was two consecutive cycles. The pregnancy pregnancy period, the lactation period free intake. 5 days before and after childbirth, Records or measurements of sows' constipation, recording or measuring the daily constipation of sows, recording or measuring the feed intake, reproductive performance and piglet performance of sows. The main results are as follows: 1. diet treatment on sow weight, back fat, weaning to estrus interval, fecal water content, milk fat in colostrum and normal milk, lactose and total dry matter, and immunoglobulin Effect. The sow in the konjac powder group increased the rate of constipation (87.1%vs 69.2%, P=0.09) at 1 days before delivery, 4 days after delivery, and 5 days' stool score (P0.05). The konjac flour diet significantly improved the milk protein and the degrease dry matter (P0.05) in the sow colostrum. The number of Lactobacillus (P0.001) and the decrease of the number of Clostridium perfringens (P0.001).2. konjak powder significantly increased the feed intake of sows during lactation and the average daily gain of piglets and weaning litter weight (P0.05). The third part used 16S R DNA sequencing technology to investigate the feed intake of sow intestinal flora controlled by the konjac meal diet and its lactation period. The mechanism of reproductive performance. The experimental samples of this study were derived from the second part of the trial. On the 10 day of pregnancy, 60 days, 90 days, 109 days, 3 days of lactation, 7 days, 2 h after 21 days of feeding, the blood was collected to measure the oxidative stress markers, and the HOMA value, short chain fat, short chain fat, and short chain fat were collected at 10 days, 109 days, lactating days and 7 days before and after eating. Acid, free fatty acids and pro-inflammatory factors. Feces were collected on 109 days of pregnancy and 21 days of lactation, and DNA was extracted for 16S R DNA sequencing, combined with bioinformatics analysis, the main results were as follows: 1. relative to pre gestation, serum thiobarbituric acid (thiobarbituric acid reactive substances, TBARS), active oxygen (reactive oxygen species). And 8- hydroxy deoxy guanosine (8-hydroxy-deoxyguanosine, 8-OHd G) level in the late pregnancy, the day of childbirth, lactation period significantly increased (P0.05). On the day of childbirth, the konjac powder group sow significantly increased the concentration of serum glutathione peroxidase (glutathione peroxidase, GSH-Px) in the sera, reduced ROS, 8-OHd G level (P0.05), decreased. The trend of lactating for 21 days GSH-Px, the trend of ROS level for 3 days of lactation (P0.1).2. was 4 h after feeding on 109 days of pregnancy, and the concentration of acetic acid, butyric acid and total acid (P0.05) in the plasma of the konjac powder group increased significantly (P0.05). On the contrary, the concentration of free fatty acids in plasma was significantly reduced (P0.05). At the same time, the Amorphophallus konjac powder group reduced the TNF- alpha in the serum of the sow for 109 days. Level (P0.05). Compared with pre gestation, the sow insulin sensitivity decreased (P0.05) in lactation period. The diet of konjac meal sow decreased the HOMA-IR value and increased the HOMA-IS value (P0.05).3. to collect 40 sow faeces through the RDP database to 28 doors, which accounted for 9 of the total operating taxa (operational taxonomic unit, OTU) 1%. The door was the first dominant gate (38.69%), followed by the Proteobacteria gate (17.12%) in turn (16.95%). The sow feeding Amorphophallus powder diet improved the phylum saliorum gate and reduced the abundances of the bacteriobacteria (P0.0001). The sow feeding Amorphophallus powder diet significantly improved the genus Roseburia, the rumen coccus (Ruminococcus), the lactic acid rod. The abundance of bacteria (Lactobacillus) and Akkermansia (P0.0001) significantly reduced the genera of the genus prytobacillus (Prevotella), the abundances of the genus Bacteroides and Chloroflexi (P0.0001).4. principal coordinates analysis showed that the sows in the lactation period were well aggregated and the discrete degree among individuals were small, while the distribution of gestation sows was relatively scattered and the degree of dispersion among individuals was large. This suggests that the structural difference between the gestation sow microbial flora is large, which means that the diet treatment has a significant influence on the intestinal microbial community structure of the sows. The correlation analysis between the key intestinal flora and the sow metabolic index of.5. shows that the Akkermansia abundance is significantly negatively correlated with HOMA-IR (r=-0.61, P0.05), and HOMA-IS (r=0.63, P0.). 05) and acetic acid (r=0.62, P0.05) showed significant positive correlation between.Clostridium- and 8-OHd G (r=-0.74, P0.05).Bacteroides and butyric acid (r=0.64, P0.05) and SCFA (r=0.73). The fourth part, using the principle of synergistic synergism of fiber materials, selected the fiber combination which was consistent with the physicochemical and fermentative properties of the konjac powder to the rat diet, studied the hydration characteristics of the fiber and the effect of fermentation to regulate satiety and its possible mechanism,.32 only SD rats were divided into four diets with the machine: the control group, respectively, The water binding force and water swelling power of the 2. diet in the konjac powder group, the fiber combination 1 and the fiber combination diet were the 2 control groups of the fiber combination 1 konjac powder group. The physical and chemical properties of the GI tract and the fermentation of the cecum contents were measured. The effects of the fiber on the satiety and satiety of the rats were evaluated through the satiety behavior and the meal pattern analysis. The main results were as follows: 1. diet treatment had no effect on weight and weight gain in rats. Fiber combination 1 and konjac powder group significantly reduced the average daily feed intake and cumulative feed intake (P0.05).2. through satiety behavior observation. Compared with the control group, the fiber group 1 and the konjac powder group significantly reduced the feeding time (P0.05). In the meal pattern analysis, the dietary intake rate, food intake and food intake duration were not affected, while the fiber combination 1 and the konjac powder group decreased the feeding times and extended the feeding interval (P0.05), thus reducing the feeding rate and food intake duration compared with the control group in the meal model analysis. The whole day food intake (P0.05).3. had no difference between the four groups, but compared with the control group, the fiber combination 1 and the konjac powder group significantly increased the content of the cecum content (P0.05), thus significantly increasing the weight of the fresh cecum (P0.05). In addition, compared with the control group, the fiber combination 1 and the konjac powder group were significantly improved. It is worth noting that the gastric dehydrated water binding force (r=-0.44, P0.05) and water swelling power (r=-0.37, P0.05) are negatively correlated with the average daily feed intake of rats, respectively. Compared with the control group, the fiber combination 1 and the konjac powder group have the tendency to reduce the retention time of the stomach (P=0.09). Fiber combination is 1, demon The concentration of propionic acid (P0.05) was significantly increased in 2 groups of taro powder group and fiber combination, and the concentration of total acid (P0.05) was significantly increased in the konjac powder group. The expression of satiety hormone (GLP-1, PYY) in the blood and the expression of GLP-1 (PYY) in the terminal tissue of the ileum (GLP-1, PYY) were not affected. The fifth part studied the hydration of fibrous combination in the pregnant rats' pregnancy diet. The effect of characteristics and fermentation on the feeding intake of lactation period and its possible mechanism.48 only SD female rats were randomly assigned to four diet treatments: the control group, the konjac powder group, the fiber combination 1 and the fiber combination 2. diet were in turn the fiber combination 1 konjac powder group fiber combination 2 control groups. The experiment (Glucose tolerance test, GTT) and insulin tolerance test (Insulin tolerance test, ITT) evaluated the effects of dietary fiber on insulin sensitivity of pregnant female rats. The main results were as follows: 1. diet treatment did not affect the body weight of the mother rats. Compared with the control group, the fibrous combination 1 significantly improved the milk 13,15,16,17 and 18 days of feeding. (P0.05), correspondingly, fiber combination 1 significantly increased the average daily gain of 1-21 days and 21 days nest weight (P0.05) of the offspring rats, 2 of the konjac flour group and the fiber combination.

【学位授予单位】：华中农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S828.5
，

本文编号：1851584