60Co-γ辐照模式下玉米中赤霉烯酮和品质的变化及对绵羊定时人工授精的影响

为研究经赤霉烯酮(ZEN)自然污染与⁶⁰Co-γ辐照处理后的玉米对绵羊定时人工授精中澳洲白种公羊、湖羊母羊的生殖性能的影响,本试验选取含ZEN玉米样本,分别用0、3、5、8、10 kGy剂量的⁶⁰Co-γ辐照,并测定辐照后玉米主要营养成分变化。然后分别将未污染玉米(Ⅰ对照组)、经10 kGy ⁶⁰Co-γ辐照的污染玉米(试验Ⅱ组)、污染玉米(试验Ⅲ组)饲喂定时人工授精的绵羊,检测澳洲白种公羊的精液质量,测定湖羊母羊的繁殖性能指标。结果表明,未经⁶⁰Co-γ辐照的玉米含ZEN 2 153 μg·kg^-1,在10 kGy ⁶⁰Co-γ辐照剂量下,玉米中ZEN降解率为83.7%;当⁶⁰Co-γ辐照剂量低于10 kGy时,玉米淀粉表面结构无变化,主要营养成分无显著变化。试验Ⅱ组澳洲白种公羊的采精量、精子活力、精子密度与试验Ⅲ组相比显著升高(P<0.05),与Ⅰ对照组相比无显著差异(P>0.05);试验Ⅲ组澳洲白种公羊第30天精子畸形率与试验Ⅱ组、Ⅰ对照组相比均显著升高(P<0.05),显微镜下观察可见双尾精子、双头精子、无尾精子等现象,其中双尾精子头部、尾部不完整;试验Ⅱ组湖羊母羊同期发情率、受胎率、产羔率和羔羊始重等指标与试验Ⅲ组相比显著升高(P<0.05),与Ⅰ对照组无显著差异(P>0.05)。综上,使用经10 kGy ⁶⁰Co-γ辐照后ZEN含量低于2 153 μg·kg^-1的玉米饲喂繁育绵羊,对绵羊定时人工授精无不利影响。本研究结果为⁶⁰Co-γ辐照模式下玉米中赤霉烯酮和品质的变化对绵羊定时人工授精的影响研究提供了理论依据。     

玉米赤霉烯酮对断奶小母猪生产性能、血清抗氧化功能和免疫功能的影响

为了研究不同水平玉米赤霉烯酮(zearalenone,ZEA)污染饲粮对断奶小母猪生产性能、血清抗氧化功能、血清抗体水平及外周血淋巴细胞增殖率的影响。将40头健康三元杂交(杜×长×大)断奶小母猪按日龄[(35±1)日龄]和平均体重[(14.01±0.86)kg]分为4组,对照组饲喂基础饲粮(ZEA水平的测定值为0 mg/kg),试验组在基础饲粮中分别添加0.5、1.0及1.5 mg/kg ZEA[ZEA水平的测定值分别为(0.52±0.07)mg/kg、(1.04±0.03)mg/kg和(1.51±0.13)mg/kg]。预试期10 d,正试期35 d。结果表明:饲粮ZEA对断奶小母猪平均日采食量、平均日增重和料重比没有显著影响(P0.05)。与对照组相比,ZEA显著降低了血清谷胱甘肽过氧化物酶(GSH-Px,0.5、1.0和1.5 mg/kg ZEA)活性、猪瘟(1.0和1.5 mg/kg ZEA)和伪狂犬病病毒抗体水平(1.5 mg/kg ZEA)以及外周血淋巴细胞增殖率(1.0和1.5 mg/kg ZEA)(P0.05),而显著升高了血清丙二醛(MDA,0.5、1.0和1.5 mg/kg ZEA)含量(P0.05)。随着饲粮中ZEA水平的升高,断奶小母猪的料重比呈一次线性降低趋势(P=0.075),血清GSH-Px、超氧化物歧化酶(SOD)活性,血清病毒(猪瘟、伪狂犬病和高致病性猪蓝耳病病毒)抗体水平和外周血淋巴细胞增殖率均呈一次线性降低(P0.05),而血清MDA含量则呈一次线性升高(P0.05)。由此可见,饲粮中0.5 mg/kg的ZEA足以诱导小母猪的氧化应激反应,1.0 mg/kg的ZEA能够显著降低断奶小母猪的特异性体液免疫和细胞免疫功能。     

