三聚氰胺在肉鸡组织中的残留和消除规律研究

本试验旨在研究日粮中三聚氰胺在肉鸡不同组织中的残留和消除规律。选用1日龄健康黄羽肉鸡400只,随机分成4个处理,每处理设5个重复,每个重复20只鸡。试验日粮中三聚氰胺的添加量分别为0%、0.25%、0.5%、和3.0%,连续饲喂42d,后改喂基础日粮。于残留试验第7、14、21、28、35和42天和改喂基础日粮的第1、2、3、4和5天分别测定肉鸡肾脏、肝脏和胸肌中的三聚氰胺含量。结果表明,黄羽肉鸡连续饲喂含三聚氰胺日粮42d,处理组各组织中三聚氰胺平均含量均显著高于对照组(P<0.05);3.0%处理组各组织中三聚氰胺含量的高低依次为:肾脏>肝脏>胸肌。组织中三聚氰胺消除较为缓慢,日粮含量越高组织中三聚氰胺消除速率越快。改喂基础日粮5d后,各组织中的三聚氰胺含量显著降低,逐渐接近对照组值,但5d各组织中三聚氰胺含量均未消除完全。日粮三聚氰胺含量越高,肉鸡组织中的残留浓度越高,消除需要的时间越长。     

饲喂不同含量三聚氰胺日粮后肉鸭组织中三聚氰胺的残留量分析

试验鸭为300只1日龄樱桃谷肉鸭SM3,随机分为10个处理.处理1-10组日粮中分别舍有0、2、5、10、20、50、100、200、500和1 000mg/kg的三聚氰胺,以研究饲喂不同水平三聚氰胺的试验日粮后在肉鸭组织中的残留量.在肉鸭1～42日龄,处理1～10组肉鸭分别饲喂含有不同水平三聚氰胺的试验日粮;在肉鸭43～49日龄,各处理组肉鸭均饲喂不含三聚氰胺的日粮.在肉鸭的14、28、42和49日龄,每个处理随机选取3只试验鸭,屠宰,取胸肉、肝脏和肾脏,用于三聚氰胺的残留测定.结果表明,用三聚氰胺含量≤50mg/kg的日粮饲喂肉鸭42d后,在胸肉、肝脏和肾脏中均未检出含有三聚氰胺;当日粮中三聚氰胺含量≥100mg/kg,肉鸭组织中三聚氰胺的残留量随日粮中三聚氰胺含量的升高而线性升高(P<0.05);在含有高水平三聚氰胺的日粮组中(500和1 000mg/kg),肉鸭胸肉、肝脏和肾脏中三聚氰胺残留量不同,以肾脏中的较高(P>0.05);43日龄开始饲喂不含三聚氰胺的日粮7 d后,各组织中均未检出含有三聚氰胺.     

日粮三聚氰胺对产蛋鸭组织氧化损伤的影响

采用单因子试验设计,研究了日粮三聚氰胺(MEL)对产蛋鸭组织氧化损伤的影响。选用体重和产蛋率相近的19周龄金定鸭648只,随机分成6个处理,每个处理6个重复,每重复18只。6种日粮的MEL添加水平分别为0、1、5、25、50mg/kg和100mg/kg。试验期21d。结果表明:与对照组相比,100mg/kg处理组血清中谷胱甘肽过氧化物酶(GSH-Px)活性显著降低(P0.05),丙二醛(MDA)含量显著升高(P0.05);50mg/kg和100mg/kg处理组肾脏中GSH-Px活性显著降低(P0.05);100mg/kg处理组肝脏中过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性显著降低(P0.05),MDA含量显著升高(P0.05);50mg/kg处理组肝脏中SOD活性显著降低(P0.05);胸肌中各抗氧化指标均未见显著差异(P0.05),表明MEL可引起产蛋鸭血清、肾脏和肝脏组织的氧化损伤。     

