苜蓿草粉对禾花鲤蛋白酶和淀粉酶活性影响的研究

选取来源一致、规格整齐的2龄禾花鲤1 200尾,采用单因子完全随机设计,分为5个处理,每处理3个重复,每重复80尾鱼,分置于15个试验池中。各处理苜蓿Medicago sativa草粉的添加量分别为0（对照组）、40（试验Ⅰ组）、80（试验Ⅱ组）、120（试验Ⅲ组）和160 g/kg（试验Ⅳ组）,正试期50 d,观测苜蓿草粉对禾花鲤前、中、后肠及肝胰脏蛋白酶和淀粉酶活性的影响。结果表明：1）添加苜蓿草粉对前肠蛋白酶活性有显著影响 (P<0.05),其中试验II组显著高于对照组和试验Ⅳ组,但和试验Ⅰ、Ⅲ组差异不显著 (P>0.05)。添加苜蓿草粉对中、后肠及肝胰脏蛋白酶活性均无显著影响 (P>0.05),但它们有相同的变化趋势,即试验Ⅰ、Ⅱ、Ⅲ组鱼的蛋白酶活性均高于对照组。2）鲤鱼的前肠、中肠、后肠蛋白酶活性依次减弱,而肝胰脏的蛋白酶活性远低于肠道。3）添加苜蓿草粉后前肠及中肠淀粉酶活性比较,试验II组显著高于对照组 (P<0.05),其余各组与对照组差异不显著 (P>0.05),后肠淀粉酶活性与对照组无显著差异 (P>0.05)。添加苜蓿草粉能提高鲤鱼肝胰脏淀粉酶活性,其中试验Ⅱ组显著高于对照组 (P<0.05),其余试验组与对照组无显著差异 (P>0.05)。4）禾花鲤前、中、后肠及肝胰脏4部分淀粉酶的活性有较大的不同,肝胰脏>后肠>中肠>前肠。     

20世纪50年代以来科尔沁沙地景观时空动态变化探析

研究分析了50年来科尔沁流动沙地和半固定沙地景观时空动态变化,并分析了沙地时空动态变化的主要成因。     

草地牧草物候发育模型的应用研究——以锡林郭勒草原为例

天然草地牧草生长发育受环境条件影响很大,牧草的发育期年际间和年内有很大变化。利用多年牧草物候观测资料,分析了影响草地牧草生长发育的主要气象要素并建立了锡林郭勒草原主要牧草物候发育模型。     

Carbon and nitrogen budgets of nematodes in arable soil

Summary The amounts of C and N that pass through the nematode biomass in four cropping systems, barley without and with N fertilization, grass ley and lucerne, has been estimated. The nematodes were sampled at the field site of a Swedish integrated research project Ecology of Arable Land: The Role of Organisms in Nitrogen Cycling. The nematode biomass was lower (200 mg dry weight m^–2) in the annual (barley) than in the perennial (grass and lucerne, 350 mg dry weight m^–2) crops. For respiration, the nematodes used 4–71 O₂m^–2 year^–1 corresponding to C liberation of 1.3%–2.0% of the carbon input to the soil. A higher relative contribution by bacterial-feeding nematodes to the C and N fluxes and a higher turnover rate of the nematode biomass is an indication of more rapid nutrient circulation in the annual than in the perennial cropping systems.     

不同饲料原料对草鱼生长和肌肉品质的影响

分别以专用配合饲料、浸泡蚕豆、浸泡豌豆喂养体质量为(1540.9±57.5)g的草鱼(Cteno-pharyngodon idellus)90d,以考察不同原料对草鱼生长和肌肉品质的影响。结果表明,配合饲料组、浸泡蚕豆组和浸泡豌豆组草鱼的增重率分别为17.3%、13.7%和12.2%,饵料系数分别为5.00、4.09和5.08,三种原料对草鱼的脏体比、肝体比没有显著影响;与普通草鱼相比,三种原料组草鱼肌肉粗脂肪含量和肌肉失水率显著降低(P0.05),胶原蛋白含量和肌原纤维长度显著增加(P0.05)。上述结果表明,三种原料均可显著改善草鱼肌肉品质;与浸泡蚕豆组相比,专用配合饲料组显著提高了草鱼的生长性能。     

锦鲤成熟系数及个体生殖力的研究

对锦鲤(Cyprinus carpiod)的成熟系数和个体生殖力进行了研究。结果显示:雌、雄锦鲤成熟系数变化规律基本一致,成熟系数在5月下旬达到最高值。2+~5+龄锦鲤个体绝对生殖力F与其年龄A、体长L、体重W呈直线相关,回归方程分别为:F=67054A+61567(R2=0.8419,P<0.01),F=8588.4L+24969(R2=0.9217,P<0.01),F=315.33W-9688.8(R2=0.9631,P<0.01)。     

用IGF—ⅠmRNA表达量评价鲮饲料配方效果的研究

试验以秘鲁鱼粉为饲料蛋白源，研究4种蛋白水平（21．5％、32．2％、42．5％和51．6％）的饲料对鲮（Cirrhinus molitorella）生长、消化酶活性及类胰岛素生长因子（IGF—Ⅰ）mRNA表达水平的影响。经过8周的养殖试验，不同饲料蛋白水平下，蛋白酶活性与特定生长率（SGR）成极显著的正相关性（P〈0．01）；鲮肝组织中IGF—ⅠmRNA的表达量与特定生长率成极显著正相关性（P〈0．01）；鲮肝组织IGF—ⅠmRNA的表达量与蛋白酶活性也成极显著正相关性（P〈0．01）。结果表明，用鲮肝组织IGF—ⅠmRNA的表达量可以快速鉴定饲料的质量。     

