硅对盐胁迫下藜麦生长及抗氧化酶活性的影响

全球气候变暖降水减少加速了土壤盐渍化进程,对农业生产造成了严重影响,低浓度的盐分对藜麦发育没有明显影响,但盐含量较高的土壤则不利于藜麦的生长。前人研究表明,硅能帮助植物在盐胁迫条件下更好的生长。本实验以4种藜麦为研究材料,在300mmol.L_-1^{盐胁迫条件下设置硅浓度梯度(CK、0、0.5、1、1.5、2 mmol.L}_-1^{),研究硅对盐胁迫条件下藜麦幼苗的}生长影响及其生理机制,为提高藜麦耐盐性提供参考。结果表明：(1)与对照相比,盐胁迫条件下藜麦幼苗的芽长均明显降低,根长均显著增加;超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)等抗氧化酶活性有不同程度的增加;可溶性糖(SS)含量降低;超氧阴离子自由基(O_2^.-)产生速率丙二醛(MDA)含量增加。(2)随硅浓度的增加,藜麦幼苗的芽长、根长、SOD、POD、CAT、SS均表现为先增加后降低的趋势,O_2.-^{产生速率和MDA含量先降低后升高。(3)}适当浓度外源硅的添加提高了盐胁迫条件下藜麦幼苗的抗氧化酶活性和SS含量,降低O_2.-^{产生速率和MDA含量,促进了藜麦幼苗在盐胁迫条件下的生长,0.5～1mmol.L}_-1^{硅浓度效果最好。}     

赤霉素A_(4+7)的分子生物学研究进展

目前发现的赤霉素种类已达136种之多,GA4+7以其较高的活性和独特的优势受到人们的广泛关注。因此,就GA4+7的合成途径、关键酶及信号转导过程等方面的研究进展进行了归纳和总结,并指出了今后的发展方向。     

非淀粉多糖复合酶制剂对断奶仔猪血液指标的影响

选用120头平均体重为(8.1±0.2)kg的PIC断奶仔猪,采用单因素完全随机化试验设计,研究在饲料中添加复合酶对断奶仔猪血液指标的影响。试验共设5个处理组,每个处理4个重复,每个重复6头猪。试验期为28 d,分为前期(1～14 d)和后期(15～28 d)两个阶段。结果表明:非淀粉多糖复合酶组能显著提高断奶仔猪前期血糖、总蛋白的含量(P<0.05);提高后期断奶仔猪血糖、总蛋白和免疫球蛋白A的含量(P<0.05),复合酶Ⅱ效果好于复合酶Ⅰ。     

东北虎主要消化腺的组织学研究

通过光镜对东北虎主要几种消化腺的H.E染色石蜡切片进行观察,结果表明,东北虎肝小叶间的结缔组织不发达,小叶的界限不清晰,肝细胞体积较大,核位于细胞一侧,肝细胞多呈索状排列,窦状隙不明显;胰腺外分泌部由腺泡和导管组成,腺泡形状不一,由单层锥状腺上皮细胞组成,胰岛是一些大小不等的细胞团和细胞索,分散于外分泌部之间,胞质染色较外分泌部浅;腮腺为纯浆液腺泡,胞质着色呈嗜酸性,颌下腺是以黏液性细胞为主,含少量的浆液性细胞半月。     

细菌耐药颉颃剂的研究现状及应用

作者介绍了具有颉颃细菌耐药性作用的物质的研究应用进展情况，包括灭活酶抑制剂、药物渗透促进剂、外输泵抑制剂、细菌生物被膜抑制剂、抗菌药物增强剂、耐药质粒消除剂等。     

Intraruminal administration of milk in the calf as a model for ruminal drinking: Morphological and enzymatical changes in the jejunal mucosa

In order to develop a calf model for studying the syndrome of ruminal drinking (RD) in veal calves, three dual-fistulated calves were used to test the effect of intraruminal administration of milk replacer on the jejunal mucosa. Biopsies of the proximal jejunal mucosa were taken through a jejunal fistula and the mucosal morphology and the activities of two brush border enzymes, lactase and alkaline phosphatase, were determined.Means of villus length and brush border enzyme activities decreased during the period of intraruminal administration of milk. The hyperplastic villus atrophy in this model was similar to that found in chronic RD patients in previous studies. This could not be associated with isolation of pathogenic micro-organisms from the faeces and is probably the consequence of the intraruminal milk feeding procedure itself.Clinical recovery from the signs of RD occurred rapidly after intraruminal administration of milk ceased and was followed by restoration of villus length and brush border enzyme activities 3–4 weeks later.     

