有机酸抑菌分子机理研究进展

有机酸作为一种可有效抑制畜禽体内病原微生物增殖的饲用生长促进剂,正日益受到关注。不同有机酸抑菌机理不尽相同。笔者综述了有机酸分子水平抑菌机理研究的最新进展,包括基于能量竞争、透化细菌外膜、提高胞内渗透压、抑制生物大分子合成、诱导宿主产生抗菌肽等5种作用机制;认为细菌胞内酸根离子的聚集是有机酸抑菌作用的重要决定因素,细菌胞内外pH梯度及胞外酸根离子浓度又是影响胞内酸根离子聚集的主要因素。     

抗菌药物的抗菌后效应研究进展及其意义

抗菌药的抗菌后效应 (PAE)是新近提出的一个重要概念 ,它是细菌对抗微生物药敏感性的结构特征性指标 ,几乎是所有抗菌药物的一种性质。PAE以时间的长短来表示 ,可作为重要的药效学参数 ,可作为设计给药方案的参考依据 ,并为临床调整用药间隔提供理论基础 ,且对给药方案中存在的疗效、不良反应、费用和方便性等问题提供了很好的解决办法。该参数能较大程度地完善药效动力学评价指标 ,全面反映药物、细菌及宿主三者之间的关系 ,为临床中抗菌药物的合理使用提供了一定的思路     

镓离子的抗菌作用及机制研究进展

细菌对抗生素的耐药性越来越强,严重威胁到人类健康,饲料端禁止抗生素的使用对养殖业来说是一个新的挑战,寻找抗生素替代品已迫在眉睫。金属离子具有显著的抗菌作用,可提高动物的生产性能。镓离子不仅对肿瘤治疗有积极作用,且具有抗菌活性,此外还具有抗炎、免疫调节、抗高钙和镇痛的作用,各种镓制剂越来越多地用于抗菌和临床的研究。镓与铁的相似性使得镓可以代替铁被细菌所摄入,从而干扰细菌含铁蛋白的功能与正常的生长代谢。本文综述了镓离子的抗菌作用及机制研究进展,为其在动物生产中的应用提供理论参考。     

多糖类化合物的抗菌作用及其机制研究进展

多糖类化合物根据来源可分为植物多糖、动物多糖以及微生物多糖三大类。其不仅具有高效低毒、来源广泛的特点,还具有调节免疫功能、抗肿瘤、抗病毒、抗氧化、抗糖尿病、抗菌等多种生理功能。目前,人们已成功从高等植物、动物细胞膜以及微生物细胞壁中提取了大量多糖并广泛应用于食品、饲料、医药等行业中。随着细菌耐药性的不断产生,多糖类作为一种抗生素替代品已经成为国内外研究的热点。本文拟通过对多糖类化合物的抗菌活性以及主要机制进行详细阐述,为进一步深入开展多糖类化合物的生物活性及其作用机理研究,开发出更加安全、绿色高效的抗生素替代品提供理论依据。     

杨树花抗菌作用及机制的研究进展

随着抗菌药物在临床预防与治疗中的广泛、长期使用,抗菌药物的预防和治疗效果下降问题日益严重。中药因其特殊的抗菌机制且不易产生耐药性等特点而受到广泛关注。杨树花作为传统中药,在我国分布广泛,具有解热、镇痛、抗炎、抗菌等作用。杨树花可通过影响细菌能量合成、改变细胞完整性和提高机体免疫力方面发挥抗菌作用,就杨树花的抗菌作用及机制的研究进展进行了综述。     

药用植物挥发油的抗菌作用及机制研究进展

由于全球范围内抗生素的广泛应用,细菌耐药形势日益严峻.寻找来源广泛、抗菌谱广、无毒或低毒、对环境友好且不易产生耐药性的抗菌活性物质具有重要意义.药用植物挥发油是存在于植物中的一类具有挥发性、与水不相混溶的油状液体的总称,因其具有良好的抗病原体作用,已广泛应用于食品、医药等领域.论文详细介绍了药用植物挥发油的抗菌活性、抗...     

抗菌药物的抗菌后效应与临床合理用药

抗菌药的抗菌后效应是细菌对抗微生物药敏感性的结构特征性指标 ,几乎是所有抗菌药物的一种性质。本文综述了抗菌后效应的研究进展及其对临床合理用药的指导意义 ,为临床中抗菌药物的合理使用提供了一定的思路。     

柑橘类植物精油的抗菌活性及其作用机制

柑橘类植物精油(CEOs)是从柑橘类植物中提取的芳香类混合物,其主要活性成分为D-柠檬烯(D?limonene),具有广泛的生物活性,包括抗菌、抗氧化和抗炎等.CEOs具有选择性抗菌活性,在动物生产中具有非常重要的应用价值.不同的CEOs具有不同的抗菌活性,研究其抗菌机制也具有非常重要的意义.本文着重介绍了CEOs的化...     

