Effects of prenatal stress on cellular and humoral immune responses in neonatal pigs

In the present study, we investigated the effects of a daily 5 min restraint stress of pregnant sows in the last five gestational weeks on the development and reactivity of the immune system of the offspring. Maternal stress resulted in significant decreased serum immunoglobulin G (IgG) concentrations in suckling piglets at 1 and 3 days of age. Furthermore, the stress treatment of the sows had an immunosuppressive effect on lymphocyte proliferation in response to the T-cell mitogen concanavalin A (ConA) at postnatal days 1 and 7. A suppressive effect was also found in response to the B-cell mitogens lipopolysaccharid (LPS) at days 1 and 35 and pokeweed mitogen (PWM) at day 1 of life, whereas natural killer (NK) cell cytotoxicity was not altered by prenatal stress. The relative thymus weights were significantly reduced in prenatally stressed piglets on the first and 35th day of life and the morbidity and mortality during the suckling period were significantly increased in prenatally stressed litters, as shown by a higher frequency of diseased and died piglets per litter. In addition, the ConA-, LPS- and PWM-stimulated lymphocyte proliferation at the age of 7, 21 and 35 days, and the NK cell cytotoxicity at the age of 21 and 35 days decreased in prenatally stressed and in control piglets 1h after a corticotropin (ACTH) injection. However, the cellular immunity was always higher in the control piglets which might be a result of the weaker stress hormone reactivity in prenatally stressed animals. In conclusion, the results provide first experimental evidence that prenatal maternal stress during late gestation is able to impair both humoral and cellular immune function in suckling piglets. The data also suggest that gestational stress in pigs may affect the ontogeny of the foetal immune system with consequences on the susceptibility to diseases and immune responsiveness to stressful stimuli of the offspring.     

断奶应激对仔猪红细胞免疫功能的影响研究

为了研究早期断奶应激对仔猪红细胞免疫功能的影响,试验采用同窝杜×(大×长)三元杂交健康仔猪12只,分别于断奶前3天、断奶后3天及断奶后2周进行红细胞受体C3b花环试验、免疫复合物IC花环试验及血常规检验,观察断奶应激对仔猪红细胞免疫功能、红细胞数量及血红蛋白含量影响的动态变化。结果表明:断奶应激导致仔猪红细胞C3b受体花环率(C3bRR率)、红细胞总数和血红蛋白含量降低,IC花环率(ICR率)的变化明显。说明断奶应激可导致仔猪红细胞免疫功能下降,红细胞免疫功能低的仔猪更容易发生(断奶)应激性腹泻。     

仔猪断奶应激对肠道微生物菌群影响的研究

为了研究仔猪断奶应激对肠道微生物菌群的影响,试验选择同1日龄来自同一窝的杜-长-大仔猪和莱芜猪仔猪各10头作为研究对象,均于28日龄断奶,每个品种为1个处理组,根据断奶时间分为5个阶段,断奶前1周(21 d)、断奶当天(28 d)、断奶后1 d(29 d)、断奶后1周(35 d)及断奶后2周(42 d),每个处理组每个阶段随机选取2头仔猪屠宰取样,测定空肠肠道微生物变化情况。试验结果表明,在各个阶段莱芜猪的微生物丰度都比杜-长-大要高,断奶后1 d两品种仔猪的肠道微生物丰度最高,分别是24和18,香农-维纳指数也最高,分别是2.94和2.78。荧光定量PCR检测双歧杆菌、乳酸杆菌和大肠杆菌相对含量,在断奶后1周莱芜猪的双歧杆菌是杜-长-大仔猪的6.4倍(P<0.01),莱芜猪比杜-长-大的大肠杆菌在各个时期都相对较低,杜-长-大断奶后1周空肠大肠杆菌比莱芜猪高87%(P<0.05)。结论:莱芜猪比杜-长-大仔猪空肠肠道微生物更加丰富,有益微生物菌群含量多,仔猪断奶后肠道微生物能够很快的建立起新的平衡。     

