白羽瘤头鸭不同生长阶段的甲状腺活动

本文报道了用放射免疫分析法测定５７例不同日龄的白羽瘤头鸭（Ｃａｉｒｉｎａｍｏｓｈａｔａ）外用血清中Ｔ４的含量和用组织学方法检查甲状腺滤泡的发育作为甲状腺活动的指标，研究不同日龄的生长速度与甲状腺活动的关系。５７例白羽瘤头鸭的血清Ｔ４含量平均为１．３６±０．３７μｇ／１００ｍｌ，其中１—４０日龄甲状腺的分泌活动除２０日龄外，其他的均随着日龄增长而升高，分泌的高峰出现在４０日龄，以后随日龄增长而下降。４０日龄组血清Ｔ４的含量与１、１０、２０、６０、和９０日龄组比较，差异极显著（Ｐ＜０．０１），血清Ｔ４的波动与相对生长率之间有统计学强的正相关，差异极显著（Ｐ＜０．０１）。组织切片检查，刚出壳的雏鸭甲状腺滤泡小。１０—４０日龄甲状腺滤泡随日龄的增长而增大，滤泡腔被甲状腺球蛋白所组成的蛋白质凝胶的均质液所充满、着色深而均匀。６０—９０日龄鸭甲状腺滤泡虽然增大，但其内部凝胶的均质液充满不完全或空虚，着色浅而不均匀。各日龄组甲状腺滤泡的变化和甲状腺分泌的含量变化与Ｔ４的波动相一致。     

Evaluating processing temperature and feeding value of extruded-expelled soybean meal on nursery and finishing pig growth performance

We conducted two experiments comparing the use of extruded-expelled soybean meal (EESoy) to solvent-extracted soybean meal (SBM) in swine diets. In Exp. 1, the objective was to determine the optimal processing temperature of EESoy for nursery pig growth performance. Pigs (n = 330, 13.2 +/- 2.3 kg of BW) were fed a control diet containing SBM with added fat or one of five diets containing EESoy extruded at 143.3, 148.9, 154.4, 160.0, or 165.6 degrees C. All diets were formulated on an equal apparent digestible lysine:ME ratio. From d 0 to 20, no differences were observed (P > 0.32) in ADG or ADFI (average of 544 and 924 g/d, respectively). However, gain:feed ratio (G/F) improved (quadratic, P < 0.01, range of 0.56 to 0.60) with increasing processing temperature, with the greatest improvement at 148.9 degrees C. In Exp. 2, the objective was to determine the feeding value of EESoy relative to SBM with or without added fat for growing-finishing pigs in a commercial production facility. A total of 1,200 gilts (initially 24.5 +/- 5.1 kg of BW) was used, with 25 pigs per pen and eight replications per treatment. Dietary treatments were arranged in a 2 x 3 factorial, with two sources of soybean meal (SBM or EESoy) and three levels of added fat. Pigs were phase-fed four diets over the experimental period and added fat (choice white grease) levels were 0, 3.4, and 7% initially, with the added fat levels decreasing in the next three dietary phases. Energy levels were based such that the higher energy in EESoy (with or without added fat) was calculated to be equal to that provided by SBM with added fat. From 24.5 to 61.2 kg, pigs fed EESoy had greater (P < 0.07) G/F than those fed SBM. Increasing added fat in either EESoy- or SBM-based diets increased G/F (linear, P < 0.0003). From 61.2 to 122.5 kg, ADG and G/F were unaffected in pigs fed EESoy and/or increasing added fat (P > 0.10). For the overall growing-finishing period, ADG was unaffected (P > 0.61) by increasing energy density of the diet; however, ADFI decreased (P < 0.05) and G/F increased (P < 0.02, range of 0.37 to 0.40) as energy density increased with either EESoy or added fat. Carcass leanness was not affected by dietary treatment. These results indicate that EESoy should be extruded at 148.9 to 154.4 degrees C, and that increasing dietary energy density by using EESoy and/or added fat improves feed efficiency in finishing pigs reared in a commercial environment.     

