饲料酶在水产动物中的应用研究

饲料酶在 动物营养上应 用越来越普 遍，它能提高 动物生产速 度，提高饲料 转化率，降低 粪便污染和动 物死亡率，综 合提高动物生 产性能，已被 人们认为是一 种无残留、无 污染、无公害 的环保型添加 剂。饲料酶在 动物营养上的 研究与应用， 现在大多集中 于畜禽生产， 而在水产动物 中的应用研究 较少，报道也 不多。本文对 饲料酶在水产饲料中的应用研究，作一简述，期能起到推动应用的作用。１水产动物消化生理特点 研究动物营养，首先要对动物营养生理进行探索和研究。水产动物在动物中是一个独特的群体，绝大多数为无脊椎动物和低…     

A review of new approaches to assessing hepatic function in animals

Although a multitude of effective liver function tests are avaiable for use in animals, a variety of modifications of currently used tests have been recently reported. In addition, newer procedures now used in human medicine may also provide unique insights into assessing and detecting acquired hepatic disorders in animals. Examples of new procedures are: assessing microsomal mixed function oxidase activity by plasma caffeine clearance; estimating the extent of active hepatic fibrogenesis through serum procollagen-III peptide levels; determining hepatic blood flow and functional mass by the galactose elimination capacity; detecting primary hepatocellular cancer through serum or urinary ligandin levels; and to estimate the liver's maximal capacity to excrete indocyanine green independent of blood flow. In evaluating drugs as to their hepatotoxicity, function tests should be included in the liver profile which measure specific metabolic alterations unique to the compound under study.This work was supported by USPHS-NIH grants RR00169 and AM32297.     

Teaching implications of different educational theories and approaches

Educational theory can and should form the basis for teaching in veterinary medicine. Nevertheless, formal training for teachers in veterinary medicine is uncommon and rarely includes study of different educational theories or perspectives, leaving educators to rely on informal or "hidden" educational constructs to guide them in their everyday teaching. Using a modified case-based format, we present critiques of a hypothetical teaching scenario from four different educational viewpoints: behaviorist, cognitive, social learning, and inspired teaching approaches. The importance and utility of formal educational theory in faculty development is discussed.     

A review of experimental approaches to the analysis of emotional behaviour and their relation to stress in farm animals

The aims of the present paper are firstly to review the methods and techniques that have been developed to analyse and quantify the variables that can produce psychological distress; and, using an integrated approach, with examples where possible, to consider the significance of the information available relating to the keeping of domestic animals under present husbandry conditions. Secondly, suggestions for future research relevant to evaluating and improving farm animal welfare are discussed.     

Board-invited review: Using behavior to predict and identify ill health in animals

We review recent research in one of the oldest and most important applications of ethology: evaluating animal health. Traditionally, such evaluations have been based on subjective assessments of debilitative signs; animals are judged ill when they appear depressed or off feed. Such assessments are prone to error but can be dramatically improved with training using well-defined clinical criteria. The availability of new technology to automatically record behaviors allows for increased use of objective measures; automated measures of feeding behavior and intake are increasingly available in commercial agriculture, and recent work has shown these to be valuable indicators of illness. Research has also identified behaviors indicative of risk of disease or injury. For example, the time spent standing on wet, concrete surfaces can be used to predict susceptibility to hoof injuries in dairy cattle, and time spent nuzzling the udder of the sow can predict the risk of crushing in piglets. One conceptual advance has been to view decreased exploration, feeding, social, sexual, and other behaviors as a coordinated response that helps afflicted individuals recover from illness. We argue that the sickness behaviors most likely to decline are those that provide longer-term fitness benefits (such as play), as animals divert resources to those functions of critical short-term value such as maintaining body temperature. We urge future research assessing the strength of motivation to express sickness behaviors, allowing for quantitative estimates of how sick an animal feels. Finally, we call for new theoretical and empirical work on behaviors that may act to signal health status, including behaviors that have evolved as honest (i.e., reliable) signals of condition for offspring-parent, inter- and intra-sexual, and predator-prey communication.     

