高效液相色谱法测定饲料添加剂25-羟基维生素D_3含量的方法研究

本研究旨在建立用高效液相色谱法测定饲料添加剂25-羟基维生素D3含量的分析方法。样品加水超声处理,将25-羟基维生素D3从包埋的基质中释放出来,用甲醇溶解后,提取液经液相色谱分离,在265 nm处检测,用外标法定量25-羟基维生素D3和预25-羟基维生素D3的量。该方法操作简单,结果准确可靠,可用于饲料添加剂25-羟基维生素D3含量的测定。     

高效液相色谱法(HPLC)双柱串联方式测定饲料中维生素A和维生素D_3

本文采用高效液相色法、ResolbeC18(150mm×3.9mm,5μm)与NovapakC18(150mm×3.9mm,4μm)双柱串联方式测定饲料中的维生素A和维生素D3。以甲醇/水(95/5)为流动相,检测波长设定维生素A在325mm、维生素D3在265mm。本方法维生素A和维生素D3精密度的变异系数均小于7.0%,回收率在90%～110%之间。因维生素A和维生素D3同属脂溶性维生素,所以二者前处理的原理和步骤基本一致。维生素A较好分离,一般采用单柱分离即可。维生素D3的检测灵敏度低,经皂化提取后,提取液中的干扰物也较多,故维生素D3较难分离。为了达到分离度好的效果,一般采用先纯化后分离的方法,测定步骤较为繁杂。所以测定样品中二者的含量通常需进样2～3次。本文由于采用了双柱串联的方式,提高了柱效,省略了纯化维生素D3的步骤,一次进样就使得二者都能得到较好的分离,也使得饲料分析工作者可以较省时省力地快速测定多个饲料样品成为可能。但同时由于双柱串联增加了死体积,分析时间加长,泵的工作压力也大。因此在使用本文方法时应综合考虑实际因素,以达到成本、工作量以及分离效果之间的适当组合。     

高效液相色谱法(HPLC)双柱串联方式测定饲料中维生素A和维生素D3

本文采用高效液相色法、Resolbe C18(150mm×3.9mm,5μm)与Novapak C18(150mm×3.9mm,4μm)双柱串联方式测定饲料中的维生素A和维生素D3.以甲醇/水(95/5)为流动相,检测波长设定维生素A在325mm、维生素D3在265mm.本方法维生素A和维生素D3精密度的变异系数均小于7.0%,回收率在90%～110%之间.因维生素A和维生素D3同属脂溶性维生素,所以二者前处理的原理和步骤基本一致.维生素A较好分离,一般采用单柱分离即可.维生素D3的检测灵敏度低,经皂化提取后,提取液中的干扰物也较多,故维生素D3较难分离.为了达到分离度好的效果,一般采用先纯化后分离的方法,测定步骤较为繁杂.所以测定样品中二者的含量通常需进样2～3次.本文由于采用了双柱串联的方式,提高了柱效,省略了纯化维生素D3的步骤,一次进样就使得二者都能得到较好的分离,也使得饲料分析工作者可以较省时省力地快速测定多个饲料样品成为可能.但同时由于双柱串联增加了死体积,分析时间加长,泵的工作压力也大.因此在使用本文方法时应综合考虑实际因素,以达到成本、工作量以及分离效果之间的适当组合.     

