发酵饲料及在我国家兔生产中的应用

文章概述了生物发酵饲料的基本概念、发酵的主要原料、菌种及发酵工艺;总结了生物发酵饲料在我国家兔生产中的应用效果,包括对生产性能的影响、替抗及对腹泻和成活率的影响、对营养物质消化率的影响、对产品品质的影响、对生理生化指标的影响、对肠道菌群的影响、对小肠黏膜形态的影响、对饲养环境的影响,以及对霉菌毒素的影响等。最后提出发酵饲料存在的问题及未来展望。     

论草原生态保护与经济效益获取平衡的影响因素

在简要介绍草原生态保护与效益获取模式的基础上,论述了影响草原生态保护与经济效益获取平衡的因素,包括自然资源的影响、草原地表获取商品状况的影响、天然草原外部因素的影响、管理制度的影响、资本投入的影响和文化、信仰与人口状况的影响。     

猪抗病力的影响因素——营养

猪机体营养对抗病力的影响包括影响机体免疫系统发育与功能、影响肠道发育与健康、影响传染性疾病的发生发展、影响抗病基因的表达、缓解霉菌毒素的危害等方面。因此,猪的营养状况影响着机体的免疫功能和对疾病的抵抗力,而机体的健康状况又影响着猪的营养需要。     

违法违规调运生猪的原因分析与综合治理对策

本文分析了违法违规调运生猪行为发生的原因:疫情影响、产能影响、季节影响、产销方式影响、利益驱动影响、监管能力及水平的影响;提出了综合治理对策:促进产能尽快恢复,转变生产经营方式,提升全链条监管能力和水平。     

用Wood模型拟合四川地区黑白花奶牛泌乳曲线的研究

用四川省阳坪种牛场 1 992年— 1 997年的黑白花奶牛共计 31 2个泌乳期的泌乳曲线 ,以研究胎次、产犊季节、干奶天数和初产年龄四个因素对模型参数估计值的影响。结果表明 :胎次的差异对参数a、b、c影响显著 ,对参数tmax影响不显著 ;产犊季节的差异对参数tmax影响显著 ,对参数a、b、c影响不显著 ;初产年龄的差异对参数a影响显著 ,对参数b、c、tmax影响不显著 ;干奶天数的差异对参数b、c、tmax影响显著 ,对参数a影响不显著 ;此外还给出了Wood模型拟合四川地区黑白花奶牛泌乳曲线的参数估计值     

浅析影响缉毒犬训练使用的几个因素

影响缉毒犬训练使用的因素很多,而单兵作战和团队合作时的影响因素又有所不同。单兵作战时,主要是一些自然因素和训导员自身的影响,团队合作时,主要是战术运用对缉毒犬的影响。一、单兵作战时的影响因素单兵作战时,主要从气流、环境、牵引带、犬舍、日常饲养等方面考虑,训导员自身是活动的主体,是各种因素的影响者。(一)室外气流对毒品气味扩散的影响气流影响毒品气味扩散的方向、速度和范围。气流对毒品气味的影响呈锥体,毒品源就是气味锥     

浅谈气象环境条件对学校教学和体育活动的影响

在学校教学和体育活动中,特别是学校体育活动,经常受到天气等环境的影响和限制,给学校教学秩序、学生身体健康和人身安全带来严重的影响和安全隐患。本文从天气对体育场地的影响、对学生人身安全危害的影响、对学生身体健康的影响、对学生情绪的影响四个方面进行了探讨,有针对性地提出了应对不利天气对学校体育活动影响的措施。     

浅析次生变化对翡翠鉴定的影响

次生变化是翡翠中常见的现象,影响翡翠的宝石学特征。本文通过对翡翠的次生变化进行分析,探讨次生变化对翡翠颜色、光泽、透明度、成分、密度和硬度等方面的影响。结果表明:次生变化对翡翠的颜色、光泽、透明度影响明显;对成分、密度影响程度受次生变化的强度、次生矿物的类别和含量所控制,次生变化强烈、次生矿物多样且含量较多时影响程度才明显;反之,成分、密度和硬度均无明显影响。     

温度对蜜蜂影响的研究进展

温度是影响蜜蜂生活的最主要因素之一.从温度对蜜蜂个体影响、蜂群与温度间关系、温度对蜜蜂发育的影响、温度与蜜蜂病虫害发生间关系四方面综述温度对蜜蜂影响的国内外研究进展.     

