西方蜜蜂长期定地饲养存在的问题和解决办法

为了弄清近年来西方蜜蜂长期定地饲养存在的问题和解决的办法,通过剖析存在的问题,采取相应的解决办法,摸索出一套适合本地的西方蜜蜂定地饲养技术很有必要。     

Effect of sodium molybdate supplementation on high concentrations of Cu in liver of yearling bulls

AIM: To determine the impact of sodium molybdate treatment, given weekly, on concentrations of Cu in liver, activity of liver enzymes, and weight gain over 4 weeks, in yearling bulls with elevated concentrations of Cu in liver.

METHODS: The study was carried on two commercial grazing farms in the Otago region of New Zealand in yearling Friesian bulls (n=150 on Farm A and n=49 on Farm B) with mean concentration of Cu in liver >3,000 µmol/kg fresh weight. On Day 0, all animals were weighed and half were systematically allocated to treatment with sodium molybdate (3?mg/kg liveweight on Farm A and 7?mg/kg liveweight on Farm B); the remainder received no treatment (Control). Sodium molybdate was given as a drench weekly for 4 weeks and all animals were weighed again on Day 28. Ten animals on each farm (five from each treatment group) were systematically selected for blood sampling and liver biopsies on Days 0 and 28. Samples were analysed for concentrations of Cu in plasma, vitamin B₁₂ in serum, activities of γ–glutamyl transferase, aspartate aminotransferase and glutamate dehydrogenase in serum, and concentrations of Cu and vitamin B₁₂ in liver. Separate multivariable linear models were used to compare the change in outcome variables between Days 0 and 28 between bulls that had been drenched with sodium molybdate or not.

RESULTS: On Farm A, mean concentrations of Cu in liver on Day 28, as a percentage of concentrations on Day 0, for the control group was 55 (95% CI=40–73)% and for the treatment group was 73 (95% CI=43–111)%. On Farm B, the equivalent mean for the control group was 75 (95% CI=42–131)% and for the treatment group was 85 (95% CI=38–134)%. The multivariable linear models indicated that the changes in concentrations of Cu in liver, activities of liver enzymes and weight gain between Days 0 and 28 did not differ between the bulls treated or not with sodium molybdate (p>0.18).

CONCLUSIONS AND CLINICAL RELEVANCE: Treatment with sodium molybdate in one bolus at weekly intervals for 4 weeks did not affect concentrations of Cu in liver, activity of liver enzymes or weight gain in animals with high concentrations of Cu liver on two farms.     

桉油溶液剂的急性毒性和安全药理学研究

灌胃给药(ig)研究桉油溶液剂对大鼠的急性毒性。安全药理学试验以高剂量(30%)、中剂量(18%)、低剂量(6%)分别给予大鼠0.3 m L/只涂抹桉油溶液剂,观察其对大鼠神经系统、心血管系统和呼吸系统的影响。桉油溶液剂对大鼠的经口半数致死量(LD50)为3811.5 mg/kg。桉油溶液剂对大鼠的中枢神经系统、呼吸系统和心率等均无明显影响。桉油溶液剂是一种较安全的局部外用药,适合在临床上推广应用。桉油溶液剂经生产实践和兽医临床试验证明具有良好的治疗动物疥螨病效果。     

An impact of Deoxynivalenol produced by Fusarium graminearum on broiler chickens

Deoxynivalenol (DON) is a major mycotoxin from the trichothecene family of mycotoxins produced by Fusarium fungi that cause disease in grains. Food and feed contaminated with DON cause a variety of adverse health effects in humans and farm animals. However, the fermentation conditions of DON for toxicological study remain to be optimised. Deoxynivalenol levels were increased in a constant temperature of 20°C after fermentation for 7 and 14 days compared with cycling temperatures between 10–20°C and 15–20°C. We have established that optimum conditions for DON production on rice‐based medium is constant temperature at 20°C. In feeding experiments, the villus height and the ratio of villus height and crypt depth were reduced in the duodenum of DON‐fed broiler chickens, whereas a mycotoxin degradation agent efficiently reversed the abnormal morphology of the small intestine in the DON‐fed broilers. The expression of pro‐inflammatory gene, COX‐2, was induced in the spleen and bursa of Fabricius of DON‐fed broilers. This effect was alleviated in the presence of mycotoxin degradation agent. DON produced in solid‐state fermentation is able to cause toxic effects in broilers and induce an abnormal morphology of the small intestine, particularly the duodenum.     

