黄酮类化合物对动物胃肠道健康调控作用的研究进展

胃肠道是动物机体内最大且功能最复杂的器官，是机体防御的最前线。胃肠道结构与功能的完整对维持动物健康极为重要。黄酮类化合物具有天然、安全和无残留等特性，可以改善动物生产性能、调节胃肠道健康等，这使其不仅有望成为极具开发潜力的替抗成员，而且因此能开发出更多有益于动物健康的调控产品。本文就黄酮类化合物对动物胃肠道形态结构、屏障防御以及重要生理防御功能的调控作用进行综述，旨在为深入了解黄酮类化合物对动物胃肠道健康的调控作用及其在动物生产的应用开发提供参考。     

新型药物递送系统在口服给药方面的应用前景

传统的给药方式主要包括注射和口服。与注射相比，口服给药途径在安全性和制造成本方面都具有更大的优势。但由于各种生理障碍严重影响了某些口服药物的利用率，因此口服给药的应用仍具有较大的挑战性。近年来，已有不少递送系统开始应用于口服药物的递送，其中一些新型的药物递送系统已被证明可以有效地保护药物免受胃肠道环境的影响，通过降低药物在体内的释放速率或实现药物靶向释放等方式提高药物的治疗效果，并且可以降低药物毒性。论文概述了近年来流行的新型药物递送系统，旨在为更多的难溶性口服药物新型制剂的开发和利用提供新思路。     

仔猪胃肠道微生物菌群定植规律及其功能的研究进展

通常情况下,动物胃肠道内正常微生物菌群与宿主建立了一种相互依存、相互制约的微生态关系,这些微生物菌群和宿主构成了一个统一的整体。它们在维持动物健康和正常生理状态,提高动物机体的抵抗力,抑制潜在病原菌在动物胃肠道的定植等方面发挥着重要作用。本文就猪胚胎期、哺乳期、断奶期胃肠道微生物菌群的定植规律及其功能等方面进行综述,供进一步研究猪胃肠道微生物参考。     

抗寄生虫药多拉菌素的研究进展

针对抗寄生虫药多拉菌素的理化特性、药物制剂、临床应用及在动物体内药物残留的标准等方面,对该药存在的不足之处提出了新的研究方向及展望.     

植物雌激素对动物乳腺发育影响研究进展

动物乳腺是雌性哺乳动物的特征之一,分泌乳汁哺育幼仔的同时,动物乳汁也成为人类非常重要的健康食品,所以动物乳腺发育、分泌乳汁及排乳和乳腺疾病的预防等已成为乳用动物重要的研究内容。植物雌激素(PE)作为纯天然活性物质,根据动物体内雌激素浓度高低、受体数目、结合程度以及本身剂量的不同表现出不同效果,利用这一特性把植物雌激素做为生理调节剂,通过它对内分泌的影响、改变内源激素水平、调控机体生理生殖和营养代谢过程来促进哺乳动物乳腺发育,增加产乳动物乳产量。论文就植物雌激素对动物乳腺发育影响研究进展进行综述,为促进乳制品产业健康发展提供参考。     

生物活性肽在饲料中的应用进展

生物活性肽(Biologically active peptides,BAP)是指对生物机体的生命活动有益或具有生理作用的一类肽类化合物。这类物质大都是一些寡肽(几个氨基酸构成)或低肽(十几个氨基酸构成),氨基酸数目比较少,不同的排列、组合会产生各种不同生物功能。这些生物活性肽本身以非活性状态存在于蛋白质氨基酸序列之中,当用适当的蛋白酶进行体外水解或在胃肠道消化过程中,就被释放出来并发挥生理调节作用。由于生物活性肽本身是动物生理活性     

微生物代谢产物调控胃肠道发育的机制

动物胃肠道中栖息着大量微生物,这些微生物通过代谢产物参与调控宿主新陈代谢、生理免疫和发育过程等。深入了解胃肠道微生物及代谢产物的调控机制,有利于人们采用相应技术手段促进胃肠道健康发育,提高动物生产性能。文章综述了胃肠道微生物产生的不同种类的代谢产物,介绍了这些代谢产物在调控宿主发育中的作用及其机制,以期为通过营养途径调节微生物代谢产物促进动物胃肠道发育提供理论依据。     

胃肠道微生态的分子生物学技术研究进展

哺乳动物胃肠道中的小型生物群被赋予高种群密度、广泛的多样性及相互作用的复杂性等特性,它们在宿主营养、生理和免疫等方面起着主要作用。作者综述了研究动物胃肠道微生物的现代分子生物学技术的原理及应用,并展望随着分子生物学技术的飞速发展,对胃肠道微生物的研究将会更加深入,从而为指导实践提供可靠的理论依据。     

动物胃肠道氨基酸感应与转运

动物胃肠道中不同类型的内分泌细胞构成了"胃肠道内分泌系统"。饲粮中的蛋白质在动物胃肠道被分解为氨基酸后,能够被内分泌细胞膜上的氨基酸感应受体所识别,介导激素的分泌,调控胃肠道生理活动。位于肠上皮细胞的氨基酸转运载体通过哺乳动物雷帕霉素靶蛋白复合物1(mTORC1)和一般性调控阻遏蛋白激酶2(GCN2)信号通路调控细胞氨基酸代谢。本文就动物胃肠道内分泌系统、氨基酸感应受体与转运载体以及氨基酸感知信号通路等方面研究进展进行综述。     

流行病学模型及建模步骤

流行病学模型可作为动物疫病风险评估及防控策略制定的有力工具。论文介绍了流行病学模型的定义及其在动物疫病管理决策中的应用,讨论了模型的分类及建模的方法,重点阐述了动物疫病流行病学模型的构建步骤,包括建模系统和研究目标的确定、动物群体和疫病流行病学数据信息的收集、概念模型的构建、概念模型的确认、概念模型的公式化或编程、模型的验证、运行有效性的评估、敏感性分析、执行研究、输出结果的解释和交流。提出了一些建模的基本准则和应该着重考虑的问题,以期为动物疫病流行病学模型和风险评估预警研究提供参考。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in