首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 187 毫秒
1.
Contents The sources and characteristics of endocrine disrupting compounds (EDCs) are reviewed and discussed with respect to their potential effects on farm animal health, welfare and productivity. The importance of certain properties of these compounds in relation to the expression of their biological effects is addressed together with potential routes of exposure. It is concluded that little is known of factors affecting the tissue concentrations of EDCs in farm animals, the concentrations that are required to perturb physiological function in these species, the effects of prolonged exposure to low doses, the effect of cocktails of EDCs and other pollutants or the responses of specific organs and physiological systems that are affected by EDCs. Much of the available information pertaining to EDCs is derived from epidemiological studies of wildlife species and from laboratory animal studies and while these studies have significant limitations, they are considered to be valuable indicators of potential effects in farm animal species. The results of such studies, together with the small amounts of data from studies of ruminants, indicate that there may be significant effects of exposure to environmental levels of EDCs on farm animal health, even although effects are not generally apparent in practice, at this time.  相似文献   

2.
Assessment of the hazard associated with residues in food animals must be based on an accurate estimate of the residue levels present in the final food product, as well as animal toxicology studies to determine the potential untoward effects of these residues. Extrapolation of residue levels or toxic effects produced by the administration of a chemical in one species to predict residue levels or toxicology that may be produced by lower doses in the same species or by equivalent or lower doses in another species is associated inextricably with knowledge of the pharmacokinetics of the chemical. There are several factors that may influence the pharmacokinetics of xenobiotics which, if left unconsidered, may introduce uncertainty in the predictions of toxicity following any chemical exposure. Two of these factors are dose level and species differences. Because initial toxicity studies are designed to characterize the type of toxicity and to elucidate target organ effects the use of high doses is the accepted practice. However, because biotransformation and excretion of many chemicals are capacity-limited processes, extrapolation of toxicity to lower doses, without adequate pharmacokinetic information at those lower dose levels may result in overestimation of predicted toxicity. Furthermore, determination of tissue residue levels following administration of doses that saturate these processes may result in an overestimation of residues remaining following lower doses. Finally extrapolation of toxicity results across species may result in an over or underestimation of hazard without adequate information on the pharmacokinetics of the chemical in both species.  相似文献   

3.
The long-term consequences of climate change and potential environmental degradation are likely to include aspects of disease emergence in marine plants and animals. In turn, these emerging diseases may have epizootic potential, zoonotic implications, and a complex pathogenesis involving other cofactors such as anthropogenic contaminant burden, genetics, and immunologic dysfunction. The concept of marine sentinel organisms provides one approach to evaluating aquatic ecosystem health. Such sentinels are barometers for current or potential negative impacts on individual- and population-level animal health. In turn, using marine sentinels permits better characterization and management of impacts that ultimately affect animal and human health associated with the oceans. Marine mammals are prime sentinel species because many species have long life spans, are long-term coastal residents, feed at a high trophic level, and have unique fat stores that can serve as depots for anthropogenic toxins. Marine mammals may be exposed to environmental stressors such as chemical pollutants, harmful algal biotoxins, and emerging or resurging pathogens. Since many marine mammal species share the coastal environment with humans and consume the same food, they also may serve as effective sentinels for public health problems. Finally, marine mammals are charismatic megafauna that typically stimulate an exaggerated human behavioral response and are thus more likely to be observed.  相似文献   

4.
There is a large body of literature describing effects of environmental chemicals (ECs), many of them anthropogenic with endocrine-disrupting properties, on development in rodent laboratory species, some of which lead to impaired reproduction and adverse health. This literature joins extensive human epidemiological data and opportunistic wildlife findings on health effects of ECs. In contrast, the effect of endocrine disruption on foetal development and reproductive performance in domestic species is less extensively documented. This applies both to domestic farm and to companion species even though the former is critical to food production and the latter share our homes and many aspects of the modern developed human lifestyle. In domestic species, the nature of chemicals exposure in utero and their consequences for animal health and production are poorly understood. A complication in our understanding is that the pace of development, ontogeny and efficiency of foetal and maternal hepatic and placental activity differs between domestic species. In many ways, this reflects the difficulties in understanding human exposure and consequences of that exposure for the foetus and subsequent adult from epidemiological and largely rodent-based data. It is important that domestic species are included in research into endocrine disruption because of their (i) wide variety of exposure to such chemicals, (ii) greater similarity of many developmental processes to the human, (iii) economic importance and (iv) close similarities to developed world human lifestyle in companion species.  相似文献   

