泌乳母猪饲粮精氨酸水平对哺乳仔猪小肠黏膜发育的影响

本试验旨在研究泌乳母猪饲粮精氨酸水平对哺乳仔猪小肠黏膜发育的影响及其抗氧化作用机理.试验选择长大二元杂交经产母猪36头,随机分为0.82%精氨酸组(n=12)、1.23%精氨酸组(n=12)和1.64%精氨酸组(n=12)3个组,分别饲喂含0.82%、1.23%和1.64%精氨酸的饲粮.试验从产后第4天开始至第22天结束.结果表明:1.64%和1.23%精氨酸组哺乳仔猪十二指肠黏膜绒毛高度显著高于0.82%精氨酸组(P<0.05);1.64%精氨酸组哺乳仔猪十二指肠和回肠黏膜隐窝深度显著低于0.82%精氨酸组(P<0.05),1.64%和1.23%精氨酸组哺乳仔猪空肠黏膜隐窝深度显著低于0.82%精氨酸组(P<0.05).1.64%精氨酸组哺乳仔猪十二指肠和空肠黏膜乳糖酶和碱性磷酸酶活性显著高于0.82%精氨酸组(P<0.05);哺乳仔猪小肠黏膜谷胱甘肽过氧化物酶(GSH-Px)活性随泌乳母猪饲粮精氨酸水平升高而升高,其中在十二指肠中各组间差异显著(P<0.05),在空肠和回肠中1.64%精氨酸组显著高于0.82%精氨酸组(P<0.05);1.64%精氨酸组哺乳仔猪十二指肠、空肠和回肠黏膜超氧化物歧化酶(SOD)活性均显著高于0.82%精氨酸组(P<0.05);哺乳仔猪小肠黏膜丙二醛(MDA)含量在十二指肠中1.64%和1.23%精氨酸组显著低于0.82%精氨酸组(P<0.05),在空肠中1.64%精氨酸组显著低于0.82%精氨酸组(P<0.05).结果提示,提高泌乳母猪饲粮精氨酸水平能够促进哺乳仔猪小肠黏膜发育,其作用机制可能与母猪饲粮中补充精氨酸改善仔猪抗氧化机能有关.     

仔猪补饲及不同类型的饲粮蛋白质对仔猪小肠粘膜形态结构的影响

试验研究了玉米—豆饼(CSM)、豆饼(SM)、乙醇处理豆饼(TSM)和乳蛋白(MP)等不同类型蛋白质对3周龄断奶仔猪小肠形态变化的影响。仔猪从7日龄起补饲,断奶后一部分仔猪换喂复合开食料(CS),其余仔猪饲料类型不变。试验至35日龄结束。结果表明,断奶导致绒毛变短(P<0.05),腺窝增深(P<0.05),绒毛/腺窝比下降(P<0.01),空肠上皮淋巴数增加(P<0.05),蔗糖酶活降低(P<0.01),血清脲氮上升(P<0.01)。断奶后肠道损伤程度与蛋白类型有关(P<0.01):豆饼引起的损伤程度最大,乳蛋白最小;玉米代替部分豆饼或用乙醇处理豆饼后可明显降低小肠粘膜损伤程度。断奶后换料组的粘膜损伤比相同料型组严重(P<0.01),但补饲豆饼组例外。十二指肠的绒毛萎缩(P>0.05)和腺窝增深(P<0.01)比空肠明显。断奶后第一周肠粘膜损伤最严重,第二周开始恢复。这些结果充分证明,仔猪对补饲及不同类型蛋白质的反应符合过敏理论。     

妊娠母猪日粮中添加精氨酸对初生仔猪肠道发育的影响

本研究旨在评估妊娠母猪日粮中添加精氨酸对初生仔猪肠道发育的影响。试验将12头第3～4胎次、体重接近、膘情和健康状况一致、妊娠第60天的长大（长白×大白）二元母猪随机分为2组,每组6头。对照组饲喂常规日粮,试验组饲喂试验日粮（常规日粮添加1%精氨酸,同时减少1%豆粕）,试验从母猪妊娠60 d开始至分娩结束。结果：妊娠母猪日粮中添加1%精氨酸能显著提高窝产活健仔数、活健仔率、平均初生个体重和初生窝重（P＜0.05）,极显著提高初生仔猪小肠重量和长度（P＜0.01）,显著提高十二指肠绒毛高度和绒毛宽度、空肠绒毛宽度（P＜0.05）,显著降低小肠各段隐窝深度（P＜0.05）,显著提高小肠各段绒隐比（P＜0.05）。结论：妊娠母猪日粮中添加精氨酸能显著提高初生仔猪肠道发育水平。 [关键词]肠道发育|精氨酸|初生仔猪|妊娠母猪     

