饲料霉变及其对猪只的危害

全世界范围内，饲料霉变的现象都很严重，霉变饲料对畜禽养殖业带来了极大的危害，根据联合国粮农组织估算，全世界每年大约有5％-7％粮食、饲料等农作物产品受霉菌污染，每年由于霉菌毒素造成的损失高迭6亿美元。本文简要综述了饲料霉变及其霉变饲料对猪只的危害。     

玉米霉变对养猪生产的影响与防制措施

当前养猪生产中因饲喂霉变玉米而导致猪只的急、慢性中毒、导致猪只的生长发育、母猪生产、繁殖性、仔猪的成活率等情况时有发生;同时,猪只肌肉、内脏中的霉菌毒素还可能通过食物链传递给人,影响人体健康,造成更大的危害。因此,充分认识玉米霉变对养猪生产的危害,制订和实施有效的防制措施,对于保护人畜健康、促进养猪业的健康发展具有重要的现实意义。     

饲料霉变及其对猪只的危害

全世界范围内,饲料霉变的现象都很严重,霉变饲料对畜禽养殖业带来了极大的危害,根据联合国粮农组织估算,全世界每年大约有5%～7%的粮食、饲料等农作物产品受霉菌污染,每年由于霉菌毒素造成的损失高达6亿美元。本文简要综述了饲料霉变及其霉变饲料对猪只的危害。     

霉变玉米对畜禽的危害及其防治

霉变玉米不仅其营养价值降低,作饲料使用会对畜禽造成危害,使增重减慢,饲料转换率下降,发病率和死亡率增加,已影响到人类食品的安全。笔者就玉米霉变对畜禽的危害及防治措施等方面进行了分析,以期为生产中避免玉米霉变,发展健康养殖提供参考。     

微波能的“美味鱼干”防霉新技术

美味鱼干、美鲜鱼干深受国内外市场的欢迎，但其“霉变”是销售市场的一大障碍。特别是出口的“美味鱼干”的防霉长年得不到解决，影响创汇。     

玉米霉变对养殖业的危害及应对措施

玉米是人类赖以生存的主要粮食品种之一,是养殖业所用饲料的主要原料之一。全世界年产玉米近5亿吨,中国年产量居世界第2位,占世界玉米总产量的20%左右。世界上每年大约有25%的玉米遭受各种霉菌污染,因污染程度不同,造成损失的不同,地区差异较大。中国是霉菌毒素的重灾国,原因是     

玉米霉变对养猪生产的危害与防制措施

气候变化是导致玉米发霉重要因素,霉变的玉米被加工成饲料喂猪,可降低了饲料适口性和营养价值,还产生一些有毒有害的代谢产物,导致猪急、慢性中毒,严重影响猪的生长发育、仔猪的成活率、母猪生产、繁殖性能,此外,残留于猪只肌肉、内脏中的霉菌毒素还可能通过食物链传递给人,从而影响人体健康,造成更大的危害。综述玉米霉变产生的原因、种类、危害以及防制对策。     

饲料霉变的原因、危害及预防措施

饲料是畜禽养殖的物质基础,但由于种种原因饲料被霉菌感染导致霉变,霉变的饲料既危害动物健康也造成极大的饲料浪费,越来越成为畜牧业生产中不可忽视的重大难题,综述了饲料霉变的原因、危害及预防措施。     

高温季节谈防霉

<正> 随着饲料产业的工业化、规模化,饲料的保质防霉工作显得更为重要,尤其是炎热、潮湿适宜霉菌生长、繁殖的季节,做好饲料防霉工作不仅可以减少损失、提高效益,还可以起到树立品牌形象、维护良好商誉的作用。现结合我厂实际情况,谈谈如何做好饲料防霉工作。     

鲣节霉中的几种肽酶的研究

对鲣节霉的5株散囊菌中几种肽酶的活性研究结果表明：在这5林霉菌中存在酸性蛋白酶和酸性波肽酶P的活性；不同菌种的这两种酶的活性有一定的差异，但大多数在PH4．0时其活性最强；该蛋白酶是以NE－3菌株（Einrotiumrepens，No8109）的活性最强，该羧肽酶P是以NU-1菌株（Enrotiumrubrum,No4454）的最强。对该羧肽酶P的性质研究结果表明：它可被Ca2+活化，可被Zn2+、Cu2+及Ag+强烈抑制，还受DFP、蛋白酶抑制剂和碘乙酸的抑制。羧肽酶P的端解活性同谷氨酸和酪氨酸两者有关。在上述5株散囊菌中均未表现亮氨酸一氨肽酶和级肽酶A及B的活性。     