5.
Conservation medicine is a discipline in which researchers and conservationists study and respond to the dynamic interplay between animals, humans, and the environment. From a wildlife perspective, animal species are encountering stressors from numerous sources. With the rapidly increasing human population, a corresponding increased demand for food, fuel, and shelter; habitat destruction; and increased competition for natural resources, the health and well-being of wild animal populations is increasingly at risk of disease and endangerment. Scientific data are needed to measure the impact that human encroachment is having on wildlife. Nonbiased biometric data provide a means to measure the amount of stress being imposed on animals from humans, the environment, and other animals. The stress response in animals functions via glucocorticoid metabolism and is regulated by the hypothalamic-pituitary-adrenal axis. Fecal glucocorticoids, in particular, may be an extremely useful biometric test, since sample collection is noninvasive to subjects and, therefore, does not introduce other variables that may alter assay results. For this reason, many researchers and conservationists have begun to use fecal glucocorticoids as a means to measure stress in various animal species. This review article summarizes the literature on many studies in which fecal glucocorticoids and their metabolites have been used to assess stress levels in various mammalian species. Variations between studies are the main focus of this review. Collection methods, storage conditions, shipping procedures, and laboratory techniques utilized by different researchers are discussed.  相似文献   

6.
Endocrine disrupting compounds (EDC) comprise a diverse group of compounds of anthropogenic origin, including organochlorine pesticides, alkyl phenols, phthalates, polychlorinated biphenyls (PCB), dioxins and polybrominated diphenyl ethers. EDC are generally present in the environment at low concentrations but they are ubiquitous and persistent and, although environmental concentrations are low, they appear to exert a range of adverse effects on animals of many species, including humans. Their effects include disruption of reproductive function and of the immune system and they can be carcinogenic. Animals may be exposed to relatively high concentrations of EDC because they persist in the environment and when ingested, they may be concentrated in fat tissue and released when the fat is mobilised during pregnancy or lactation, thus exposing, to relatively high concentrations, embryos and neonates. These stages of development are particularly susceptible to EDC effects. Very little is known of EDC body burdens in domestic animal species and particularly in those exposed to unpolluted environments. EDC concentrations in soils and plant material and their rates of ingestion and metabolism have been little studied but it is concluded that there is a potential risk of significant bioaccumulation and of associated effects on the health and reproductive capacity of domestic animals and of humans consuming animal products.  相似文献   

7.
This paper reviews available literature on the efficacy of acaricides against Amblyomma hebraeum and other tick species, and presents information on tests done with registered chemicals in the laboratory. Little published information is available on the efficacy of chemicals specifically against A. hebraeum. A host of formulations are registered for use as acaricides on cattle, sheep, and goats in South Africa and thus, by implication, against this species. Resistance has only been described to arsenic and toxaphene in Southern Africa; the other registered products are generally considered to be effective. In contrast, many efficacy tests of various chemicals in different formulations against other Amblyomma spp. have been described. These publications have mainly emanated from the USA, where bite-wounds of these ticks serve as oviposition sites for screwworm flies. In this paper, Amblyomma maculatum and Amblyomma variegatum are included as potential heartwater vectors. The acaricidal efficacy of a number of compounds, representative of different chemical classes, was tested in South Africa against an arsenic and organochlorine resistant strain of A. hebraeum. The engorged adult female immersion method was used. A disconcerting discovery was that several of these registered products failed to control this tick when used at their recommended concentrations. It is concluded that many chemicals which fail against A. hebraeum on cattle do so because of insufficient persistence. Exposure of this tick to lower levels of existing chemicals, but for longer periods, ought to provide satisfactory control for many years.  相似文献   

8.
Most of the chemicals contaminating the environment may penetrate animal organisms, causing various noxious effects there and being transferred to man via food of animal origin. It seems obligatory for veterinary medicine to play an important role in preventing environmental pollution and protecting human health. Pesticide residues may serve as a good example of the problem. Achievements and difficulties of pesticide residue analysis are discussed in view of the veterinary needs for xenobiotic toxicology.  相似文献   

9.
氯霉素残留的危害及其检测方法   总被引:22,自引:0,他引:22  
氯霉素属广谱抗生素 ,曾在畜牧业中广为应用。但氯霉素有较强的副作用和毒性作用 ,如果氯霉素在食用动物中残留 ,可通过食物链传给人类 ,长期微量摄入氯霉素 ,不仅使人体肠道正常菌群失调 ,而且还会引起多种疾病 ,对人类的健康造成危害。世界上许多国家禁止此药用于生产食品动物 ,并规定了在畜产品中氯霉素不得检出。对于氯霉素的残留 ,存在多种检测方法 ,不同的检测方法具有不同的检出限。检测限问题已成为关注的焦点 ,发达国家对检出限的要求越来越严格  相似文献   

