苜蓿抗寒性研究进展

在国内外大量研究成果的基础上,对苜蓿经过低温胁迫后的形态、生理生化方面的变化,苜蓿秋眠性与抗寒性的关系,现代生物技术以及辐射诱变和太空搭载在苜蓿抗寒育种中的应用进行了系统阐述,讨论了当前苜蓿抗寒性研究工作中存在的不足,并对未来的研究重点进行了展望。     

Are the Australian poultry industries vulnerable to large outbreaks of highly pathogenic avian influenza?

Objective   To describe the structure of the Australian poultry industry and discuss the potential for highly pathogenic avian influenza (HPAI) to spread between Australian poultry farms.
Procedure   High densities of poultry farms, frequent contacts between farms by service providers, the supply of live poultry markets (LPM) and the presence of free-range duck flocks in affected regions have been identified as risk factors for the spread of HPAI between flocks in outbreaks causing the death or destruction of over 1 million poultry overseas. Data on 1,594 commercial Australian chicken meat, chicken egg, duck and turkey farms were collected by a telephone questionnaire of farm managers to assess the risk of a HPAI outbreak in Australia.
Results and Discussion   Five regions of Australia had farm densities comparable to overseas regions that experienced widespread HPAI. Common service providers routinely contacted different classes and types of farms over wide geographic areas. However, no responding farms supplied LPM and the majority of duck farms did not produce free-range ducks.
Conclusion   Outbreaks of HPAI have the potential to cause serious impacts on the Australian poultry industry. The risk posted by LPM and free-range ducks is limited, but the movement of genetic stock and common service providers could spread infection between companies, industries or geographical regions. Biosecurity measures are therefore considered critical to limit the secondary spread of infection should an outbreak occur.     

GC-MS分析慢性氨气应激对肉鸡血清代谢物的影响

【目的】随着养殖业集约化和规模化的发展,舍内环境对畜禽生长的影响日益突出。在密闭舍饲条件下,不断产生有毒有害气体,其中氨气的危害最大,降低畜禽生产性能,威胁动物健康。为此开展慢性氨气应激对肉鸡血清代谢物影响的研究,从小分子物质和代谢途径方面探究氨气导致机体代谢发生的变化,为舍内氨气的合理调控提供数据支持。【方法】试验采用单因素完全随机设计,将96只21日龄健康AA肉鸡随机分成对照组和试验组,每组设4个重复,每个重复12只鸡。对照组氨气浓度为0 mg·kg^-1,试验组氨气浓度为45 mg·kg^-1。试验在人工模拟呼吸舱内进行,呼吸舱采用全自动化控制温湿度等养殖条件,采用网上平养,自由采食和饮水,24h光照,试验期为21d。在肉鸡42日龄时,从每个重复中随机抽取2只,翅静脉采血,分离血清。将血清样品预处理后,采用气相色谱/质谱联用技术(gas chromatograph tandem mass spectrometer technology, GC-MS)检测代谢产物,利用质谱数据库对其进行鉴定。通过主成分分析、偏最小二乘法判别分析、正交偏最小二...     

动态调节人工乳粘稠度和营养成分饲喂无菌大鼠效果研究

根据无菌大鼠乳鼠吮吸乳汁的规律,建立一套新的人工哺乳(AR)无菌乳鼠的方法.设计并配制6种适合不同日龄乳鼠的人工乳(LWF),并测定人工乳主要的营养成分含量和粘稠度等.无菌剖腹产术得到30只无菌乳鼠,采用吮吸法饲喂乳鼠至21日龄断乳,以30只代乳母鼠哺乳(MR)的乳鼠为对照,每日称量乳鼠体重,观察生长发育情况,计算离乳时乳鼠的生存率,检查8对100日龄以上AR无菌大鼠的生育能力.6种人工乳除LWF-6外,其余人工乳的蛋白质、脂肪、糖类、灰分、钙、钾、钠、氯、磷的含量、总能量和pH与大鼠乳相似,但这些人工乳的粘稠度不同.从LWF-1至LWF-5,蛋白质、脂肪、糖类的含量、能量和粘稠度不断增加.虽然AR乳鼠的体重增长不如MR乳鼠(2日龄时,P＜0.05;3日龄时,P＜0.01),但其生长发育正常.AR乳鼠的离乳率为73.3%,MR鼠为100%.8对AR无菌大鼠都有生育力.说明采用动态调节人工乳粘稠度和营养成分含量的方法可以用于饲喂无菌乳鼠,并且存活率较高.     