两种添加剂联合使用对种公猪精液量及品质的影响

正猪的生产和繁殖性能会因环境、疾病、营养及管理等的不同而受到影响,其中环境的影响,尤其是夏季高温高湿的影响,特别是对公猪精液品质的影响巨大,生产中可以借助添加剂来改善。猪的生产和繁殖性能受到环境、疾病、营养及管理等各方面的影响,其中环境的影响,尤其是夏季高温高湿的影响,特别是对公猪精液品质的影响巨大,并且已经有大量的试验论     

体外培养鸽嗉囊组织形态学、酶活力及基因表达动态变化规律

本试验旨在探究体外培养鸽嗉囊组织形态学、酶活力及基因表达变化规律。取60周龄美国王鸽嗉囊组织于体外培养7 d,动态检测其形态学、代谢和凋亡相关酶活力以及角蛋白和凋亡相关基因表达的变化。形态学结果表明:鸽嗉囊组织于体外培养第2~4天结构清晰,上皮层细胞排列紧密,体外培养5 d后嗉囊结构显著退化,形态学受到破坏。酶活力和基因表达结果显示:Caspase-3酶活力于培养第1、5、6、7天显著高于培养第2~4天(P0.05);琥珀酸脱氢酶、Na~+-K~+-ATP酶、Ca~(2+)-Mg~(2+)-ATP酶和总ATP酶活力以及Bcl-2和角蛋白19基因表达均于培养第1、6、7天显著下调(P0.05),于培养第2~4天显著升高(P0.05);Bak1基因表达于培养第2~5天稳定,随后于培养第6天显著上调(P0.05)。综上所述,体外培养鸽嗉囊组织形态学、酶活力和基因表达随培养时间延长而显著改变。本试验条件下,鸽嗉囊组织体外培养稳定时间为4 d,且开展后续药理、病理及生理学试验前的1 d预培养十分必要。     

2,4-D和BAP对蒙古冰草幼胚愈伤组织诱导及生长的影响

以蒙古冰草为材料。在离体培养条件下对其幼胚的发育进行了研究。结果表明：蒙古冰草的幼胚在不含任何激素的培养基上能直接萌发，幼胚发芽率因培养基而异。N6＋7％蔗糖培养基萌发率最高，达96％；其次为MS＋5％蔗糖培养基。萌发率为90％。当幼胚被培养在减半的N6培养基或减半的MS培养基上时，发芽率均显著降低。以上四种培养基均未发生脱分化现象。相反，在含有2，4-二氯苯氧乙酸（2，4-D）的培养基上，蒙古冰草幼胚不同程度地发生了脱分化，并出现了少量再生芽。在继代培养基中，降低2，4D浓度，附加低浓度6-苄氨基嘌呤（BAP）可以改善蒙古冰草幼胚愈伤组织状态，增加胚性愈伤组织诱导率。从而提高分化率。     

酵母粉对黑腹果蝇生长发育及产卵能力的影响

为探索不同浓度的酵母粉(0、1.5%、3.0%)对黑腹果蝇生长发育及雌虫产卵能力的影响,分别对果蝇幼虫发育时间、白色预蛹重量以及雌虫产卵数进行测定。结果表明:利用不添加酵母的培养基饲养的果蝇在1龄幼虫阶段即发生死亡;随着培养基中酵母粉含量的增加,果蝇幼虫发育时间缩短,当酵母粉含量为1.5%时,幼虫发育时间与理论值接近,同时,雌虫产卵量显著提高(P<0.05);酵母浓度对蛹重无显著影响(P>0.05)。研究结果为实验室果蝇的正常饲养以及果蝇发育生物学的研究提供了理论基础。     