肉种鸡的维生素D3需要量

本研究以25～66周龄的Ross肉种鸡为试验对象,在无紫外光照射的环境中,检测不同维生素D3摄入量对于母鸡每日产蛋量、孵化率、子代雏鸡初生重、入孵种蛋胚胎发育各阶段死亡率（早期：入孵1～10d;中期：入孵11～15d;后期：入孵16～21d）、蛋重、蛋比重、1日龄雏鸡躯体灰分含量等的影响。母鸡从25～66周龄分别饲喂5个浓度水平的维生素D3（每千克饲料的含量分别为：125IU、250IU、500IU、1000IU和2000IU）。另加一组母鸡在36周前饲喂不添加维生素D3的饲料,36周后开始饲喂添加维生素D34000IU/kg的饲料。预测母鸡每日产蛋量最大值相对应的维生素D3水平,产蛋高峰期和高峰后分别为1424IU/kg和2804IU/kg。预测孵化率最大值相对应的维生素D3水平,产蛋高峰期和高峰后分别为1390IU/kg和2708IU/kg。早期胚胎死亡率最小相对应的维生素D3水平,产蛋高峰期值1288IU/kg,然而高峰后未现显著的影响。胚胎中期死亡率最小相对应的维生素D3水平,产蛋高峰期和高峰后分别为1130IU/kg和2568IU/kg,以及胚胎后期死亡率最小相应的维生素D3水平,产蛋高峰期和高峰后分别为1393IU/kg和2756IU/kg。蛋重最大相应的维生素D3水平,产蛋高峰期1182IU/kg,比重最大相应的维生素D3水平,产蛋高峰期为1337IU/kg,高峰后大于2000IU/kg。1日龄雏鸡躯体灰分含量最大相应的维生素D3水平〉2000IU/kg。27～36周龄的母鸡（每千克饲料提供维生素D3水平分别为0、125、250、500、1000和2000IU）从原始设计试验得到的数据分析显示,肉种鸡母鸡饲料需要维生素D3约1400IU/kg。37～66周龄母鸡的试验,包括提供维生素D3水平0至4000IU/kg的不同饲料,高峰后修正设计得到的数据分析显示,饲料需要维生素D3约2800IU/kg。     

饲料中维生素B1检测方法学认证

本实验旨在考察高效液相色谱法测定饲料中维生素B1的国标方法在本实验室的适用性。通过对标准曲线、精密度、回收率、准确度和测定低限五方面的实验,结果表明：本实验室进行的饲料中维生素B1的测定（GB/T14700-2002）检测方法具有可接受的定量限,较好的准确度和精密度,回收率可达97.29～111.63%,符合GB/T27404-2008实验室质量控制规范中有关检测方法确认的要求。     

种公猪的饲养管理技术

种公猪是繁殖群遗传组成的一半,对猪群品质有巨大的影响.因此,应对种公猪精心管理,最大限度的发挥其遗传潜能. 1 饲养 1.1 日粮营养 公猪使用配比合理的全价饲料,避免营养不均衡.在其配种前后推荐以下配方:配种前粗蛋白13.5％,消化能12.38MJ/kg、精氨酸0.65％,维生素D3 531U、维生素D3 177IU、维生素E 8.9U;配种后粗蛋白15.0％、消化能13.7MJ/kg、精氨酸0.80％、维生素A3 500～4000U、维生素D3177～200U、维生素E 22～44U、钙0.65％～0.90％、磷0.6％～0.7％.日喂2～3kg,日喂2次,定时定量,乳头饮水,每天补喂优质鲜牧草或青贮料0.5～1.0kg/头.配种后饲粮粗蛋白14.5％ ～15.2％、精氨酸0.7％～0.8％可维持公猪正常性欲、精液量和品质.     

方斑东风螺配合饲料中维生素D的适宜添加量研究

本试验旨在研究方斑东风螺配合饲料中维生素D的最适添加量。采用单因素设计,在基础饲料中添加不同水平的维生素D,每100 g饲料中分别添加维生素D 0、50、100、500、1000、10000 IU(D0、D1、D2、D3、D4、D5组),饲养方斑东风螺幼螺80 d。结果表明:增重率、壳增长率随饲料中维生素D含量的增加呈先增大后减小的变化趋势,在添加量为100 IU/100 g时达到最大生长速度,显著高于对照组和D4、D5组(P<0.05)。维生素D对软体组织总灰分、粗蛋白质、粗脂肪及贝壳的总灰分、钙、磷的含量影响显著。成活率、肥满度在本试验条件下未受到显著影响。根据生长指标,方斑东风螺饲料中维生素D的适宜添加水平为50～500 IU/100 g,最适添加量为100 IU/100 g。     