Investigations on the digestibility and metabolizability of the major nutrients and energy of maize leaves and barnyard grass in grass carp (Ctenopharyngodon idella)

In the uplands of northern Vietnam, culture of grass carp contributes significantly to income and household food security of Black Thai farmers. Maize is one of the most important upland crops and barnyard grass is the most important weed in the paddy rice fields. Thus, these are frequently used by small‐scale fish farmers as fish feed. An 8‐week feeding trial was conducted simultaneously in a recirculation and in a respirometric system to determine the digestibility and metabolizability of the nutrients of maize leaves and barnyard grass, to assess their crude protein, lipid and energy conversion and to estimate the energy allocation in grass carp. The following diets were used: diet ‘A’ (reference diet) containing 39% crude protein with 19.8 MJ kg^?1 gross energy; diets ‘B’, ‘C’ and ‘D’, which contained the same amount of the reference diet as the control diet, supplemented with a known amount of dried barnyard grass, dried maize leaves or fresh maize leaves, respectively. Five fish were assigned to each treatment in each experimental unit. Reference and test diets were fed to fish and faecal samples were collected and the oxygen consumption was measured in order to set up an energy budget of the fish over the whole experimental period. The weekly development of the body weight was recorded. The body weight gain of the fish fed diet D was significantly higher than that of the group fed diet A, which also in turn was significantly higher than that of fish fed diet B or C. The apparent digestibility coefficients (ADC) of nutrients and gross energy for the different experimental diets in fish kept in the aquaria were, for diets A, B, C and D respectively, 94.1%, 60.9%, 70.5% and 84.7% for protein, 91.3%, 60.7%, 76.8% and 71.8% for lipid; 95.9%, 44.5%, 60.6% and 69.1% for gross energy. The partial ADC of plant leaf ingredients were determined and barnyard grass and dried maize leaves were found to be not only poorly digestible but having negative impact on the digestibility of the reference diet, while fresh maize leaves were well digested. The results of the present study indicated that fresh maize leaves have a good potential to be used as supplement in diets for grass carp.     

Inheritance and reliability of random amplified polymorphic DNA-markers in two consecutive generations of common carp (Cyprinus carpio L.)

Random amplified polymorphic DNA (RAPD) markers have been used in a variety of genetic studies in fisheries and aquaculture. Most population studies are performed without preliminary data demonstrating the Mendelian inheritance and reproducibility of RAPD markers. In this study, the inheritance and reproducibility of RAPD markers was examined in two consecutive generations of common carp, Cyprinus carpio L. Variability and segregation of RAPD markers were investigated in one F₁ progeny and three F₂ progenies. Seventy-four RAPD markers were generated by five primers using DNA extracted from the initial ornamental (koi) common carp female and wild-type colour common carp male. Fifty-five of these RAPD markers were transmitted to the F₁ progeny and the inheritance patterns were analysed. Twenty RAPD markers were fully reproducible and demonstrated dominant simple Mendelian inheritance patterns in two consecutive generations. Twenty-four RAPD markers were not reproducible in all progenies. Thirteen markers displayed inheritance ratios in the progenies that did not fit simple Mendelian inheritance patterns. Non-reproducibility of RAPD markers and distorted ratios may be caused by the absence of amplification, poor amplification or by the appearance of artefact bands. Random amplified polymorphic DNA markers with poor reproducibility and non-Mendelian inheritance can lead to misinterpretations of data in population studies, resulting in errors in the estimation of genetic diversity within and between individual populations. Therefore, it is recommended to first identify the set of reproducible RAPD markers that demonstrate Mendelian inheritance before application of the RAPD technique in population studies.     

银鲫不动杆菌病原菌鉴定及药敏试验

从患病的异育银鲫体内分离到5株可疑菌株,经API 20NE细菌生化鉴定,YCS07-04株鉴定率为99.5%,T值符合率0.9,菌株鉴定为鲍曼不动杆菌。采用3种不同浓度进行感染试验,5.0×106cfu/ml浓度组注射感染14 d死亡率达100%,浸泡感染14 d死亡3尾;对照组未出现病症和死亡。菌株在营养琼脂菌落生长良好,在营养肉汤培养基中混浊,有菌膜及沉淀生长;血琼脂平皿菌落呈灰白色,直径2~3 mm,不溶血;麦康凯琼脂菌落半透明圆形;在SS琼脂培养基中不生长。经负染电镜观察,菌株末端圆形短杆状,偶尔可见不规则丝状体,大小为(1.0~1.5)μm×(1.5~2.5)μm,无芽孢、荚膜和鞭毛,表面凹凸不平,静止期呈球形。药敏试验表明,菌株对丁胺卡那霉素、链霉素、妥布霉素、庆大霉素、左氟沙星、复方新诺明和洛美沙星高度敏感;对四环素中度敏感;对羧苄青霉素、氧哌嗪青霉素、苯唑青霉素、头孢他啶、头孢噻肟、头孢哌酮、头孢三嗪和氨曲南等耐药。