Thirty minutes transport causes small intestinal acidosis in pigs

Long duration (>10 hours) transport has been described as having either adverse or no effects on porcine health. However, the effect of short duration transport on porcine health is unknown. In the present paper, pigs fed ad libitum (n = 6) were transported for 30 minutes, anaesthetised, instrumented, and cardiovascular and gastrointestinal parameters were measured. Non-transported pigs (n = 6) served as controls. No significant differences between groups were found concerning blood flow in the arteria mesenterica cranialis, heart rate, cardiac output, pulmonal blood pressure, haemoglobin content and haematocrit value. Systolic systemic blood pressure was higher (though not significant), and diastolic systemic blood pressure was significantly higher in the transported pigs than in the controls. Small intestinal pH was significantly lower in transported pigs than in control pigs. We conclude that a 30-minute transport of fed pigs results in small intestinal acidosis. As small intestinal acidosis predisposes to bacterial translocation, even short duration transport should be avoided when possible.     

Enteral exposure to crude red kidney bean lectin induces maturation of the gut in suckling pigs.

The present investigation characterized the effect of red kidney bean lectin exposure on gut maturation and function in young piglets. Eleven suckling pigs were given by stomach tube a crude red kidney bean lectin preparation (containing about 25% lectin, 400 mg/kg BW) (lectin-treated pigs) at 10, 11, and 12 d of life, and an additional 16 pigs (control pigs) were given saline instead. On the next day, the intestinal absorptive capacity was determined in vivo, and on the 14th d of life the piglets were killed and organs and small intestine samples were collected for analyses and in vitro permeability experiments. The lectin-treated pigs showed an increase in stomach weights and mucosa thickness, whereas no weight effect was found for the small intestine, spleen, liver, or adrenals. Morphometric analyses of the small intestine in lectin-treated pigs showed a decrease in villus heights, an increase in crypt depths and crypt cell mitotic indices, and fewer vacuolated enterocytes per villus and reduced vacuole size. Lectin treatment also resulted in a decrease in the absorption of different-sized marker molecules after gavage feeding, a decrease in intestinal marker permeability, and a change in small intestinal disaccharidase activities, with increased maltase and sucrase activities. The size of the pancreatic acini was also greater in the lectin-treated pigs, but no increases in enzyme content or pancreatic weight could be determined. In addition, the blood plasma levels of cholecystokinin were higher in the lectin-treated than in the control pigs. The results indicate that exposure to crude red kidney bean lectin induces structural and functional maturation of the gut and pancreatic growth in young suckling piglets. This possibility of inducing gut maturation may lead to an improvement in the piglets' ability to adapt to weaning and to an increase in the growth and health of these animals.     

Dietary fibre enrichment of supplemental feed modulates the development of the intestinal tract in suckling piglets

Background: Commercial pre-weaning diets are formulated to be highly digestible and nutrient-dense and contain low levels of dietary fibre. In contrast, pigs in a natural setting are manipulating fibre-rich plant material from a young age. Moreover, dietary fibre affects gastrointestinal tract(GIT) development and health in older pigs. We hypothesised that supplemental diets that contain vegetal fibres are accelerating GIT development in suckling piglets in terms of size and functionality. From d 2 of life, sow-suckled piglets had access to a low fibre diet(CON),a diet with a fermentable long-chain arabinoxylan(lc-AXOS), a diet with a largely non-fermentable purified cellulose(CELL), or a diet containing both fibres. During the initial 2 weeks, the control diet was a high-density milk replacer,followed by a dry and highly digestible creep meal. Upon weaning at 25 d, 15 piglets from each treatment group,identified as eaters and originating from six or seven litters, were sacrificed for post-mortem examination of GIT morphology, small intestinal permeability and metabolic profile of the digesta. The microbiota composition of the mid-colon was evaluated in a sub-set of ten piglets.Results: No major statistical interactions between the fibre sources were observed. Piglets consumed the fibrecontaining milk supplements and creep diets well. Stomach size and small intestinal permeability was not affected.Large intestinal fill was increased with lc-AXOS only, while relative large intestinal weight was increased with both fibre sources(P 0.050). Also, CELL decreased ileal pH and tended to increase ileal DM content compared to CON(P 0.050). Moreover, the concentration of volatile fatty acids was increased in the caecum(P 0.100) and midcolon(P 0.050) by addition of CELL. lc-AXOS only stimulated caecal propionate(P 0.050). The microbiota composition showed a high individual variation and limited dietary impact. Nonetheless, CELL induced minor shifts in specific genera, with notable reductions of Escherichia-Shigella.Conclusions: Adding dietary fibres to the supplemental diet of suckling piglets altered large intestinal morphology but not small intestinal permeability. Moreover, dietary fibre showed effects on fermentation and modest changes of microbial populations in the hindgut, with more prominent effects from the low-fermentable cellulose.     

