金属硫蛋白对奶牛血液抗氧化酶GSH-Px和CAT基因表达的影响

为探讨金属硫蛋白(MT)对奶牛抗氧化应激机能的调控效果及其机理,选取24头中国荷斯坦奶牛经产泌乳母牛,随机均分为I、II、III、IV4组,分别按每头0(对照组),4.0,8.0和12.0mg静脉注射Zn-MT。每隔15d逐头采取血样,测定不同剂量的外源性MT和MT不同作用时间对奶牛抗氧化酶GSH-Px和CAT基因表达水平的影响。结果表明,补给外源性MT后,3个试验组GSH-Px和CAT基因表达水平都有不同幅度的提高,其中III组和IV组GSH-Px基因表达量分别较对照组有显著(P<0.05)提高。III组CAT基因表达水平显著(P<0.05)高于对照组;IV组CAT基因表达水平又比对照组、II组和III组分别提高了22.88%(P<0.01),17.71％(P<0.05)和7.10％(P>0.05)。而II组GSH-Px和CAT基因表达量与对照组差异均不显著(P>0.05)。从正试期间不同时间看,补给外源性MT后,各组GSH-Px和CAT基因表达水平逐步升高,至30d时达最高,45d时又有下降。尤其是30d时的GSH-Px基因表达水平及15和30d时的CAT基因表达水平均显著(P<0.05)高于第1天。说明外源性MT能有效调控奶牛GSH-Px和CAT基因表达水平,并表现出较为明显的剂量效应和时间效应。     

A review of nutritional biology and dietary requirements of redclaw crayfish Cherax quadricarinatus (von Martens 1868)

Redclaw crayfish (Cherax quadricarinatus, von Martens 1868) is a freshwater decapod crustacean with a number of biological and commercial attributes that make it an excellent aquaculture species. The redclaw aquaculture industry has been growing rapidly since the mid‐1980s in tropical and subtropical regions of the world. Redclaw aquaculture is mostly in extensive pond systems, but interest in developing more intensive systems is increasing. To support continued intensification, development of high‐quality practical diet formulations and information about redclaw nutrition requirements are necessary. A number of studies have determined optimum dietary protein and lipid requirements for juvenile redclaw. However, there is limited information on essential amino acid and fatty acid requirements. Several studies report the presence of various digestive enzymes that have been linked to the ability of the species to digest a wide range of dietary components. Furthermore, as in many other aquaculture species, there is a need to replace fishmeal with other protein sources. A number of studies explored the possibility of replacing fish meal with various terrestrial plant sources of protein and lipids and showed that redclaw can be offered diets containing low‐cost, plant‐based ingredients without compromising survival, growth and, to a certain extent, reproduction. Formulated diets containing less expensive, plant ‐ based ingredients will contribute to a more profitable and environmentally sustainable redclaw aquaculture industry. Finally, there is also a paucity of information on vitamin and mineral requirements of redclaw and little information on nutrient requirements of broodstock. For the redclaw aquaculture industry to thrive, we need to have a better understanding of nutrient requirements at all life stages.     

Effects of feeding rates on growth performances of white sturgeon (Acipenser transmontanus) fries

Four 1‐week growth trials were conducted to determine the effects of feeding rates on the growth performances of white sturgeon (Acipenser transmontanus) fries 6–9 weeks after initiation of feeding. Six feeding rates with four replications were used in each of the four trials, and the feeding rates were 3.0–8.0, 2.0–7.0, 1.0–6.0 and 1.0–6.0% body weight (BW) per day in 1% increment, respectively. Number of fries per replicate and their initial BW (means ± SEM) were 60, 45, 30 and 30 and 2.8 ± 0.1, 4.5 ± 0.4, 8.5 ± 0.7 and 10.0 ± 0.7 g, respectively. The fries were kept at 18–19 °C and fed a commercial salmonid feed (488 g kg^?1 protein and 123 g kg^?1 fat). Mortality was low and unrelated to feeding rates. Final body weights, body weight increases, specific growth rates and feed efficiency were significantly (P < 0.05) affected by the feeding rates. Body moisture and lipid contents were significantly affected by feeding rates except body moisture content in trial II. Body protein contents were not affected by feeding rates except in trial III. Broken‐line analysis on specific growth rates indicated that the optimum feeding rates were 6.5 ± 0.4, 4.8 ± 0.2, 4.2 ± 0.1 and 3.8 ± 0.2% body weight per day, respectively, for white sturgeon fries 6–9 weeks after initiation of feeding.     

Factors affecting nutrient digestibility in rainbow trout (Oncorhynchus mykiss) fed a plant protein–based diet supplemented with microbial phytase

Factors influencing apparent digestibility coefficient (ADC) of nutrients from a plant protein–based diet supplemented with microbial phytase were investigated in a series of experiments with rainbow trout (Oncorhynchus mykiss). The influence of phytase level, water temperature, feed particle size and addition of a protease/non‐starch polysaccharidase (PNSP) enzyme cocktail were tested in a phytase‐supplemented (2000 FTU kg^?1) diet. Finally, the influence of Ca/P ratio, addition of 1,25‐hydroxycholeocalciferol, or inclusion of lactic acid (LA) in diets with and without phytase was evaluated. Addition of microbial phytase improved ADC of dry matter (DM), protein, ash and minerals (P, Ca, Mg, Fe and Zn) (P < 0.05). Reducing feed particle size potentiated the effect of phytase on P and ash ADC, as did the addition of a PNSP enzyme cocktail; the latter also significantly improved DM ADC in both control and phytase‐supplemented diets. Increasing the Ca/P ratio reduced the effect of phytase on P and ash ADC. Addition of 1,25‐dihydroxycholecalciferol and LA had no effect on DM, P and ash ADC in control diets and tended to reduce the phytase‐induced increase in P ADC.     