不同培养时间对绵羊卵泡颗粒细胞分泌雌二醇和孕酮的影响

以绵羊卵泡颗粒细胞为研究对象，采用体外培养细胞的方法，分别于不同时间收集细胞培养液，用放射免疫法（RIA）测定雌二醇和孕酮含量。结果表明：不同培养时间对卵泡颗粒细胞分泌雌二醇影响显著，24h、36h、48h之间差异均极显著（P＜0.001），并随时间延长，雌二醇含量呈下降趋势；在不同时间收集的细胞培养液中检测不到孕酮。     

ELISA and fecal culture for paratuberculosis (Johne's disease): sensitivity and specificity of each method

The sensitivity and specificity of the ELISA and fecal culture tests for paratuberculosis in dairy cattle are examined. ELISA and fecal culture data from seven dairy herds where both fecal cultures and ELISA testing was done concurrently are included. A cohort of 954 cattle including 697 parturient adults, cultured every 6 months from 10 herds followed over 4 years served as the basis to determine fecal culture sensitivity. The fecal culture technique utilized a 2g sample with centrifugation and double incubation. Of the 954 cattle cohort of all ages (calf to adult) that were fecal sampled on the first herd visit, 79 were culture positive. An additional 131 animals were detected as culture positive over the next seven tests at 6-month intervals. The sensitivity of fecal culture to detect infected cattle on the first sampling was 38%. Of the 697 parturient cattle cohort, 67 were positive on the first fecal culture, while an additional 91 adult cattle were culture positive over the next seven tests, resulting in a sensitivity of 42% on the first culture of the total animals identified as culture positive. Animals culled from the herds prior to being detected as infected and animals always fecal culture negative with culture positive tissues at slaughter are not included in the calculations. Both groups of infected cattle will lower the apparent sensitivity of fecal culture. Infected dairy herds tested concurrently with both fecal culture and ELISA usually resulted in more than twofold positive animals by culture compared to ELISA.The classification of infected cattle by the extent of shedding of Mycobacterium paratuberculosis in the feces helps define the relative proportion of cattle in each group and therefore the likelihood of detection by the ELISA test. ELISA has a higher sensitivity in animals with a heavier bacterial load, i.e. high shedders (75%) compared to low shedders (15%). Repeated testing of infected herds identifies a higher proportion of low shedders which are more likely to be ELISA negative. Thus, the sensitivity of the ELISA test decreases with repeated herd testing over time, since heavy shedders will be culled first from the herds.     

Comparative sensitivity of various faecal culture methods and ELISA in dairy cattle herds with endemic Johne's disease

In three New South Wales dairy cattle herds with endemic Johne's disease, prevalence rates by faecal culture were determined to be 12, 18 and 22%, respectively. Whole herd faecal culture was shown to detect markedly more infected cattle than whole herd testing by the EMAI absorbed ELISA, particularly in the two herds with greatest prevalence. In the three study herds, five methods for whole herd faecal culture were compared in each. These included two methods based on primary culture on Herrold's egg yolk medium with mycobactin J (HEYM): (1) conventional decontamination with sedimentation and primary culture on HEYM; (2) Whitlock decontamination and culture on HEYM. The remaining three methods were based on radiometric (BACTEC) culture: (3) decontamination and filtration to BACTEC medium; (4) modified Whitlock decontamination to BACTEC medium and (5) Whitlock decontamination to BACTEC medium. For BACTEC cultures, two methods were compared as confirmatory tests for Mycobacterium paratuberculosis: mycobactin dependence on conventional subculture to HEYM and IS900 PCR analysis of radiometric media.Among 179 cattle tested simultaneously by all five culture methods, 38 cattle were confirmed to be shedding M. paratuberculosis. In identifying shedder cattle, method 5 was the most sensitive, followed by methods 2, 4, 1, and 3 was the least sensitive. The number of BACTEC cultures confirmed by mycobactin dependence or PCR was similar.     