三聚氰胺在鸭蛋中的沉积和消除规律的研究

本试验旨在研究日粮中添加不同水平的三聚氰胺(melamine,MEL)在鸭蛋中的沉积和消除规律.选用体重为(1.66±0.16)kg和产蛋率为(75.15±3.29)%的19周龄健康金定产蛋鸭756只,随机分成7个处理,每个处理设6个重复,每个重复18只.7种试验日粮的MEL添加水平分别为:0、1、2、5、25、50和100 mg/kg.各处理分别连续饲喂含不同水平MEL的日粮21 d(沉积试验),随后改喂基础日粮21 d(消除试验),试验期共42 d.于沉积和消除试验的第1～11天、第13天、第15天、第17天和第21天分别测定鸭蛋可食部分中的MEL和三聚氰酸(cy-anuric acid,CYA)含量.结果表明,0～5 mg/kg的4个处理之间鸭蛋中MEL含量差异不显著(P>0.05),25～100 mg/kg的3个处理之间差异极显著(P<0.01),且均极显著高于0～5 mg/kg的4个处理(P<0.01);鸭蛋MEL含量(Y,mg/kg)与日粮MEL添加水平(X,mg/kg)的关系方程为:y=0.0121X+0.0165(R2=0.9994),MEL由日粮到鸭蛋中的生物富集系数为0.0121;通过鸭蛋排出的MEL(Y,mg/d)与蛋鸭摄人的MEL(X,mg/d)拟合的曲线为:Y=0.2618X+0.0947(R2=0.9999),MEL由蛋鸭到鸭蛋的母体转移系数为0.2618.日粮MEL添加水平越高,鸭蛋中的消除半衰期越短,完全消除需要的时间越长;5、25、50和100 mg/kg处理鸭蛋中的MEL含量(Y,mg/kg)随时间(X,d)消除方程分别为:Y=0.0802X-0.747(R2=0.7775)、Y=0.3268X-1.1608(R2=0.9871)、Y=0.5912X-1.3403(R2=0.9922)和Y=1.2004X-1.3956(R2=0.9883),根据上述方程计算各处理鸭蛋中MEL完全消除时间分别为3.48、7.81、9.31和14.61 d;鸭蛋中未检测到CYA.结果显示,MEL在产蛋鸭日粮中浓度越高,其鸭蛋中沉积最越大,消除时间越长.     

日粮三聚氰胺在鸡蛋和蛋鸡组织中残留规律的研究

试验拟通过在日粮中添加不同剂量的三聚氰胺,研究其在鸡蛋和蛋鸡组织中的残留规律。选用65周龄的海兰灰商品蛋鸡240只,随机分为6个处理,分别饲喂添加了0、2、10、100、1000 mg/kg和2000 mg/kg三聚氰胺的日粮,试验期21 d。结果表明:随着日粮三聚氰胺添加量的增加,鸡蛋、肝脏、肾脏、血浆、肌肉和小肠组织中三聚氰胺的沉积量均呈线性增加(R2≥0.93);蛋鸡饲喂三聚氰胺7 d后,鸡蛋中三聚氰胺的沉积量基本保持稳定;而肝脏、肾脏、血浆、肌肉和小肠中的三聚氰胺沉积量呈现先增加后降低的趋势,14 d时达到最大值,第21天略微下降。结果提示,日粮中的三聚氰胺会富集在鸡蛋和蛋鸡组织中,且随着日粮三聚氰胺添加量的增加,鸡蛋和组织中三聚氰胺沉积量均呈线性增加。     

三聚氰胺对蛋鸡生产性能影响及其排泄规律的研究

本试验旨在研究三聚氰胺对蛋鸡生产性能影响及其排泄规律。分两部分进行:试验1,选用28周龄海兰褐壳蛋鸡144只,随机分为3组,每组6个重复,分别饲喂玉米-豆粕型基础日粮(对照组)和三聚氰胺添加水平为50、100 mg/kg的日粮(处理组),测定蛋鸡生产性能和粪样中三聚氰胺、三聚氰酸、消化率的变化;试验2,选用42周龄海蓝褐壳蛋鸡24只,分为2组,每组12个重复,处理组在基础日粮中添加100 mg/kg三聚氰胺,测定蛋鸡不同等级卵泡中三聚氰胺的变化。结果显示,日粮中添加50、100 mg/kg三聚氰胺对蛋鸡生产性能和粪中三聚氰酸的浓度均无显著影响(P0.05);试验1两处理组粪中三聚氰胺的浓度均显著高于对照组(P0.05),两处理组粪中三聚氰胺至停喂三聚氰胺日粮后96 h时仍未消除完毕。试验2在不同等级卵泡中均含有三聚氰胺,且随卵泡发育呈稳定增长趋势。结果表明,日粮中添加50、100 mg/kg三聚氰胺对蛋鸡生产性能无显著影响;三聚氰胺可在体内蓄积并达到稳定状态;可通过粪便及蛋黄排除体外;停喂三聚氰胺日粮96 h蛋鸡体内三聚氰胺仍未消除完毕。     

