Application of crude and recombinant ELISAs and immunochromatographic test for serodiagnosis of animal trypanosomosis in the Umkhanyakude district of KwaZulu-Natal province,South Africa

A total of 231 serum samples were collected from sheep (n=9), goats (n=99) and cattle (n=123) in northeastern KwaZulu-Natal, South Africa. Trypanosome infection was detected using Trypanosoma brucei brucei crude antigen (TbbCA) and T. congolense crude antigen (TcoCA) ELISA assays. Recombinant antigen (T. evansi GM6 which consisted of 4 repeat domains, TeGM6-4r) ELISA and immunochromatographic test (ICT) were also used. Crude antigen ELISA, TeGM6-4r-ELISA and ICT detected 27.3%, 29% and 19.9% of trypanosome seropositive samples, respectively. Trypanosome infection prevalence in cattle and goats was 35.8–46.3% and 0–9.1%, respectively. Out of 9 sheep serum samples, 2–4 sera (22.2–44.4%) were positive. The detection performance of crude and recombinant antigen ELISAs was relatively similar (K=0.6–0.7); both are recommended for reference diagnosis and large scale epidemiological surveys. There is potential application for ICT in on-site diagnosis, but its sensitivity should be improved.     

Risk profile of low pathogenicity avian influenza virus infections in farms in southern Vietnam

The impact of low pathogenicity avian influenza (LPAI) has been confirmed mainly in farms. Unlike apparent losses caused by the high pathogenicity avian influenza (HPAI), the LPAI impact has been hardly evaluated due to underestimating its spread and damage. In 2019, a questionnaire study was conducted in southern Vietnam to identify the specific risk factors of LPAI virus (LPAIV) circulation and to find associations between husbandry activities and LPAI prevalence. A multilevel regression analysis indicated that keeping Muscovy ducks during farming contributed to LPAIV positivity [Odds ratio=208.2 (95% confidence interval: 13.4–1.1 × 10⁴)]. In cluster analysis, farmers willing to report avian influenza (AI) events and who agreed with the local AI control policy had a slightly lower risk for LPAIV infection although there was no significance in the correlation between farmer characteristics and LPAI occurrence. These findings indicated that keeping Muscovy ducks without appropriate countermeasures might increase the risk of LPAIV infection. Furthermore, specific control measures at the local level are effective for LPAIV circulation, and the improvement of knowledge about biosecurity and attitude contributes to reducing LPAI damage.     

Application of a real-time PCR assay for the detection of Ascaris suum DNA in the liver of experimentally infected chickens

This study aimed to evaluate the sampling method for the detection of Ascaris suum larval DNA in chicken livers using real-time PCR. Chickens were inoculated with A. suum eggs of a single dose (Group A) or repeatedly low doses (Group B). White spots (WSs) were continuously observed on liver from day 3 after the last infection in Group B and day 14 in Group A. In Group A, larval DNA was detected in WS lesions (78.6%) at a significantly higher rate than in the remaining tissue samples (31.3%). In conclusion, applying WS lesions to the assay improved the detection rate of A. suum DNA in chicken livers, especially in the case of a single infection.     

Migration of phosphate into aggregated particles of ferrihydrite

The slow reaction of phosphate with aggregated particles of ferrihydrite, after initial rapid phosphate sorption, was investigated by measuring the changes, with time and temperature, in the amount of phosphate sorbed, and the extractability of the sorbed phosphate. The ferrihydrite was, subsequently, recovered and examined by infra–red spectrometry (IR) and electron probe micro–analysis.
Phosphate continued to react with ferrihydrite for at least 90 d at 25°C, but was completely recovered by extraction with 0.1 m NaOH. The IR spectra of sorbed phosphate was insensitive to the temperature and duration of the reaction. Electron probe micro–analysis of the aggregates showed that phosphate migrated to surface sorption sites within the aggregated particles of ferrihydrite.
There was no evidence for the formation of surface coatings of ferric phosphate, for changes in the type of bonding, or for penetration of phosphate into the crystal lattice. The slow reaction was attributed to the migration of phosphate to surface sorption sites of decreasing accessibility within aggregates.     