10.
由于反刍动物生产性能的提高和抗病的需要,目前动物生产上很普遍使用抗生素,但随着公众对动物源性食品中化学残留物以及对抗生素的日益关注,需要开发新的安全性添加剂代替化学性添加剂。皂甙作为纯天然提取物在调节瘤胃发酵和动物性能方面可以代替化学添加物,由于皂甙的化学结构和添加量及日粮组成不同,许多研究结果不一致,文中就皂甙在瘤胃微生物区系、瘤胃发酵和反刍动物生产性能等方面的研究进展进行综述,以促进皂甙在反刍动物生产上的应用。  相似文献   

11.
A case-control study was carried out to determine whether residential exposure to environmental pollutants increased risk for canine lymphoma in pet dogs. One hundred one cases with cytologically or histologically confirmed lymphoma diagnosed at a veterinary teaching hospital between the middle of 1996 and the middle of 1998 were examined. Controls were obtained by choosing twice the number of dogs without neoplastic disease, with overlapping distributions of province of residence, age, sex, and breed. Information regarding animal management, residence type, professional or hobby use of chemicals by owners, and treatment with herbicides or other pesticides in the area frequently visited by the dogs was obtained with a multiple-choice questionnaire by telephone interview. Two variables were positively and independently associated with the disease, namely residency in industrial areas (odds ratio [OR]; = 8.5; 95% confidence interval [CI], 2.3-30.9) and use of chemicals by owners, specifically paints or solvents (OR = 4.6; 95% CI, 1.7-12.6). A significantly lower value of the mean age of disease onset was found in the group of dogs at risk in comparison with the group of all other dogs (6.1 +/- 0.4 years, n = 36 versus 7.5 +/- 0.4 years, n = 65, respectively; P = .008). Variables describing animal care and pesticide use were either not associated with the disease or were uninformative. We suggest that canine lymphoma may be considered a sentinel of potentially hazardous situations for humans, because of the relatively short latency between exposure and disease onset.  相似文献   

12.
Veterinary practices are unique environments that bring humans into close contact with many different species of animals; therefore, the risk of exposure to infectious pathogens is inherently different in veterinary medicine than in human medicine. In contrast to the risk of exposure to blood in human medicine, infections from zoonotic diseases in veterinary personnel are primarily related to exposure to animal faeces, infected skin, wounds, droplets and puncture wounds. Infection-control measures in veterinary practices are often insufficient to prevent zoonotic disease transmission. The Veterinary Standard Precautions (VSP) Compendium is designed to help prevent transmission of zoonotic pathogens from animal patients to veterinary personnel in private practice.  相似文献   

13.
To avoid health risks in farm animals it is necessary to limit the intake of unwanted chemical compounds via air, feed or drinking water. The basis for this procedure are experimental results of Veterinary Toxicology, after which acceptable daily intakes can be estimated. A health risk is not present, if those limits are not exceeded. Risks may not only occur as an impairment of health itself but as well as a reduction of yield of food producing animals (body growth, production of meat and fat, fertility, milk and egg production). In addition the cumulation of unwanted compounds in tissues, which are used for the production of food of animal origin, is of great importance for the limitation of daily intakes of those environmental pollutants. Following the results of toxicological experiments in the target animals "Toxicological Drinking Water Standards for Animals" can be established.  相似文献   

14.
Cryptosporidium species are intestinal protozoan parasites and are excreted in animal feces as stable oocysts. Cryptosporidium has now been detected in the feces of a wide range of ruminant and non-ruminant farmed animals, wild animals, domestic pets and birds and the parasite appears to be well adapted to survive and persist in feces for extended periods, ranging from several weeks to many months. Because of this persistence, these materials are important as potential vehicles of transmission within herds, farms, the water chain, the fresh food chain, and the wider environment. Appropriate handling of animal waste is necessary to control spread of this pathogen and to limit the significant risks of human infection. While water is a well-recognized vector of Cryptosporidium, it has only recently emerged that food may play a more significant role than previously realized in the transmission of the Cryptosporidium to humans. In the last 3-5 years, research efforts have been directed both at the development of suitable methods for isolation and detection of the parasite in foods and at the application of these methods to assess the prevalence and persistence of the parasite in a range of foods. Additionally, molecular subtyping methods have been used to establish the transmission routes of the parasite. This paper summarizes the general biology of Cryptosporidium and overviews the current research on C. parvum in the food chain. The risks posed by certain foods, such as salad/vegetable crops and beef, are discussed and control measures which may be useful in the farm-to-fork chain for these products are described.  相似文献   