抗母猪生殖应激剂和抗仔猪断奶应激剂对断奶仔猪血清乳酸脱氢酶同工酶的影响初探

选取18头大白经产母猪及其所产仔猪,随机分为3组,分别于断奶时和断奶后15d时上午采血,采用聚丙烯酰胺凝胶电泳法分析了血清中乳酸脱氢酶同工酶酶谱的分布特征,结果如下：与对照组相比,在母猪料中添加了2％的抗母猪生殖应激剂和在断奶仔猪料中添加了2％的抗仔猪断奶应激剂的试验1组仔猪在断奶时和断奶后15d时血清中LDH1的活性均极显著增强（P〈0．01）,试验1组和只有仔猪在断奶前后按其采食量的2％添加抗仔猪断奶应激剂的试验2组断奶后15d时LDH3、LDH4、LDH5的Rf值都极显著减弱（P〈0．01）,其他差异不显著。     

Early development of immune system in pigs

Prenatal and early postnatal immune system development has been studied in minipigs. First leukocytes were observed in the yolk sac and fetal liver (FL) on the 17th day of gestation, the majority of them being SWC3(+). The colonization of the thymus (TH) with leukocytes was observed 21 days later. Two waves of fetal TH colonization with pro-T cells were deduced from the frequency of thymocyte subsets. Thymic B cells and immunoglobulin-secreting cells (Ig-SC) were studied by flow cytometry and ELISPOT, respectively. When the total numbers of fetal Ig-SC were compared, the TH was identified as the main source of natural antibodies and the only site of IgA and IgG synthesis. In germ-free animals, the TH also represented the major site of IgG and IgA production and the number of Ig-SC was not influenced by colonization with microflora. FL and bone marrow were identified as primary B lymphopoietic sites. The phenotype of B precursors was characterized and pre-B II cells were shown to be the dominant mononuclear fraction between DG50 and DG105. In the periphery, relative proportions of lymphocyte subsets were determined. Studies in gnotobiotic piglets have revealed that the appearance of CD4(+)CD8(+) T cells and CD2(-) B cells is absolutely dependent on the contact of immune system with live viruses and bacteria, respectively.     

环磷酰胺对断奶仔猪免疫功能的影响

本试验旨在探讨环磷酰胺(CY)对断奶仔猪免疫功能的影响。选取12头(28±3)d的杜×长×大断奶仔猪,随机分为对照组和CY组。第1天和第7天,给CY组仔猪注射50mg/kg BW的CY,对照组仔猪注射等量的生理盐水;第7天和第14天,前腔静脉采血待测;第14天,测定迟发型超敏反应。结果表明:(1)CY可降低第7天断奶仔猪的中性粒细胞数量(P0.1)及第14天白细胞、淋巴细胞、中性粒细胞(P0.05)和单核细胞数量(P0.1);(2)CY可降低第14天牛血清白蛋白抗体水平(P0.05);(3)CY可降低第7天干扰素-γ水平(P0.05)。本研究结果表明,CY可抑制断奶仔猪的免疫功能。     

Effects of weaning on diarrhea caused by enterotoxigenic Escherichia coli in three-week-old pigs

We attempted to determine whether weaning is required for induction of diarrhea in pigs with postweaning enterotoxigenic Escherichia coli infection. Three-week-old newly weaned pigs and their suckling littermates were inoculated with the K88+ enterotoxigenic E coli strain M1823B. Fourteen of 21 weaned and 12 of 20 suckling pigs were genetically resistant to intestinal adhesion by the K88+ strain of E coli; they remained healthy, and gained weight at similar rates. Both groups of K88-resistant pigs gained weight faster, and shed fewer bacteria of strain M1823B in their feces, than did their K88-susceptible counterparts. Diarrhea developed in K88-susceptible pigs in the weaned (6 of 7 pigs) and suckling (4 of 8 pigs) groups, and 1 of the 4 affected suckling pigs died from complications resulting from diarrhea. The incidences of diarrhea, weight gain rates, and the numbers of strain M1823B shed in feces of susceptible weaned and suckling pigs were not significantly (P greater than 0.05) different. Diarrhea scores of susceptible weaned pigs were significantly (P less than 0.02) higher than those of susceptible suckling pigs on the second day after inoculation. In this experimental model, it was concluded that weaning is not required for induction of diarrhea, but may modestly increase its severity.     

甘露寡糖对断奶仔猪生长性能和肠道菌群的影响

选用28日龄断奶仔猪90头，随机分为5组，每组3个重复，每个重复6头仔猪，分别施以5种不同日粮，自由采食和饮水。第一组为对照组，第2、3、4、5组在基础日粮中分别添加0.6%-0.05%甘露寡糖（商品名为奥奇素，Bio-MOS）、0.2%甘露寡粮、0.1%甘露寡糖、0.05%甘露寡糖＋3mg/kg黄霉素的试验组。以测定甘露寡糖对仔猪生产性能和肠道菌群浓度的影响。试验结果表明：（1）添加奥奇素组的平均日增重（ADG）均高于对照组、腹泻率显著低于对照组，而平均日采食量（ADFI）低于对照组（4组除外）和饲料转化效率（F／G）高于对照组，但差异不显著。各试验组之间的ADG、腹泻率、ADFI和F／G差异不显著，但以0.1%的甘露寡糖组相对综合效果最好。（2）各试验组肠道大肠杆菌的浓度极显著低于对照组。第2组和第3组其结肠、盲肠和直肠中双歧杆菌得到增殖。第4组的结肠和直肠中双歧杆菌浓度显著高于对照组，但盲肠中的双歧杆菌的增殖效果不明显。各组肠道中乳酸杆菌的浓度与对照组相比差异不显著。     

Interference of the humoral immune response against resident and nonresident intestinal commensal strains in weaning pigs

Not nocuous bacteria are important for the maturation and the modulating activity of the gut immune system. However, the humoral immune response against commensal and probiotic bacteria is less documented, particularly in farmhouse animals. Blood serum and saliva were collected in two trials where probiotics, Lactobacillus rhamnosus GG (LbR), well-defined human isolate (Trial A), and a novel and abundant porcine commensal, Lactobacillus sobrius strain 001^T (LbS) (Trial B), were supplemented to weaning pigs. Anti-LbR IgA were present in serum of pigs before treatment with LbR, but also after 1 or 2 weeks in control pigs, notwithstanding the absence of DNA from LbR in colon. Pigs fed or not LbS for 1 or 2 weeks had LbS-specific IgA, in saliva and in serum. Colon contents of control subjects were positive for DNA from LbS. We hypothesized that part of this IgA strain-specific activity is partially related to immune cross-reactivity between different Lactobacillus-species. With the procedure of Shu et al. [Shu, Q., Bird, S.H., Gill, H.S., Rowe, J.B., 1999. Immunological cross-reactivity between the vaccine and other isolates of Streptococcus bovis and Lactobacillus. FEMS Immunol. Med. Microbiol. 26, 153–158], after ELISA test on blood serum or saliva pre-incubated with LbR or LbS, each strain blocked a relevant part of IgA specific for the other. So bacteria with different affinity for the pig present reciprocal crossed immune activity. When probiotics are supplied to weaning pigs, the possible action of already present multi-effective IgA should be considered. The mechanism of IgA induction by certain probiotics needs to be addressed in further studies.     

Effects of dietary Selenomethionine supplementation on growth performance,antioxidant status,plasma selenium concentration,and immune function in weaning pigs

Background

This study was designed to evaluate the efficacy of DL-selenomethionine (DL-SeMet) supplementation on growth performance, antioxidant status, plasma selenium (Se) concentration, and immune function of weaning pigs. 216 weaning pigs were randomly allocated to 6 treatments with 6 replicates each according to a complete randomized block design. Each replicate had six pigs. Diet of group one was corn-soybean basal diet without any additional Se supplement. Group 2 was supplemented with 0.3 mg/kg of Se from sodium selenite. Groups 3-6 were supplemented with 0.1, 0.3, 0.5, and 0.7 mg/kg of Se from DL-SeMet, respectively. The trial lasted for 42 days.

Results

Pigs supplemented with 0.3 and 0.7 mg/kg DL-SeMet obtained better feed gain ratio (P < 0.05). The best antioxidant ability (serum, liver, and muscle) was shown in 0.1-0.3 mg/kg DL-SeMet groups (P < 0.05). The plasma Se concentration increased as the dietary DL-SeMet level elevated. The immunity among groups was not affected.

Conclusions

DL-SeMet supplementation in the diet significantly improved the growth performance, antioxidant ability and plasma Se content of weaning pigs. DL-SeMet can replace sodium selenite in the diet of weaning pigs.     

仔猪断奶应激对肠道功能和组织结构影响的研究

为了研究仔猪断奶应激对肠道功能和组织结构的影响,试验选择不同抗应激能力的莱芜猪和杜长大(DLY)商品仔猪各10头作为研究对象,分别于断奶前1周(21 d)、断奶当天(28 d)、断奶后1 d(29 d)、断奶后1周(35 d)、断奶后2周(42 d)5个阶段,测定十二指肠和空肠的消化酶活性、肠绒毛组织发育的变化。试验结果表明,两品种仔猪断奶后1周莱芜猪胰蛋白酶含量和活性比杜长大仔猪分别高81.48%(P<0.01)和21.44%(P<0.01);两品种仔猪的十二指肠肠绒毛长度在断奶后1周都比断奶前变短(P<0.05),断奶后1周莱芜猪的十二指肠和空肠肠绒毛长度比杜长大分别长73.62%(P<0.01)和65.63%(P<0.01)。莱芜猪比杜长大有更高的消化酶活性和肠道组织修复能力,具有更强的抗断奶应激的能力。     

Effects of dietary Selenomethionine supplementation on growth performance,antioxidant status,plasma selenium concentration,and immune function in weaning pigs

Background:This study was designed to evaluate the efficacy of DL-selenomethionine(DL-SeMet) supplementation on growth performance,antioxidant status,plasma selenium(Se) concentration,and immune function of weaning pigs.216 weaning pigs were randomly allocated to 6 treatments with 6 replicates each according to a complete randomized block design.Each replicate had six pigs.Diet of group one was corn-soybean basal diet without any additional Se supplement.Group 2 was supplemented with 0.3 mg/kg of Se from sodium selenite.Groups 3-6 were supplemented with 0.1,0.3,0.5,and 0.7 mg/kg of Se from DL-SeMet,respectively.The trial lasted for 42 days.Results:Pigs supplemented with 0.3 and 0.7 mg/kg DL-SeMet obtained better feed gain ratio(P 0.05).The best antioxidant ability(serum,liver,and muscle) was shown in 0.1-0.3 mg/kg DL-SeMet groups(P 0.05).The plasma Se concentration increased as the dietary DL-SeMet level elevated.The immunity among groups was not affected.Conclusions:DL-SeMet supplementation in the diet significantly improved the growth performance,antioxidant ability and plasma Se content of weaning pigs.DL-SeMet can replace sodium selenite in the diet of weaning pigs.     

Influences of quorum‐quenching probiotic bacteria on the gut microbial community and immune function in weaning pigs

The aim of this study is to investigate the dynamic gut microbial diversity in weaning swine after administering feed supplemented with probiotic bacteria that specifically inhibit the activity of quorum molecules. Initially, the universal quorum molecule autoinducer‐2 (AI‐2) bioassay results indicated that AI‐2 activity was profoundly inhibited in enterohemorrhagic Escherichia coli (EHEC) O157:H7 in the presence of Lactobacillus acidophilus strain 30SC cell extract, although the growth of EHEC was not affected. Based on plate counting results, bacterial community analysis revealed a specific reduction in coliforms compared to the control, whereas the population of lactobacilli increased in weaning swine in in vivo trials. Supplementation with L. acidophilus strain 30SC did not affect the counts of other communities, such as total aerobes and yeast/mold. In addition, PCR‐denaturing gradient gel electrophoresis analysis showed a significant difference in the 16S rRNA gene products after administering L. acidophilus strain 30SC. Selected bands were sequenced, and most of them were identified as uncultured bacterium clones or a Lactobacillus‐ and Bifidobacterium‐specific community. Therefore, our results indicate that quorum‐quenching probiotic bacteria can significantly modulate the gut microbiota of swine and these beneficial effects can contribute to the improvement of performance and health in the gastrointestinal tract of weaning pigs.     

小肽对断奶獭兔生长性能和免疫性能的影响

100只体重为(891.42±23.68)g,健康状况良好的断奶獭兔,随机分为5组。对照组为基础日粮组,A、B、C、D组分别为基础日粮添加0.25%、0.50%、0.75%、1.00%的小肽。试验预试期7d,正试期30d。试验结果表明:添加0.50%小肽后,獭兔平均日增重比对照组提高24.16%(P<0.05),平均日采食量显著降低(P<0.05),料重比降低25.19%(P<0.05)。添加小肽后,獭兔胸腺指数、下颌淋巴结重显著高于对照组(P<0.05)。獭兔日粮中添加小肽可以增强断奶獭兔生长性能和免疫性能。     

绞股蓝微粉发酵物对断奶仔猪免疫功能的影响

为研究绞股蓝微粉发酵物对断奶仔猪免疫功能的影响,选取70头21日龄杜×长×大断奶仔猪,随机分为7组,每组10头,试验期42d。其中,Ⅰ组为对照组,Ⅱ-Ⅳ组分别为未发酵绞股蓝微粉0.5%、1.0%、1.5%剂量组,Ⅴ-Ⅶ组分别为绞股蓝微粉发酵物0.5%、1.0%、1.5%剂量组。在试验期第1、14、28和42天时检测血清中的猪瘟抗体水平。在试验期第21、42天时测定外周血T淋巴细胞亚群(CD4~+/CD8~+)的比值和血清免疫球蛋白(IgG、IgA)的含量。结果显示:1.0%绞股蓝微粉发酵物能显著提高断奶仔猪的猪瘟抗体水平(P0.05);1.0%绞股蓝微粉发酵物可以显著提高断奶仔猪血清免疫球蛋白(IgG、IgA)的含量(P0.05);1.0%、1.5%绞股蓝微粉发酵物均可显著提高断奶仔猪外周血T淋巴细胞亚群(CD4~+/CD8~+)比值(P0.05),且1.5%绞股蓝微粉发酵物差异显著(P0.05)。结果表明:绞股蓝微粉发酵物可显著提高断奶仔猪免疫功能,且显著优于未发酵绞股蓝微粉。     

Effect of age on absorption and immune responses to weaning or introduction of novel dietary antigens in pigs

Pigs weaned at three weeks old absorb food protein antigens from the intestine. The amount of antigen absorbed declines over the next three weeks, and this decline is associated with an increasing level of serum antibody to the fed proteins. There was no difference in the rate of immune elimination of intravenously injected antigen in fed and unfed controls. The reduction of serum antigen is thus likely to reflect reduced absorption, possibly mediated by locally produced antibody. Pigs weaned at 10 weeks old also absorbed antigens and produced an antibody response when introduced to soya; and after three weeks of feeding soya the absorption of antigen was substantially reduced. This latter exclusion was specific for soya as a second novel protein (ovalbumin) was absorbed when introduced to the diet at this time. At six months, pigs no longer absorbed soya proteins when they were introduced to the diet. Furthermore, pigs of this age had serum 'antibody' to soya and other proteins such as keyhole limpet haemocyanin to which they had never been exposed.