日粮组成和能量水平对乌金猪肉品质的影响

本文旨在研究不同日粮组成和能量水平对乌金猪肉品质的影响,确定最优肉品质所需的日粮适宜能量水平.选取体重(15.18±0.85)kg的乌金猪90头,公、母各占1/2,随机分为5组,每组18头,下设3个重复,每个重复6头.试验采用单因子随机分组设计,以中国肉脂型生长肥育猪饲养标准能量需要设计中能量水平(组Ⅲ,消化能12.98 MJ/kg),以NRC(1998)生长肥育猪饲养标准能量需要设计最高能量水平(组Ⅰ,消化能14.22 MJ/kg),此两个能量水平间设计中高能量水平(组Ⅱ,消化能13.60 MJ/kg),在中能量水平下依次分别设计中低能量水平(组Ⅳ,消化能12.36 MJ/kg)和最低能量水平(组Ⅴ,消化能11.74 MJ/kg),每个能量水平间的梯度为0.62 MJ/kg.各组在不同生长阶段日粮蛋白质、微量元素、氨基酸等水平基本固定.试验期至100 kg体重,分别在30、60和100 kg体重时屠宰,测定肉品质指标及肌肉营养成分,采用模糊综合评定系统分析并确定最优肉品质日粮适宜能量水平.结果表明,不同日粮组成和能量水平对乌金猪不同生长阶段肌肉pH、系水力、剪切力、烹煮损失和滴水损失有明显影响,组Ⅰ、Ⅲ、Ⅴ及其日粮的组间差异显著(P<0.05),大理石纹在60和100 kg体重时差异显著(P<0.05).随着日粮能量水平的降低,肌肉中粗蛋白质含量提高,在100 kg体重时达显著水平(P<0.05);粗脂肪、肌内脂肪和肌苷酸含量降低,不同生长阶段组Ⅰ、Ⅲ、Ⅴ及其日粮的组间差异显著或极显著(P<0.05或P<0.01).以大理石纹、剪切力、滴水损失为评定肉品质的代表指标,通过综合评定确定30、60和100 kg体重时最优肉品质适宜的日粮能量水平分别为13.10、13.08和13.11 MJ/kg.研究结果可为乌金猪的合理饲养和改善肉品质提供科学依据.     

3周龄断奶仔猪胰酶发育规律的研究

以 3周龄断奶仔猪为试验材料 ,研究了断奶对仔猪胰酶活性的影响。试验表明 ,3周龄断奶可以显著降低仔猪胰脏中胰淀粉酶、胰蛋白酶、胰糜蛋白酶和胰脂肪酶的活性 ,且在断奶后 2周继续维持断奶时水平。断奶降低了小肠内容物中胰淀粉酶和胰脂肪酶的活性 ,但空肠和回肠胰蛋白酶、胰糜蛋白酶的活性在断奶后并未下降。     

Serum enzyme status of Chios ewes fed increasing amounts of copper from copper sulfate

This study aimed to evaluate effects of orally administered copper (Cu) to Chios sheep breed on serum levels of aspartate aminotransferase (AST), l-alanine aminotransferase (ALT), lactate deydrogenase (LDH) and alkaline phosphatase (ALP), in order to establish a practical and effective method in diagnosing the prehemolytic stage of chronic Cu poisoning. Eighteen ewes were allocated to three treatments of six ewes and fed a diet that contained 16.4 mg/day of Cu. Ewes in treatment Cu-0 received no additional Cu (control), while those in treatments Cu-60 and Cu-95 received 60 and 95 mg additional Cu/day, respectively, as an oral solution of copper sulfate. Therefore the ewes in treatment Cu-0, Cu-60 and Cu-95 consumed 16.4, 76.4 and 111.4 mg Cu/day, respectively. Serum enzyme levels were similar among treatments and all ewes remained clinically healthy until the end of the experiment. Results suggest that Chios ewes exhibit tolerance to Cu supplementation for up to 6 weeks.     

Comparison of the Value of Pulsed-field Gel Electrophoresis,Random Amplified Polymorphic DNA and Amplified rDNA Restriction Analysis for Subtyping Taylorella equigenitalis

Eight strains of Taylorella equigenitalis were identified by a polymerase chain reaction using a primer pair specific to the 16S rDNA of T equigenitalis. These eight strains were chosen because they had previously been shown to represent eight distinct genotypes by pulsed-field gel electrophoresis analysis after separate digestion of the genomic DNA with ApaI or NotI. The eight strains could be classified into six or seven types by random amplified polymorphic DNA analysis using different kinds of primers. Amplified rDNA restriction analysis after separate digestion with five restriction enzymes, including AluI and MboI, of the 1,500 bp fragments of rDNA amplified by polymerase chain reaction did not discriminate the genomic variations among the eight strains of T equigenitalis. Thus, pulsed-field gel electrophoresis was shown to discriminate these eight organisms better than random amplified polymorphic DNA analysis, while amplified rDNA restriction analysis was found to be unsuitable for subtyping T equigenitalis.