兽用氟喹诺酮类的抗菌后效应、抗菌后亚抑制浓度效应、亚抑制浓度效应

5种兽医专用氟喹诺酮类抗菌药在体外对猪链球菌、大肠杆菌、多杀性巴氏杆菌均具有不同程度的PAE，最长者可达3.23h。其中对猪大肠杆菌、多杀性巴氏杆菌的PAE略长于对猪链球菌的PAE。各抗菌药对3种细菌同时也具有较PAE更长的抗菌后亚抑制浓度效应（PA-SME），并受诱导PAE的药物浓度、亚抑菌药物浓度（Sub-MIC)及细菌种类的影响。不定期一接种量细菌暴露于各Sub-MIC的药物中也表出现一定的亚抑制浓度效应（SME），且随Sub-MIC的增加而增加。     

有机酸对猪肠道菌群的调节作用及其抑菌机制研究进展

肠道菌群平衡与动物机体健康及生长发育密切相关,有机酸(organic acid, OA)作为一种绿色安全的功能性饲料添加剂,对动物具有抑菌、促消化、调节菌群平衡等作用。随着饲料产业的不断发展,OA已从饲料酸化、防腐、防霉逐渐向制剂化、动物生长促进剂和替抗产品转变,已成为畜牧行业广泛使用的一种功能性添加剂。笔者综述了猪肠道菌群的形成和分布,OA调节猪肠道菌群的组成结构和多样性及其对肠道菌群代谢产物产生和肠道免疫反应等方面的影响,并对其调控猪肠道菌群的作用机制进行探讨,旨在进一步揭示OA与肠道菌群的相互影响机制,为促进猪肠道健康与OA的合理利用提供借鉴。     

有机酸对肠道内源菌的影响及作用机理

为了研究有机酸内源菌在肠道的影响及作用机理,文章主要从仔猪、反刍、肉鸡等畜禽品种进行阐述。作为一种优质的饲料添加剂,不同的有机酸及其盐类在动物瘤胃调控功能中均能起到有益的作用。另外,短链有机酸能改善动物的免疫力和抗应激能力,而在仔猪中使用经特殊工艺包被的有机酸对于其提高健康水平和生长速度也起到很大作用。     

Effect of organic acids on the microbial quality of Taiwanese-style sausages

The effects of organic acids on the microbial quality of Taiwanese‐style sausages were studied. Pork meat from a Taiwan retail market was decontaminated with various organic acids (citric, lactic and tartaric acid), then, the raw meat was used to make Taiwanese‐style sausages and stored from 0 to 40 days at 4°C. The total plate counts, lactic acid bacteria, Micrococcus, Listeria monocytogenes, Hunter‐L and Hunter‐a values were determined. The total plate counts of the control group were initially greater than those of the treated groups. Higher incidence rates of L. monocytogenes in the products were obtained from the control group, but were not detected in the treated groups during storage. Lactic acid bacteria counts following the lactic acid treatment were lower than those of the other groups. Micrococcus counts of the controls increased by 0.6–1.2 log₁₀ colony‐forming unit (CFU)/g greater than those of treated groups throughout storage at 4°C. The light color (L‐value) of the control group gradually decreased during storage. Pork meat dipped in various organic acids was found to be suitable to extend the shelf‐life and improve the microbiological quality of Taiwanese‐style sausages.     

Effect of prebiotic fructans and organic acids on mineral retention in laying hens

Abstract

The aim of the study was to evaluate the effect of organic acids and prebiotic fructans added to the layer's diet on balance of calcium, phosphorus, and zinc. The basal experimental diet contained 3.30% Ca and 0.60% P, and was either unsupplemented or supplemented with additives as follows: 0.75% inulin, 0.75% oligofructose; 0.50% short-chain fatty acids (SCFA); 0.25% medium-chain fatty acid (MCFA); 0.30% SCFA+0.20% MCFA; and 0.75% inulin+0.50% SCFA. It was concluded that some additives used in the experiment had a positive effect on the mineral balance in hens. Inulin significantly improved retention of Ca, P, and Zn, SCFA – retention of Ca, SCFA+MCFA – retention of Zn, inulin+SCFA – retention of P and Zn.     

