中华鳖台湾群体耶尔森氏菌病的研究

从中华鳖台湾群体病鳖的肝脏分离到菌株９７－７－２Ｃ,９７－９－２Ａ‘,用这两种菌株人工感染１０－１５ｇ稚鳖,发病率和死亡率均为１００％,经菌体形态特征,培养特性和生理生化反应测定,鉴定９７－７－２Ｃ为小肠结肠炎耶尔森氏菌,９７－９－２Ａ’为结核耶尔森氏菌,这两种菌都会引起鳖败血症。     

中华绒螯蟹对赖氨酸、蛋氨酸和精氨酸的需要量

试验以酪蛋白、白鱼粉、豆粕和晶体氨基酸为蛋白源,配制了15组试验饲料,分别测定了中华绒螯蟹幼蟹对赖氨酸(Lys)、蛋氨酸(Met)和精氨酸(Arg)的需要量。养殖试验在室内玻璃纤维水族缸中进行,试验水温为(28±3.0)℃,pH为7.4左右,试验周期为56 d。试验组1～试验组5为Lys试验,试验组6～试验组10为Met试验,试验组11～试验组15为Arg试验,试验用蟹平均初重分别为:Lys试验(2.050±0.027)g,Met试验(2.027±0.033)g,Arg试验(2.05±0.032)g。每个试验设5个氨基酸梯度,其中Lys梯度为:1.58%、1.98%、2.38%、2.78%和3.18%;Met梯度为:0.50%、0.75%、1.00%、1.25%和1.50%;Arg梯度为:1.39、2.09、2.79、3.49和4.19%。每个梯度设3重复。试验结果表明,Lys试验中,试验组3(含2.38% Lys)获得最大的增重率和特定生长率,但与试验组2(1.98%Lys)和试验组4(2.78%Lys)之间没有显著性差异;且试验组3的全蟹水分含量显著较低,而蛋白质含量显著较高(P<0.05)。Met试验中,试验组8(含1.00% Met)的增重率和特定生长率显著较高(P<0.05),而其它试验组的增重率和特定生长率差异不显著(P>0.05);试验组10 全蟹水分含量显著较高,而粗蛋白含量显著较低(P<0.05)。Arg试验中,试验组14(日粮含3.49% Arg)的增重率和特定生长率显著高于其它试验组(P<0.05);而各试验组间全蟹营养组成均没有显著性差异。根据试验的生长反应和二次曲线回归分析,确定了中华绒螯蟹幼蟹饲料中最适赖氨酸、蛋氨酸和精氨酸的需要量分别为2.34%,1.12% 和 3.62%。     

The loss of genetic diversity in Dabry's sturgeon (Acipenser dabryanus,Dumeril) as revealed by DNA fingerprinting

• 1. Dabry's sturgeon, a large, long‐lived migratory fish is endemic to the Yangtze River. Over‐fishing and habitat destruction have caused large‐scale declines in natural stocks in the last two decades.
• 2. Examining patterns of genetic diversity has become an integral component of many management plans for endangered species. DNA fingerprinting was applied to detect genetic diversity in Dabry's sturgeon collected in 1958–1959, 1980–1981 and 1998–1999.
• 3. Studies on direct genetic parameters (genetic variability, hypervariable loci and heterozygosity) and indirect parameters (band‐sharing coefficient and allelic frequency) showed that the continuous decline in wild populations has caused the loss of genetic diversity in present‐day sturgeon.
• 4. The present‐day populations have the lowest genetic variability; thus, effective management is needed to preserve genetic diversity.
• 5. A conservation strategy is urgently required, comprising artificial rearing facilities coupled with breeding management plans.

Copyright © 2003 John Wiley & Sons, Ltd.     

奥尼罗非鱼淀粉酶、脂肪酶的分布与特性

以奥尼罗非鱼(Oreochromisniloticus×O.aureus)为实验材料,研究其淀粉酶、脂肪酶分布与特性。结果表明,Ⅰ(体重55.14g)、Ⅱ(体重122.82g)、Ⅲ(体重225.68g)组实验鱼肠道淀粉酶、脂肪酶活性均表现出相似规律:活性从大到小依次为前肠、中肠、后肠。实验鱼体重从55g增至122g,肠道淀粉酶活性急剧上升,实验鱼体重从122g增至225g,酶活性增幅减缓。3组实验鱼肠道各肠段淀粉酶活性相对比值(前肠、中肠、后肠)分别为1:0.95:0.52、1:0.44:0.21和1:0.50:0.24;脂肪酶活性相对比值(前肠、中肠、后肠)分别为1:0.17:0.12、1:0.34:0.14和1:0.98:0.64。3组实验鱼淀粉酶活性相对比值(Ⅰ、Ⅱ、Ⅲ组)在全肠、肝胰脏中分别为1:8.25:18.94和1:3.43:9.31;3组实验鱼脂肪酶活性相对比值(Ⅰ、Ⅱ、Ⅲ组)在全肠中为1:3.82:13.09。奥尼罗非鱼肠道、肝胰脏淀粉酶最适pH值分别为6.5～7 0和7.5;最适反应温度均为30℃;最适反应底物浓度均为0.8%。肠道脂肪酶最适pH值为7.0～7.5,最适反应温度为35℃。     