Diet and cancer prevention in humans: review of the evidence and its application to companion animals

What is cancer? Cancer is disease of damaged DNA. DNA in every cell is under constant attack, from by‐products of normal metabolism as well as external factors such as radiation and carcinogens. Humans have evolved complex mechanisms to protect DNA from damage so that affected cells either repair their DNA or die. But under certain conditions, cells with damaged DNA can both survive and gain a growth advantage over surrounding cells. Over many years, these rapidly‐growing cells can accumulate additional DNA damage (called somatic mutations) and eventually, when the damage is quite severe, they can become cancers. There are three abnormal characteristics that cells must acquire to become cancers: (1) independence from normal controls on cell growth (proliferation) and death (apoptosis); (2) the ability to stimulate formation of blood vessels to provide nutrients to support rapid cell growth (angiogenesis); and (3) the ability to grow beyond their normal location first locally (invasion) and eventually in distant sites (metastasis). Although these characteristics are shared by all cancers, the clinical characteristics of cancer vary enormously. Some cancers, for example low‐grade prostate cancer, are very slow growing and take decades to become metastatic; other cancers, such as pancreas cancer, are highly invasive and uniformly and rapidly fatal. How could diet affect cancer? The two key components underlying the development of cancer are damage to DNA and rapid cell proliferation. Many mechanisms that protect DNA from damage are dependent upon dietary intake of antioxidants or are regulated by bioactive compounds found in foods. Cell growth is regulated by many factors, including steroid hormones and growth factors such as the insulin‐like growth factors. Cell growth is also influenced by inflammatory cytokines, which stimulate the replacement of cells damaged by inflammatory reactions. Dietary patterns and diet‐related factors such as obesity affect both the levels of circulating hormones and growth factors, and the levels of pro‐ and anti‐inflammatory cytokines. In laboratory experiments, based on cell cultures and animal models, we can consistently show that bioactive food compounds and dietary manipulation can affect DNA damage and cell growth, and that these effects mediate the development and/or growth of cancer cells. Thus, most scientists believe that diet has an important influence on the risk of developing cancer. What is the evidence that diet affects cancer risk? The strongest evidence that diet affects cancer risk in humans is from comparisons across countries. In these studies, there are strong associations between “food disappearance,” (total food production and imports minus food used as animal feed) and cancer incidence, for example between dietary fat and breast cancer. From these studies we have estimated that about 35% of all cancers are associated with diet. However, more analytically rigorous approaches to examining diet and cancer relationships, such as epidemiological studies and large randomized clinical trials, have not yielded consistent and clear answers. This has been very frustrating to scientists working in the field, and has challenged us to examine both our hypotheses about diet and cancer and the approaches we use to study diet and cancer. We now understand that cancer is a very complex disease which is affected strongly both by an individual's genetic characteristics and their life‐long environmental exposures. We have learned that the standard methods used to measure diet in large epidemiological studies are probably not sufficiently accurate to detect moderate diet/cancer associations. And we have learned that randomized clinical trials to test effects of dietary change or dietary supplements on cancer risk can fail to detect associations. Thus, the entire field is now in flux as the next generation of studies are being designed. What specific diet and diet‐related factors affect cancer risk? Currently, the best evidence that diet affects cancer risk is based on the well‐established associations of obesity with increased cancer incidence and mortality. Obesity increases the risk of cancer mortality by about 30‐50%, but this association is remarkably different across cancers. Obesity appears to have an effect both on the risk of developing cancer and on the risk of dying from cancer after diagnosis and treatment. Alcohol is a direct irritant which, in combination with smoking, causes oral and esophageal cancer. Alcohol also increases the risk of breast cancer by interfering with folate metabolism, and it increases the risk of liver cancer through the inflammatory response to cirrhosis. Other dietary factors for which we have strong evidence are fat, selenium, and vegetables, especially cruciferous vegetables. Studies examining antioxidant intake from either foods or supplements have been most often negative, suggesting that in humans the role of dietary antioxidants and cancer is much more complex than in animal models. Finally, there are a long list of foods and food components that have been picked up by the media and food manufacturers as ‘cancer prevention agents,’ most notably lycopene (tomatoes), resveratrol (red wine), and genistein (soy), however most of these have not stood up to scientific scrutiny. Does studies in humans obtain for domestic animals? The applicability of studies on cancer risk in humans to domestic, companion animals is uncertain. Some mechanisms linking diet and diet‐related factors with cancer, for example the associations of obesity with serum steroids and inflammatory cytokines, the importance of selenium for the antioxidant activity of selenoproteins, and the function of vitamin E as an antioxidant, are likely similar between humans and domestic animals. In contrast, the types, distributions and activity of xenobiotic enzymes differ across species; thus the dietary induction of enzyme activity, the prevalence and types of genetic polymorphisms, and the relative susceptibility to carcinogens will likely differ as well. Finally, requirements for nutrients differ across species, with the most obvious being the requirement of dietary vitamin C that is exclusive to humans and guinea pigs. The very limited research on diet and cancer in dogs suggests that obesity, especially when young, and exposure to table foods increase breast cancer risk, while the relationship of obesity with cancer overall are probably as complex as those seen in humans. Rigorous studies to understand the association of diet with cancer risk in domestic, companion animals will be difficult, primarily because the costs of this research are high.     

