Lysine, Methionine and Tryptophan Requirements of Beijing Ducklings of 0-2 Weeks of Age

A feed trial was conducted with a total of 1 134 Beijing ducklings to study the optimum level of dietary lysine （Lys） （0.95, 1.10, 1.25%）, methionine （Met） （0.26, 0.46, 0.66%） and tryptophan （Trp） （0.20, 0.30, 0.40%） for those ducklings during a phase of 0-2 weeks. Ducklings were randomly allotted to 27 groups according to a 3 × 3× 3 factorial arrangement and fed a basal corn-soybean-peanut meal diet containing 20.26% CP, 12.45 MJ kg^-1 ME. The results from this study indicate that Lys affected body weight （P〈0.01）, feed intake （0-14 d） （P〈0.01）, but had no effect on feed/gain （0-14 d） （P〉0.05）, uric acid concentration （P 〉 0.05）. Methionine influenced body weight （P 〈 0.01）, feed/gain （P 〈 0.05）, and feed intake （P 〈 0.01）. Tryphtophan had no effect on indices measured. The requirement of the Lys and Met for Beijing ducklings of 0-2 weeks of age were 1.10 and 0.46%. The requirement of Trp for Beijing ducklings of 0-2 weeks of age was not more than 0.20%.

Study on the Effects of Cytokine Level in Ducklings with Selenium Poisoning

One-day-old healthy ducklings （n = 100） were randomly allocated into two groups （n = 50, respectively） to investigate the effect of cytokines on ducklings with selenium poisoning. The ducklings in control group （Group Ⅰ） were fed with full rations containing 0.3 mg kg^-1 selenium, and the ducklings in selenium poisoning group （Group Ⅱ ） were fed with seleniumexcessive rations containing 8.0 mg kg^-1 selenium. One mL blood was collected by cardiac puncture at d 15, 30, 60, and 90 （n = 10, respectively）, serum was separated by centrifugation. Contents of cytokines were determined by the radioimmunity method （RIA）. The results showed that the contents of IL-113, IL-213 in Group Ⅱ were higher than that in control group at d 15 （P〉0.05）, but were significantly lower at d 30, 60, and 90 （P〈0.01）; the contents of IL-8β in Group II were significantly lower than that in control group （P〈0.01）; the contents of erythropoietin （EPO） and IGF-2 in Group II were significantly lower in different degree than that in control group at d 60 and 90 （P〈0.01）; the contents of granulocyte- macrophage colony stimulating factor （GM-CSF） in the two groups were lower in different degree and significantly lower at d 60 and 90 （P〈0.01）. It can be concluded that the excessive selenium could result in a decrease in immunity and a series of clinical pathology changes, such as anemia, tissue hemorrhage, and necrosis.

Phosphorus Deficiency in Ducklings

20 one-day-old Tianfu ducklings were fed on a natural diet deficient in phosphorus (Ca 0.80%, P 0.366%) for three weeks and examined for signs and lesions. Signs began to appear at the age of one week, and became serious at two weeks. 13 ducklings died during the experiment. Morbidity was 100% and mortality was 65%. The affected ducklings mainly showed leg weakness, severe lameness, depression, lack of appetite and stunted growth. The serum alkaline phosphatasc activities increased markedly. The scrum phosphorus concentration, tibial ash, ash calcium and phosphorus content decreased obviously. At necropsy, maxillae and ribs were soft, and the latter was crooked. Long bones were soft and broke easily. The hypcrtrophic zone of the growth- plate in the epiphysis of long bones was lengthened and ostcoid tissue increased in the mctaphyseal spongiosa histopathologically. The above mentioned symptoms and lesions could be prevented by adding phosphorus to the natural deficient diet (up to 0.65%). The relationship between lesions and signs, pathomorphological characterisation and pathogcnsis were also discussed in this paper.