饲料中不同维生素D含量对鲈鱼幼鱼生长性能和钙磷代谢的影响

本研究旨在探讨饲料中不同维生素D含量对鲈鱼幼鱼生长性能和钙磷代谢的影响。以初始体重为(2.26±0.03)g的鲈鱼幼鱼为试验对象,随机分为6组(每组3个重复,每个重复15尾鱼),饲喂维生素D含量实测值分别为34.2、219.4、393.8、775.9、1 534.1和3 091.2 IU/kg的等氮等能饲料,进行9周的养殖试验。结果表明:1)当饲料中维生素D含量在34.2~393.8 IU/kg时,鲈鱼的增重率随着饲料中维生素D含量的升高显著上升(P0.05),但是当饲料中维生素D含量高于393.8 IU/kg时,鲈鱼的增重率变化不显著并且出现平台期(P0.05)。同样,鲈鱼的特定生长率、饲料效率和蛋白质效率均表现出与增重率相似的变化趋势。2)饲料中维生素D含量显著影响了鱼体粗灰分、钙和磷含量,脊椎骨、鳃盖骨和鳞片粗灰分含量以及脊椎骨钙和磷含量(P0.05),但对鱼体粗蛋白质、粗脂肪和水分含量没有显著影响(P0.05)。3)饲料中维生素D含量对鲈鱼血清碱性磷酸酶活性及羟脯氨酸、钙离子和无机磷含量均有显著影响(P0.05)。4)饲料中维生素D含量显著影响了鲈鱼肝体指数及肝脏脂肪和维生素D含量(P0.05)。随着饲料中维生素D含量的升高,肝脏维生素D含量呈现升高的趋势,并在饲料中维生素D含量达到1 534.1 IU/kg时变化趋于平稳。以增重率为评价指标,采用折线模型分析得出鲈鱼幼鱼获得最大生长时对饲料中维生素D的需求量为431.0 IU/kg饲料。以肝脏维生素D含量为评价指标,采用二次曲线模型分析得出鲈鱼幼鱼获得最大肝脏维生素D沉积量时对饲料中维生素D的需求量为2 444.4 IU/kg饲料。     

维生素D在动物营养中的应用研究

维生素D2主要存在于植物性饲料中,如麦角和酵母;而维生素D3则主要由存在于动物的皮肤、血液、神经和脂肪组织中的7脱氢胆固醇在紫外线照射下生成。维生素D2与维生素D3对哺乳动物的活性基本相同;对于包括家禽在内的鸟类,维生素D3的活性远高于D2,前者约为后者的20～40倍;奶牛维生素D2的效价可能只有维生素D3的1/2～1/4。近年来,对活性维生素D的研究有了进一步的认识,逐渐发现活性维生素D除具有经典的钙磷调节作用以外,还参与调节许多细胞的代谢过程,对机体的免疫功能、生殖等方面均有着十分重要的意义。作者就近年来国内外对维生素D在动…     

利用酶解法测定复合维生素溶液中维生素D_3含量的研究

建立碱性蛋白酶-高效液相色谱法测定复合维生素溶液中维生素D3的含量。利用碱性蛋白酶的方法处理样品,并采用EcoSic HPLC CoumwODS,C18柱(4.6 mm×200 mm,5μm)分离,检测波长280 nm,流动相为甲醇-水(95∶5)等高效液相色谱条件检测样品中维生素D3的含量。结果:样品中维生素D3与其他组分分离良好,维生素D3质量浓度在500～5 000 U/mL范围内与峰面积呈良好的线性关系,线性回归方程A=52.59C-3.28,r=0.999 8(n=6);平均回收率为99.9%,RSD=0.97%(n=5)。研究表明本试验建立的方法简便、快捷,结果准确、可靠、重现性好,可作为企业控制生产过程中液体复合维生素质量控制的方法之一。     

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     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -