Sulphur availability and microbial fermentation in the fauna-free rumen.

The concentration of H2S and rate of feed digestion, VFA and methane production in the rumen were measured in sulphur deficient (-S) and S supplemented (+S) sheep while fauna-free (-P) and after refaunation (+P). The concentration of rumen H2S was increased by S supplementation but was not affected by the presence of protozoa. When fauna-free, -S sheep had reduced rates of feed digestion (30 v 48%/d), acetate synthesis (35 v 115 g/d) and methane synthesis (0.4 v 7.4 g C/d) compared to +S sheep and up to 36% (v/v) of total rumen gas was H2. When these sheep were given a single dose of 8.8 g Na2SO4, the proportion of methane increased and the proportion of H2 in rumen gas decreased. After refaunation of sheep, their rates of feed digestion, VFA production and methane production were higher and were not affected by the level of S. From this differential response to S deficiency by -P and +P sheep, it is concluded rumen protozoa increase the availability of S to other rumen microbes. This is probably because they degrade protein through to peptides and amino acids.     

Renal regulation of the excretion of urea in fasting camels

Experiments were performed with young two-humped camels exposed to 36-hour starvation with free access to water. The renal functions were measured by the standard clearance method. In spite of the administration of 20 micrograms DDAVP, a higher urine flow rate was recorded in the camels subjected to control measurements (feed intake) than in the fasting period (1.45 +/- 0.06 vs. 0.96 +/- 0.06 ml . min-1, P less than less than 0.001). On the second day of fasting the camels had a significantly reduced glomerular filtration rate (GFR 317.5 +/- 23.2 vs. 170.2 +/- 17.4 ml . min-1, P less than 0.001), urea output (700.5 +/- 62.9 vs. 352.2 +/- 64.7 mumol . min-1, P less than 0.005), and fractional excretion of urea (26.9 +/- 2.8 vs. 17.9 +/- 1.7%, P less than 0.01), whereas their tubular resorption. of urea (Reab urea/GFR) increased (6.28 +/- 0.61 vs. 9.12 +/- 0.82 mumol . ml-1, P less than 0.02). No significant difference was found in the concentration of urea in plasma in the fed camels and in fasting camels (8.55 +/- 0.64 vs. 11.18 +/- 1.09 mmol . l-1, N. S.). The creatinine inulin clearance ratio (C creat/Cin) was 0.92 +/- 0.07 when the animals were fed and 1.17 +/- 0.05 when the animals starved (P less than 0.001); this suggests that the clearance of endogenous creatinine is not suitable for GFR measurement in camels under different conditions of nutrition. The kidneys of camels regulate the excretion of urea during short-time fasting mainly through the reduction of glomerular filtration rate and just partly through an increased tubular resorption.     

生材单板挤压脱水的研究

经分析计算，基本密度为０．３６ｇ／ｃｍ￣３的木材，在１２０％的含水率状态下木材中细胞壁物质、水和空气三者的体积比约为１：１：１，因此当该木材体积压榨率达到６６％时，木材中的水分（自由水）几乎将被全部挤出。据此，使用表面有沟槽的几种不同模板对速生树种Ｉ－６９杨和火炬松的生材单板进行了不同压榨车的挤水试验，结果表明：Ｉ－６９杨２．０２ｍｍ生材单板用７０％的压榨率挤压后，含水率显著降低，组内试件间的合水率差异显著缩小；火炬松２．３８ｍｍ和３．３３ｍｍ生材单板，压榨率６０％比４０％的挤水量大、挤后与挤前组内含水率极差比值小，因而达到了降低并均匀生材单板含水车的目的。另外，模板不同也显出不同的挤水效果。     

海南农资店开到了农家门口

2005年，海南省瓜菜总产量达370万吨，水果162．5万吨，干胶32．9万吨，槟榔6．3万吨，肉类64．08万吨。农产品产量和商品化的大幅度增长，使农村市场交易总量随之迅速增长，农民收入也持续增加，2005年海南省农村人均纯收入达3004元。其中，海南农药、化肥等农资的需求量在大幅度增长的同时，假冒伪劣的问题也成为老百姓最关心、亟待解决的突出问题之一。     