Tick vaccines and the transmission of tick-borne pathogens

Ticks transmit pathogens that cause diseases which greatly impact both human and animal health. Vaccines developed against Boophilus spp. using Bm86 and Bm95 tick gut antigens demonstrated the feasibility of using vaccines for control of tick infestations. These vaccines also reduced transmission of tick-borne pathogens by decreasing exposure of susceptible hosts to ticks. The recently discovered tick antigens, 64P putative cement protein and subolesin involved in the regulation of tick feeding and reproduction, were also shown to reduce tick infestations. These antigens, together with the TROSPA receptor for Burrelia burgdorferi OspA were effective against tick-borne pathogens by reducing the infection levels in ticks and/or the transmission of the pathogen. Development of a vaccine targeted at both the tick vector and pathogen would contribute greatly to the control of tick infestations and the transmission of tick-borne diseases. These results have demonstrated that tick vaccines can be developed for control tick infestations and show promise for the prevention of the transmission of tick-borne pathogens.     

生产优质水产饲料设备的选用

~~生产优质水产饲料设备的选用@姜伟忠$江苏正昌集团有限公司科研院!江苏省溧阳市正昌路28号,邮编:213300 @宋富平$江苏正昌集团有限公司科研院!江苏省溧阳市正昌路28号,邮编:213300     

Serotypes and anti-microbial susceptibility of Plesiomonas shigelloides isolates from humans, animals and aquatic environments in different countries

A total of 73 strains of Plesiomonas shigelloides isolated from humans (24 strains) animals (21 strains) and aquatic environment (28 strains) were determined for their O:H serotype and susceptibility to 18 anti-microbial substances and to the vibriostatic agent O/129. Of all strains, 86.3% were typeable by the O and 94.5% by the H anti-sera used. The serotype distribution was heterogeneous within a country and between the countries. Of the 57 different serotypes identified, O11:H2 (2 strains), O22:H3 (4 strains), O35:HH11 (2 strains), O52:H3 (2 strains) and O90:H6 (2 strains) were found among isolates from humans and animals (mainly in cats) in Finland and Cuba, and O23:H1a1b (3 strains) among isolates from environmental sources in Slovak Republic and Italy. Most (93-100%) of all strains were susceptible to all anti-microbials tested but resistant (92-96%) to the broad-spectrum penicillins (ampicillin, mezlocillin). No correlation between anti-microbial resistance patterns and serotypes was found.     

A review of electroretinography waveforms and models and their application in the dog

Electroretinography (ERG) is a commonly used technique to study retinal function in both clinical and research ophthalmology. ERG responses can be divided into component waveforms, analysis of which can provide insight into the health and function of different types and populations of retinal cells. In dogs, ERG has been used in the characterization of normal retinal function, as well as the diagnosis of retinal diseases and measuring effects of treatment. While many components of the recorded waveform are similar across species, dogs have several notable features that should be differentiated from the responses in humans and other animals. Additionally, modifications of standard protocols, such as changing flash frequency and stimulus color, and mathematical models of ERG waveforms have been used in studies of human retinal function but have been infrequently applied to visual electrophysiology in dogs. This review provides an overview of the origins and applications of ERG in addition to potential avenues for further characterization of responses in the dog.     