热应激蛋白在动物应激反应中的作用机制

热应激蛋白(heatshockproteins,HSPs)是动物在不良因素作用下所产生的一组特异性蛋白质,任何应激均可诱导机体的HSPs合成增加,它能使动物迅速适应环境变化,保护机体不受或少受损害。HSPs作为应激的调控蛋白对阐明动物的应激机理有着非常重要的作用。文中从热应激蛋白的国内外研究现状、生物学功能、在应激反应中的作用机制等方面加以综述,以期为探讨畜禽应激机理提供可行性参考。     

Effect of organic acids and mannanoligosaccharide on excretion of Salmonella typhimurium in experimentally infected growing pigs

The effect of organic acids and mannanoligosaccharide addition to the diet was assessed in pigs orally inoculated with Salmonella typhimurium. Forty-six growers were distributed among four treatments: Basal Diet (BD); BD+encapsulated organic acids; BD+free organic acids; BD+mannanoligosaccharide. Seroconversion was monitored, and feces and tissue samples were tested for Salmonella isolation. No treatment prevented the carrier state, but a tendency of lower fecal excretion was observed in the group treated with mannanoligosaccharide.     

Treatment of broiler litter with organic acids

Experiments for treatment of contaminated broiler litter with citric, tartaric and salicylic acids were performed. At days 2 and 6 after the treatment, pH values (using a pH-meter), the ammonia concentrations (titration with 0.1 N HCl) and the microbial cells counts were determined in both experimental and control specimens of litter. The cost of acidification of litter was also determined. Our studies showed that the treatment of the contaminated litter with 5 per cent citric acid, 4 per cent tartaric acid and 1.5 per cent salicylic acid created an acid medium with pH under 5.0 and thus reduced the microbial counts to 2.2 x 10(3)colony forming units per gram manure litter. The treatment reduced the content of ammonia in the litter and in the air under the hygienic limits, i.e. 25-50 ppm. The cost of acidification of litter with these organic acids amounted to 0.1 $ per bird and 1.5 $ per 15 birds on one square metre in a growth period of 50 days.     

Effect of bran diet on organic acids in the gastrointestinal tract and apparent digestibility in weanling piglets

Over a period of four weeks 88 piglets of an average weaning weight of 9.5 kg received rations with 2.1, 3.1 and 5.5% crude fibre in the original substance in the form of wheat bran. Between the 42nd and 49th day of life a digestibility investigation was carried out by means of Cr2O3, and on the 42nd and the 63rd day of life the organic acids in the complete gastro-intestinal tract could be ascertained, the causes of which are to be found in the lack of easily soluble carbohydrates (increased passage rate, bran quota). Due to crude fibre, the apparent digestibility of all nutrients decreased, which resulted in a lower live weight on the 63rd day of life. The effect of a bran diet in the alimentary prophylaxis of coli enterotoxaemia is thus furthermore substantiated.     

Effect of organic acids on numbers of yeasts and mould fungi and aerobic stability in the silage of corn

The aim of these studies was to assess the effect of chemical conservants (FA = formic acid, PA = propionic acid, FPA+i = formic acid, propionic acid and ammonium ions) on the cell counts of yeasts and mould fungi in silage. The silage was prepared from corn (Zea mays L), cultivar Buran FAO (240). The effect of the applied conservants on silage aerobic stability was also assessed. The performed chemical analyses comprised the determination of: the content of dry matter (DM), lactic acid (LA), acetic acid (AA), ethanol, water soluble sugars (WSC), crude protein (CP) and pH. The applied preparations were found to reduce the number of yeast and mould fungi cells in all the examined silages. The growth of fungi was inhibited most strongly by the FPA+i preparation (containing a mixture of formic and propionic acids and ammonium ions). The yeast cell counts dropped (P<0.05) from 8.50 107 CFU g(-1) silage in the control (CCS = control corn silage) to 2.60 107 CFU g(-1) in silage treated with FPA+i, whereas counts of the mould fungi cells - from 15.20 104 CFU g(-1) silage in the control to 4.60 104 CFU g(-1) in silage treated with FPA+i. The applied conservants increased (P<0.05) the content of DM from 255.00 g kg(-1) in control to 266.60 g kg(-1) with PA, WSC from 27.10 g kg(-1) DM to 30.50 g kg(-1) DM with FPA+i and ethanol from 9.10 g kg(-1) DM to 11.21 g kg(-1) DM with FPA+i in the silage. The additives decreased concentrations of lactic acid, acetic acid and crude protein concentration after opening the barrels. The diversifying factors decreased the pH value in the examined silage. The experimental conservants were found to improve the aerobic stability of silages after 7 days of air exposure.     

在饲料中使用有机酸可获得更好的效果

今天,我们在养殖场里所遇到的大多棘手问题往往与动物的健康有关,而与饲料无关。然而,我们却能利用计算机来优化饲料配方和饲料加工厂的生产工艺,以生产出更好的饲料。但是,利用饲料,通过利用包被型有机酸减少动物肠道中定植的病原体．我们还能够优化动物的生产性能。