多糖、寡糖、蛋白酶对凡纳滨对虾生长、消化酶活性及血清非特异性免疫的影响

在基础饲料(对照组)中分别添加0.2%β-葡聚糖、0.05%黄芪多糖、0.4%甘露寡糖、175 mg/kg蛋白酶PT,饲喂初始体重为(4.55±0.08)g的凡纳滨对虾(Litopnnaus vannamei)6周,考察对凡纳滨对虾生长性能、血清非特异性免疫及消化酶活性的影响。结果表明:与对照组相比,饲料中添加0.2%β-葡聚糖、0.4%甘露寡糖及175 mg/kg蛋白酶PT可分别提高凡纳滨对虾增重率16.19%、12.78%、11.25%(P<0.05),降低饲料系数0.10、0.09、0.09(P<0.05);各处理组在肌肉水分、灰分、粗脂肪和粗蛋白含量上无显著差异(P>0.05);在血清非特异性免疫方面,各多糖、寡糖和蛋白酶添加组均显著提高血清酚氧化酶活力(P<0.05),添加0.4%甘露寡糖可提高溶菌酶、碱性磷酸酶活力(P<0.05),添加0.2%β-葡聚糖、0.4%甘露寡糖可显著提高超氧化物歧化酶活力(P<0.05);在消化酶活性方面,添加175 mg/kg蛋白酶PT可显著提高肝胰脏蛋白酶、脂肪酶和肠蛋白酶活性(P<0.05),添加0.2%β-葡聚糖及0.4%甘露寡糖可显著提高胃蛋白酶和肝胰脏脂肪酶活性(P<0.05)。上述结果表明,饲料中添加0.2%β-葡聚糖、0.4%甘露寡糖、175 mg/kg蛋白酶PT可提高凡纳滨对虾生长性能、改善消化酶活性,葡聚糖和甘露寡糖还具有改善血清非特异性免疫的功能,而添加0.05%黄芪多糖对凡纳滨对虾增重率、血清非特异性免疫无显著影响。     

柿果类胡萝卜素化学成份及其含量研究

对柿果中类胡萝卜素化学成份及其含量的季节性变化以及栽培条件的影响等进行了调查,旨在为柿色素代谢及其功能性成分合成与调控等的深入研究奠定基础。结果如下:柿果实中的色素成份为玉米黄质、β-隐黄质、β-胡萝卜素、叶黄素和番茄红素;果皮中的类胡萝卜素总含量约是果肉中的6-11倍;按类胡萝卜素组成成分的含量由高至低,果皮依次为玉米黄质、β-隐黄质、β-胡萝卜素、叶黄素和番茄红素;而果肉依次为β-隐黄质、玉米黄质和β-胡萝卜素。结果表明,柿果肉主要色素成份为功能性β-隐黄质。温室栽培磨盘柿果中功能性成分β-隐黄质含量是露地的3倍。供试7品种间色素成分与含量有很大区别。     

异育银鲫对维生素C需要量的研究

在饲料中添加不同含量的结晶Vc（AA）和包膜从（CAA）饲养异育银鲫，结果发现，当饲料中缺乏Vc时，异育银鲫并没有表现出明显的缺乏症状，当饲料中的Vc添加量为AA400mg／kg或CAA200mg／kg时，异育银鲫的增重率和肝脏、血浆中的Vc含量达到最大。在本研究条件下，作者建议，异育很鲫对维生素C的需要量为200mg／kg饲料。     

苹果叶表附生微生物区系及其有益菌的研究 Ⅱ、有益芽孢杆菌的筛选、初步鉴定和电镜观察

在分析了同一生态条件下苹果褐斑病抗感品种的叶部微生物类群的基础上，从已获得的７株Ｂａｃｉｌｕｓ中筛选出３株普遍对苹果轮纹病、炭疽病、霉心病具拮抗作用的菌株，再通过对其菌体代谢液中激素的定性定量分析，筛选出Ｂ０１７（经鉴定为Ｂａｃｉｌｕｓｃｅｒｅｕｓ）作为本实验的益菌．扫描电镜观察表明Ｂ０１７能在苹果叶面定殖和繁衍