Effect of Copper Toxicity on Lymphoid Organs in Ducklings

one-day-old Tianfu meat ducklings were divided into three groups, and fed on dietsas follows:(1)control (Cu 12.16 mg kg-1),(2) copper toxicⅠ(Cu 850 mg kg-1) and (3)copper toxicⅡ( Cu 1050 mg kg-1) for studies on effects of copper toxicity on lymphoidorgans in duckling with the methods of experimental pathology and flow cytometry (FCM).The weight and growth index of the thymus, spleen and bursa of Fabricius were markedlyreduced (P<0.05 or P<0.01) in both copper toxic groupⅠand Cu toxic group Ⅱ whencompared with control group. The G0/G1 phase of the cell cycle of the thymus, spleen andbursa of Fabricius was much higher, and S, G2+M phases lower in Cu toxic groupsⅠand Ⅱthan in the control group. There were lymphocyte degeneration and depletion of lymphoidorgans, and the reticular cells of spleen and bursa of Fabricius proliferated and thereticular cells of thymus were also degenerate and necrotic in Cu toxic groups. Theresults demonstrated that Cu toxicity seriously impaired the progression of lymphocytesfrom the G0/G1 phase to S phase, inhibited the development of lymphoid organs and causedmarked pathological injury in lymphoid organs. The results also showed that the effectof Cu toxicity on the primary lymphoid organs occurred stronger than on the secondarylymphoid organs. The effect of Cu toxicity was the greatest on the bursa of Fabricius,followed by the thymus, and then the spleen. Potential mechanisms underlying aforementionedobservation were also discussed.

Study on the NO Concentration and NOS Activity in the Serum and Tissues of Ducklings with Selenium Poisoning

One-day-old healthy ducklings(n=100)were divided into control group and experimental group randomly, and selenium poisoning of ducklings was artificially caused by feeding ration containing 8 mg kg-1 Se every day. The dynamic changes of No content and NOS activity in the serum and tissues were determined by means of the method of nitric acid reductase. Results showed that the NO content and NOS activity in serum and tissues in experimental group increased significantly(P<0. 05)and they were time-dependent. It was suggested that the high level of selenium in bodies could increase the NOS activity and NO content as it destroyed the metabolism of material and energy as well as structure and function of tissues and cells. These changes of NO content and NOS activity might be involved in the metabolism of selenium poisoning.

Man Attacked for Protecting Ducklings

本文真有点黑色幽默的味道。为了保护小鸭子,结果自己被几个少年打伤!最可咀嚼的是本文的主题句。一个复合形容词的运用令表达趋于紧凑。这个复合形容词是stone-throwing teenagers。

移动科研在线中基于冲突解决的数据同步策略

移动科研在线是协同工作环境套件Duckling的应用之一,但由于移动计算环境存在低带宽、长延迟和频繁断接等问题,当多个用户对同一数据进行操作时容易引发冲突,因此冲突处理和数据同步是该应用的关键问题。为此,提出一种基于冲突解决的数据同步策略。给出数据同步的总体框架和策略,分析冲突处理流程,根据冲突发生的场景,结合用户分类和优先级建立消息推送模型。以移动科研在线中的团队通讯录为例在Android平台上进行原型实现,结果显示,该策略可有效节约网络带宽,提高同步效率,具有良好的用户体验。

Bioassay Procedure for the Diagnosis of Aflatoxicosis in a Pig Farm in Nsukka, South East Nigeria

The owner of an intensively reared pig farm in Nsukka, South-East Nigeria reported the deaths (within one week) of 90 piglets (2-3 months of age) out of 150 piglets on the farm. The piglets were being fed home-compounded ration composed of spent grain (which appeared moldy) and other locally sourced materials. Clinical signs observed in affected piglets include sudden loss of appetite, diarrhea and distress grunting sound prior to death. Symptomatic treatment of the piglets which included the use of antibiotics (tetracycline, LA) did not appear to have ameliorated the condition. At necropsy carcasses were generally in fair to good body condition;with subcutaneous hemorrhages, mainly under the skin of head and neck regions. Lungs were congested and edematous, with froth along the tracheal and bronchial airways. The liver and spleen were moderately congested, while the mucosae of the gastrointestinal tract (which was free of ingesta) appeared mildly hyperaemic. No pathogenic bacterium was isolated from the heart blood and spleen. Histologic section of the liver showed centrilobular hepatocytes vacoulation and necrosis with hypertrophy of Kupffer cells that were in erythrophagocytosis. There was moderate fibrinous exudation into the interlobular septae. Spleen section showed severe erythrophagocytosis, but mild haemosiderosis. White pulp was either reactive or depopulated. Lungs were severely haemorrhagic with bronchitis and bronchiolitis. A tentative diagnosis of mycotoxicosis was made and the spent grain-compounded ration was fed to different groups of ducklings, with/without arginine and lysine supplementation. On the bases of clinical signs and mortality pattern;gross and histologic changes in the liver of the ducklings, a definitive diagnosis of aflatoxicosis was made. This paper emphasizes the experimental feeding of suspected feeds/feed ingredient to ducklings as a reliable diagnostic model for aflatoxicosis.