东北民猪母猪日粮添加青粗饲料的效果

东北民猪是我国优良的地方猪种，曾以耐粗饲，繁殖力高，抗逆性强，杂交效果好而著称。近年来，我们以农户饲养东北民猪母猪日粮添加青粗饲料为条件，对东北民猪的耐粗饲和生产性能进行试验。     

猪IL-2基因在毕赤酵母中的高效表达及生物活性分析

本研究根据密码子偏爱原则设计猪IL-2引物,克隆其基因后构建pPIC9k-IL-2重组表达载体,线性化后电转化毕赤酵母GS115,获得优化密码子的重组酵母转化子;再用G418抗性梯度法筛选得到多拷贝重组菌株,不同条件下进行甲醇诱导表达。结果表明:经PCR鉴定IL-2基因已整合到酵母基因组中。表达产物经SDS-PAGE电泳分析发现相对分子质量为16、20ku两条目的蛋白表达带,脱糖基化分析表明目的蛋白得到了适度的糖基化修饰,Western blotting分析显示表达的蛋白具有良好的免疫反应性,分子筛纯化可以获得纯度为95%的蛋白质,淋巴细胞增殖活性分析表明所得的蛋白质具有促淋巴细胞增殖的活性。毕赤酵母表达系统可以高效地表达具有生物活性的重组猪IL-2蛋白分子。     

谷氨酰胺对妊娠期饲喂精氨酸民猪母猪后代肠道发育及ZO-1、occludin基因表达的影响

试验仔猪选用妊娠45日龄至分娩期间饲喂精氨酸民猪母猪所产7日龄仔猪,共48头,随机分成2组,每组3个重复,每个重复8头仔猪。对照组和试验组分别在基础饲粮水平上添加0、0.8%的谷氨酰胺。结果显示:与对照组相比,谷氨酰胺组的十二指肠和回肠绒毛长度显著升高(P0.05);实时荧光定量PCR检测发现,谷氨酰胺组十二指肠、空肠以及回肠ZO-1和occludin mRNA的表达量均显著增加(P0.05)。结果表明:谷氨酰胺对仔猪小肠绒毛具有一定的改善作用,并能促进细胞间紧密连接结构的形成,增强小肠黏膜的屏障功能。     

饲粮中添加二甲双胍对猪PRKAG3基因表达量及肉质的影响

旨在研究二甲双胍(Metformin)对PRKAG3基因表达量以及对猪生长性能及肉质的影响.挑选80 kg左右的杜洛克×长白×大约克三元杂交(DLY)阉公猪10头,随机分为对照组和试验组.试验组日粮中添加400 mg·kg-1体质量的Metformin,对照组日粮除不含Metformin外,其它日粮成分与试验组相同.2周试验结束后所有猪只全部屠宰,测定生长性能、AMPK活性、PRKAG3基因表达量、AMPKγ3蛋白表达量、胴体品质和肉质性状.结果表明:1)日粮中添加400 mg·kg-1体质量的Metformin后,试验组AMPK活性、PRKAG3基因mRNA含量和AMPKγ3蛋白表达量分别比对照组提高了13.92％、4.39倍和35.53％ (P＜0.05).2)试验组采食量和平均日增体质量分别比对照组下降13.80％ (P＜0.05)和13.14％,而料肉比则比对照组提高6.77％.3)试验组胴体长显著低于对照组(P＜0.05),屠宰率、背膘厚、眼肌面积和瘦肉率均低于对照组,但差异均不显著(P＞0.05).4)试验组pH2、滴水损失、a值低于对照组(P＞0.05);pH1、剪切力和熟肉率高于对照组(P＞0.05);L值和b值则极显著高于对照组(P＜0.01).结果提示,Metformin可激活PRKAG3基因表达,进而可能影响猪生长性能和肉质.     

日粮中添加L-精氨酸对母猪繁殖性能的影响

精氨酸是NO和多胺合成的底物,而这两者对哺乳动物胎盘血管形成至关重要。本试验旨在验证日粮中添加精氨酸可能提高母猪繁殖性能的假设。试验选用52头体重为166.3±1.8kg怀孕母猪,单栏饲养。玉米豆粕基础日粮。试验分为两组,一组在日粮添加1.0%的L-精氨酸;另一组添加1.7%L-丙氨酸。在第30d时将妊娠母猪随机分组,分别饲喂该两种日粮,日粮每千克均含有13.0MJ代谢能和12.2%粗蛋白。在妊娠的第30、70、90、110d对测定母猪的背膘厚和体重并进行采血。母猪在妊娠第110d转入产房。产后记录产仔数,活仔数及仔猪初生重。在妊娠第90d（P〈0.010）和第110d（P〈0.001）的时精氨酸组母猪血浆尿素氮较对照组低。精氨酸组活仔率和窝重比对照组相分别高22%（11.40vs.9.37,P=0.032）和24%（16.38vs.13.19kg,P=0.016）。结果表明：通过精氨酸营养调控能使母猪窝产活仔数提高2头。     

细胞因子IL-2和IL-4对病毒保护性抗原基因真核表达影响的研究

如何提高和改善疫苗的免疫效果是目前疫苗研究的热点,近年来许多研究发现与DNA疫苗联合应用的细胞因子可通过不同的环节调节和增强DNA疫苗免疫效应,白细胞介素作为免疫佐剂能协同DNA疫苗能取得较好的免疫效果。细胞因子是动物体内特异高效调控免疫细胞和协调免疫应答重要的信号分子,它主要包括淋巴毒素(LT)、肿瘤坏死因子(TNF)、干扰素(INF)、白细胞介素(IL,如IL-2、IL-4、IL-5、IL-6、IL-7、IL-8、IL-12)和集落刺激因子(GM-CSF)等。其中IL-2和IL-4对病毒保护性抗原基因真核表达影响的研究较多。主要综述了IL-2和IL-4作为免疫佐剂对病毒保护性抗原基因真核表达的影响,以期为更深入地进行IL-2和IL-4对DNA疫苗免疫增强作用的深入研究提供参考。     

哺乳期使用植物小肽对断奶后仔猪肠道微生物及肠道形态的影响

选用(25±2)日龄的PIC五元杂交断奶仔猪300头,根据哺乳期使用的4种不同的日粮(对照日粮,以及含有2%血浆蛋白、2%植物小肽和4%植物小肽日粮)分为4组,每组设3个重复,每个重复25头,探讨哺乳期使用植物小肽对断奶后仔猪肠道微生物和肠道形态的影响。结果表明,与对照组相比,哺乳期日粮中使用植物小肽,对减少断奶后仔猪肠道内大肠杆菌和沙门菌的繁殖,增加断奶仔猪肠道内有益菌属乳酸菌的繁殖有一定作用(P>0.05)。使用4%植物小肽提高了十二指肠、空肠和回肠的绒毛高度(P>0.05)和绒腺比(P<0.05),减小了隐窝深度(P<0.05)。植物小肽能够刺激断奶后仔猪肠道发育,使断奶后仔猪肠道绒毛高度增加,隐窝深度变浅,这种趋势随着植物小肽添加量的增加而提高。     

母猪妊娠和泌乳阶段饲喂两种不同的锌源对其所产仔猪生长性能和肠道形态的影响

对于锌在仔猪保育和生长肥育阶段的作用已经有大量报道．但有关不同来源锌对母猪生产性能及其所产仔猪生长性能的研究却较少。在家禽．当肉用种母鸡饲喂补充锌时．其后代的免疫力可得到增强（Kidd等,1992,1993）。Caine等（2001）报道从母猪妊娠第80d到分娩期间饲喂氨基酸锌复合物对14日龄仔猪断奶后24h的肠道发育和免疫功能有良好效果．但未对保育阶段的仔猪进行过报道。     

Body weight of newborn and suckling piglets affects their intestinal gene expression

Modern hyperprolific sows must deal with large litters (16–20 piglets) which reduce piglet birthweight with a concomitant increase in the proportion of small and intrauterine growth retarded piglets. However, larger litters do not only have a greater variation of piglet weights, but also a greater variation in colostrum and milk consumption within the litter. To further understand the impact that body weight has on piglets, the present study aimed to evaluate the degree of physiological weakness of the smallest piglets at birth and during the suckling period (20 d) compared to their middle-weight littermates through their jejunal gene expression. At birth, light piglets showed a downregulation of genes related to immune response (FAXDC2, HSPB1, PPARGC1α), antioxidant enzymes (SOD2m), digestive enzymes (ANPEP, IDO1, SI), and nutrient transporter (SLC39A4) (P < 0.05) but also a tendency for a higher mRNA expression of GBP1 (inflammatory regulator) and HSD11β1 (stress hormone) genes compared to their heavier littermates (P < 0.10). Excluding HSD11β1 gene, all these intestinal gene expression differences initially observed at birth between light and middle-weight piglets were stabilized at the end of the suckling period, when others appeared. Genes involved in barrier function (CLDN1), pro-inflammatory response (CXCL2, IL6, IDO1), and stress hormone signaling (HSD11β1) over-expressed compared to their middle-weight littermates (P < 0.05). In conclusion, at birth and at the end of suckling period, light body weight piglets seem to have a compromised gene expression and therefore impaired nutrient absorption, immune and stress responses compared to their heavier littermates.     

碳水化合物/油脂比对断奶仔猪免疫机能及肠道形态的影响

为了研究饲料中以玉米淀粉和大豆油作为能量来源对断奶仔猪免疫机能和肠道形态的影响,本试验选用18头健康仔猪,按随机区组分为3个处理,每组6个重复。采用单因子设计,饲喂仔猪碳水化合物与植物性脂肪的能值比(carbohydrate energy value,(CEV)/fat energy value,FEV)分别为:11.7∶1.0(低油脂组),1.5∶1.0(中油脂组)和1.0∶6.9(高油脂组)的日粮,各处理组消化能均为14.6 MJ/kg、粗蛋白含量均为17%的等能、等氮日粮,饲养试验结束后屠宰。结果显示,仔猪饲喂低油日粮组脾脏质量显著高于中油组和高油组(P<0.05),各组之间胸腺质量以及免疫器官指数无显著性差异(P>0.05);仔猪饲喂低油日粮组血清溶菌酶含量显著高于中油组和高油组(P<0.05);仔猪饲喂低油日粮组血清IgG含量最高(P<0.05),IgG含量从高到低含量排序为:低油组>中油组>高油组(P<0.05);同时,仔猪饲喂低油日粮不同程度提高仔猪十二指肠、空肠前段、空肠后段及回肠绒毛高度(P<0.05)。结果表明,高油日粮使仔猪肠道绒毛不同程度萎缩、损伤,免疫器官质量下降。低油日粮上述情况有所改观,表现为肠道绒毛较高、结构较为完整,免疫器官质量升高。可见,高CEV/FEV比日粮有益于改善动物机体免疫机能及肠道形态结构。     

植物多糖对断奶仔猪小肠黏膜形态及肠黏膜屏障功能的影响

旨在探讨断奶仔猪饲粮中单独或联合添加黄芪多糖、牛膝多糖及白术多糖对其小肠黏膜形态及肠黏膜屏障功能的影响。选取256头35日龄的杜长大三元杂交断奶仔猪,随机分为8个组,每组4个重复,每个重复8头猪,采用三因素两水平(2×2×2)试验设计,饲粮中黄芪多糖、白术多糖和牛膝多糖的添加水平均为0,800mg/kg,试验共进行28d。结果显示:植物多糖能显著提高断奶仔猪十二指肠、空肠和回肠的黏膜绒毛高度,提高绒腺比(P0.05),3种多糖联用效果最适。与对照组相比,多糖组断奶仔猪回肠V/C比值显著提高(P0.05),各单一多糖组之间差异不显著(P0.05),3种多糖联合添加与两两添加及单一添加相比显著提高了V/C比值(P0.05)。多糖组断奶仔猪血清中二胺氧化酶(DAO)的活性、血清中内毒素(ET)含量及D-乳糖的含量均显著降低(P0.05),3种多糖联用效果最适。多糖能显著提高断奶仔猪肠道黏膜Occludin、Claudin和ZO-1的基因表达量(P0.05)。单一添加黄芪多糖、白术多糖及牛膝多糖能显著提高断奶仔猪肠道钠-葡萄糖共转运载体1(SGLT1)的mRNA相对表达量(P0.05),对葡萄糖转运载体2(GLUT2)mRNA相对表达量有提高的趋势,但差异不显著(P0.05)。多糖两两联用及3种多糖联合添加能显著提高断奶仔猪肠道SGLT1和GLUT2mRNA相对表达量(P0.05)。结果表明,在断奶仔猪饲粮中添加植物多糖可显著改善断奶仔猪肠道黏膜形态结构和肠道的通透性,其机制可能与植物多糖改善断奶仔猪肠黏膜屏障功能作用有关。     