一个水稻温敏黄化突变体的表型分析和基因定位

对水稻叶色进行表型分析与基因定位,可为图位克隆该类基因和研究水稻光合系统功能奠定基础。利用甲基磺酸乙酯(ethyl methanesulfonate,EMS)诱变的方法,从籼稻品种"南京11"(简称NJ11)中获得温敏黄化突变体dy1;与野生型相比,dy1在自然环境下,从苗期至成熟期始终表现叶片黄化,透射电镜显示dy1类囊体结构异常;同时株高、分蘖数、结实率等农艺性状也表现出极显著的差异;实验室光照培养箱条件下,dy1苗期在20℃下表现白化,在25℃表现黄化,在30℃下为浅绿的表型;遗传分析表明水稻温敏黄化突变体dy1的表型是由1对隐性基因控制;将突变体与粳稻广亲和品"02428"杂交,构建F2群体,从中选出隐性极端个体,通过基因定位,将控制黄化的基因限定在第1染色体长臂上标记Y-4和Y-35之间的115 kb的区间内,含有16个开放阅读框(ORF),测序发现,dy1中编码尿嘧啶核苷酸激酶的基因LOC_Os01g73450的第4个内含子与第5个外显子交界处存在单碱基替换,拟作为候选基因;且叶绿体合成相关基因表达量显著降低,猜测该基因可能参与了叶绿素合成途径。     

马脑震荡的诊断与治疗

脑震荡及脑挫伤,是由于钝性暴力物作用于颅骨或头部受大力撞击引起的脑神经全面损伤的一种急性疾病,军马多发。随着社会生产力水平的不断进步,马的功能属性由役用转变为休闲骑乘,现阶段马脑震荡的病例并不多见。本文介绍了一例调教训练操作不慎,撞击引起的马脑震荡的诊断和中西医结合治疗,为该病的预防和治疗提供一定参考。     

Effects on digestibility and growth of juvenile cobia (Rachycentron canadum) fed fish or crab silage protein

The study was conducted in Cam Ranh, Vietnam, in 1000‐L tanks supplied with recirculated and biofiltered saltwater (33‰ and 28.4 °C) to evaluate the potential use of lizard fish (Saurida undosquamis) or blue crab (Portunus pelagicus) acid silage protein for juvenile cobia (23–25 g). Six isoenergetic test moist diets (4915–5125 kcal kg^?1), using either raw fish diet, fish silage diet (FSD), raw crab diet, crab silage diet (CSD), mixed raw fish/raw crab diet or mixed fish/crab silage diet (MSD), as part of the protein sources in the steam‐cooked diets, were fed to satiety to triplicate groups of 20 fish each for a 6‐week growth trial. Y₂O₃ was added as an inert indicator to determine the apparent digestibility coefficients (ADC) for macro nutrients and gross energy. Weight gain (185–286%) and specific daily growth rate (2.5–3.2% per day) were significantly higher in cobia fed the raw‐based diets and FSD than in fish fed CSD and MSD (34–90 and 0.7–1.5% per day). Feed conversion ratios (FCR) were significantly higher in the groups fed CSD and MSD diets (2.1–6.5) than the groups fed the other diets (1.0–1.2), resulting in significantly lower protein productive values (0.1–0.2) in the groups fed CSD and MSD than in the other groups (0.3–0.4). The FCR results were confirmed by significantly lower ADC values in fish fed CSD and MSD than those in fish fed the other diets. We thus conclude that the present raw‐based diets were better utilized by juvenile cobia than silage‐based diets, particularly the diet made from crab silage.     

基于SRAP标记的土沉香遗传多样性分析

【目的】在我国野生土沉香被大量被采伐,种质资源越来越少,甚至面临消失的情况下,为了利用与保护野生土沉香提供理论依据,采用SRAP分子标记对其种源遗传多样性进行分析。【方法】基于我国11个土沉香种源群体和越南2个土沉香种源群体的SRAP结果,应用POPGEN32软件对遗传多样性参数进行计算。【结果】各群体Nei's基因多样度指数的变化范围为0.1715~0.5394,Shannon多样性指数的变化范围为0.2491~0.4837,多态位点百分比的变化范围为42.03%~76.81%。运用GenAlex 6.4软件对土沉香13个群体进行分子方差分析(Analysis of molecular variance,AMOVA),结果显示有30%的遗传变异来自土沉香群体间,70%的遗传变异来自土沉香群体内。【结论】13个土沉香种源有中度的遗传多样性和遗传分化,野生土沉香种质资源正日渐稀少,应该加强资源的保护与利用。