酵母硒对肉仔鸡屠宰性能和肉品质及组织硒含量的影响

本试验研究了日粮中添加不同水平酵母硒对肉仔鸡屠宰性能、肉品质及组织硒含量的影响,以评价酵母硒在肉仔鸡上的使用效果。试验选用540只1日龄AA肉仔鸡公雏,随机分为5个处理,每个处理6个重复,每个重复18只鸡,5个处理组分别在基础日粮中添加0(对照组)、0.1、0.2、0.3、0.4 mg/kg的酵母硒(以硒计),试验期42 d。结果表明:各处理组间的生长性能、屠宰性能(屠体率、半净膛率、全净膛率)、肉品质(滴水损失、红度、黄度和亮度)等指标均无显著差异(P0.05);随着日粮酵母硒添加量的增加,血清、胸肌、肝脏和肾脏硒的含量随之增加(线性,P0.01),各组织硒的含量由高到低依次为肝脏和肾脏、血清、胸肌。     

日粮中锌水平对肉仔鸡体组织中铁和铜的影响

试验选择180只1日龄艾维茵肉仔鸡,随机分为6组,每组30只,公母各半。对照组饲喂锌水平为22.61mg/kg的基础日粮,5个处理组分别在基础日粮中添加25、65、145、305和625mg/kg的锌,锌源为硫酸锌,旨在研究日粮中锌水平对鸡组织铁和铜浓度的影响。试验结果表明,日粮中锌水平较低时,肉仔鸡肝脏、胫骨、肾脏、胸肌和羽毛各组织铁浓度呈不同程度的增加;而锌水平较高时,各组织铁浓度均呈不同程度的降低。由此可见,锌和铁之间存在颉颃作用。此外,随日粮中锌水平的升高,胸肌和肾脏中铜的浓度均有升高的趋势,而胰腺中铜的浓度显著降低。     

高铜日粮对肉鸡肝脏TrxR2基因mRNA表达和还原活性的影响

本文旨在了解高铜日粮对肉鸡肝脏TrxR2基因mRNA表达和还原活性的影响。200羽1日龄Cobb商品代肉鸡随机分为4组,各组日粮中铜含量分别为:对照组(Ⅰ组)11mg.kg-1、试验Ⅱ组110mg.kg-1、试验Ⅲ组330mg.kg-1和试验Ⅳ组550mg.kg-1。饲养至10、30、50d时每组各取5只鸡用于采集肝脏样品,提取肝脏线粒体用DTNB法测定肝脏TrxR2的还原活性,提取肝脏总RNA用RT-PCR法测定TrxR2mRNA在肝脏中的表达量。结果显示,饲喂铜含量为550mg.kg-1日粮50d时还原活性降低(P<0.05)、TrxR2基因mRNA的表达量降低(P<0.05),饲喂铜含量为330mg.kg-1日粮30d时TrxR2的还原活性升高(P<0.05)、50d时降低(P>0.05),表明饲喂高铜日粮(330～550mg.kg-1)可导致TrxR2mRNA在肝脏中的表达量降低,还原活性先升高后降低。     

花尾榛鸡的组织中重金属含量测定

从吉林省吉林地区,延边地区.通化地区采集花尾榛鸡样本,分别取肝脏、肾脏、肌肉3种组织.采用加热浓硝酸高氯酸消化法消化各组织样品。测定以上组织中铅、镉、镍等重金属元素的含量。检验结果:组织中铅的含量以肝脏中最高,(0.5906±0.3452)mg/kg,肾脏次之(0.4045±0.1628)mg/kg,胸肌最低(0.1121±0.0146)mg/kg,组织中镉的含量以胸肌最高(0.2595±0.0472)mg/kg,肝脏次之(0.2205±0.0852)mg/kg,肾脏中最低(0.1929±0.1386)mg/kg,组织中镍的含量以肝脏中最高(0.7653±0.1524)mg/kg,胸肌次之(0.3990±0.2413)mg/kg,肾脏最低(0.1664±0.1683)mg/kg,组织样品中肝脏中少量铅超标,肝脏、肾脏中的镉也有不同程度超标,肝脏、胸肌中镍超标。     

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 -