弧菌影响斑节对虾受精卵和无节幼体发育的研究

用8种弧菌对斑节对虾受精卵和无节幼体进行感染试验,结果表明,8种弧菌严重地影响虾卵的孵化和幼体的正常发育,其中以混合弧菌感染致病性最强。试验还显示了弧菌对越是早期的胚胎侵害力越强。     

Birth of puppies of predetermined sex after artificial insemination with a low number of sex‐sorted,frozen–thawed spermatozoa in field conditions

The aim of this study was to evaluate fertility and sex ratios after artificial insemination in dogs under field conditions. Semen was cryopreserved as unsorted (control) or was separated into X‐ and Y‐chromosome‐bearing sperm using a cell sorter. Sixty female dogs were inseminated with frozen–thawed spermatozoa of 100 × 10⁶ unsorted (a dose in practice) and 4 × 10⁶ sorted (X and Y group, respectively). A total of 20 dogs became pregnant and 126 puppies were born from the three groups. The percentage of parturition was similar for the X (5/20; 25.0%) and Y (4/20; 20.0%) group (P > 0.05), but lower than controls (11/20; 55.0%) (P < 0.05). Ultimately 28 out of the 32 puppies produced from X group were female (87.5%) and 19/22 (86.4%) puppies of Y group were male. In contrast, sex ratio (51.4% to 48.6%) in the control was significantly different from the X, Y group (P < 0.05). However, male and female puppies in the control had similar birth weights and weaning weights to those from the X and Y groups. This preliminary information indicated that normal puppies of predicted sex can be produced with low numbers of sorted cryopreserved dog spermatozoa at a farm level, making sperm‐sexing technology potentially applicable for elite breeding units.     

马尾松低效林不同改造模式土壤微生物及土壤酶活性的研究

马尾松是我国南方主要用材树种之一,在红壤低山丘陵区因立地条件较差,存在着大面积的低效马尾松林.选择经补植阔叶树改造后的低效马尾松林为研究对象,并以附近自然恢复(受到人为干扰)的低效马尾松林地作对照,研究不同林型的土壤微生物、酶活性以及土壤理化性质.结果表明:(1)马尾松低效林进行改造后土壤微生物数量明显增加,且上层微生物数量明显多于下层,各改造模式中马尾松-木荷混交模式最多.(2)在0～20 cm土层,改造后的林分其林地土壤过氧化氢酶、多酚氧化酶和脲酶活性均明显高于对照地;20～40 cm土层,不同酶的活性在不同林分中表现不同.(3)土壤微生物总量与土壤速效N、速效P含量以及多酚氧化酶、脲酶、蔗糖酶活性均为极显著相关;经多元逐步回归分析,蔗糖酶活性是影响微生物总量的第一位因子.(4)全磷含量是影响多酚氧化酶和过氧化氢酶活性的最主要因子;速效P是影响土壤脲酶活性的第一位因子;pH值是影响土壤蔗糖酶活性的关键因子.     

家蚕滞育卵长期保存的研究

调查了不同温度保存的９个原种及２对杂交种的滞育性及多元醇量的变化，对长期保存卵进行了养蚕试验。结果表明：５℃保存卵在产卵１００日后滞育开始解除，１５０日左右孵化率达到最高峰，２００日后急剧下降。不同品种间无明显差异。１℃保存卵在产卵后１８０日左右开始解除滞育，原种在２００－３００日之间孵化率最高，３００日后显著降低，而杂交种产卵后４５０日孵化率仍在８０％以上。－１．５℃保存卵在产卵后５００日仍呈滞育状态，但转入５℃保存８０日后可获得孵化能力，到产卵后７００日孵化率大致在６０％左右。不同温度保存卵滞育的解除，与卵内山梨醇及甘油量的减少呈相同趋势。养蚕结果表明，用１℃保存４１０日以及－１．５℃保存７００日的杂交种，除孵化率比当年生产的冷藏浸酸种低外，其它饲育成绩无明显差异。     

6个不同地理湖泊中华绒螯蟹(Eriocheir sinensis)肌肉组织氨基酸组成、营养评分及其差异性分析

为探究江苏省长荡湖、固城湖、高邮湖、洪泽湖、太湖、阳澄湖6个不同地理湖泊中华绒螯蟹(Eriocheir sinensis)群体的氨基酸组成及其对应的营养品质评价,本研究采用OPA-FMOC柱前衍生化HPLC法测定中华绒螯蟹肌肉组织中氨基酸组成及含量,并根据联合国粮食及农业组织/世界卫生组织(FAO/WHO)标准对其进行...     

茯苓液体培养条件研究及其营养浓缩液的相关检测

研究表明，液体培养条件下，茯苓经0～48h的适应期，48～144h的增殖期后进入稳定期，发酵液pH骤降。经检测，发酵液中含有包括十六烷酸和十八烷酸在内的有机酸；发酵罐培养120h，生物量≥30g/l00mL(鲜重)。茯苓营养浓缩液多糖含量≥5．0mg/mL，氨基酸含量≥480mg/100mL。动物实验证明，茯苓营养浓缩液具有显著的抗疲劳和提高机体免疫力作用，其重金属和微生物指标均符合国家标准。