氟中毒鸡微核率的研究

目的:探讨高氟对鸡微核率的影响。方法:实验组鸡饮用不同浓度的含氟水,对照组鸡饮用正常自来水,比较两组鸡的微核率,用X2检验方法作显著性检验。结果:实验组微核率明显高于对照组,有显著性差异(P<0.01);微核率与饮水含氟量有明显剂量-效应关系。结论:高氟可增高鸡骨髓嗜多染红细胞的微核率,且对鸡的染色体有损伤作用,高氟可能是致突变物。     

利用小鼠的遗传损伤检测竹炭板对甲醛的吸附作用

试验以不同剂量的气态甲醛对小鼠采用静式吸入染毒,利用小鼠的遗传损伤检测竹炭板对甲醛的吸附作用。结果发现:甲醛能引起小鼠骨髓细胞微核率升高,呈现一定的剂量-反应关系;中剂量组和高剂量组与对照组相比细胞微核率差异均有极显著性(P<0.01),具有统计学意义。高剂量甲醛经竹炭板吸附后,小鼠骨髓细胞微核率显著下降,差异有统计学意义(P<0.05,P<0.01),且随着吸附时间的增长,微核率降低。     

三氟氯氰菊酯对小鼠骨髓细胞微核及精子畸形和蓄积毒性的影响研究

通过三氟氯氰菊酯对小鼠的骨髓细胞微核及精子畸形和蓄积毒性影响的研究,进一步阐明三氟氯氰菊酯的毒理作用。选取健康成年小鼠50只,随机分为给药高、中、低剂量组,阳性对照组和空白对照组,每组各10只。给药组分别以三氟氯氰菊酯水溶液9.18、4.59、2.29 mg/kg体重灌胃,空白对照组给予等量的生理盐水灌胃,每天1次,连续4 d;阳性对照组以环磷酰胺80 mg/kg体重腹腔注射1次;评价三氟氯氰菊酯对小鼠骨髓细胞微核的影响;另取健康成年雄性小鼠50只,随机分为给药高、中、低剂量组,阳性对照和空白对照组,每组10只;给药组分别以三氟氯氰菊酯水溶液9.18、4.59、2.29 mg/kg体重灌胃;阳性对照组以环磷酰胺80 mg/kg灌胃,空白对照组给予等量的0.9%生理盐水灌胃,每天1次,连续5 d,计算精子畸形率。选择健康小鼠40只,随机分20只为蓄积毒性试验组,20只为空白对照组。试验组采用剂量递增连续染毒法来评价三氟氯氰菊酯的蓄积毒性,计算累积系数,按累积系数的评价标准评价蓄积毒性。结果表明,三氟氯氰菊酯为明显蓄积物质,对小鼠生长造成严重损害;三氟氯氰菊酯高剂量组精子畸形率与空白对照组相比差异极显著;三氟氯氰菊酯高剂量组微核率与空白对照组相比差异极显著。因此,三氟氯氰菊酯为明显蓄积物质,且具有极强的致畸、致突变作用。     

环磷酰胺对鸡红细胞的微核效应

将３００只２０日龄罗曼鸡随机分为１０组，每组３０只。第１～９组为实验组，分别按体重皮下注射环磷酰胺０．００１、０．０１、０．１、１、２、４、８、１６、３２μｇ／ｇ；第１０组为对照组，注射生理盐水。第９组（３２μｇ／ｇ）和对照组于注射后０、４、８、１２、１６、２０、２４、２８、３２ｈ，采血涂片，瑞氏染色并观察；而其他各组于注射后１６ｈ，采血涂片，瑞氏染色并观察。结果表明，环磷酰胺０．００１μｇ／ｇ剂量组，红细胞微核细胞率、微核率与对照组无明显差异，其他各组微核细胞率、微核率随环磷酰胺剂量的增加而升高，二者呈正相关（ｒ＝０．８），而白细胞数则随环磷酰胺剂量的增加而逐渐减少；从时间上看，随着环磷酰胺作用时间的延长，微核细胞率和微核率逐渐增加，至１６ｈ达到高峰，以后随时间的增加而减少。鸡红细胞微核率的变化，说明环磷酰胺的毒性可直接影响动物遗传物质，也说明鸡红细胞对环磷酰胺的毒性作用非常敏感。     

