气相色谱法测定香味剂中桉油精肉桂醛百里香酚及香芹酚的含量

为建立气相色谱法测定饲料香味剂中桉油精、肉桂醛、百里香酚及香芹酚的方法,试样经无水乙醇提取后,用GC测定桉油精、肉桂醛、百里香酚及香芹酚。桉油精、肉桂醛、百里香酚及香芹酚在浓度为20~200g/kg添加水平时,平均回收率分别在97.6%~98.3%、97.8%~98.7%、97.4%~98.8%和97.4%~98.8%,相对标准偏差(RSD)分别在0.5%~0.7%、0.4%~1.0%、0.4%~0.6%和0.5%~0.8%。方法定量限为100mg/kg。本方法对饲料香味剂中桉油精、肉桂醛、百里香酚及香芹酚的检测分析准确性高、重现性好。     

香味剂中大茴香脑、d-柠檬烯、香芹酚含量测定的研究

本研究建立了气相色谱法测定饲料香味剂中大茴香脑、d-柠檬烯、香芹酚的方法。试样经丙酮提取后,用GC测定大茴香脑、d-柠檬烯和香芹酚。大茴香脑、d-柠檬烯和香芹酚的线性范围为1.0～500.0μg/mL。大茴香脑、d-柠檬烯和香芹酚在浓度为1～10 g/kg添加水平时的回收率分别在96.2%～101.5%、97.1%～102.5%和96.5%～99.8%,RSD分别为1.3%、1.5%和1.1%。方法定量限为50 mg/kg。本方法对饲料香味剂中大茴香脑、d-柠檬烯和香芹酚的检测分析准确性高、重现性好。     

高效液相色谱法同时测定饲料香味剂中肉桂醛、丁香酚、香芹酚和百里香酚含量的研究

本研究建立了同时测定饲料香味剂中肉桂醛、丁香酚、香芹酚和百里香酚含量的高效液相色谱方法。试样经甲醇提取后,采用C18色谱柱;以45%乙腈为流动相等度洗脱,流速为1.0 mL/min,检测波长为275 nm,用标准曲线外标法定量。结果表明:四种香味剂在25 min内得到良好分离,分离度R≥2.3,在两个数量级浓度范围内线性关系良好,相关系数r≥0.9997,高、中、低3个浓度添加回收率为95.0%~102.7%,RSD≤2.0%。本方法简便、准确、重现性好,可用于饲料香味剂中肉桂醛、丁香酚、香芹酚和百里香酚的测定。     

饲料添加剂牛至油中香芹酚和百里香酚含量的测定

试验建立了高效液相色谱法测定饲料添加剂牛至油中香芹酚和百里香酚含量的方法。采用高效液相色谱法,色谱柱Diamonsil C18(2)柱,流动相为甲醇-水-冰醋酸(60??4??2),检测波长274 nm,流速1.0 ml/min。结果显示,牛至油中香芹酚含量为37.81%,百里香酚含量为7.05%,香芹酚和百里香酚的回收率分别为98.2%、98.4%,变异系数分别为1.0%、1.3%。试验为牛至油中香芹酚和百里香酚的检测提供了准确、灵敏、可靠的分析方法。     

高效液相色谱法测定混合型饲料添加剂中肉桂醛、丁香酚、香芹酚和百里香酚含量

研究建立了同时测定混合型饲料添加剂中肉桂醛、丁香酚、香芹酚和百里香酚含量的液相色谱方法。混合型饲料添加剂样品用甲醇提取,以C_(18)柱(150 mm×4.6 mm×5μm)为分析柱,紫外检测器检测,外标法定量。结果表明:在所选择的色谱条件下,空白载体中肉桂醛、丁香酚、香芹酚和百里香酚能达到很好的分离;丁香酚、香芹酚和百里香酚在1.0～500 mg/L内线性关系良好,肉桂醛在0.10～50.0 mg/L内线性关系良好;丁香酚、香芹酚和百里香酚最低定量限为50 mg/kg,肉桂醛最低定量限为5.0 mg/kg;加标回收率为83.7%～112%,变异系数为0.70%～6.39%。该方法样品前处理简单、简便可靠,可用于混合型饲料添加剂中肉桂醛、丁香酚、香芹酚和百里香酚的同步检测。     