Effects of crude red kidney bean lectin (phytohemagglutinin) exposure on performance, health, feeding behavior, and gut maturation of pigs at weaning

The aim of this study was to obtain information that could help to ease the weaning transition in commercial pig production. Before weaning, phytohemagglutinin (PHA) in the form of a crude preparation of red kidney bean lectin was fed by gavage to 24 crossbred [(Swedish Landrace x Yorkshire) x Hampshire] piglets, whereas 24 control piglets were fed alpha-lactalbumin by gavage, to study the effect on growth, occurrence of postweaning diarrhea, feeding behavior, and some anatomical and physiological traits of the gastrointestinal tract. Within the litter, piglets were randomly assigned to PHA treatment or control and remained in the same pen from the beginning (PHA exposure at 7 d before weaning) until the end of the experiment (14 d post-weaning). Weaning took place at the age of 31 to 34 d. Pigs treated with PHA grew faster (P = 0.013) during the first week postweaning and tended to have lower total diarrhea scores (P = 0.10) than did control pigs. On d 5 after weaning, piglets treated with PHA spent more time eating (P = 0.028) than control pigs. No immunostimulating effect of PHA, measured by plasma immunoglobulin G, could be detected. An increase in the intestinal barrier properties before weaning, as a response to PHA treatment, was demonstrated in intestinal absorption studies using Na-fluorescein and BSA as gavage-fed markers. Less uptake (measured as plasma concentrations) of the marker molecule Na-fluorescein occurred during a 24-h study period, and numerically lower levels of BSA were observed compared with studies in control pigs of the same age. A total of 12 pigs (6 control, 6 PHA-treated) were euthanized on the day of weaning for analyses of gastrointestinal properties. The PHA-treated pigs tended to have a longer total small intestinal length (P = 0.063) than that of the control pigs. The enzyme profile of the jejunal epithelium responded to PHA exposure with a decrease in lactase activity and an increase in maltase and sucrase activities, which is similar to changes normally observed after weaning. No differences were found in the size of the pancreas or in its contents of trypsin and amylase. In conclusion, exposing piglets to crude, red kidney bean lectin for 3 d during the week before weaning led to changes in performance and small intestinal functional properties that would be expected to contribute to a more successful weaning.     

A defined intestinal colonization microbiota for gnotobiotic pigs

Maximising the ability of piglets to survive exposure to pathogens is essential to reduce early piglet mortality, an important factor in efficient commercial pig production. Mortality rates can be influenced by many factors, including early colonization by microbial commensals. Here we describe the development of an intestinal microbiota, the Bristol microbiota, for use in gnotobiotic pigs and its influence on synthesis of systemic immunoglobulins. Such a microbiota will be of value in studies of the consequences of early microbial colonization on development of the intestinal immune system and subsequent susceptibility to disease. Gnotobiotic pig studies lack a well-established intestinal microbiota. The use of the Altered Schaedler Flora (ASF), a murine intestinal microbiota, to colonize the intestines of Caesarean-derived, gnotobiotic pigs prior to gut closure, resulted in unreliable colonization with most (but not all) strains of the ASF. Subsequently, a novel, simpler porcine microbiota was developed. The novel microbiota reliably colonized the length of the intestinal tract when administered to gnotobiotic piglets. No health problems were observed, and the novel microbiota induced a systemic increase in serum immunoglobulins, in particular IgA and IgM. The Bristol microbiota will be of value for highly controlled, reproducible experiments of the consequences of early microbial colonization on susceptibility to disease in neonatal piglets, and as a biomedical model for the impact of microbial colonization on development of the intestinal mucosa and immune system in neonates.     

