水培下42份偃麦草种质苗期耐盐性评价

采用水培法对42份偃麦草种质苗期在200mmol/L NaCl胁迫下的盐害评分、相对电导率、叶绿素含量、Na~+/K~+、地上部干重、根系干重以及根冠比进行测定,以各指标耐盐系数作为衡量耐盐性的依据,运用主成分分析、隶属函数分析结合聚类分析对种质耐盐性进行综合评价,通过多元逐步回归分析获得区分偃麦草耐盐能力的关键指标,构建耐盐预测模型。结果表明,与对照相比,盐胁迫后偃麦草种质的盐害评分、相对电导率及Na~+/K~+增加,叶绿素含量、地上部及根系干重降低;隶属函数分析表明,供试种质耐盐性综合评价D值在0.273～0.862之间;用聚类分析将种质划分为4类,其中耐盐种质2份,为材料E34、E40,不耐盐种质8份,分别为材料E10、E36、E07、E26、E44、E15、E23、E14,其余种质耐盐性居中;偃麦草苗期耐盐性预测回归模型为D=0.05-0.04X_1-0.003X_2+0.341X_3+0.234X_4+0.075X_5,式中,X_1为盐害评分;X_2为相对电导率;X_3为叶绿素含量;X_4为根系干重;X_5为根冠比;这5个指标可作为偃麦草耐盐性评价的关键指标。     

偃麦草属植物种质材料苗期耐盐性综合评价

采用温室苗期模拟NaCl盐分胁迫方法,对来自于21个国家的偃麦草属8个植物种34份种质材料苗期的叶片相对含水量、相对电导率、脯氨酸、K⁺/Na⁺、相对生长速度变化率、耐盐系数、存活率和出现盐害到死亡的时间等指标进行测定与分析,并对偃麦草属植物种质材料苗期的耐盐性进行综合评价。结果表明,上述指标均是偃麦草属植物种质材料苗期耐盐性评价的有效指标。且通过对0.9%NaCl浓度下的各项指标进行综合聚类,可将34份偃麦草属植物种质划分为3个耐盐级别,即耐盐种质有ER030、ER035、ER041、EE011、EE014、EE017、EE023、EE026、EE047、EH001、EH002和EPU02;中度耐盐种质有ER008、ER014、ER027、ER032、ER037、ER038、ER044、ER045、EE007、EE027、EJ001、EPO02、EPO03和EPO04;敏盐种质有ER028、ER033、ER036、ER039、EE022、EJ003、EL001和EI022。     

不同多花黑麦草品种萌发期耐盐性评价

采用0、23.4、35.1、46.8和58.5 mol/L NaCl溶液对24个多花黑麦草(Lolium multiflourum)品种种子进行处理,测定了发芽率、生长状况和叶片含水量。结果表明,随着盐浓度的增加,相对发芽率、相对幼苗和相对根长、相对生物量和相对叶片含水量呈下降趋势,且23.4 mol/L NaCl 溶液处理下的各指标值显著高于46.8和58.5 mol/L处理（P<0.05）。盐胁迫对参试材料相对根长的影响最大,其次是相对苗长,对相对叶片含水量影响最小。盐胁迫下各材料间的相对根长和相对生物量差异较明显。综合评价24个种质材料耐盐性,耐盐材料为LM05、LM07、LM10、LM20和LM23,盐敏感材料为LM03、LM08、LM09和LM16。     

不同盐浓度下9份老芒麦种质材料的萌发及生理特性

为研究不同老芒麦(Elymus sibiricus)种质材料耐盐性表现,以筛选出耐盐品种,为耐盐老芒麦种质材料育种提供科学支撑,采用不同浓度梯度NaCl溶液(0.3%、0.6%、0.9%、1.2%、1.5%和1.8%)模拟盐胁迫,对9份来自全国不同地区的老芒麦种质材料进行耐盐处理,筛选出老芒麦萌发期适宜浓度,分别测定其萌发指标及幼苗叶片生理指标(脯氨酸、超氧化物歧化酶、丙二醛),分析不同浓度胁迫下指标的变化情况,并对9份老芒麦的耐盐性进行综合评价。结果表明,NaCl胁迫对老芒麦种子的相对发芽率、发芽指数均产生抑制影响,抑制了胚根与胚芽的生长,其叶片中超氧化物歧化酶活性、丙二醛及脯氨酸含量对盐胁迫浓度变化响应灵敏,0.9%NaCl盐浓度为合适的萌发期筛选浓度,根据隶属函数法进行综合评价,9份老芒麦材料耐盐性由强到弱依次为E03、E04、E08、E09、E07、E05、E06、E02和E01。     