饲料添加剂百里香油中百里香酚和香芹酚含量的测定

本实验采用高效液相色谱法测定了饲料添加剂百里香油中百里香酚和香芹酚的含量。色谱柱为DiamonsilC18(2)柱,流动相为甲醇-水-冰醋酸(60∶4∶2,V∶V∶V),检测波长为274 nm,流速为1.0 mL/min。结果显示,百里香油中百里香酚和香芹酚含量分别为22.70%和5.12%,回收率分别为98.42%和97.81%,变异系数分别为1.18%和0.90%。     

气相色谱法测定饲料中香芹酚和百里香酚的含量

文章建立了饲料中2种香料香芹酚和百里香酚的气相色谱检测方法。样品中香芹酚和百里香酚经乙酸乙酯超声提取90 min,经GCB和PSA净化后,用GC-FID测定。在1~500μg/ml的浓度范围内,香芹酚和百里香酚的峰面积响应与其浓度呈线性相关(R≥0.99),香芹酚和百里香酚定量限为10 mg/kg,在10种饲料中3个不同添加浓度的回收率为77.97%~104.04%,RSD为0.63%~9.92%,并通过气质联用仪进行确证。     

气相色谱法同步测定饲料添加剂中百里香酚、香芹酚的研究

本研究建立了饲料添加剂中百里香酚、香芹酚的气相色谱同步测定方法。用无水乙醇振摇提取后,气相色谱进行同步测定,采用外标法定量。结果表明:浓度在0.005~2.00 mg/mL线性关系良好,相关系数均大于0.99,方法检测限为50 mg/kg,本方法前处理简单,回收率高,可实现饲料添加剂中百里香酚、香芹酚的同步测定。     

利用气相色谱法同步测定饲料香味剂中肉桂醛、香芹酚的研究

研究通过添加回收试验和检测市场香味剂产品的方法建立了饲料香味剂中肉桂醛、香芹酚的同步测定方法。用无水乙醇振摇提取后,气相色谱进行同步测定,用外标法定量。结果表明,此方法前处理简单,回收率高,检测限为100mg/kg,可实现饲料香味剂中肉桂醛、香芹酚的同步测定。     

体外法评估不同植物精油对需氧菌的抑菌活性

本试验采用琼脂平板法,测定肉桂醛、百里香酚、香芹酚、牛至油、丁香酚和山苍子油对产肠毒大肠杆菌、宋氏志贺氏菌、乙型溶血性链球菌的最低抑菌浓度,从中选出抑菌能力较强的精油,继续测定其对产肠毒大肠杆菌、出血性大肠杆菌、宋氏志贺氏菌、痢疾志贺氏菌、猪霍乱沙门氏菌、鼠伤寒沙门氏菌和乙型溶血性链球菌的抑菌效果,筛选出具有替抗潜力的精油并评估精油作为抑菌剂应用在饲料中的前景。本试验采用琼脂平板培养法,在固态培养基中添加不同浓度的肉桂醛、百里香酚、香芹酚、牛至油、丁香酚和山苍子油,分别接种产肠毒大肠杆菌、宋氏志贺氏菌、乙型溶血性链球菌,测定其最低抑菌浓度,初步筛选出抑菌作用较强的精油,利用同样的方法,继续测定其对产肠毒大肠杆菌、出血性大肠杆菌、宋氏志贺氏菌、痢疾志贺氏菌、猪霍乱沙门氏菌、鼠伤寒沙门氏菌和乙型溶血性链球菌的最低抑菌浓度,最终筛选出抑菌能力较强的精油。结果表明:①通过初筛,发现肉桂醛、百里香酚、香芹酚、牛至油和丁香酚的抑菌效果较好,选择该五种精油进行复筛;②复筛结果表明,精油对供试菌株的抑菌能力由强到弱为百里香酚>肉桂醛>香芹酚>牛至油>丁香酚,其最低抑菌浓度分别为为0.02%～0.07%、0.02%～0.08%、0.03%～0.07%、0.04%～0.09%、0.07%～0.18%;③百里香酚、肉桂醛、香芹酚、牛至油作为饲料添加剂具有极好的潜力。     

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.     

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.     

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.     

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