几种生长调节剂对四翅滨藜全光喷雾扦插效果的影响

四翅滨藜全光照喷雾嫩枝扦插试验结果表明:采用NAA、ABT 2号生根粉、IBA等3种外源植物生长调节剂处理插条2 h,对插条具有良好的促根作用,其中100 mg/L NAA为最好,生根率可达到93.6%;100 mg/LABT2号生根粉和100 mg/L IBA次之,生根率分别可以达到92.6%,92.3%.     

Evaluation of maternal parent and puroindoline allele on kernel texture in a reciprocal cross between two hard spring wheat cultivars

Kernel texture is an important characteristic for both the milling and the end-use quality of wheat (Triticum aestivum L.). Gene sequence variation and mutations to the two puroindoline genes (Pina and Pinb), located at the Ha locus on chromosome 5DS, account for the majority of variation in wheat kernel texture. Other factors also influence kernel texture, including effects associated with different maternal parent backgrounds. To investigate the effect of two hard puroindoline alleles in different maternal backgrounds, a population of 228 recombinant inbred lines (RILs) derived from a reciprocal cross between two wheat cultivars ID377s (Pina-D1b/Pinb-D1a) and Klasic (Pina-D1a/Pinb-D1b) were examined in two succeeding generations (F₇ & F₈). Kernel texture was determined using the Single Kernel Characterization System (SKCS) and the RIL puroindoline haplotype was identified by the sequence-specific PCR amplification of each gene. Analysis of variance identified a significant (P 0.001) effect of the maternal parent and puroindoline mutation on kernel texture. RILs containing the Pina-D1b mutation were significantly harder than lines containing the Pinb-D1b mutation. RILs which had Klasic as the maternal parent were significantly harder than those which had ID377s as the maternal parent. When the maternal parent and puroindoline allele were analyzed in combination, RILs derived from Klasic as the maternal parent and the Pina-D1b allele were significantly harder (P 0.001) than those containing the same allele but ID377s as the maternal parent. The same occurred for RILs containing the Pinb-D1b allele, lines with Klasic as the maternal parent were harder than lines with ID377s as the maternal parent. These results corroborate the harder phenotype of the Pina-D1b allele and indicate a significant maternally-inherited contribution to kernel texture variation.     

三株芽孢杆菌抑菌活性分析及对肉鸡舍空气微生物的影响

【目的】分析2株解淀粉芽孢杆菌（Bacillus amyloliquefaciens）和1株苏云金芽孢杆菌（Bacillus thuringiensis）的基本特性以及对大肠埃希氏菌（Escherichia.coli,CVCC1570）的抑制活性;分析3株芽孢杆菌复合制剂对肉鸡舍空气大肠杆菌和金黄色葡萄球菌的抑制作用,为改善畜舍环境提供基础数据。【方法】对3株芽孢杆菌进行形态学观察、镜检和生长曲线测定,以大肠埃希氏菌（CVCC1570）为指示菌株,采用琼脂扩散法对单一菌株的抑菌特性进行测定,筛选出适宜的抑菌浓度;利用三因子三水平的正交试验设计,筛选出最佳抑菌效果的复合芽孢杆菌组合;鸡舍喷洒试验采用单因子设计,分为3个处理组,每个处理设3个重复,分别为空白对照组,化学消毒剂阳性对照组（苯扎氯铵）,喷洒复合芽孢杆菌菌剂处理组。在肉鸡不同日龄检测鸡舍内大肠杆菌和金黄色葡萄球菌的变化规律。【结果】3株芽孢杆菌为革兰氏阳性需氧菌。芽孢杆菌SKN01和芽孢杆菌SKN02生长曲线相近,在培养2h开始进入对数生长期。芽孢杆菌SKN03生长较缓慢,进入对数生长期的时间相对较长。单一菌株对大肠埃希氏菌有效抑菌浓度均为108CFU•mL-1。经正交试验测定,3株芽孢杆菌复合菌液最佳抑菌组合为4×108 CFU•mL-1、4×108 CFU•mL-1、6×108 CFU•mL-1。最佳组合复合芽孢杆菌喷洒鸡舍,能够有效抑制大肠杆菌和金黄色葡萄球菌的生长,在肉鸡生长后期复合制剂的抑菌效果明显。【结论】3株芽孢杆菌能够有效抑制大肠埃希氏菌,同时复合菌液能够有效减少鸡舍有害微生物的数量,起到改善鸡舍环境的作用。     

金霉素与赖氨酸和蛋氨酸交互作用研究

采用3×2×2因子饲养试验和2×2×2因子代谢试验,研究金霉素与赖氨酸和蛋氨酸的交互作用对肉仔鸡生产性能的影响,及金霉素对两种氨基酸代谢的影响。金霉素在饲料中添加150 mg/kg时,对0-3周肉仔鸡具有显著的促生长作用（P<0.01）;并显著提高肉仔鸡的饲料采食量和饲料转化率（P<0.01）,促进氮沉积（P<0.01）。对4-6周肉仔鸡的生产性能无显著影响（P>0.05）;金霉素、赖氨酸和蛋氨酸存在显著的互作关系（P<0.05）。金霉素的促生长效果受饲料中赖氨酸和蛋氨酸含量的影响,当日粮中赖氨酸水平为1.3％,蛋氨酸水平为0.6％时,肉仔鸡的生长性能最高。金霉素对赖氨酸的利用率没有显著影响（P>0.05）,对蛋氨酸和胱氨酸的表观利用率具有显著抑制作用（P<0.05）。研究结果表明持续低剂量金霉素与蛋氨酸和赖氨酸具有交互作用,这种互作关系影响彼此对肉仔鸡生产性能的作用效果,金霉素具有提高肉仔鸡赖氨酸需要量的作用。     

芦荟对肉仔鸡生长性能和免疫功能的影响

将360只1日龄雄性AA肉仔鸡随机分成6个组,每组设6个重复,每个重复10只.Ⅰ组为空白对照组,饲喂基础日粮,Ⅱ-Ⅵ组分别在基础日粮中添加600 mg.kg-1芦荟粉、600 mg.kg-1芦荟水提取物、600 mg.kg-1芦荟醇提取物、600mg.kg-1芦荟水提取物+600 mg.kg-1芦荟醇提取物和150 mg.kg-1金霉素.结果表明:Ⅲ组3、6周鸡的体增重均显著高于Ⅰ组(P<0.05);Ⅲ-Ⅳ组的料肉比与Ⅰ组比较均极显著降低(P<0.01),Ⅲ组与Ⅵ组比较显著降低(P<0.05);Ⅱ-Ⅴ组3周鸡的脾脏指数与Ⅰ组相比,差异均显著提高(P<0.05);Ⅲ组3周鸡的胸腺指数显著高于Ⅰ组(P<0.05);Ⅱ-Ⅴ组3周鸡的自然杀伤细胞的杀伤活性均极显著高于Ⅰ组(P<0.01),Ⅱ-Ⅴ组6周鸡均极显著高于Ⅰ、Ⅵ组(P<0.01).可见芦荟粉、水提取物、醇提取物和提取物混合组均能提高肉仔鸡的生产性能和免疫功能,其中水提取物组的效果最佳.