Involvement of the Fas and Fas ligand in testicular germ cell apoptosis by zearalenone in rat

Zearalenone (ZEA), a nonsteroidal estrogenic mycotoxin, is known to cause testicular toxicity in animals. In the present study, the effects of ZEA on spermatogenesis and possible mechanisms involved in germ cell injury were examined in rats. Ten-week-old Sprague-Dawley rats were treated with 5 mg/kg i.p. of ZEA and euthanized 3, 6, 12, 24 or 48 h after treatment. Histopathologically, spermatogonia and spermatocytes were found to be affected selectively. They were TUNEL-positive and found to be primarily in spermatogenic stages I-VI tubules from 6 h after dosing, increasing gradually until 12 h and then gradually decreasing. Western blot analysis revealed an increase in Fas and Fas ligand (Fas-L) protein levels in the ZEA-treated rats. However, the estrogen receptor (ER)α expression was not changed during the study. Collectively, our data suggest that acute exposure of ZEA induces apoptosis in germ cells of male rats and that this toxicity of ZEA is partially mediated through modulation of Fas and Fas-L systems, though ERα may not play a significant role.     

一株苯酚降解菌的筛选、鉴定及相关降解特性

【目的】筛选苯酚化合物相关降解微生物,确定其相关功能特性,为进一步揭示相关降解机制以及开发利用该菌株提供科学依据和基础。【方法】以苯酚为筛选压力对盐爪爪根际微生物进行分离筛选,采用16S rDNA序列测序确定相关降解菌的生物学地位,并对其抗逆特性和功能特性进行分析,开展其对苯酚和玉米赤霉烯酮降解的研究。【结果】获得了一株编号YZZ-9的菌株,经鉴定该菌为沼泽考克氏菌(Kocuria palustris),其能够在10%的NaCl,3.5 g/L的苯酚下生长良好,且能利用多种苯类化合物为单一碳源生长。当培养基中苯酚浓度低于1.0 g/L时,苯酚可在120 h内完全降解;当苯酚浓度达到1.5 g/L,培养基中的苯酚降解几乎完全被抑制。同时,菌株可明显降解玉米赤霉烯酮,当菌株培养144 h时,培养基中玉米赤霉烯酮降解率可达68.9%。【结论】菌株YZZ-9具有良好的苯酚和玉米赤霉烯酮降解能力。     

线粒体凋亡途径在玉米赤霉烯酮致大鼠睾丸支持细胞凋亡中的作用

为探讨玉米赤霉烯酮(zearalenon,ZEA)雄性生殖毒性作用机理,研究ZEA诱导大鼠睾丸支持细胞(sertoli cell,SC)的凋亡途径,试验选取大鼠原代SC为研究材料,用不同浓度ZEA(0、5、10、20μmol/L)处理SC 24 h后,采用实时荧光定量PCR法检测Bax和Bcl-2 mRNA表达水平;用Western blotting法检测Bax、Bcl-2等线粒体凋亡途径相关蛋白表达;同时检测了20μmol/L ZEA联合Caspase-8抑制剂(Z-IETD-FMK)处理对SC凋亡率和线粒体凋亡相关蛋白的影响。结果显示,与对照组相比,20μmol/L ZEA组细胞Bcl-2转录水平显著下降(P<0.05),Bax转录水平显著上升(P<0.05);10、20μmol/L ZEA组Bax/Bcl-2比值及Cyto-CytC、Cleaved Caspase-9、Cleaved Caspase-3表达量极显著上升(P<0.01),而Mito-CytC表达量极显著下降(P<0.01);与ZEA组相比,ZEA与Z-IETD-FMK联合处理可使ZEA诱导的SC凋亡率极显著下降(P<0.01),tBid/Bid、Bax/Bcl-2、Cyto-CytC、Cleaved-Caspase3、Cleaved-Caspase9蛋白表达显著或极显著下降(P<0.05;P<0.01),而Mito-CytC表达量极显著上升(P<0.01)。综合试验结果,ZEA能够通过线粒体途径诱导大鼠SC发生凋亡。     

