"龙桑1号"不同部位中1-脱氧野尻霉素含量测定研究

采用高效液相色谱法测定"龙桑1号"不同部位中1-脱氧野尻霉素的含量。结果:不同部位中DNJ含量差异很大,其中桑根皮中含量最高,为0.624%;秋采桑叶中含量最低,为0.074%。     

Macrocyclic lactone toxicity due to abamectin in farm dogs without the ABCB1 gene mutation

Abstract

CASE HISTORY: A 5-year-old entire female Huntaway from a sheep and beef farm was one of four dogs that developed clinical signs including hypersalivation, depression, blindness and ataxia after the death of another dog. A 4-year-old female Huntaway farm dog from a second farm was observed to be sitting down more often than usual on the day after being fed part of a calf carcass that had been treated with an abamectin pour-on.

CLINICAL FINDINGS: The first dog was ataxic and depressed but did respond to sound. The second dog presented with an acute onset of blindness, mydriasis, absence of a menace response, hypersalivation, gait abnormalities (e.g. high stepping gait and ataxia), and depression. Other presenting signs included muscle tremors, dehydration and difficulty eating. No abnormalities were detected from routine haematology and biochemistry. Analysis of samples of plasma from both dogs revealed concentrations of abamectin of 0.149 mg/L and 0.260 mg/L for the first and second dogs, respectively. Buccal swabs taken from the first dog for DNA testing for the ABCB1 gene mutation, gave a negative result.

DIAGNOSIS: In addition to the presenting signs which suggested a toxicosis, both dogs had measurable concentrations of abamectin in plasma confirming exposure.

CLINICAL RELEVANCE: Farm dogs exposed to concentrated pour-on products containing abamectin have been poisoned and recover or die. The product labels do not carry any warnings as to the risk of poisoning to dogs. This paper discusses two incidents affecting six farm dogs, but the authors are aware of more toxicoses in farm dogs exposed to abamectin.     

Inductive expression of the NOD1 signalling pathway in chickens infected with Salmonella pullorum

1. The aim of this study was to describe the role of Nucleotide-binding oligomerization domain-containing protein 1 (NOD1) receptor signalling in chicken.

2. Tissue-specific expression analysis of NOD1, receptor-interacting serine-threonine kinase 2 (RIPK2), nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase 11 (MAPK11 or p38) by quantitative real-time PCR (qRT-PCR) revealed their wide distribution in various organs and tissues.

3. Salmonella pullorum infection activated NOD1 receptor signalling in vivo and in vitro, resulting in significant induction of downstream signalling molecules RIPK2, NF-κB/p65, MAPK11/p38 and the effector molecules IL-1b and IL-8.

4. Activation of NOD1 by its agonist bacterial γ-D-glutamyl-meso-diaminopimelic acid (iE-DAP) in HD11 cells induced the adapter molecular RIPK2 and activated the NF-κB/p65 and MAPK11/p38 pathways, resulting in an increase in IL-8 but not IL-1β. Additionally, inhibition of NOD1 using NOD1-shRNA resulted in downregulation of RIPK2, MAPK11 and IL-8, while NF-κB/p65 and IL-1β were unaltered.

5. These results highlight the important role of NOD1 receptors in eliciting the innate immune response following pathogenic invasion in chicken.     

不同日龄仔猪骨髓组织抗菌肽Protegrin-1mRNA的表达

分别于出生当天、3、14、23和28日龄随机屠宰杜×长×大三元杂交公猪4头，采集股骨骨髓组织。用一优化的RT—PCR方法，以18S rRNA作内标，定量分析不同日龄仔猪骨髓组织抗菌肽Protegrin-1（PG-1）mRNA表达的差异。结果表明，不同日龄仔猪骨髓组织PG-1mRNA相对丰度有明显的差异。出生时最低，随着日龄的增加，其表达显著增加。     

6种植密度对玉草1号产量与品质的影响

研究了种植密度对玉草1号产量、品质及植株性状的影响。结果表明,45 000与52 500株/hm2 2种密度的总鲜草产量差异不显著（分别为128 944和133 167 kg/hm2）,但二者均显著的高于密度为37 500株/hm2的总鲜草产量（117 370 kg/hm2）;但这3种密度处理的总干草产量差异不显著。分析这3种密度间各品质指标、植株性状指标总体表现,结果密度为37 500株/hm2的粗蛋白（CP）含量、CP产量、相对饲用价值（RFV）、分蘖数、总茎粗、干物率均为最高,密度为45 000株/hm2次之,处理52 500株/hm2最低;中性洗涤纤维（NDF）含量密度为37 500株/hm2最低,52 500株/hm2最高。综合产量与饲用品质比较研究表明,玉草1号种植密度为45 000株/hm2左右在我国南方最适宜。     

