Parasitism in llamas

Llamas in North America are infected with a number of helminth parasites, including: gastrointestinal nematodes, lungworms, meningeal worms, tapeworms, and flukes. Most of these helminths can be treated with the anthelmintic currently used to treat cattle and sheep. At least two protozoan parasites, coccidia and toxoplasma, have been reported in the llamas in North America. Coccidia can be controlled with the anticoccidial drugs used to control these organisms in other domestic animals. Toxoplasma has been reported uncommonly in llamas in North America and control is very difficult. Several external parasites occur in llamas in North America, including lice, mites, ticks, and the deer nasal bot. Except for the deer nasal bot, the other external parasites in the llama can be treated with pesticides approved for use in cattle.     

The Effects of Anthelmintic Treatments on the Development of Gastrointestinal Parasitism in Calves

Fortnightly treatment of susceptible calves with 1-tetramisole during the first two months of continuous exposure to pastures residually heavily-infected with Ostertagia ostertagi, Cooperia oncophora and Nematodirus helvetianus did not prevent the development of clinical parasitic gastroenteritis, although the infections were not as severe as in nontreated calves. Development of resistance in treated calves was manifested by significantly smaller numbers of Cooperia eggs in utero (which were reflected by reduced fecal egg counts) and by significantly smaller Nematodirus worm burdens than in susceptible calves that commenced grazing coincident with cessation of treatment. The findings also indicated that resistance to Nematodirus helvetianus was slower in developing in treated than in nontreated infected calves.     

营养素对动物表观遗传的影响及其机制

表观遗传是环境因素和细胞内的遗传物质相互作用的结果.表观遗传学是在DNA碱基序列不变的前提下引起的基因表达或细胞表观型变化的一种遗传现象,具体表现在以下3个既相互独立又相互作用的方面:DNA甲基化、组蛋白修饰和microRNA (miRNA)调控.本文就表观遗传的研究进展及营养素对动物表观遗传的影响及其机制进行综述.     

锌对动物免疫功能的作用效应

综述锌对畜禽、实验动物和人类免疫器官产生的不同效应及对免疫反应调节的环节、部位、方式,并提出了在未来研究中应当注意的一些重要问题。     

The Effects of Age and Previous Infection on the Development of Gastrointestinal Parasitism in Cattle

An age resistance in cattle to establishment of infection with Cooperia oncophora was not demonstrated. Cattle exposed to a heavy infection for the first time at approximately 15 months of age were as susceptible to establishment of infection as 3 to 4 month old calves, but stunting of worms and inhibition of ovulation did occur in the older animals, possibly due to a rapid development of resistance as a result of sensitization by a previous extremely light infection.

An age resistance in cattle to infection with Nematordirus helvetianus was not clearly demonstrated. At necropsy, 8 of 9 calves and 2 of 6 yearlings exposed to pasture infections for the first time did harbour Nematodirus worm burdens, while yearlings which were heavily infected previously were completely free of this species.

Under the conditions of this investigation, age and acquired resistance to Ostertagia ostertagi were not demonstrated, since previously non-exposed calves and yearlings and previously infected yearlings had comparable worm burdens.

This study demonstrated the adverse effect that heavy parasitism has on the development of susceptible animals. Animals which had little or no exposure to parasitism were found to be much more susceptible to the effects of parasites than were resistant animals.

     

The Effects of Hypertonic Saline in Healthy and Diseased Animals

In this review, the pharmacological effects of administering hypertonic solutions to both healthy animals and during experimentally induced diseases are considered with a view to understanding the mechanisms behind the possible clinical efficacy of such treatment. The review focuses successively on haemorrhagic shock, endotoxic shock and hypokalaemic metabolic alkalosis. How hypertonic saline solutions affect oxygen transport by haemoglobin is also considered.     

牛磺酸对动物中枢神经系统的作用

牛磺酸(taurine)在大脑中含量丰富,对中枢神经系统具有重要作用,其可作为神经递质,参与细胞的生理活动;可作为神经营养因子,参与中枢神经系统的发育;也可作为渗透调节物质,调节钙的运输;同时牛磺酸还是神经保护剂,维持细胞膜结构的完整性,对谷氨酸产生的神经毒作用及内质网应激、线粒体紊乱具有保护作用。论文主要从神经递质、神经营养因子及神经保护作用等方面对牛磺酸在动物中枢神经系统的作用进行阐述,旨在为牛磺酸在动物神经发育及神经损伤修复中的应用提供参考。     

音乐对动物福利水平的影响

论文简述了音乐对动物的作用机理,并从生长性能、行为表达、生理指标等方面综述了音乐对动物福利水平的影响,以期为福利养殖中应用音乐缓解畜禽应激提供理论依据。     

Klossiella Muris Parasitism in Laboratory Mice

Parasitic infection with Klossiella muris was encountered in two strains of laboratory mice. Various developmental stages of the organism were observed in the glomerular endothelium and tubular epithelium.     

硒对雄性动物繁殖性能影响的研究进展

硒作为许多具有重要生物功能的硒酶的活性中心,与机体的抗氧化作用、免疫应答及内分泌等功能密切相关,直接或间接影响动物的生长、发育和繁殖[1,2]。长期低硒可以引起雄性动物的亚不育[3～7],这表明微量元素硒缺乏影响着雄性动物的繁殖性能。