玉米赤霉烯酮对小鼠原代培养T淋巴细胞细胞因子分泌的影响

为探讨玉米赤霉烯酮(zearalenone,ZEA)对动物免疫功能的影响及其机理,试验以分离培养的原代小鼠脾脏淋巴细胞材料,研究了ZEA对T淋巴细胞细胞因子分泌的影响。以刀豆蛋白A(Con A,5 mg/L)作为T细胞活化特异性刺激剂,试验设空白对照组(不加Con A)、Con A组(5 mg/L Con A)、不同浓度的ZEA染毒组(Con A+ZEA 10、20和40μmol/L),处理48,72 h后,使用流式液相多重蛋白定量技术检测T细胞分泌IL-2、IL-3、IL-5、IL-6和GM-CSF等细胞因子的含量。结果显示,与空白对照组相比,Con A组细胞在48,72 h时间段5种细胞因子分泌均明显上升;与Con A组比较,染毒48,72 h后,10,20,40μmol/L ZEA染毒组各细胞因子分泌浓度均有极显著下降(P<0.01),并呈剂量-效应关系。结果表明,ZEA可以抑制T淋巴细胞细胞因子IL-2、IL-3、IL-5、IL-6和GM-CSF的分泌,从而影响机体正常免疫反应的进行,降低整体的免疫功能。     

玉米赤霉烯酮的危害及物理吸附剂脱毒研究进展

玉米赤霉烯酮（Zearalenone, ZEN）主要是由镰刀真菌所产生的一种非甾体类真菌毒素。大量分布于玉米、大麦、小麦、高粱等作物中,对动物和人体健康造成严重危害。本文综述了ZEN的理化性质、毒性危害、检测方法及物理吸附剂对ZEN吸附脱毒的研究进展。     

Growth of Moulds and Production of Mycotoxins in Wheat during Drying and Storage

Abstract

Studies were carried out on the growth of mould and the production of mycotoxins in grain during drying and storage. Various amounts of forced ambient air, 800, 600, 400, 200 and 0 m³ (air)/(hour ton), were used to dry wheat, which contained 32% moisture at harvest. Samples for mycological examination and determination of mycotoxins and moisture content were taken weekly. At harvest the mould flora consisted of various field fungi with less than 10% Fusarium spp. An increasing proportion of Aspergillius and Penicillium spp. were recorded in the bins at 0 and 200 m³ (air)/h t. The mycotoxin analysis indicated that the Fusarium spp. were also metabolically active until at least five weeks after the grain was put into the store room. The concentration of deoxynivalenol (DON) reached about 10 mg/kg after three weeks in the bins with no air flow, and about 2 mg/kg in the bins at 200 m³ (air)/h t. The zearalenone concentration also increased considerably, to about 5 mg/kg, in the bins with no air flow. The present results show that drying of grains using forced ambient air may produce good conditions for growth of field fungi as well as storage fungi if the flow of air is too low.     

ELISA与HPLC-MS对饲用玉米中2种霉菌毒素的比较分析

实验采集饲用玉米样品共30份,通过酶联免疫法(ELISA)和高效液相色谱-串联质谱联用(HPLC-MS)法对玉米赤霉烯酮(ZEA)和T-2毒素(T-2)2种霉菌毒素进行检测,旨在比较两种方法对饲用玉米中霉菌毒素的检测效果。结果表明:两种检测方法对饲用玉米中的ZEA均100%检出。检测T-2时ELISA法的检出率为83.33%,HPLC-MS法则未检出。两种方法检测出的霉菌毒素含量均都表现出ELISA法的检出值普遍高于HPLC-MS法。ELISA法前处理简单、检出速度较快且适合大批量样品检测,但因干扰因素较多易出现假阳性。HPLC-MS法前处理复杂、成本昂贵、操作要求高,但检测结果较为稳定和准确。说明在实际生产应用中,应结合两种检测方法的优缺点,用ELISA法初筛,检测结果呈阳性后,再用HPLC-MS法进行精确定量,这样既能实现检测目的又能节省检测费用。