Micrometer and nanometer scale photopatterning of proteins on glass surfaces by photo-degradation of films formed from oligo(ethylene glycol) terminated silanes

Exposure of films formed by the adsorption of oligo(ethylene glycol) (OEG) functionalized trichlorosilanes on glass to UV light from a frequency-doubled argon ion laser (244 nm) causes photodegradation of the OEG chain. Although the rate of degradation is substantially slower than for monolayers of OEG terminated thiolates on gold, it is nevertheless possible to form micrometer-scale patterns by elective adsorption of streptavidin to exposed regions. A low density of aldehyde functional groups is produced, and this enables derivatization with nitrilotriacetic acid via an amine linker. Complexation with nickel enables the site-specific immobilization of histidine-tagged yellow and green fluorescent proteins. Nanometer-scale patterns may be fabricated using a Lloyd's mirror interferometer, with a sample and mirror set at right angles to each other. At low exposures, partial degradation of the OEG chains does not remove the protein-resistance of the surface, even though friction force microscopy reveals the formation of patterns. At an exposure of ca. 18 J cm(-2), the modified regions became adhesive to proteins in a narrow region ca. 30 nm (λ/8) wide. As the exposure is increased further the lines quickly broaden to ca. 90 nm. Adjustment of the angle between the sample and mirror enables the fabrication of lines of His-tagged green fluorescent protein at a period of 340 nm that could be resolved using a confocal microscope.     

不同盖度沙柳林和柠条沙柳混交林行间植物特征研究

本文以内蒙古东胜区泊江海镇覆沙地3种不同盖度沙柳林和柠条沙柳混交林行间植物为研究对象,在典型样地内采取样方法对行间植物特征进行研究,结果表明：随灌木林盖度增加,植物种数、一年生草本植物重要值、中生植物重要值、植物多样性指数和丰富度增加,多年生草本植物重要值、旱生植物重要值降低;灌木重要值为低盖度柠条沙柳混交林〉低盖度沙柳纯林〉中盖度沙柳纯林;均匀度为中盖度沙柳纯林〉低盖度沙柳纯林〉低盖度柠条沙柳混交林。     

Spirometric Variables Recorded after Lobeline Administration in Healthy Friesian and Belgian White and Blue Calves: Normal Values and Effects of Somatic Growth

The purposes of the present study were: (1) to develop original equations to predict spirometric variables (SV) in healthy Friesian and Belgian White and Blue (BWB) calves < 1 year of age; and (2) to determine the effects of somatic growth on SV. Sixty-seven Friesian and 500 BWB calves were investigated. For each calf, the following SV were calculated: (1) the average minute volume derived using all the ventilatory cycles recorded during the 15 s of maximal ventilatory changes induced by lobeline administration (0.25 mg/kg, i.v.) (15-s LMV); (2) the maximal tidal volume, the maximal peak expiratory flow and the maximal peak inspiratory flow recorded from single breaths after lobeline administration (MVTL, MPEFLand MPIFL, respectively); (3) the ventilatory reserve (VRL= 15-s LMV - VEr; VEr= minute volume at rest). Mass specific (s) values were also calculated. All SV changed linearly with somatic growth in both Friesian and BWB calves. Since the rise in SV was more related to body weight than the age of calves, equations for reference values of SV always had body weight as the only independent variable. In the youngest calves, s SV were lower in the BWB breed. In the oldest calves (i.e. 1 year of age), s MPEFLand s MPIFLremained small in BWB calves whereas s MVTL, s 15-s LMV and s VRLwere almost equal in both breeds. These results could be related to the lower resistance to respiratory disorders in BWB calves < 1 year of age than in Friesian calves < 1 year of age.     

不同下垫面对校园小气候的影响

改善人居生存环境、建设生态城市是城市规划和设计的重要内容之一,越来越受到人们的广泛关注.对于人居密度较大的大学校园,规划设计和建设有利于学生培养的校园环境,关系到人们对学校的直观印象和莘莘学子的学习与生活.本文以内蒙古农业大学东区校园内学生室外学习、运动和休闲经常涉及到的几种典型城市下垫面--片林、小游园、硬化地面为研究对象,分析其对校园小气候的影响,结果表明,园林绿地具有改善和调节小气候的作用.     

青南地区退化天然草地综合复壮技术研究

以青南地区称多县歇武乡典型的退化高寒草地为对象,采用正交试验方法,通过施肥、补播、除杂等综合技术,对退化天然草地进行综合复壮试验。结果表明：施肥是最主要的复壮措施,当施以尿素105．0kg/hm^2,二铵60．0kg/hm^2,氯化钾22．5kg/hm^2时,经济效益最高。复壮技术组合中,以A3B3C2最好,即除杂100％,施用尿素150kg/hm^2、二铵105kg/hm^2、氯化钾30kg/hm^2、披碱草15kg/hm^2为首选技术组合。     

歇武乡藏羊最优畜群结构的选择

根据数学优选法原理,结合歇武乡示范户藏羊生产实况,对羊群结构进行分析,找出藏羊的最优畜群结构方案,分析、计算歇武乡示范户藏羊最优畜群结构。