Impact of Yersinia enterocolitica enteritis on disaccharidase activity and small intestinal morphology in colostrum-deprived newborn piglets

The effect of enteritis on the development of the small intestine was examined in newborn, colostrum-deprived piglets infected with a human isolate of Y. enterocolitica (serotype 0:3, biotype 4) soon after birth. The piglets were killed 3 days (n = 6) or 5 days (n = 8) after infection, or antibiotic therapy was commenced on day 5 and the animals killed on day 14 (n = 5). Compared with the non-infected controls, infected animals had reduced mucosal lactase and sucrase, but not maltase activity, while after antibiotic therapy, previously infected piglets had a lower lactase and a higher maltase and sucrase activity. Lactase activity was significantly reduced in the duodenum and jejunum, and mean values were lower in the ileum, but the difference did not reach significance; maltase activity was greater at all ages from the distal jejunum to the mid-ileum; sucrase activity was reduced in all segments up to day 5 but after antibiotic therapy was increased in the jejunum and appeared early in the ileum. Enzyme profiles were more mature along the crypt-villus axis in some segments of the intestine in previously infected piglets. Sodium-potassium-ATPase activity was unchanged. There was a reduced villus height:crypt depth ratio, crypt hyperplasia and increased crypt cell proliferation. Morphological maturation, indicated by loss of vacuoles and location of the nucleus at the base of the enterocyte, proceeded distally from the duodenum to ileum from 3 to 14 days of age when only the ileum remained immature. In infected piglets, there was reduced vacuolation and earlier location of the nucleus at the base of the cell in the distal intestine. Accelerated maturity of specific disaccharidases and enterocyte morphology in infected piglets appears to be due to physical damage to the mucosa resulting in faster proliferation of crypt cells and migration of enterocytes. It is suggested that this may reduce macromolecular internalisation and impair the ability to utilise dietary carbohydrate and may have long-term effects on growth and immunological responses of the gut.     

Small intestinal morphology in weaned piglets fed a diet containing spray-dried porcine plasma

The hypothesis tested in this study was that the reported beneficial effects of spray-dried porcine plasma (SDPP) on piglet post-weaning performance and health are associated with a trophic effect on small intestinal mucosa. At 24 days of age, the piglets of seven sows were assigned to one of three treatment groups. One group continued to be suckled. The other two groups were weaned and offered a diet containing either 15 per cent SDPP or casein. From each treatment group, one piglet was anaesthetised and samples were taken from the small intestinal wall at 26, 28 and 31 days of age. There were no significant effects of SDPP versus casein on villus length. On average, there was less mitotic activity in the SDPP -fed piglets than in those fed casein on days 4 and 7 after weaning. As less mitotic activity leads to less immature enterocytes, this may provide a mechanism for the reported beneficial effects of SDPP on performance and health.     

Effects of age and diet on small intestinal structure and function in gnotobiotic piglets

The effects of age and dietary change on the structure and function of piglet small intestine were investigated in gnotobiotic pigs. The small intestinal mucosa was damaged when gnotobiotic pigs were weaned on to a pelleted meal diet; villus height, crypt cell production rate, and activities of brush border enzymes were reduced. Small intestinal damage was associated with reduced weight gain over a three week period; diarrhoea was not observed. The continuous consumption of meal appeared to perpetuate the intestinal damage for three weeks, although evidence of intestinal repair, as indicated by an increased crypt cell production rate, was present three weeks after weaning. Antibodies to soya antigen were detected in serum after weaning and the intestinal damage could have been caused by antibody-mediated immune reactions to soya proteins. Villi of milk fed gnotobiotic pigs shortened significantly with age.