Effect of group culture and embryo-culture conditioned medium on development of bovine embryos

We investigated the effect of group culture on bovine embryo development, and also investigated the effect of embryo-culture conditioned medium on developmental competence of individually cultured bovine embryos. Slaughterhouse-derived bovine oocytes were matured and fertilized in vitro. The presumptive zygotes were cultured individually or cultured in groups of 2 to 5 embryos with a constant culture density (5 mul/embryo). After 7 days of culture, the rates of embryos developed to the blastocyst stage were significantly higher (P < 0.05) in group cultures of more than 3 embryos/drop than for embryo culture of 1 or 2 embryos/drop. These results suggest a beneficial effect of group culture may be exerted by possible growth promoting factors secreted by embryos. In the next experiment, we investigated the effect of timing of fresh medium replacement on the development of embryos cultured in groups. The blastocyst formation rate was lower when culture medium was replaced freshly on days 2-4 after fertilization than on days 5-6. The blastocyst formation rates of single-cultured embryos were significantly (p < 0.05) increased by the addition of conditioned medium derived from multiple-embryo culture. These results indicate that group culture promotes embryo development and that embryo culture-derived conditioned medium is effective for supporting development of single cultured embryos.     

Usefulness of aerobic microbial culture and cytologic evaluation of corneal specimens in the diagnosis of infectious ulcerative keratitis in animals

OBJECTIVE: To determine the diagnostic value of aerobic microbial culture and cytologic evaluation of corneal specimens in the diagnosis of infectious ulcerative keratitis (IUK). DESIGN: Prospective study. ANIMALS: 48 animals (26 dogs, 13 horses, 7 cats, 1 bird, and 1 llama) with corneal ulcers. PROCEDURE: Scrapings from corneal ulcers were examined cytologically. Corneal swab specimens were submitted for microbial culture. Animals were grouped according to whether they had been receiving antimicrobials at the time of admission. RESULTS: Of the 38 animals receiving antimicrobials, 19 had positive results for IUK on cytologic evaluation, 20 on microbial culture, and 26 on cytologic evaluation, microbial culture, or both. Of the 10 animals not receiving antimicrobials at the time of admission, 7 had positive results for IUK on cytologic evaluation, and 9 had positive results on microbial culture. In this group of 10 animals, additional animals with IUK were not identified on the basis of cytologic evaluation alone. When all 48 animals were considered irrespective of antimicrobial treatment, 26 and 29 had positive results for IUK on cytologic evaluation and microbial culture, respectively, whereas IUK was confirmed in 35 animals on the basis of cytologic evaluation, microbial culture results, or both. CONCLUSIONS AND CLINICAL RELEVANCE: Microbial culture and cytologic evaluation of corneal specimens maximizes identification of IUK, especially in animals receiving antimicrobial treatment. Because of serious consequences of untreated IUK, we recommend that both diagnostic tests be used to tailor treatment and reduce risk of vision impairment in animals.     

Comparison of Aerobic Culturette, Synovial Membrane Biopsy, and Blood Culture Medium in Detection of Canine Bacterial Arthritis

Canine joints were cultured 24 hours after inoculation with Staphylococcus intermedius using synovial membrane biopsy, synovial fluid on aerobic culturette and in blood culture medium, and synovial fluid incubated 24 hours in blood culture medium before being cultured. A mildly virulent strain consistently yielded positive cultures when incubated in blood culture medium 24 hours and negative cultures with the other techniques. A highly virulent strain also yielded positive cultures when incubated in blood culture medium 24 hours, which was significantly better than synovial membrane biopsy. When both strains were considered together there was no significant difference between the first three techniques; blood culture medium incubated 24 hours was significantly more reliable. These results suggest that the trauma of synovial membrane biopsy is not justified because synovial fluid culture is more reliable. Synovial fluid should be placed on an aerobic culturette and in blood culture medium, and the samples cultured immediately upon arrival at the laboratory to allow the most rapid results of culture and antibiotic sensitivity testing. The blood culture medium should be recultured after 24 hours of incubation to permit culture and antibiotic sensitivity testing of those samples (approximately 50%) that have no growth on initial culture.     

猪睾丸间质细胞的分离及培养

为丰富体细胞核移植的供体细胞种类,本研究对猪睾丸间质细胞的分离和培养方法进行了系统研究。运用酶消化法和钢网过滤筛选法获得的猪睾丸细胞,呈现圆形、细胞体积较大,培养4~6 h后开始贴壁;培养48 h后,贴壁增殖;培养3~5 d后可形成单层细胞。这一研究结果为研究和建立睾丸间质细胞体外培养体系提供技术方法和试验依据。