D-Lactic acidosis in calves as a consequence of experimentally induced ruminal acidosis

In order to test the hypothesis that ruminal drinking in calves can lead to D-lactic metabolic acidosis, ruminal acidosis was induced in nine calves by intraruminal application of untreated whole milk via a stomach tube. The amount of the daily force-fed liquid was 3 x 1 l. The experimental design called for an end of intraruminal applications if two or more of the following signs were observed: severe depression, estimated degree of dehydration >10%, absence of sucking reflex, lack of appetite for two consecutive feedings, severe metabolic acidosis with calculated Actual Base Excess (ABE) <-15 mmol/l. The procedure was scheduled to be discontinued on the 17th day of experiment. The onset of ruminal acidification occurred rapidly, and mean pH value fell from 6.70 (+/-0.48) to 4.90 (+/-0.38) after the first application. The following days the pH values varied between 4 and 5. Rumen acidity was characterized biochemically by a significant increase in both isomers of lactic acid. The effects of the intraruminal administration on the calves were detrimental; eight of nine calves showed an acute disease process. According to the pre-established clinical standard, seven of nine calves were removed from the intraruminal feeding schedule. All but one of the calves developed severe systemic acidosis. The increase in anion gap demonstrated the net acid load. In all the calves D-lactate levels were found to show a significant and rapid increase. On the contrary, L-lactate never deviated from physiological levels. These observations confirm that, in young calves as in adult cattle, ruminal acidosis may lead to a clinically manifested D-lactic metabolic acidosis.     

外源粪菌干预对受体猪肠道屏障功能的影响研究

为研究外源粪菌干预对受体猪肠道屏障功能的影响,试验选取初生重相近、胎次相同、同日出生的杜×长×大三元杂交哺乳仔猪12窝,随机分为2组,每组6窝(每窝10~12头)。试验组于1~10日龄隔天灌喂1 m L金华猪粪菌悬液进行外源粪菌干预;对照组灌喂等量无菌0.1 mol/L无菌磷酸盐缓冲液(PBS)。试验期间,仔猪自由哺乳采食和饮水,分别于12日龄和27日龄进行屠宰、采样。结果表明:外源粪菌干预可明显减少腹泻,提高受体猪的平均日增重和成活率(P0.05);外源粪菌干预能显著降低27日龄受体猪肠道隐窝深度(P0.05),显著提高肠道绒毛高度/隐窝深度(P0.05);外源粪菌干预能显著增加肠道杯状细胞数和12日龄肠道分泌型免疫球蛋白A阳性(SIgA~+)细胞数(P0.05),同时显著提高肠道黏蛋白Muc2、紧密连接蛋白ZO-1和Occludin表达水平(P0.05),而27日龄试验组的肠道SIgA~+细胞数与对照组无显著差异(P0.05)。综上可知,外源粪菌干预能通过增加肠道杯状细胞和SIgA~+细胞数、提高黏蛋白和紧密连接蛋白表达的方式调节受体猪肠道屏障功能,具有维持猪肠道功能稳态和促进肠道健康的作用。     

高锌对早期断奶仔猪肠黏膜屏障和肠上皮细胞紧密连接蛋白表达的影响

为研究高剂量氧化锌对早期断奶仔猪肠黏膜屏障的影响并探讨其作用机理,选取54头21日龄断奶仔猪按胎次一致、体质量相近和公母各半方法分为3组,每组3个重复,每个重复6头.哺乳组仔猪继续哺乳至35日龄,基础日粮组饲喂基础日粮(110 mg·kg~(-1)锌),高锌组饲喂基础日粮+3 000 mg·kg~(-1)锌(氧化锌).分别于28和35日龄取样测定血浆D-乳酸、内毒素含量和二胺氧化酶(DAO)活性、肠系膜淋巴结细菌移位率以及结肠内容物大肠杆菌数,并分析回肠上皮细胞紧密连接蛋白Occludin和ZO-1的表达.结果显示:与哺乳组相比,断奶仔猪饲喂基础日粮,28日龄时血浆中D-乳酸、内毒素含量和DAO活性显著升高(P<0.05),至35日龄时,肠黏膜仍维持较高的通透性;添加高锌抑制上述3个指标的升高,进而阻止肠黏膜通透性的增加,达到与哺乳组相同的效果;与哺乳组相比,基础日粮组和高锌组在28和35日龄时均存在肠系膜淋巴结细菌移位现象,但是高锌组低于基础日粮组(P>0.05);28日龄时,基础日粮组结肠内容物大肠杆菌数大于哺乳组(P<0.05),与高锌组比较差异不显著(P>0.05),35日龄时各组间差异不显著(P>0.05);与哺乳组相比,仔猪断奶后饲喂基础日粮使Occludin和ZO-1mRNA丰度以及ZO-1的表达下降(P<0.05),高锌组Occludin和ZO-1 mRNA丰度、ZO-1蛋白表达均显著高于基础日粮组(P<0.05).结论:仔猪断奶后肠黏膜通透性增加,肠上皮细胞紧密连接蛋白表达下降;而添加高剂量氧化锌可抑制细菌在肠道黏膜上的黏附,阻止上皮细胞渗透性增加,能保护肠黏膜屏障功能.     

Validation of ELISAs for the detection of antibodies to Sarcoptes scabiei in pigs

An Enzyme-linked ImmunoSorbent Assay (ELISA) was developed for the detection of antibodies to Sarcoptes scabiei. This 'Animal Health Service'-ELISA (AHS-ELISA) was compared with a commercial test (Checkit(R) Sarcoptest) using experimental and field sera. The experimental study was a contact infestation experiment. Eighty piglets were randomly divided between the experimental and control group. After introduction of three Sarcoptes scabiei var. suis infested pigs in the experimental group, both groups were monitored by determining scratching indices, taking ear scrapings and blood samples in Weeks 0, 2, 4, 6, 8, 12 and 16. Four pigs in the control group were immunised with either Dermatophagoides pteronyssinus (Dp) antigens (n=2), or Acarus siro (As) antigens (n=2). In the control group all (non-immunised) pigs were negative in all tests. In the experimental group only slightly elevated scratching indices were observed, with a maximum in Week 8. After 2 weeks for the first time an ear scraping was positive (2.5%). In Week 8 the highest number of positive ear scrapings were found (25.0%). Positive results in the Sarcoptest were first obtained in Week 12 (10.5% positive), while eventually 29.0% of the finishing pigs were positive after 16 weeks. The AHS-ELISA first detected a serological response after 6 weeks (5. 0% positives), increasing until after 16 weeks a large proportion (74.2%) of the finishing pigs were seropositive, making the AHS-ELISA the most sensitive test. In the AHS-ELISA one As-immunised pig remained seronegative, but the other hyper-immunised pigs crossreacted. In the Sarcoptest, only Dp-immunised pigs had elevated Optical Densities (OD's) albeit below the cut-off level. Although hyper-immunisation is not a representation of field conditions, it cannot be excluded that the AHS-ELISA is not 100% specific.Field samples were taken from 20 sows in 30 herds, classified as mange-free, suspect, or infested. On a herd level there was high agreement among the ELISAs. Both serological tests were suitable to distinguish mange-free herds from infested herds. In one infested herd the decline of maternal antibody in piglets was studied by sampling 40 piglets from 20 different litters. The lowest average OD using the AHS-ELISA was found at 5 weeks of age, followed by a significant increase at 7 weeks. The average OD with the Sarcoptest was at a minimum level at 3 weeks, but no increase was found later. For screening of herds, interference of maternal antibodies is avoided by sampling at an age of 7 weeks or older.     

断奶对仔猪肠道屏障的影响及营养调控

在集约化养殖中,3~4周龄早期断奶是仔猪生命周期中一个非常紧张的时期,此时仔猪胃肠道还未发育成熟。肠道屏障由上皮、免疫和肠神经系统组成,这些系统控制上皮屏障的完整性以及肠道功能,包括肠腔营养物质、水和电解质的运输。早期断奶导致肠道通透性增加,出现胃肠功能紊乱的情况,可能对猪只一生产生长期的影响。因此,仔猪断奶饲粮需要正确水平的营养素、营养源和高质量的添加剂,鼓励仔猪快速进食,减轻或消除断奶应激综合症,降低死亡率和发病率。养猪就是养"肠道",合理使用功能性氨基酸、植物化学物质和有机酸等添加剂,能够修复由于断奶应激综合症导致的肠道屏障功能障碍。     

Chronic metabolic acidosis in dairy cows]