Regulation of protein metabolism by insulin: value of different approaches and animal models

Insulin induces protein accretion by stimulating protein synthesis and inhibiting proteolysis. However, the mechanisms of regulation of protein metabolism by insulin are complex and still not completely understood. The use of approaches combining hyperinsulinemic clamp and isotopic methods, or measurement of the activation of intracellular kinases involved in insulin signaling, in addition to the use of different animal models in a comparative physiology process, provide better understanding of the potential regulation of protein metabolism by insulin. Studies using the clamp technique in lactating goats have shown a clear inhibitory effect of insulin on proteolysis, with an interaction between the effects of insulin and amino acids. Such studies revealed that the insulin-inhibited proteolysis is improved in lactating goats, this adaptative process limiting the mobilization of body protein under the conditions of amino acid deficit which occurs during early lactation. Insulin signaling studies in growing chickens have also provided some interesting features of insulin regulation compared to mammals. Refeeding or insulin injection leads to the activation of the early steps of insulin receptor signaling in the liver but not in the muscle. Muscle p70 S6 kinase, a kinase involved in the insulin activation of protein synthesis, was found to be markedly activated in response to insulin and to refeeding, suggesting that other signaling pathways than those classically described in mammalian muscles may be involved in signal transduction. Finally, although the role of insulin has been doubtful and has long been considered to be minor in ruminants and in avian species, this hormone clearly regulates protein metabolism in both species.     

Stress-induced and emotional eating in animals: A review of the experimental evidence and implications for companion animal obesity

Eating in response to stress or negative emotional states is well-documented in humans as well as animals in experimental settings and has been shown to work by alleviating the unpleasant emotional experience. This type of eating behavior, termed stress-induced or emotional eating, is linked to the development of obesity. Standard approaches to companion animal obesity have failed to incorporate this concept. Not every animal given more food than they need will become overweight, which raises the critical question: Why does the animal that overeats do so? If it is to help alleviate stress or negative emotional states, then the standard obesity management approach of restricting food intake without alleviating the emotional distress may actually exacerbate the distress by removing one of the animal's coping mechanisms. Moreover, because emotional eating is a coping mechanism, overeating may be a sign that an animal's psychological well-being is impaired.     

Susceptibility of different bacterial species isolated from food animals to copper sulphate, zinc chloride and antimicrobial substances used for disinfection

A total of 569 different bacterial isolates (156 Salmonella, 202 E. coli, 43 S. aureus, 38 S. hyicus, 52 E. faecalis, 78 E. faecium) were tested for susceptibility to copper sulphate, benzalkonium chloride, hydrogen peroxide and chlorhexidine using MIC determinations. A total of 442 isolates were also tested for susceptibility to formaldehyde and 177 isolates for susceptibility to zinc chloride. Enterococcal isolates formed a bimodal distribution of MICs to copper sulphate, whereas the other bacterial species formed one large population. Otherwise the isolates formed one large population of susceptibilities to the different antimicrobial agents. Large variations were observed in the susceptibility of the different bacterial species to the different compounds. Staphylococci were in general very susceptible to all antimicrobial compounds tested. The Salmonella isolates were in general less susceptible to copper sulphate, benzalkonium chloride and chlorhexidine followed by E. coli and the Gram-positive species. The opposite was the case for zinc chloride. All isolates were very susceptible to H(2)O(2) with MICs ranging from 0.002 to 0.016%, and to formaldehyde with MICs at 0.003 and 0.006%. This study showed that Danish bacterial isolates from livestock so far have not or have only to a limited degree developed resistance to antimicrobial compounds commonly used for disinfection. Acquired copper resistance was only found in enterococci. There were large differences in the intrinsic susceptibility of the different bacterial species to these compounds, and Salmonella especially seems intrinsically less susceptible than the other bacterial species, which might have human health implications.     

