《微生物学》实验教学改革与实践——以“工业微生物菌种保藏技术”综合设计性实验的开设为例

通过分析《微生物学》实验教学中存在的问题,提出了完善《微生物学》实验教学的措施。实践证明,＂工业微生物菌种保藏技术＂综合设计性实验采用一种新颖的教学模式,不仅调动和激发了学生的学习热情,锻炼了学生的独立能力,提高了学生的综合科研素质,而且培养了学生相互合作的团队精神。该教学模式为工业微生物学实验课程教学注入了新的活力。     

EPA/DHA对体外发酵及瘤胃液脂肪酸组成的影响

试验旨在研究日粮中添加不同水平的DHA/EPA对体外发酵和瘤胃液脂肪酸变化的影响。试验通过采用持续动态人工瘤胃装置,向发酵罐中添加EPA/DHA,连续培养7 d,分析脂肪酸组成的变化及发酵模式的改变。试验结果表明,日粮添加EPA/DHA使瘤胃液pH升高（与CK相比,Trt1和Trt2分别升高了0.11和0.35）,Trt2 与CK相比差异极显著（P<0.01）;与CK相比处理组3种主要挥发酸中乙酸浓度下降（P<0.01）,丙酸浓度升高(P<0.01),丁酸浓度下降(P<0.01),总挥发性脂肪酸浓度与对照组相比略有下降但差异不显著（P>0.05）;日粮添加EPA/DHA使瘤胃液脂肪酸成分发生改变。与CK相比处理组C18∶0含量显著下降（P<0.01）; t 11 C18∶1含量显著升高（P<0.01）;c-9,t-11 CLA含量显著升高（P<0.01）,但是两组之间差异均不显著。因此,日粮中添加不同水平的EPA/DHA可以改变瘤胃发酵模式,影响不饱和脂肪酸瘤胃氢化过程,使脂肪酸组成发生改变,为采用新的营养措施调控反刍动物产品中CLA的含量提供理论依据。     

不同精粗比饲粮对牦牛瘤胃内环境的影响

旨在研究不同精粗比饲粮对西藏牦牛瘤胃内环境的影响.选取3周岁、平均体重(154.8±13.6)kg、健康无病的牦牛20头随机分为低精料组和高精料组,每组10头,公母各半,分别饲喂低精料(精粗比40∶60)和高精料(精粗比60 ∶ 40)饲粮,预试期10d,正试期90d(8、9和10月).结果:饲粮精料水平的提高显著降低...     

Oxfendazole efficacy in calves: A comparison of oral and intraruminal routes of administration

Summary

Twenty‐seven calves of the Dutch Friesian breed were housed after their first grazing season and divided into 3 groups, each of 9 animals. Two of the groups were treated with oxfendazole 9.06 per cent suspension administered either orally or intraruminally, whilst the third group was retained as an untreated control. No differences in efficacy were observed between the two treated groups and oxfendazole administered by either route was 100 per cent effective in removing adult populations of the major strongylids and trichostrongylids present.     

不同处理菌糠细胞壁成分及有机物瘤胃降解特性

对经化学、生物及复合 3种处理的菌糠的细胞壁成分进行分析 ,研究不同处理对提高菌糠饲用价值的效果 .选用 4头装有永久瘤胃瘘管的杂交黄牛 ,按 4× 4拉丁方设计 ,采用尼龙袋法研究化学、生物及复合等 3种处理菌糠 OM瘤胃降解特性 .结果表明 :(1)香菇、茶树菇及金针菇等 3种菌糠经化学处理后 ,NDF、ADF、ADL均有不同程度降低 ,其中以 Na OH处理效果最佳 ,NDF、ADF、ADL分别下降 5 .71% - 9.92 %、7.4 3% -13.36%及 10 .5 5 % - 2 0 .4 7% ;经筛选 ,Y4、Y5及 Y8种真菌能显著降低香菇菌糠 NDF、ADF、CEL、HC及 ADL含量 ,其中以 Y8菌种效果最佳 ;Na OH和生物 (Y4 )复合处理对改善香菇菌糠细胞壁成分的效果优于单独的Na OH-生物 (Y4 )处理 .(2 )香菇菌糠经 Na OH、氨化 (尿素 )及氨化 (尿素 ) +Na OH处理后 ,OM的动态降解率(P)分别提高 19.60 %、13.16%、2 1.0 2 % (p<0 .0 5 ) ;生物处理中以 Y4、Y5及 Y8三种真菌的处理效果最佳 ,菌糠 OM动态降解率 (p)分别提高 31.65 % (p<0 .0 5 )、4 7.69% (p<0 .0 1)及 5 5 .82 % (p<0 .0 1) ,其中 Y8和 Y5菌种的效果又优于 Y4 (p<0 .0 5 ) ;Na OH-生物 (Y4 )复合处理效果优于单独的 Na OH或生物 (Y4 )处理     