6种杀菌剂对蓝莓煤污病菌的室内毒力测定

为探明不同杀菌剂对蓝莓煤污病菌的室内抑菌活性,采用菌丝生长速率法测定6种杀菌剂对3种蓝莓煤污病菌的室内毒力。结果表明,煤污病菌对不同杀菌剂的敏感性差异较大,其中供试药剂氟菌.戊唑醇、多抗霉素、异菌脲对3种病原菌抑制作用较强,EC50值介于0.2409~3.1832 mg/L。     

The effect of arbuscular mycorrhiza fungal propagules on the growth of subterranean clover (Trifolium subterraneum L.) under Mn toxicity in ex situ experiments

The role of intact extraradical mycelium (ERM) as the most effective fungal propagule in the formation of the tripartite symbiosis between indigenous arbuscular mycorrhizal fungi (AMF), rhizobia and subterranean clover was investigated under conditions of Mn toxicity. ERM was previously developed in 8 L pots under greenhouse conditions by growing plants, which exhibited various levels of mycotrophicity and were tolerant to the levels of Mn in the soil used in the experiment (Silene gallica L, Lolium rigidum L, Ornithopus compressus L. and Rumex bucephalophorus L). Contrasting conditions of the integrity of the ERM at the planting of subterranean clover were created by soil disturbance (ERM fragmented – soil disturbed; ERM intact – soil undisturbed). Where an intact ERM was present at the time of planting, growth of subterranean clover was 2.5 times greater after 21 days and 3.9 times after 42 days relative to other forms of AMF propagule. This enhanced growth was associated with a reduction in the Mn concentration of roots due to a greater AMF colonization at 21 days after planting. The protection granted by an enhanced AMF root colonization allowed a greater root nodule development, leading to more N acquisition and plant growth. The ERM can be developed in the soil by mycotrophic plants tolerant to the stressing agent and kept intact at the seeding of the crop to be protected by adopting appropriate tillage techniques.     

Study on Acute Toxicity Test of Anticoccidial Oral Liquid from Dichroa febrifuga in Mice

The purpose of this study was to evaluate drug safety of Dichroa febrifuga oral liquid (DFOL),and the acute toxicity test of DFOL was established in mice based on modified Karber's method and dose increasing method,and histopathological examination had been applied to explore the main target organs of its toxic injury.The dosage was determined by preliminary experiment,a total of 60 Kunming mice were selected and divided randomly into one control group and five experimental groups,DFOL was administered by intragastric gavage at five different doses (1.00,1.40,1.96,2.74,3.84 g/(kg·BW)),and observed for 7 days continuously,the LD₅₀ value and 95% confidence interval of LD₅₀ were determined by the modified Karbers method.It showed that LD₅₀ was 2.0961 g/(kg·BW) and its 95% confidence interval was 1.7414 to 2.5429 g/(kg·BW).The liver and kidney of some mice in 1.96,2.74 and 3.84 g/(kg·BW) drug groups appeared severe edema,congestion and white necrotic foci by necropsy.Acute liver injury was found in mice by histopathological examination and the liver cell showed degenerative change,kidney damage showed renal congestion,interstitial edema,renal tubule epithelial cloudy swelling and degeneration.The liver was damaged seriously in the main organ and the main toxic organ of DFOL was liver.The test showed that the toxicity of DFOL was lower and it had high security in a conventional doses for clinical anti-coccidiosis application,however,high dose,long course of medication had toxicity,and the toxicity of DFOL should be analyzed and evaluated combining with long-term toxicity tests and many other inspection results.     

几种杀菌剂对魔芋灰霉病病菌的毒力研究

在生产上防治魔芋灰霉病发生的药剂种类选择混乱,及很多药剂对魔芋灰霉病菌的毒力作用也不明确,因此采用菌丝生长速率法测定了7种杀菌剂对魔芋灰霉病菌的毒力。结果表明:多菌灵、异菌脲对魔芋灰霉病菌的抑制效果好,EC50分别为0.001、0.005 mg/L;其次是宁南霉素、嘧霉胺、菌核净,EC50分别为0.043、0.052、0.084 mg/L;王铜和硫酸铜钙的抑菌效果最差大于200 mg/L。     

Long-Term Application of Chemical Fertilizers and Rice Straw on Soil Aluminum Toxicity

The red soil region in China is very important to agriculture. However, soil aluminum (Al) toxicity often occurs as a result of the high soil acidity. In a long-term experiment, we analyzed soil samples to determine the effect of fertilization on soil acidity and potential Al toxicity. The results showed that after 12 years of utilization, Al toxicity occurred in the soil of the control plot. Chemical fertilizer further decreased soil pH and intensified Al toxicity. However, rice straw effectively improved soil pH and ameliorated soil Al toxicity from 0 to 50 cm deep, which may be attributed to the accumulated soil organic matter (SOM) and the decomposition of the rice straw. Corresponding to the lower Al content in soil, peanut crops grew healthier with greater yields in the rice straw plot, indicating that returning crop stalks to the field should be a feasible fertilization strategy in the region.