Investigations on the efficacy of routinely used phenotypic methods compared to genotypic approaches for the identification of staphylococcal species isolated from companion animals in Irish veterinary hospitals

Background

Identification of Staphylococci to species level in veterinary microbiology is important to inform therapeutic intervention and management. We report on the efficacy of three routinely used commercial phenotypic methods for staphylococcal species identification, namely API Staph 32 (bioMérieux), RapID (Remel) and Staph-Zym (Rosco Diagnostica) compared to genotyping as a reference method to identify 52 staphylococcal clinical isolates (23 coagulase positive; 29 coagulase negative) from companion animals in Irish veterinary hospitals.

Results

Genotyping of a 412 bp fragment of the staphylococcal tuf gene and coagulase testing were carried out on all 52 veterinary samples along with 7 reference strains. In addition, genotyping of the staphylococcal rpoB gene, as well as PCR-RFLP of the pta gene, were performed to definitively identify members of the Staphylococcus intermedius group (SIG). The API Staph 32 correctly identified all S. aureus isolates (11/11), 83% (10/12) of the SIG species, and 66% (19/29) of the coagulase negative species. RapID and Staph-Zym correctly identified 61% (14/23) and 0% (0/23) respectively of the coagulase-positives, and 10% (3/29) and 3% (1/29) respectively of the coagulase-negative species.

Conclusions

Commercially available phenotypic species identification tests are inadequate for the correct identification of both coagulase negative and coagulase positive staphylococcal species from companion animals. Genotyping using the tuf gene sequence is superior to phenotyping for identification of staphylococcal species of animal origin. However, use of PCR-RFLP of pta gene or rpoB sequencing is recommended as a confirmatory method for discriminating between SIG isolates.     

Prevalence of Toxoplasma gondii infection among animals in Algeria: A systematic review and meta-analysis

Toxoplasma gondii is a zoonotic parasite that can infect all warm-blooded animals. It is responsible for considerable economic losses in some regions and farming systems. This review aims to synthesize current findings on the prevalence and risk factors associated with T. gondii infection in animal species in Algeria. It was performed according to the recommendations of the PRISMA guideline. A total of 14 papers from 1955 to 2020 were eligible to be included in this systematic review and meta-analysis study including a number of 10,187 animals of which 2594 were positive cases (25.46 %) (24.62–26.31 %, 95 %CI). Prevalence of Toxoplasma-infection was 20.04 % in cattle, 22.57 % in sheep, 33.61 % in goats, 28.17 % in horses, 30 % in donkeys, 70.31 % in stray cats, 14.57 % in local rabbits, 30.47 % in dogs and 50.70 % in poultry farms. Adult animals and females were most infected. The highest prevalences were reported in stray cats and poultry. Rabbits were the least infected. This analysis showed a trend of increasing infection since 2015 (R² = 0.129, p > 0.05) which requires further studies to provide better prevention strategies.     

VC对水产动物的免疫增强作用研究与应用展望

VC（L－抗坏血酸）是一种具有广泛生理和免疫作用的免疫调节因子，它作为免疫增强剂应用于水产动物时，可以增强水产动物对多种传染性病原的非特异性免疫反应，提高其机体抗病力，缓解水产动物的应激症状，并提高水产动物的存活率。本文主要从VC对水产动物的体液免疫和细胞免疫两个方面阐述VC对水产动物的免疫增强作用，还就水产动物VC最适免疫剂量的影响因素作了浅议。     

基于地黄研发水产动物免疫增强剂——地黄的免疫调节研究进展

传统的免疫增强剂,如左旋咪唑、催乳素等多属于化学合成或激素类物质。它们虽然通过增强养殖动物免疫力,提高了生产性能,但却降低了产品的营养价值,并可能危及食品安全,基于中草药研制的免疫增强剂应用于养殖业可解决这一难题。地黄对免疫系统具有广泛的药理作用:地黄多糖、低聚糖、水提液以及合剂等可通过调节免疫器官、免疫细胞和免疫分子的功能,平衡机体免疫系统。众多国内外学者开展了地黄的免疫调节研究,文中通过查阅大量国内外文献,综述了近年来地黄调节机体免疫作用的研究进展,以期为研制地黄类免疫增强剂提供参考。