沙咪珠利对小鼠精子畸形和骨髓细胞微核的影响

为评价沙咪珠利的安全性,对其进行了小鼠精子畸形和骨髓细胞微核试验研究。选择健康ICR小鼠随机分为受试物高、中、低剂量组,阳性对照组和阴性对照组,进行精子畸形试验和骨髓细胞微核试验,计算精子畸形率和微核率。结果显示,受试物各剂量组精子畸形率与骨髓细胞微核率与阴性对照组比较,差异不显著(P0.05),与阳性对照组比较,差异有统计学意义(P0.01)。表明沙咪珠利对小鼠精子和骨髓细胞微核无影响,不具有遗传毒性。     

亚硒酸钠小鼠骨髓嗜多染红细胞微核试验研究

为评价亚硒酸钠的致突变性,进行了小鼠骨髓嗜多染红细胞(PCE)微杭试验。结果表明:当受试物终浓度为2mg/kg,1mg/kg剂量组PCE微核率与阴性对照组比较有极显著性差异(p0.01),结果为阳性;0.5mg/kg剂量组PCE微核率与阴性对照组比较,差异均无统计学意义(p0.05),为阴性结果。结论:亚硒酸钠具有一定的致突变性。     

罗红霉素对鸡毒支原体感染的治疗试验

20日龄京白雏鸡210只,随机分成七组,其中六组用鸡毒支原体攻毒发病,五组分别饮用50ppm,25ppm,12.5ppm的罗红霉素、125ppm的硫氰酸红霉素、50ppm的氧氟沙星,连用5天,一组作阳性对照组,末攻毒组作阴性对照组,结果各试验组的死亡率分别为0、0、0、3.3％、3.3％、33％、0。对鸡毒支原体感染的治疗试验表明,罗红霉素能明显降低鸡气囊损伤,较好地提高鸡的成病率,其中以中、高剂量的效果最好,低剂量与对照药物硫氰酸红霉素和氧氟沙星相当。     

阿特拉津对雏鸡的急性毒性作用和骨髓微核率的影响

为了研究阿特拉津对雏鸡的急性毒性作用和致突变作用,本试验运用Weil's方法设计试验,测得阿特拉津对雏鸡的半数致死量(LD50),在此基础上,将雏鸡分为试验组(高、中、低浓度3组)、阴性对照组(生理盐水)、阳性对照组(环磷酰胺),连续染毒9d后采样,取胸骨骨髓,检测骨髓细胞微核率.结果表明,LD50为451 mg/kg体重,试验组骨髓细胞微核率与阴性对照组比较有极显著性差异(P＜0.01),且呈剂量-效应关系,表明阿特拉津对雏鸡骨髓细胞突变有诱变作用.     

小檗碱透皮制剂对小鼠骨髓细胞的微核效应

本采取小鼠骨髓细胞微核试验方法。研究小檗碱透皮制剂对体细胞的诱变性。结果表明：阴性对照组微核率为1．125±0．9‰,环磷酰胺阳性对照组的微核率为5．125±0．976‰,与阴性对照组比较,差异极显（P＜0．01）;小檗碱透皮制剂低,中,高剂量组微核率分别是1．125±0．69‰,1．5±0．9‰,1．875±0．787‰,与阴性对照比较,差异均不显（P＞0．05）,试验结果为阴性。小檗碱透皮制剂对小鼠骨髓细胞不具诱变性。     

磺胺二甲嘧啶对小鼠亚慢性毒性、骨髓细胞微核及精子畸形的影响

试验选取昆明种小鼠,采用经口灌胃法,研究磺胺二甲嘧啶对小鼠亚慢性毒性、骨髓细胞微核和精子畸形的影响。结果显示,亚慢性毒性试验中,高、中剂量组小鼠体重与对照组和低剂量组差异极显著(P＜0.01);高剂量组雄性小鼠心脏的脏器系数与对照组和低剂量组差异显著(P＜0.05);高剂量组雄性小鼠肾脏的脏器系数显著低于对照组(P＜0.05),雌性小鼠肾脏的脏器数显著低于对照组与低剂量组(P＜0.05);小鼠骨髓细胞微核试验中高剂量组与空白对照组差异显著(P＜0.05),高、中、低剂量组间无显著差异;小鼠精子畸形试验中,高、中剂量组与空白对照组差异极显著(P＜0.01),低剂量组与空白对照组差异显著(P＜0.05),高剂量组与中、低剂量组差异显著(P＜0.05)。结果表明,高剂量的磺胺二甲嘧啶对小鼠的心脏和肾脏及微核发生率有一定影响;中剂量的磺胺二甲嘧啶对雌性小鼠的微核发生率具有一定影响;高、中、低剂量的磺胺二甲嘧啶对精子畸形率均具有一定影响。     

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 -