益生菌在肥胖动物模型中的研究进展

肥胖已成为严重威胁人类健康的全球性疾病之一,肠道菌群组成的改变与肥胖密切相关。由于益生菌在调节肠道菌群平衡、提高机体免疫力方面具有重要功能,因此益生菌为肥胖治疗带来可能。本文从作用机制、不同动物模型等角度综述近年来益生菌在肥胖模型中的研究现状,为益生菌在临床实验和实际中的应用提供参考。     

动物源性食品和环境中磺胺类药物及其代谢物检测的样品前处理技术研究进展

兽用磺胺类药物常添加到动物饲料中用来治疗疾病和促进生长,但不合理的用药会导致磺胺类药物在动物组织中残留,影响食品安全,从而损害人类健康。此外,磺胺类药物在人体及动物体内并不能完全被吸收,大部分以原型及代谢物形式随尿液及粪便排出体外,引起细菌耐药性等一系列问题。因此建立食品和环境中磺胺类药物及其代谢物的检测方法对于保障环境及食品安全,保护人们身体健康具有重要意义。目前,检测磺胺类药物及其代谢物以色谱和质谱等仪器分析方法为主。由于食品和环境中样品基质复杂,药物浓度偏低,所以,在仪器分析前需采取适当的样品前处理对目标物进行富集和纯化。近年来,微型化、无溶剂化、自动化成为样品前处理的发展趋势,作者介绍了固相萃取、固相微萃取、分散液液微萃取、中空纤维液相微萃取、基质固相分散、分子印迹、免疫亲和色谱、场辅助萃取、QuEChERS法、浊点萃取等前处理技术的原理、优缺点及应用,并对未来样品前处理发展方向作出展望,旨在为磺胺类药物及其代谢物的检测提供理论依据。     

SMAD3基因在畜牧生产中的应用研究进展

SMAD3基因是SMADS基因家族成员之一,其编码的SMAD3蛋白是转化生长因子-β(TGF-β)超家族特异的细胞内信号转导分子,SMAD3基因通过TGF-β超家族参与疾病、免疫调节、生长发育、创伤愈合、软骨与骨骼的发育及维持等重要的生理过程,同时还参与调节生殖细胞的增殖、分化、成熟、黏附、闭锁、凋亡和甾体激素的产生等,因此,了解SMAD3基因的结构与功能对动物生长发育、繁殖等研究具有重要意义。文章简述了SMAD3基因结构、功能、作用机理,分析了其在畜牧生产方面相关的应用研究进展发现,目前SMAD3基因在畜牧生产上的应用研究主要集中在参与调控脊椎动物(猪、牛、羊、鸡等)生长、发育、细胞免疫与凋亡、激素分泌及繁殖功能方面;SMAD3基因在调控动物机体疾病发生、生长发育、脂肪沉积及繁殖性能方面仍是国内外研究的热点,而该基因对畜禽疾病发生、生长和繁殖性能的精确分子调控机制仍有待进一步研究。     

Toxoplasma gondii seroprevalence in veterinarians in Finland: Older age,living in the countryside,tasting beef during cooking and not doing small animal practice associated with seropositivity

Practising veterinary medicine has an inherent risk of exposure to zoonotic agents, including the protozoan parasite Toxoplasma gondii. We screened sera of veterinarians authorized to work in Finland for the presence of specific immunoglobulin G antibodies against T. gondii with an enzyme‐linked fluorescent assay, and evaluated potential risk factors for T. gondii seropositivity from extensive questionnaire data with almost 1,300 quantitative variables. We used a causal diagram approach to address the complexity of the life cycle of the parasite and its numerous possible transmission routes, and built a multivariable binomial logistic regression model to identify risk factors that are particularly relevant for veterinarians. The samples and questionnaire data were collected in 2009. Altogether, 294 veterinarians, almost 15% of the Finnish veterinary profession, were included in the study. The median age was 39 years, and the majority, 86%, were women. Altogether, 43 (14.6%; 95% confidence interval: 10.9–19.0) of the 294 veterinarians tested seropositive for T. gondii. According to the final model, veterinarians who were at least 40 years old had 2.4 times higher odds to be seropositive than younger veterinarians; veterinarians who lived in the countryside had 4.0 times higher odds to be seropositive than veterinarians who lived in towns; female veterinarians who tasted beef during cooking had 2.6 times higher odds to be seropositive than male veterinarians who did not taste beef during cooking; and veterinarians who did not do small animal practice had 2.3 times higher odds to be seropositive than those who did. The results illustrate the numerous transmission routes of T. gondii.     