Influences of diet and vaccination on colonisation of pigs by the intestinal spirochaete Brachyspira (Serpulina) pilosicoli

The purpose of this study was to determine whether methods used to control swine dysentery (SD), caused by the intestinal spirochaete Brachyspira (Serpulina) hyodysenteriae, would also be effective in controlling porcine intestinal spirochaetosis (PIS) caused by the related spirochaete Brachyspira (Serpulina) pilosicoli. Weaner pigs in Groups I (n=8) and II (n=6) received a standard weaner pig diet based on wheat and lupins, whilst Group III (n=6) received an experimental diet based on cooked white rice and animal protein. Pigs in Group II were vaccinated intramuscularly twice at a 3-week-interval with a formalinised bacterin made from B. pilosicoli porcine strain 95/1000 resuspended in Freund's incomplete adjuvant. Eleven days later pigs in all groups were infected orally with 10(10) cells of strain 95/1000 on three successive days. One control pig in Group I developed acute diarrhoea, and at post-mortem had a severe erosive colitis with end-on attachment of spirochaetes to the colonic epithelium. All other pigs developed transient mild diarrhoea and had moderate patchy colitis at post-mortem 3 weeks later. B. pilosicoli was isolated from the faeces of all pigs, except for one fed rice, and was isolated from the mesenteric nodes of three pigs from Group I and from one vaccinated pig in Group II. Consumption of the rice-based diet, but not vaccination, delayed and significantly (p<0.001) reduced the onset of faecal excretion of B. pilosicoli after experimental challenge. Vaccination induced a primary and secondary serological response to B. pilosicoli, as measured using sonicated whole cells of strain 95/1000 as an ELISA plate coating antigen. Antibody titres in the vaccinated pigs then declined, despite intestinal colonisation by B. pilosicoli. Both groups of unvaccinated animals also failed to develop a post-infection increase in circulating antibody titres.     

混合瘤胃微生物体外利用蛋氨酸、赖氨酸的研究

为研究瘤胃微生物对瘤胃液中添加的蛋氨酸、赖氨酸的利用情况，并进一步探讨添加氨基酸对瘤胃液中尿素氮、部分酶活的影响，将采集到的来自3头装有永久性瘤胃瘘管的成年萨能山羊的瘤胃液混合后，平均分装成18个瓶，随机分成3个处理组，每组6个重复。采用6重复随机因子试验设计。第1组中每瓶添加蛋氨酸2mM（0．25mol／L．Met溶液8mL），第2组中每瓶添加赖氨酸2mM（0．25mol／L Lys溶液8mL），第3组中每瓶加等体积蒸馏水作为空白对照组，体外培养16h。结果表明：添加氨基酸后，混合瘤胃液中的尿素氮（UN）含量显著高于对照组（P〈0．05）；谷氨酸脱氢酶（GLDH）活性随着体外培养时间的延长而迅速增加，并且添加蛋氨酸组的GLDH的活性明显高于其他两组（P〈0．01），而添加赖氨酸组的GLDH活性则极显著低于蛋氨酸组和对照组（P〈0．01）；添加的氨基酸和体外培养时间对于谷丙转氨酶（GPT）活性没有显著的影响（P〉0．05）；添加氨基酸组的谷草转氨酶（GOT）的活性显著低于对照组（P〈0．05），但体外培养时间对各组中GOT的活性没有显著的影响。说明体外培养过程中瘤胃微生物分解赖氨酸的速率要比蛋氨酸快；添加的氨基酸使UN增加，但对GOT、GPT的活性起抑制作用；添加蛋氨酸可增加GLDH活性，但添加赖氨酸却有抑制作用。     