Cu污染条件下封闭循环水养虾系统的效能

为获得Cu2+污染对封闭循环水养虾系统的影响,选用0.3 mg/L Cu2+浓度,研究其对系统中水质、对虾生长、存活及生物滤器水处理效能的影响。结果表明,经过84 d的试验,养殖水体中Cu2+质量浓度在系统水处理单元作用下降为(0.089±0.012)mg/L,对虾能正常生长和存活,0.3 mg/L Cu2+处理质量浓度对生物滤器的化学需要量（COD）、NH4-N和NO2-N去除率及滤器中异养细菌、氨氧化菌和亚硝酸盐氧化菌的数量不造成显著影响。处理系统对虾体内Cu质量分数为(42.91±6.10)mg/kg,与对照中质量分数(29.36±4.06)mg/kg相比,具有显著差异,但均在国家无公害食品水产品中有毒有害物质限量标准（Cu≤50 mg/kg）范围内。在0.3 mg/L Cu2+质量浓度污染下,封闭循环水养虾系统仍能提供较好的水质条件,获得较高的产量和较低的饵料转化率,所养对虾符合无公害水产品要求。     

高职类食品微生物检验技术课程教学改革探讨

食品微生物检验技术是一门实践性和应用性很强的学科,是质检专业的职业技术核心课程之一。通过对教学内容、教学方法以及课程考试考核等方面的改革,提高食品微生物检验技术课程教学质量及学生的职业能力。使学生实践动手能力大大加强,为学生的就业奠定坚实基础。     

Effect of the administration of young leaves of Quercus pyrenaica on rumen fermentation in relation to oak tannin toxicosis in cattle

Three experiments were conducted to study the effect of the administration of young leaves of Quercus pyrenaica (OL) on in vivo ruminal fermentation in relation to oak tannin toxicosis in cattle. In Experiment 1, six bulls were fed up to 5 kg fresh matter (FM) of OL per animal and day for 14 days. In Experiment 2, another six bulls were first subjected to severe feed restriction for 8 days and then fed a higher amount of OL (approximately 10 kg FM daily) for 3 days. In Experiment 3, three bulls received the same amount of OL as in Experiment 1 for 6 days, but adding a severe feed restriction as in Experiment 2. In situ DM disappearance of grass hay and OL, and pH and ammonia and volatile fatty acid concentrations were recorded throughout the three assays. Daily administration of up to 5 kg OL did not considerably affect ruminal fermentation, unless it was preceded by a severe feed restriction period. Administration of 10 kg OL preceded by undernutrition triggered a critical reduction in rumen fermentation activity concomitantly with an acute intoxication. Interestingly, some results differ from those observed previously in vitro, which highlights the importance of validating in vitro data with in vivo measurements, given the complexity of extrapolation in ruminants.     

生草提高山核桃林土壤有机碳含量及微生物功能多样性

山核桃(Carya cathayensis)是中国特有的高档干果和木本油料树种,但高强度经营导致林地土壤性质的改变,为了解生草对土壤的修复效果,在山核桃主产区设置了紫云英(Astragalus sinicus)、油菜(Brassica campestris)、黑麦草(Lolium perenne)和免耕4种处理,对土壤有机碳及微生物功能多样性进行分析。结果表明,不同生草栽培后,山核桃林地土壤总有机碳(total organic carbon,TOC)质量分数显著增加,与免耕相比,种植油菜、黑麦草、紫云英4 a后土壤TOC分别提高了23.12%,26.61%和24.74%,增加的组分以羰基碳为主,但并未改变土壤碳库的稳定性;同时也显著提高了林地土壤微生物量碳(microbial biomass carbon,MBC)和水溶性有机碳(water-soluble organic carbon,WSOC)的质量分数,MBC增加了138.61%～159.68,WSOC提高了56.24%～69.47%%。3种生草的土壤微生物活性(average well color development,AWCD)显著高于免耕,微生物多样性指数(Shannon index, H)和均匀度指数(evenness index, E)则表现为油菜、紫云英处理显著高于免耕。研究表明,生草栽培能有效提高林地土壤TOC质量分数和微生物功能多样性,为山核桃林地土壤修复和科学管理提供参考。     

Rumen fermentation and degradability in buffalo and cattle using the in vitro gas production technique

An in vitro trial was conducted to investigate the effect of different inoculum sources (buffalo vs. cattle) on rumen fermentation and degradability. Incubations were carried out using rumen fluid obtained from buffalo or cattle fed the same diet [60% grass hay and 40% concentrate; 18 kg dry matter (DM)/day]. The fermentation kinetics of eight feeds commonly used in ruminant nutrition (alfalfa hay, barley meal, beet pulp, corn meal and silage, ryegrass hay and silage and soya bean meal s.e.) were studied with the in vitro gas production technique and rumen fermentation parameters (substrate disappearance, pH and volatile fatty acids production) were determined after 120 h of incubation. The linear relationship indicates that the microbial metabolic pathways of the two inocula for all the substrates were qualitatively similar, albeit often quantitatively different. In this in vitro study, a significant influence of rumen inoculum (buffalo vs. cow) on fermentation and degradability of the examined substrates was found. The differences in buffalo and cattle rumen fermentation can be explained with a different microbial activity of the two ruminant species, because of different amount of microbial population or microbial population constituted by different species of bacteria and protozoa.