Outbreaks of Salmonella enterica infections linked to animal contact: Demographic and outbreak characteristics and comparison to foodborne outbreaks—United States, 2009–2014

In the United States, multistate Salmonella outbreaks are most commonly linked to a food source; however, contact with live animals can also result in outbreaks of human illness. To characterize Salmonella outbreaks linked to animal contact and examine differences compared to foodborne outbreaks, we analysed data reported to the Centers for Disease Control and Prevention through the National Outbreak Reporting System (NORS) from 2009 to 2014 with a primary mode of transmission listed as “animal contact” or “food.” Four hundred and eighty‐four outbreaks with animal contact or foodborne transmission were reported through NORS; of these outbreaks, 99 (20.5%) resulted from Salmonella transmission through animal contact and 385 (79.5%) resulted from foodborne transmission, which resulted in 3,604 (19.8%) and 13,568 (80.2%) illnesses, respectively. A higher proportion of illnesses among children aged <1 year and children aged 1–4 years were linked to animal contact outbreaks compared to foodborne outbreaks (15.2% vs. 1.4%, p < 0.01 and 24.5% vs. 5.6%, p < 0.01, respectively). Illnesses resulting in hospitalizations (OR: 1.81, 95% CI: 1.62, 2.02) were more likely to be associated with animal contact compared to food. Animal contact outbreaks reported to NORS were more likely to be multistate compared to foodborne outbreaks (OR: 5.43, 95% CI: 3.37, 8.76) and had a longer median duration (99.0 days vs. 9.0 days, p < 0.01). Characterizing the differences between outbreaks of illness linked to animal contact and outbreaks linked to food provides useful information to investigators to improve public health response.     

The face of animal cognition

As an increasing number of researchers investigate the cognitive abilities of an ever‐wider range of animals, animal cognition is currently among the most exciting fields within animal behavior. Tinbergen would be proud: all four of his approaches are being pursued and we are learning much about how animals collect information and how they use that information to make decisions for their current and future states as well as what animals do not perceive or choose to ignore. Here I provide an overview of this productivity, alighting only briefly on any single example, to showcase the diversity of species, of approaches and the sheer mass of research effort currently under way. We are getting closer to understanding the minds of other animals and the evolution of cognition at an increasingly rapid rate.     

Bedding hygiene,cleanliness and lying behaviour for heifers housed on wood chip or straw deep bedding

The aim of this project was to compare the hygienic quality of the bedding, as well as the parasitic load, cleanliness and lying behaviour in heifers kept on either straw or wood chip deep bedding. Fourteen heifers kept in two pens were housed on straw or wood chip bedding for 43 days, after which the bedding material was switched for 43 additional days. Significantly more mould was found in wood chip than in straw and there was a tendency towards less yeast in wood chip. The heifers had a low faecal parasitic load. The results indicate that the wood chip treatment resulted in somewhat cleaner animals. The heifers had a significantly longer total lying time when kept on straw. In conclusion, wood chip deep bedding could be an option as bedding material, but the impact on hygiene of bedding material and lying behaviour needs to be further investigated.     

Effect of steam explosion on solid‐state fermentation of maize stalk by Penicillium decumbens and Phanerochaete chrysosporium for animal feed production

Pre‐treated maize stalk could be used for animal feed due to the improved digestibility. Steam explosion (SE) and solid‐state fermentation (SSF) are two methods in maize stalk pre‐treatment. To evaluate the effect of combination of SE and SSF on the maize stalk pre‐treatment, the maize stalk was treated with steam explosion and microbial fermentation with Penicillium decumbens and Phanerochate chrysporium in this study. The steam explosion severity (logR₀) affected component of the corn stover and then affected the SSF. The highest weight loss of substrate (23.20%), protein (12.71%) and cellulase filter paper activity (FPA) (7.42IU/g) could be obtained at logR₀ = 3.64 and the IVDMD of SE‐SSF‐treated straw could reach 75.8%. The SE‐SSF pre‐treatment method could improve the utilization of straw as animal feed and overcome the shortage of feed source in animal husbandry.