大肠埃希氏菌和肺炎克雷伯氏菌的药敏试验

大肠埃希氏菌和肺炎克雷伯氏菌是动物肠道内的常见细菌,体弱和幼龄动物受气温变化或食物变换等因素的影响时,肠道内的这些条件性病原菌便大量繁殖,引起胃肠道疾病或败血病。采集这2种病原菌EL-1株(大肠埃希氏菌)和EL-2株(肺炎克雷伯氏菌),在培养基上培养生长,再制备各种抗菌药片进行药敏试验。经动物试验肠霉素试验和抗原性研究,证明EL-1株和EL-2株能致死小白鼠,能产生肠毒素,具有较好的抗原性和较强的毒性。本试验通过药敏试验来检测这2种病原菌对不同抗菌药物的敏感性,以选择出有效药物用于预防和治疗这类疾病。试验表明,EL-1株和EL-2株除对氟哌酸、氟嗪酸、氯霉素和复方磺胺抗菌素有较高敏感性外,对其它抗菌药物具有不同程度抗药性。     

一种保存鱼类鳍条的便捷方法

鳍条是研究鱼类分子生物学常用的组织样本,长期保存的鳍条为实验提供源源不断的基因组DNA。本研究介绍一种便捷保存鱼类鳍条用于DNA提取的方法---干燥法,并说明了用此方法保存鲤（Cyprinus carpio）、施氏鲟（Acipenser schrenckii）和虹鳟（Onchorynchus mykiss）鳍条效果。采集新鲜鳍条,贴在滤纸等吸水性强的纸张上,覆盖另一张滤纸,防止受潮、霉变,自然干燥后在室温保存3个月。剪取部分鳍条样本,用常规酚、氯仿抽提法提取基因组DNA,分别用紫外分光光度计、琼脂糖凝胶电泳、PCR扩增方法检测基因组DNA的质量。结果显示：用干燥法保存的3种鱼类的鳍条样品,提取获得的基因组DNA的OD260/OD280值在1.82-1.89之间, OD260/OD230值在2.29-2.70之间,琼脂糖凝胶电泳条带清晰明亮,可以用于后续的分子生物学研究。本研究证实用干燥法长期保存鱼类鳍条能够获得高质量的基因组DNA,为珍贵样品的长期保存提供了一种行之有效的方法,也为远距离、大样品的采集和保存提供了便捷的选择。     

The duality of teleost gonadotropins

The duality of salmon gonadotropins has been proved by biochemical, biological, and immunological characterization of two chemically distinc gonadotropins. GTH I and GTH II were equipotent in stimulating estradiol production, whereas GTH II appears to be more potent in stimulating maturational steroid synthesis. The ratio of plasma levels and pituitary contents of GTHs and the secretory control by a GnRH suggest that GTH I is the predominant GTH during vitellogenesis and early stages of spermatogenesis in salmonids, whereas GTH II is predominant at the time of spermiation and ovulation. GTH I and GTH II are found in distinctly separate cells. In trout, GTH I is expressed first in ontogeny, whereas GTH II cells appear coincident with the onset of spermatogenesis and vitellogenesis, and increase dramatically at the time of final reproductive maturation. Comparison of the amino acid sequences of polypeptides and the base sequences of cDNA revealed that salmon GTH I β is more similar to bovine FSHβ than bovine LHβ and salmon GTH II β shows higher homology to bovine LHβ than to bovine FSHβ. The existence of two pituitary gonadotropins in teleosts as well as tetrapods suggests that the divergence of the GTH gene took place earlier than the time of divergence of teleosts from the main line of evolution leading to tetrapods.     

The basics of bio-flocs technology: The added value for aquaculture

The expansion of the aquaculture production is restricted due to the pressure it causes on the environment by the discharge of waste products in the water bodies and by its dependence on fish oil and fishmeal. Aquaculture using bio-flocs technology (BFT) offers a solution to both problems. It combines the removal of nutrients from the water with the production of microbial biomass, which can in situ be used by the culture species as additional food source. Understanding the basics of bio-flocculation is essential for optimal practice. Cells in the flocs can profit from advective flow and as a result, exhibit faster substrate uptake than the planktonic cells. The latter mechanisms appear to be valid for low to moderate mixing intensities as those occurring in most aquaculture systems (0.1–10 W m^− 3). Yet, other factors such as dissolved oxygen concentration, choice of organic carbon source and organic loading rate also influence the floc growth. These are all strongly interrelated. It is generally assumed that both ionic binding in accordance with the DLVO theory and Velcro-like molecular binding by means of cellular produced extracellular extensions are playing a role in the aggregation process. Other aggregation factors, such as changing the cell surface charge by extracellular polymers or quorum sensing are also at hand. Physicochemical measurements such as the level of protein, poly-β-hydroxybutyrate and fatty acids can be used to characterize microbial flocs. Molecular methods such as FISH, (real-time) PCR and DGGE allow detecting specific species, evaluating the maturity and stability of the cooperative microbial community and quantifying specific functional genes. Finally, from the practical point of view for aquaculture, it is of interest to have microbial bio-flocs that have a high added value and thus are rich in nutrients. In this respect, the strategy to have a predominance of bacteria which can easily be digested by the aquaculture animals or which contain energy rich storage products such as the poly-β-hydroxybutyrate, appears to be of particular interest.     