Complex clinical and clinico-biochemical examination of the blood, urine and rumen liquor in a herd of dairy cows revealed chronical metabolic acidosis accompanied by rumen dysfunction and by a reduced butterfat content of milk. During the first examination of the acid-base state of the blood was almost at a standard level. An increased level of urea in blood plasma and a higher GOT transaminase activity testified to an excessive load on the liver. Urine pH was considerably deviated towards the acidic side and inorganic phosphorus was present in urine in a greater concentration. The pH of rumen liquor was slightly shifted towards alkalinity owing to the release of NH3 from urea in the food ration. The diagnosis--suspect chronical metabolic acidosis--was determined on the basis of the first examination. Chronical metabolic acidosis was definitely proved by the second examination when urea had been excluded from the feed ration. Repeated examinations revealed chronical metabolic acidosis which had originally been accompanied by a higher rumen liquor pH. On the basis of case histories and mechanisms of chronical acidosis, measures were proposed, resulting in an increase of the butterfat content of milk. Chronical metabolic disorders often follow a long-lasting latent pattern, manifesting themselves as a reduced milk yield and lower resistance; the clinical form of disease appears only at a later stage. The system of preventive diagnostics provides information on the changes in the composition of internal medium and of the faeces before a drop occurs in milk and fat production. These measures prevent metabolic disorders and high losses of produce which otherwise remain hidden for a long time.     

日粮中添加凝结芽孢杆菌对仔猪血浆抗氧化指标和肠黏膜生长的影响

试验研究了日粮中添加凝结芽孢杆菌对仔猪血浆抗氧化指标和肠黏膜生长的影响。选取30头体重相近的21日龄健康断奶仔猪随机分为3组(对照组、试验Ⅰ组和试验Ⅱ组),每组10个重复,每个重复1头猪。对照组饲喂基础日粮,试验Ⅰ、Ⅱ组在基础日粮的基础上分别添加2.0×10~6、2.0×10~7 CFU/g的凝结芽孢杆菌。正试期21 d,试验结束时前腔静脉采血后屠宰取样。结果显示:与对照组相比,试验Ⅰ和Ⅱ组断奶仔猪血浆超氧化物歧化酶(SOD)活性、空肠和回肠绒毛高度与隐窝深度的比值、回肠总蛋白(TP)含量及RNA与DNA的比值均显著提高(P<0.05);试验Ⅱ组仔猪血浆丙二醛(MDA)含量显著降低(P<0.05);试验Ⅰ组空肠TP含量及TP/DNA显著提高(P<0.05)。在本试验条件下,日粮中添加凝结芽孢杆菌可以提高断奶仔猪的抗氧化能力,促进仔猪肠道黏膜细胞的增殖与更新,从而改善了肠道黏膜形态结构。     

Risk Assessment of Antibiotic Marker Gene neo Drifts in Transgenic Pigs

This study was designed to study the possibility of gene drift of the antibiotic marker gene neo in transgenic pigs.First,dominance and recessiveness of neo gene in 6 piglets of F1 were identified using Southern blotting.It was found that 3 piglets were positive transgenic piglets and the other 3 piglets were non-transgenic piglets.The neo gene in blood and digestive tract tissue of experimental piglets were detected using PCR.The result showed that no gene drift was showed in blood and digestive tract tissues of experimental piglets.Then PCR technology was used to detect neo gene in intestinal bacteria of experimental piglets.The result showed that neo gene did not exist in the genome of intestinal bacteria.This study suggested that no gene drift was found in blood,intestinal bacteria and digestive tract tissues of piglets.     

转基因猪中抗生素标记基因neo漂移风险评估

本试验旨在研究转基因猪中抗生素标记基因neo漂移的可能性。利用Southern blotting鉴定F1代仔猪的显隐性,结果发现6头仔猪中有3头为转基因仔猪,3头为阴性仔猪。通过PCR技术对试验仔猪血液和消化道组织中neo基因进行检测,结果发现neo基因没有在血液水平和消化道组织中发生漂移。通过PCR技术对试验仔猪肠道细菌中neo基因进行检测,在肠道细菌基因组中没有检测到neo基因的存在。检测结果表明,仔猪血液、肠道细菌和消化道组织等都没有发生neo基因的漂移。     

Ruminant Nutrition Symposium: Productivity, digestion, and health responses to hindgut acidosis in ruminants

