The realisable potential supply of woody biomass from forests in the European Union

Forests are important for providing wood for products and energy and the demand for wood is expected to increase. Our aim was to estimate the potential supply of woody biomass for all uses from the forests in the European Union (EU), while considering multiple environmental, technical and social constraints.The potential woody biomass supply was estimated for the period 2010-2030 for stemwood, residues (branches and harvest losses), stumps and other biomass (woody biomass from early thinnings in young forests). We estimated the theoretical biomass potential from recent, detailed forest inventory data using the EFISCEN model. Constraints reducing the availability of woody biomass were defined and quantified for three mobilisation scenarios (high, medium, low). Finally, the theoretical potentials from EFISCEN were combined with the constraints to assess the realisable potential from EU forests.The realisable potential from stemwood, residues, stumps and other biomass was estimated at 744 million m³ yr⁻¹ overbark in 2010 and could range from 623 to 895 million m³ yr⁻¹ overbark in 2030, depending on the mobilisation scenario. These potentials represented 50-71% of the theoretical potential. Constraints thus significantly reduced the biomass potentials that could be mobilised. Soil productivity appeared to be an important environmental factor when considering the increased use of biomass from forests. Also the attitude of private forest owners towards increased use of forest biomass can have an important effect, although quantifying this is still rather difficult.The analysis showed that it is possible to increase the availability of forest biomass significantly beyond the current level of resource utilisation. Implementing these ambitious scenarios would imply quite drastic changes in forest resource management across Europe.     

欧拉羊与山谷型藏羊杂交后代各年龄段生长速度分析

对欧拉羊与山谷型藏羊杂交试验组和山谷型藏羊本交对照组所产的后代进行了初生、3月龄、6月龄、12月龄、18月龄的体重跟踪测定和差异显著性检验。结果表明,欧山杂交F1代公、母羊初生～3月龄,3～6月龄,6～12月龄、12～18月龄日增重分别比同期对照组后代日增重均快,差异极显著(P﹤0.01),并且随着月龄的增加,日增重降低。说明欧山杂交后代的生长速度在初生至12月龄增长速度快,而12～18月龄的增长速度减慢,适宜羔羊肉生产。     

陶藏杂一代羔羊与藏羔羊育肥效果比较研究

试验选择体重相近、健康良好的无角陶赛特羊与藏羊杂一代羔羊28只,藏羊羔羊15只进行育肥,测定其育肥效果。结果表明,试验组绝对增重、平均日增重和相对增重分别比对照组提高4．35kg、72．5g／d和23．87％,差异显著（P〈0．05）;试验组胴体重、屠宰率分别较对照组提高4．55kg和4．74％,差异显著（P〈0．05）,试验组GR值和眼肌面积分别较对照组提高2．12cm。和0．7mm,但差异不显著（P〉0．05）;经济效益分析表明,育肥后杂一代羊较藏羊多收入174．0元／只。     

欧拉羊与山谷型藏羊杂交效果观察初报

引进草地型藏羊欧拉羊杂交改良山谷型藏羊,结果表明:引进的欧拉羊生理指标正常,对在林间草甸类和高山灌丛草场与山谷型藏羊同群放牧较适应;试验组受胎率、繁殖率、繁殖成活率比对照组分别高2.65%、2.69%、3.81%;欧×山杂交F1代初生公、母羊体高、体长、胸围及管围比同期对照组公、母羊分别提高了3.20 cm和4.50 cm、1.97 cm和2.25 cm、4.10 cm和2.20 cm、0.53cm和0.40 cm;体重提高0.62 kg和0.53 kg,比对照组分别提高了19.68个百分点和17.97个百分点。经过t检验,杂交F1代初生公、母羊体重、体高、体长、胸围极显著的高于对照组初生公、母羊(P0.01);管围差异显著(P0.05)。     

阴外动脉灌注氨基酸、葡萄糖混合物对奶山羊血浆总蛋白、白蛋白及相关激素受体mRNA表达量的影响

本试验旨在研究阴外动脉乳成分前体物浓度的变化对奶山羊乳腺吸收及相关激素受体mRNA表达量的影响.选用2～3岁,体重、产奶量相近、安装有阴外动脉和腹部皮下静脉血插管的关中奶山羊3只,由阴外动脉灌注氨基酸和葡萄糖混合物,在灌注前后分别采集动静脉血浆、乳腺组织,测定动静脉血浆中总蛋白、白蛋白的含量及乳腺组织β-酪蛋白、催乳素受体、生长激素受体和类胰岛素生长因子Ⅰ的mRNA表达量。结果表明,与灌注前相比,乳成分前体物含量及乳腺对其的摄取量均提高(P<0.05).乳腺组织中β-酪蛋白、生长激素受体和类胰岛素生长因子Ⅰ的mRNA表达量显著提高(P<0.05),催乳素受体的mRNA表达量极显著提高(P<0.01),说明阴外动脉灌注氨基酸、葡萄糖混合物可以显著地提高乳成分前体物的浓度,有效地刺激血液中激素发生变化,提高乳腺组织中相关受体mRNA的表达.     

嘧肽霉素高产菌株的选育

以不吸水链霉菌辽宁变种为出发菌株,经紫外线、亚硝酸诱变和紫外线与嘧肽霉素复合诱变,选育出了嘧肽霉素的高产菌株,抑菌圈直径由原来的20.5mm提高到36.4mm。传代培养5代表明,该高产菌株遗传特性稳定。     

Effect of Donor Age on the Developmental Competence of Bovine Oocytes Retrieved by Ovum Pick Up

To study the effect of donor age on oocyte developmental competence and steroid profiles, the crossbred cow (Murray Grey × Brahman) in Yunnan province of China were selected and divided into three groups according to its age. The three groups were young cows (n = 12; 12 months old), middle‐aged cows (n = 15; parity: ≤3 calvings; age: 7–8 years old) and old cows (n = 10; parity: ≥8 calvings; age: ≥15 years old). Cumulus–oocyte complexes (COCs) were collected by 10 consecutive ovum pick up (OPU) sessions with a 4‐day interval between each session, followed by in vitro maturation, fertilization and embryo development. Results showed that cleavage rates (CR) and blastocyst rates (BR) were higher in the young cows than those in the middle‐aged and old cows (p < 0.05). CR and BR from COCs of the first and the fourth OPU sessions were lower than those from other sessions in the young cows and the middle‐aged cows (p < 0.05), whereas the similar phenomenon was not observed in the old cows. Plasma concentrations of oestradiol were higher, and plasma concentrations of progesterone were lower before and during OPU sessions in the young cows compared with those in the same period in the middle‐aged cows or the old cows (p < 0.01). In conclusion, donor age of oocytes could affect developmental competence of oocytes recovered by OPU through the action of steroid hormonal balance on follicle development.