辽宁省主要河流水生态状况评价及保护对策

从水文水资源、水环境状况、河流的物理形态、生物状况和社会环境等5方面,基于2012年各河流水功能区水质监测数据以及1956-2010年长序列水文资料分析、各河流水生态现状调查及水质监测结果,应用模糊数学的方法建立水生态状况评价模型,评价辽河干流、浑河、太子河等12条河流水生态状况。浑江桓仁水库以下、蒲石河、爱河和大洋河总体评价为优,太子河葠窝水库以上段为良,清河、小凌河和六股河为中,辽河干流、绕阳河、浑河、太子河葠窝水库以下段、大凌河为劣。各河段的约束指标,浑江桓仁水库以下、爱河、蒲石河等为纵向连通性,清河和太子河葠窝水库以上为水资源开发利用程度和纵向连通性,辽河干流、绕阳河和大凌河白石水库以下为生态基流满足程度和水功能区达标率,六股河为生态基流满足程度,小凌河为生态基流满足程度和纵向连通性,太子河葠窝水库以下河段为水资源开发利用程度和水功能区达标率,浑河为水资源开发利用程度、生态基流满足程度、纵向连通性和水功能区水质达标率。     

The glutathione S-transferases of fish

Substantial soluble glutathione S-transferase activity and millimolar reduced glutathione (GSH) are present in most tissues of both teleosts and elasmobranchs. The hepatic enzymes of fish conjugate a range of electrophilic substrates with GSH, although their specificities are less broad than those of the transferases in rodent liver. There is no good evidence that fish transferases have ligandin-like activity or a suicide function. All fish livers tested have several transferase isoenzymes. They are dimers of subunits whose M_rs are about 25 kDa and which may have different catalytic properties. In some species transferase activity is induced by agents such as phenols or 3-methylcholanthrene. Glutathione S-transferases are important detoxication enzymes in fish.     

The Pelagos Sanctuary for Mediterranean marine mammals

• 1. In February 2002, France, Italy and Monaco agreed to establish an international sanctuary for Mediterranean marine mammals. The resulting Pelagos Sanctuary encompasses over 87500 km² of the north‐western Mediterranean Sea, extending between south‐eastern France, Monaco, north‐western Italy and northern Sardinia, and surrounding Corsica and the Tuscan Archipelago.
• 2. The Pelagos Sanctuary illustrates how the tenets of Marine Protected Area (MPA) design can be reconciled with the dynamic nature of oceanic systems, because its spatial scale was defined by oceanographic and ecological considerations, specifically the location of the Ligurian permanent frontal system.
• 3. By expanding protective measures beyond national waters, the Pelagos Sanctuary also sets a precedent for the implementation of pelagic protected areas in the high seas. The Pelagos Sanctuary will contribute to the conservation of the Mediterranean Sea at two scales: (i) locally, by protecting important cetacean foraging and breeding grounds in the Ligurian Sea, and by providing ‘umbrella’ protection to other marine predators in this area; and (ii) regionally, by empowering other conservation measures, such as the Specially Protected Areas Protocol of the Barcelona Convention and the wider goals of the Agreement on the Conservation of Cetaceans of the Black and Mediterranean Seas (ACCOBAMS).
• 4. However, because few cetacean species are resident within the Sanctuary, their effective long‐term conservation will require large‐scale management and coordinated monitoring throughout the Mediterranean basin.

Copyright © 2007 John Wiley & Sons, Ltd.     

The barefoot ecologist goes fishing

Haliotid (abalone) fisheries are comprised of small‐scale (<5 km²) stocks and serve as a model for many such fisheries. Extremely valuable to local fishing communities in aggregate, these micro‐stocks are myriad and complex to study, monitor, assess and manage. Micro‐stocks need assessment and management at local scales to prevent small components from suffering the tragedy of commons. This paper asks how can we ever hope to address the research and management needs of so many small resources? Community‐based and territorial rights‐based systems may help in sustaining these resources, but servicing the technical needs of many small communities of stakeholders raises problems. A new generation of ‘barefoot ecologists’ is envisaged to perform this task.     

The solubility of oxygen in physiological salines

The oxygen solubility coefficient (O₂) of several different physiological saline solutions was measured over a broad range of temperatures (0 to 25C). Distilled water had a higher value than a physiological salt solution (similar to Cortland's saline). Plasma expanders (polyvinylpyrrolidone, dextran, albumin) lowered the O₂ value of the physiological salt solution. A salt solution with a 4% (w/v) mixture of protein substitute had a lower O₂ value than the corresponding 1% mixture. The solubility of oxygen was inversely related to temperature.