15.
Physiologically based pharmacokinetic (PBPK) models for chemicals in food animals are a useful tool in estimating chemical tissue residues and withdrawal intervals. Physiological parameters such as organ weights and blood flows are an important component of a PBPK model. The objective of this study was to compile PBPK-related physiological parameter data in food animals, including cattle and swine. Comprehensive literature searches were performed in PubMed, Google Scholar, ScienceDirect, and ProQuest. Relevant literature was reviewed and tables of relevant parameters such as relative organ weights (% of body weight) and relative blood flows (% of cardiac output) were compiled for different production classes of cattle and swine. The mean and standard deviation of each parameter were calculated to characterize their variability and uncertainty and to allow investigators to conduct population PBPK analysis via Monte Carlo simulations. Regression equations using weight or age were created for parameters having sufficient data. These compiled data provide a comprehensive physiological parameter database for developing PBPK models of chemicals in cattle and swine to support animal-derived food safety assessment. This work also provides a basis to compile data in other food animal species, including goats, sheep, chickens, and turkeys.  相似文献   

16.
This paper reports physical, psychological, and chemical hazards relevant to western Canadian veterinarians as obtained by a self-administered mailed questionnaire. Nine-three percent (750/806) of veterinarians reported some form of injury during the previous 5 years; 17% of respondents (131/791) indicated injuries that resulted in 1 or more days off work. Median stress levels were similar across work environments; overall, 7% (57/813) indicated either no stress or severe stress, while 53% (428/813) indicated moderate stress. Twenty percent (3/15) of food animal practitioners and 37% (114/308) of companion animal practitioners who took X-rays reported accidental exposure. Accidental exposure to gas anesthetic was reported by 69% (394/570) of those in private practice. Exposure to chemicals occurred in all work environments. Veterinarians in western Canada are at risk of minor to severe injury due to both animal and non-animal related causes.  相似文献   

17.
Corticosteroids are invaluable therapeutic agents for treatment of ocular inflammation in small animal patients. The use of potent anti-inflammatory agents carries with it the risk of some side effects, however. Although some of these may be lessened by topical or subconjunctival administration, these routes are associated with specific ocular side effects about which the practitioner must be aware. With judicious use, corticosteroids remain a mainstay for the prevention and treatment of many painful and potentially blinding ocular diseases.  相似文献   

18.
The risk related to the presence of residues in food of animal origin has to be carefully evaluated and it is important to distinguish between the residues of veterinary drugs and environmental contaminants. The first are easily monitored and only difficultly and occasionally exceed MRL concentrations, whereas the second ones can have prolonged and high level exposures. The Safety Margins of environmental contaminants are thus lower, and the risk increases for high level consumers. It is therefore important to ovoid transfer of pollutants to food of animal origin, especially when local contamination occur.  相似文献   

19.
The risk related to the presence of residues in food of animal origin has to be carefully evaluated and it is important to distinguish between the residues of veterinary drugs and environmental contaminants. The first are easily monitored and only difficulty and occasionally exceed MRL concentrations, whereas the second ones can have prolonged and high level exposures. The Safety Margins of environmental contaminants are thus lower, and the risk increases for high level consumers. It is therefore important to ovoid transfer of pollutants to food of animal origin, especially when local contamination occur.  相似文献   

20.
There is an increasing concern over ozone depletion and its effects on the environment and human health. However, the increase in ultraviolet-B radiation (UV-B) that would result from significant losses of ozone is also potentially harmful to animals. Any increase in disease in domestic species would not only have serious animal welfare implications but may also be economically important. The diseases which are likely to increase if ozone depletion continues include the squamous cell carcinomas of the exposed, non-pigmented areas of cats, cattle, sheep and horses. Uberreiter's syndrome in dogs is also associated with exposure to UV-B and may be expected to increase, as may the severity of conditions such as infectious keratoconjunctivitis (New Forest eye) in cattle. Aquaculture systems in which fish often have little or no protection by shading may also be at risk. Cataracts and skin lesions have been associated with the exposure of farmed fish to ultraviolet radiation and have resulted in significant losses.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号