Microbial fermentation of carbohydrates in the hindgut of dairy cattle is responsible for 5 to 10% of total-tract carbohydrate digestion. When dietary, animal, or environmental factors contribute to abnormal, excessive flow of fermentable carbohydrates from the small intestine, hindgut acidosis can occur. Hindgut acidosis is characterized by increased rates of production of short-chain fatty acids including lactic acid, decreased digesta pH, and damage to gut epithelium as evidenced by the appearance of mucin casts in feces. Hindgut acidosis is more likely to occur in high-producing animals fed diets with relatively greater proportions of grains and lesser proportions of forage. In these animals, ruminal acidosis and poor selective retention of fermentable carbohydrates by the rumen will increase carbohydrate flow to the hindgut. In more severe situations, hindgut acidosis is characterized by an inflammatory response; the resulting breach of the barrier between animal and digesta may contribute to laminitis and other disorders. In a research setting, effects of increased hindgut fermentation have been evaluated using pulse-dose or continuous abomasal infusions of varying amounts of fermentable carbohydrates. Continuous small-dose abomasal infusions of 1 kg/d of pectin or fructans into lactating cows resulted in decreased diet digestibility and decreased milk fat percentage without affecting fecal pH or VFA concentrations. The decreased diet digestibility likely resulted from increased bulk in the digestive tract or from increased digesta passage rate, reducing exposure of the digesta to intestinal enzymes and epithelial absorptive surfaces. The same mechanism is proposed to explain the decreased milk fat percentage because only milk concentrations of long-chain fatty acids were decreased. Pulse-dose abomasal fructan infusions (1 g/kg of BW) into steers resulted in watery feces, decreased fecal pH, and increased fecal VFA concentrations, without causing an inflammatory response. Daily 12-h abomasal infusions of a large dose of starch (~4 kg/d) have also induced hindgut acidosis as indicated by decreased fecal pH and watery feces. On the farm, watery or foamy feces or presence of mucin casts in feces may indicate hindgut acidosis. In summary, hindgut acidosis occurs because of relatively high rates of large intestinal fermentation, likely due to digestive dysfunction in other parts of the gut. A better understanding of the relationship of this disorder to other animal health disorders is needed.     

幼龄仔猪PEDV感染肠道损伤模型的建立

试验旨在建立猪流行性腹泻病毒（PEDV）感染幼龄仔猪肠道损伤模型。试验选用16头7日龄健康幼龄仔猪（杜×长×大）,随机分为两个处理组：对照组和PEDV组,每个处理8个重复,每个重复1头猪。试验期为10 d,试验期间两个处理组饲喂相同的基础日粮。于试验第7天晚上对PEDV组仔猪口腔灌服PEDV病毒（剂量为10^4.5 TCID₅₀）,对照组灌服等量的生理盐水。于试验第10天早上空腹灌服D-木糖（0.1 g/kg体重）,1 h后前腔静脉采血,屠宰取样,取十二指肠、空肠、回肠等组织样品,测定平均日增重（ADG）、腹泻率（DR）、肠道形态结构、肠道黏膜损伤相关基因mRNA水平。试验结果表明：①PEDV感染显著降低了仔猪ADG（P<0.05）,极显著提高了仔猪腹泻率（P<0.01）;②PEDV感染极显著降低了血浆D-木糖含量、空肠和回肠绒毛高度、十二指肠、空肠和回肠绒毛高度与隐窝深度的比值（P<0.01）,显著提高了十二指肠和空肠隐窝深度（P<0.05）;③PEDV感染极显著提高了仔猪空肠黏膜PEDV M基因的相对表达量（P<0.01）,极显著降低了肠绒毛蛋白（villin）和肠型脂肪酸结合蛋白（i-FABP）基因的相对表达量（P<0.01）。以上结果表明,口腔灌服PEDV可以成功诱导建立幼龄仔猪肠道损伤模型。     

早期断奶对仔猪肠通透性和肠上皮紧密连接蛋白Occludin mRNA 表达的影响

本文旨在研究早期断奶仔猪的肠通透性变化并探讨其机制.试验采用32头21日龄断奶仔猪,并于仔猪21、28和35日龄取样测定血浆D-乳酸含量、二胺氧化酶(DAO)活性和尿中乳果糖/甘露醇比率观察肠通透性改变,同时检测肠上皮紧密连接蛋白Occludin mRNA表达水平.结果显示:与断奶前相比,28日龄时血浆D-乳酸含量、DAO活性和乳果糖/甘露醇比差异达到显著水平(P<0.05),且至35日龄时,肠道仍然维持这种较高的通透性;仔猪断奶后Occludin mRNA相对表达量下降明显,与断奶前相比差异显著(P<0.05),35日龄时,表达量有所恢复,但仍然低于断奶前表达水平.试验结果提示,早期断奶后仔猪肠道的通透性增加,肠屏障功能破坏,可能归因于肠上皮细胞紧密连接蛋白Occludin mRNA表达下降.     