山羊瘤胃给饲蛋氨酸和拉沙里菌素对血液指标的影响

采用3只装有永久性瘤胃瘘管的萨能母山羊为试验动物．试验分为4期，每期6d。每期为一个处理。对照组：基础日粮；处理Ⅰ：基础日粮＋15g蛋氨酸；处理Ⅱ：基础日粮＋15g蛋氨酸＋0．15g拉沙里菌素；处理Ⅱ：基础日粮＋15g蛋氨酸＋0．20g拉沙里菌素。每期的最后一天为血样的采样日，采样日的采样时间点为3个，即当日早晨饲喂前（0h）、饲喂后2h和5h。血样经处理后．测定样本中血浆游离蛋氨酸（PFM）的含量和有关酶的活性。试验结果表明：不同处理之间，在0h处理Ⅲ的谷氨酸脱氢酶（GLDH）、γ-谷氨酰转移酶（GGT）活性显著高于对照组（P＜0．05），谷草转氨酶（GOT）极显著低于对照组（P＜0．01），谷丙转氨酶（GPT）活性极显著高于对照组（P〈0．01），处理ⅡGOT活性极显著低于对照组和处理Ⅰ（P〈0．01）；在2h处理ⅡGGT活性显著低于处理Ⅱ（P＜0．05），极显著低于处理Ⅰ（P〈0．01），处理ⅢGPT活性显著高于处理Ⅱ（P〈0．05），极显著高于对照组和处理Ⅰ（P＜0．01）；在5h处理IGGT活性显著高于处理Ⅱ（P＜0．05），处理ⅢGPT活性极显著高于对照组（P〈0．01），处理Ⅰ的PFM水平在0、2、5h均极显著高于对照组、处理Ⅱ和处理Ⅱ（P〈0．01）；不同处理内，处理Ⅰ的0hGGT活性显著低于2、5h（P〈0．05）。5h的PFM水平显著高于0、2h（P〈0．05），处理Ⅲ的5hGGT活性低于0h（P〈0．05）。     

Validation of RT‐PCR Assays for Molecular Characterization of Porcine Teschoviruses and Enteroviruses

Porcine enteroviruses (PEVs) and teschoviruses (PTVs) are described as causative agents of neurological disorders, fertility disorders and dermal lesions of swine. Difficulties in the serological detection of these viruses may lead to a significant underestimation of infections with clinical symptoms. With the recent availability of genome sequence data for all the serotypes, molecular diagnosis is a possibility. The present study describes a new approach to molecular ‘serotyping’ of PTVs and PEV‐B viruses, involving the amplification and sequencing of a genomic fragment of the VP1 coding region. A molecular characterization of Italian entero‐teschovirus isolates was performed using a set of previously published and newly designed polymerase chain reaction primers. A total of 33 porcine isolates and 10 reference strains were analysed. Porcine enterovirus‐B samples were first diagnosed as positive for enterovirus by amplification of the 5′‐non‐translated region. Samples were then typed by amplification and sequencing of a portion of the VP1 coding region. Porcine enterovirus‐A and PTVs were detected by a published assay in the 5′‐NC region that allows them to be differentiated according to the size of amplification product, using the same set of primers. For serotype characterization of PTV, we evaluated four different regions: the N terminus of the capsid protein VP2, the region encoding for RNA‐dependent RNA polymerase, and the capsid VP1 and VP4 regions. The newly designed primers in the VP1 region was proved to be broad in range and suitable for serotype assessment and therefore constitute a useful diagnostic tool for molecular diagnosis of porcine teschovirus/enterovirus strains and for the study of molecular epidemiology and evolution of these viruses.     

Identification and evaluation of chloroplast uni- and trinucleotide sequence repeats in citrus

A cpDNA fragment of 34 genotypes belonging to Citrus and four related genera was amplified and sequenced. Chloroplast microsatellites were revealed with the length of repeats ranging from 25 to 44 bases. Other than the normal uninucleotide poly(A) repeats, a trinucleotide poly(TAA) motif was also found, the first report of such repeats in a plant chloroplast genome. According to SSR structure variations, 18 Chloroplast SSR Types (CST) were identified. The CST sequences were informative for better understanding the genetic relationships of chloroplast genomes among the analyzed genotypes and confirmed some previous hypotheses about the female parent of several hybrid accessions.     

Serine protease HtrA2/Omi and cell death or survival

The serine protease HtrA2/Omi is released from the mitochondrial intermembrane space following apoptotic stimuli.Once in the cytosol,HtrA2/Omi has been implicated in promoting cell death in caspase-dependent or caspase-independent pathway.On the other hand,HtrA2/Omi can refold and degrade misfolded proteins in the mitochondria during cell stress.