种子萌发期38份偃麦草种质耐盐性评价

为评价偃麦草(Elytrigia repens)种子萌发期耐盐性强弱,采用常规纸上发芽法,以1.2%氯化钠和硫酸钠（质量比为1∶1）模拟盐胁迫,对38份偃麦草的发芽率、发芽势、胚芽长、胚根长、活力指数、萌发耐盐指数、萌发胁迫指数等进行测定。结果表明,盐胁迫降低了偃麦草种子的发芽率、发芽势、发芽指数、活力指数,抑制了其胚芽和胚根的生长,降低了偃麦草萌发性能;根据综合评价值,38份偃麦草材料的耐盐性由强到弱依次为E03、E31、E16、E17、E42、E26、E04、E25、E12、E38、E15、E36、E13、E32、E09、E21、E07、E08、E01、E29、E10、E18、E24、E28、E30、E23、E11、E39、E02、E34、E19、E35、E06、E40、E33、E41、E37、E27。     

33份偃麦草种质芽期耐盐性评价

为了解33份新疆偃麦草(Elytrigia repens)种质芽期耐盐性强弱,分别对其在0、0.4%、0.8%、1.2%Na Cl胁迫下的发芽率、发芽指数、胚芽长、胚根长、苗重进行测定,并采用隶属函数法对其耐盐性进行评价。结果表明,随着盐浓度的增加,33份种质的发芽率、发芽指数、胚根长、胚芽长表现出明显的降低趋势,而苗重变化不规律;对不同浓度下33份种质各指标变异分析认为,1.2%Na Cl是偃麦草芽期耐盐评价的适宜浓度;根据耐盐性综合评价,认为材料E04、E08、E23、E11、E25耐盐性较强,而E27、E35、E37、E38的耐盐性较弱。     

PEG模拟干旱胁迫下29份偃麦草种质种子萌发期抗旱性评价

以20%聚乙二醇溶液(PEG-6000)为渗透介质模拟干旱胁迫条件,对29份偃麦草种质资源进行了种子萌发期抗旱性评价。结果表明:PEG胁迫降低了偃麦草种质资源的发芽率、发芽势、发芽指数、活力指数,抑制了胚芽和胚根的生长发育。以相对发芽率、相对胚根长、相对胚芽长、萌发抗旱指数、胁迫指数、相对发芽势及相对活力指数为依据,通过隶属函数法综合评价认为,29份偃麦草种质资源的抗旱性顺序依次为:E39E14E11E13E16E03E07E25E34E42E09E29E17E31E21E26E06E10E12E27E38E08E01E04E41E19E37E02E24。     

黑麦草属9个品种萌发及苗期耐盐性研究

通过不同浓度的NaCl对黑麦草属Lolium 9个品种的种子和幼苗期进行处理,研究其对相对发芽率、相对发芽势、发芽进程、盐害级别、生长高度、相对地上生物量、细胞膜透性、叶绿素含量、叶片相对含水量、叶片脯氨酸含量等的影响,筛选出主要的耐盐指标和耐盐性强的品种.结果表明:随着盐浓度的升高,相对发芽率、相对发芽势、生长高度、相对地上生物量、叶片相对含水量呈现出下降的趋势;细胞膜透性、叶片脯氨酸含量与盐浓度成正比;而叶绿素的变化表现出的规律则不明显.通过萌发期和苗期耐盐性的综合评价得出,草坪型爱神特、金石和饲用型海湾属耐盐材料,而草坪型美达丽、夜影,饲用型凤凰属敏感材料,其他材料属中等耐盐材料.     

等渗PEG和NaCl胁迫对不同偃麦草种质苗期抗性影响

采用PEG 6000和NaCl模拟干旱和盐胁迫(在-0.6M Pa等渗透势下),对9份偃麦草的株高、根长、生物量、枯黄率、质膜透性以及相对含水量进行测定,并利用隶属函数法和灰色关联度法对其抗旱耐盐性进行综合评价,筛选出表现优良的材料及关键评价指标.结果表明:与对照相比,等渗干旱、盐胁迫均导致供试种质枯黄率、质膜透性显著...     

14份新麦草种质材料苗期抗旱性差异

采用温室模拟干旱胁迫-复水方法,对14份新麦草种质材料苗期的叶片相对含水量、叶绿素的SPAD值、相对电导率、丙二醛和脯氨酸含量等5个抗旱生理指标进行了测定,综合评价其抗旱性能.采用欧氏距离法进行聚类分析,将14份新麦草种质材料的抗旱性划分为3个级别,相对抗旱的材料包括XMC01、XMC06、XMC10,XMC11,中度抗旱的包括XMC02、XMC04、XMC08、XMC09、XMC12、XMC13,相对敏感的包括XMC03、XMC05、XMC07、XMC14.     

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.     

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

Tropical Animal Health and Production -     

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.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

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