D-Lactic acidosis in calves

Metabolic acidosis has long been known as a frequent and potentially severe complication of neonatal calf diarrhoea. It has also been described in 'acidosis-without-dehydration' syndrome in calves and was suspected to occur during ruminal drinking. Clinical signs of central nervous impairment, particularly changes in behaviour and posture, progressing to coma and recumbency, were originally attributed to this metabolic disturbance. The loss of bicarbonate in the faeces was regarded as the main cause of acidosis in this context. During the past decade, however, evidence has accumulated that d-lactic acidosis is a more common occurrence in calves with neonatal diarrhoea. The most probable source of D-lactataemia is bacterial fermentation of undigested substrate that reaches the large intestine due to damage to small intestinal mucosal epithelium. Recent research has shown that most of the clinical signs that were formerly attributed to acidosis were in fact due to elevated blood levels of D-lactate. The aim of this review is to provide a current overview of d-lactic acidosis.     

Immunization with a Streptococcus bovis vaccine administered by different routes against lactic acidosis in sheep

Streptococcus bovis is an important lactic acid bacterium in the rumen, which contributes to the development of lactic acidosis. This study was designed to test the efficacy of immunization with S. bovis primed either intramuscularly (i.m.) or intraperitoneally (i.p. ) against lactic acidosis. Forty-five wethers were allocated to three treatment groups. Two groups were injected with a S. bovis vaccine by either the i.m. or i.p. route for primary immunization; both groups were further immunized by the same route(s) (oral and/or i.m.) for boosters. The third group was not immunized (control). Antibody concentrations were measured in saliva prior to and following animals being fed a grain diet, and also in the rumen fluid, before the animals were suddenly introduced to a grain diet. The average antibody concentration in the animals of the i.m. group was higher than the i.p. group (P< 0.05). The antibody concentration in the rumen fluid of immunized sheep was higher than the control animals (P< 0.01). The difference in the rumen fluid antibody concentration between the i.m. and i.p. groups was not statistically significant (P> 0.05). In the i.m. group, there was a significantly greater feed intake, higher rumen pH, lower diarrhoea scores, and less increase in blood packed cell volume following grain feeding than in the animals of the control group. The severity of diarrhoea and the increase of blood packed cell volume in the animals of the i. p. group were also less than in the animals of the control group. The results suggest that the risk of lactic acidosis can be reduced by immunization against S. bovis, and that the immunization primed i. m. is more effective than the immunization primed i.p.     

N-乙酰半胱氨酸灌胃对超早期断奶仔猪血浆中游离氨基酸及小肠形态结构与功能的影响

本试验旨在研究N-乙酰半胱氨酸(N-acetylcysteine,NAC)灌胃对超早期断奶仔猪血浆中游离氨基酸、小肠形态结构及功能的影响。将22头体重为(2.99±0.41)kg的7日龄断奶仔猪随机分为对照组和NAC组,每组11个重复,每个重复1头猪。在饲喂人工乳的基础上,NAC组每天每头按50 mg/kg体重进行NAC灌胃,对照组每天每头进行同体积的生理盐水灌胃。于试验第11天按0.1 g/kg体重的剂量给仔猪灌服D-木糖溶液,1 h后前腔静脉采血,然后屠宰取小肠组织样,刮取肠黏膜及制作组织切片。结果表明:与对照组相比,NAC组显著提高了超早期断奶仔猪平均日增重(P0.05);提高了超早期断奶仔猪血浆中谷氨酰胺、胱氨酸、γ-氨基丁酸水平(P0.05),降低了血浆中尿素氮、半胱氨酸、色氨酸水平和二胺氧化酶活力(P0.05);NAC灌胃提高了哺乳仔猪十二指肠黏膜的绒毛高度/隐窝深度(P0.05),有降低十二指肠隐窝深度的趋势(P0.10),有提高空肠绒毛宽度和回肠绒毛高度的趋势(P0.10)。在本试验条件下,NAC灌胃可改善小肠形态结构与屏障功能,提高氨基酸的利用率,调节血浆中部分氨基酸的含量。