The Potential of Duck Hepatitis Virus(DHV-1) Stimulating the Body Weight Gain and the Effects of Silymarin on It in Duckling

To evaluate the effects of duck hepatitis virus-1 （DHV-1） on the body weight gain in duck and the effects of silymarin on it in vivo, 100 10-d-old ducks, both male and female, were collected to be subjected to the test. The experiments were conducted in 8 groups： in group 1-3, the animals were inoculated with 1：105 diluted duck hepatitis virus （DHV-1） infected allantoic fluid and given 0, 30, and 50 mg kg^-1 BW d^-1 silymarin orally, respectively. In group 4-6, the animals were inoculated with 1：5 × 105 diluted DHV-1 infected allantoic fluid and given 0, 10, and 30 mg kg^-1 BW d^-1 silymarin orally, respectively. In group 7, the animals were given 10 mg kg^-1 BW d^-1 silymafin only. Group 8 was the control one treated by injecting sterillized saline into the leg muscles. All the silymarin was given from 0 to 4 d after inoculation of the virus. By the 5th d after inoculation, the vein blood was drawn from the dorsal foot vein and the plasma samples were collected and stored at -20℃. The body weight gain （BWG） was measured from 0 to 10 d after inoculation. The plasma IGF-I, T3, and T4 concentrations were measured by radioimmunoassay （RIA）. At the virus dose of 1：5 ×105 diluted virus infected allantoic fluid, the inoculation of the virus enhanced the BWG significantly compared with that of the control （P〈 0.01）, while 10-50 mg kg^-1 BW d^-1 silymarin could counteract the effects of the virus on the BWG dose-dependently. The plasma IGF-I levels showed no correlation with the BWG, but the T3 levels showed a same tropism with the body weight gain. The present results indicated that sublethal DHV-1 enhanced the body weight gain of ducklings significantly, and the silymarin could counteract this effect in vivo.

集成ANN和Markov的土地利用变化模拟与情景分析——以黄河三角洲为例

基于GIS空间分析、ANN方法、Markov理论和Duckling协同环境,通过研发及集成,形成可同时本地化及协同化运行的土地利用变化模拟和预测的ANNMarkov方法,进而,以黄河三角洲为案例区:1)基于1995、2000年1:10万的土地利用信息和GIS空间分析技术,计算5年间的土地利用转移面积及转移概率矩阵,分析各个土地利用类型的扩展与收缩特征;2)基于ANN方法和地形、区位等多因子空间信息,模拟各个土地利用类型空间变化(扩展与收缩)的概率分布,并按照ANN-Markov方法,模拟得到2000年土地利用分布图,进而进行精度评价,宏观总量、误差矩阵及Kappa系数(达0.82)均表明模拟结果精度总体较高;3)将模型推广至2005、2010年土地利用的空间化模拟(情景分析),得到2005和2010年的土地利用分布模拟图。研究表明,集成ANN-Markov方法能够得到比较理想的LUCC模拟结果,包括非常准确的总量信息与吻合度较高的空间格局特征,而且在情景分析及其空间化模拟方面有较大的优势;通过开发/改进和集成,该方法可在协同环境平台中运行,从而极大地便利了模型的推广应用以及模拟结果的比对。

Effect of hybrid rice varieties on growth and development of broilers and ducks

Three experiments(Exp.1,n=144 broilers[Ross×Ross];Exp.2,n=118 mallard ducklings[Anas platyrhynchos];and Exp.3,n=75 mature mallard ducks)were conducted to determine the effects of 3 levels of unmilled hybrid rice on growth performance and organ and gastrointestinal tract develop-ment.The dietary treatments were 1)corn-soybean meal(basal),2)basal+5%hybrid rice,and 3)basal+10%hybrid rice for Exp.1 to 3,respectively.One bird from each pen in Exp.1(n=24)and all the birds in Exp.2(n=118)and Exp.3(n=75)were randomly selected and euthanized to determine linear measurements and organ and gastrointestinal tract weight.In Exp.1 and 2,birds fed 10%rice experi-enced slower growth(P<0.05)than birds fed the basal diet.In Exp.3,the addition of rice did not affect growth performance.Rice addition did not affect organ length or weight(P>0.05)in Exp.1.However,birds fed 5%rice had significantly increased(P<0.05)pancreas,ileum,and jejunum weights in Exp.2,and 10%rice significantly increased(P<0.05)liver weight in Exp.3.The addition of 10%unmilled rice to broiler and duck diets may reduce growth performance.

《The ugly duckling》教学反思——故事教学初探

教学流程:一、课前准备及热身入境1.出示Class rules.确定评价机制。2.Listen and guess.引出故事人物。设计意图:通过听听猜猜的活动,引出本课谈论话题:duckling二、围绕主题,了解故事1.观察封面,了解故事背景知识。T:Look at the cover of the storybook.What can you see in the picture?Ss:I can see some ducklings.Two are yellow.One