应用反转录聚合酶链式反应检测鸡Th1样淋巴因子mRNA表？…

应用反转录聚合酶链式反应（ＲＴ－ＰＣＲ）和限制性酶切分析技术对鸡脾细胞体外受到有丝分裂原ＣonＡ刺激的情况下,其Ｔh1样淋巴因子mＲＮＡ的表达水平进行了研究。实验结 果表明,ＣonＡ诱导培养３个小时的鸡脾细胞表达α－干扰素（ＣhＩＦＮ－α）、γ－干扰素（ＣhＩＦＮ－γ）和白细胞介素－２（ＣhＩＬ－２）等鸡的Ｔh1样淋巴因子mＲＮＡ 。未诱导但培养了３小时的鸡脾细胞可表达ＣhＩＦＮ－α和ＣhＩＦＮ－γmＲＮＡ,而未     

小肽的吸收与转运及其营养作用

随着动物营养学研究的发展,蛋白质营养的研究也在逐步深入,由原来的粗蛋白营养发展到氨基酸营养,进一步发展到现在的小肽营养。本文就小肽的吸收、转运、营养及其在动物生产中的应用,以及目前小肽研究领域中存在的问题等方面进行阐述。     

H5N1亚型禽流感病毒A/Guangxi/1/2005株抗药机制的研究

为研究H5N1亚型禽流感病毒(AIV)的抗药机制,本研究选取Clade2.3.4亚群中一株对金刚烷胺敏感的人源AIV A/Guangxi/1/2005(H5N1)(S-GX05),用抗流感病毒药物金刚烷胺对其进行定向诱导,筛选出一株抗药性病毒株,命名为R-A/Guangxi/1/2005(R-GX05)。通过全基因测序并与S-GX05全基因序列进行对比,结果显示S-GX05只在其M2蛋白中有一个氨基酸位点发生突变,即A30P;抗药性鉴定这两株病毒的半数药物抑制浓度(IC50)分别为0.9μM和48.9μM,表明R-GX05对金刚烷胺表现出一定程度的抗性。动物实验证实,这两株病毒对BALB/c小鼠的致病性基本一致,均表现出高致病性,其MLD50分别为4.7 log10 EID50和5.0 log10 EID50,两株病毒在小鼠体内各组织脏器中的分布及增殖能力也基本相同。这些结果表明,S-GX05在药物压力下产生抗药性后,并未引起其它生物学特性的改变。A30P的发现为进一步从分子水平上研究H5N1亚型AIV的抗药机制及新型抗流感新药的研发奠定了基础。     

Changes in growth performance, digestive enzyme activities and nutrient digestibility of cherry valley ducks in response to aflatoxin B1 levels

The objective of this study was to investigate toxic effects of aflatoxin B1(AFB₁) on growth performance, organs, hepatic enzyme activities, apparent digestibility of nutrients and digestive enzyme activities in ducks. Ninety 1-day-old Cherry Valley commercial ducks were designed to three treatment groups with three replicates of ten birds each. Group I (control) was fed conventional feed free of AFB₁, group II or III was fed the diets containing 20 μg/kg or 40 μg/kg AFB₁-contaminated rice respectively. The feeding trial lasted 6 weeks. The results were that decreased body weight gain and feed intake, increased feed to gain ratio and selected organ weights (liver, kidney and pancreas) were observed in AFB₁-treated groups. The activities of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly increased in AFB₁-contamined groups. The apparent digestibility of crude protein (CP) was significantly lower while activities of digestive enzyme from duodenum contents including protease, chymotrypsin, trypsin and amylase were increased in AFB₁-treated group. These results indicated that AFB₁ of feed could decrease growth performance and apparent digestibility of nutrients, change digestive enzyme activities of duodenum contents in duck.     

Repeat tuberculin skin testing leads to desensitisation in naturally infected tuberculous cattle which is associated with elevated interleukin-10 and decreased interleukin-1 beta responses

The principal surveillance tool used to control bovine tuberculosis in cattle is the removal of animals that provide a positive response to the tuberculin skin-test. In this study we performed a longitudinal investigation of the immunological and diagnostic consequences of repeated short-interval skin-tests in cattle naturally infected with Mycobacterium bovis. Tuberculin skin-test positive cattle were subjected to up to four further intradermal comparative cervical skin-tests at approximately 60-day intervals. A significant progressive reduction in the strength of the skin-test was observed after successive tests. In contrast, the magnitude of interferon-γ (IFN-γ) responses was not influenced by repeat skin-testing either transiently around the time of each skin-test or longitudinally following repeated tests. A significant boost in blood interleukin-10 (IL-10) production was observed within 3 days following each skin-test although the magnitude of this boosted response returned to lower levels by day 10 post-test. The application of a novel multiplex assay to simultaneously measure seven cytokines and chemokines also identified that skin-testing resulted in a significant and progressive reduction in antigen specific interleukin-1β (IL-1β) whilst confirming stable IFN-γ and elevated IL-10 responses in the blood. Therefore, we have demonstrated that in cattle naturally infected with M. bovis, repeat short-interval skin-testing can lead to a progressive reduction in skin-test responsiveness which has potential negative consequences for the detection of infected animals with marginal or inconclusive skin-test responses. The desensitising effect is associated with decreased IL-1β and elevated IL-10 responses, but importantly, does not influence antigen specific IFN-γ responses.