开放式呼吸测热系统的研制

东北农业大学研制的猪鸡用开放式呼吸测热装置由４个呼吸小室并联构成。可同时测定４头（或４组）动物的代谢产热量。注入氮气的系统检验结果表明,４个呼吸小室的氖气回收率分别为９２．９％,９３．１％,１００．７％及１００．２％,其重复误差（标准差）为０．０８％－３．５９％。利用该装置对４头体重２０ｋｇ的长哈生长猪进行呼吸测热,其代谢产热率为２７．０±０．７４ｋＪ／ｋｇｈ。系统检验及动物实验结果均表明该装置性能良好。     

挤出滚圆造粒法制备玉米粉球形微丸的工艺研究

采用自行研制的挤出滚圆机制备了玉米粉球形微丸,可为饲料行业提供便捷、优质的产品。采用正交试验法,以表面形态、粒径分布、收率和圆整度作为综合评价指标,并探讨了物料比例和工艺条件对制备微丸的影响。结果表明,200g玉米粉加10g粘合剂糊精、130ml水,调整滚圆机频率20Hz,可以制备圆整度良好,收率达90%以上的玉米粉球形微丸。     

硫对蔬菜产量与品质的效应

报道了１９９４－１９９６年施用中量元素硫肥对蔬菜产量与品质的效应,盆栽及微区试验结果表明,在氮、磷、钾肥,每公顷土壤施硫肥３０ｋｇ,可使蔬菜作物增产４．３８－２９．８６％,维生素Ｃ含量提高４．６５－１４．８１％,硝酸盐含量降低４．８０－１０．７５％,部分蔬菜总糖含量提高２．０４－３．１８％,马铃薯淀粉含量提高５．９１％。     

Essential oils in diets for Nile tilapia juveniles: Productive performance and plasmatic biochemistry

The objective of this study was to evaluate the inclusion of increasing levels of a commercial mix of essential oils (EOs) from cashew (Anacardium occidentale) and castor bean (Ricinus communis) as an additive in diets for Nile tilapia. Thus, 240 juveniles with an initial weight of 35.06 ± 1.02 g were distributed in a completely randomized design (four treatments and six replicates) in 24 cylindrical‐tapered tanks; the fish were fed for 60 days, four times a day, diets containing increasing levels of EO (0.10, 0.15 and 0.20%) and a control diet (without the additive). After the experimental period, the animals were desensitized, and an aliquot of blood was collected for the biochemical analysis; they were subsequently euthanized for the evaluation of productive performance and fillet chemical composition. No significant differences (p > .05) were observed in the analyses of productive performance, fillet chemical composition, and triglycerides, VLDL, total proteins, urea and glucose. However, significant differences (p < .05) were observed in the analyses of total cholesterol, HDL and LDL. Inclusion above 0.15 of the additive showed an improvement in the levels of lipoprotein carriers, increasing HDL levels and decreasing LDL values, without interfering with the fish productive performance.     

斑地锦与地锦总黄酮含量及抗氧化活性比较

以5月营养生长期、7月开花前期、9月果期的斑地锦与地锦为材料,比较它们的总黄酮含量及抗氧化活性的差别.结果表明,斑地锦的总黄酮含量均低于地锦;开花前期斑地锦总黄酮含量为20.28～22.23 mg/g,地锦的为34.67～37.50 mg/g;斑地锦提取液还原力明显弱于地锦,并与总黄酮含量呈正相关;两者在超氧阴离子和羟自由基清除能力上差别不大,斑地锦提取液含量为1 mg/g时,对超氧阴离子的清除率为54%,地锦的为56%;斑地锦提取液含量为10 mg/g时,对羟自由基的清除率为89%,地锦的为92%.     

干酪乳杆菌表面展示IBDV VP2蛋白

旨在利用pLA载体将IBDV B87株VP2蛋白展示在干酪乳杆菌表面。首先通过RT-PCR扩增VP2基因片段,测序鉴定正确后,将目的片段构建在pLA穿梭质粒上,命名为pLA-VP2,然后将重组质粒电转化到干酪乳杆菌中,构建IBDV重组干酪乳杆菌。应用SDS-PAGE检测重组菌表达目的蛋白VP2,得到约90 kDa的融合蛋白,与预期结果相符。Western blot结果显示VP2蛋白可以与抗IBDV多抗血清发生特异性反应,具有很好反应原性。流式细胞仪的散射光检测器可以捕捉到pLA-VP2重组菌菌体表面的荧光,且重组菌荧光强度强于pLA菌对照组,应用正态分布函数计算pgsA-VP2融合蛋白的表达效率,约为80%。结果表明IBDV VP2蛋白成功展示在干酪乳杆菌表面。     

去势公猪和小母猪对饲粮蛋白质或赖氨酸水平的反应

利用２８头杜×哈去势公猪和小母猪在３０—９０ｋｇ体重阶段，研究两种饲粮对其生长性能、胴体性状和胴体组成的影响。试验前期饲粮１含粗蛋白１５％，赖氨酸０．７５％；饲粮２含含粗蛋白１６．５％，赖氨酸０．８０％；后期饲粮１含粗蛋白１３．５％，赖氨酸０．６５％，饲粮２含粗蛋白１５％，赖氨酸０．８０％。试猪采用小群趴卧、个体单栏饲喂方法进行肥育，于９０ｋｇ体重结束肥育并屠宰测定胴体性状和胴体组成。结果表明，饲粮２使屠宰年龄提前１０．６日（Ｐ＜０．０１），平均日增重提高１０７．４ｇ（Ｐ＜０．００１），耗料增重比降低０．３０（Ｐ＜０．０１），平均日采食量增加１１０ｇ（Ｐ＜０．０５），平均背膘厚降低０．４５ｃｍ（Ｐ＜０．０１），瘦肉率提高４．７６个百分点（Ｐ＜０．００１），脂肪率减少５．４１个百分点（Ｐ＜０．００１）；去势公猪较小母猪采食量高、生长速度快（Ｐ＞０．０５），小母猪的胴体瘦肉率较去势公猪高２．４５个百分点（Ｐ＜０．０５），脂肪率低２．４２个百分点（Ｐ＜０．０５），各生长性能、胴体性状和胴体组成均不存在显著的性别和饲粮间的工作效应。     

嵌套式PCR超灵敏检测马铃薯环腐病菌

马铃薯种薯中存在环腐病菌潜伏侵染,这种潜伏侵染逐代累积、逐渐表现症状,这是马铃薯环腐病无法根除的根本原因。本研究应用国外成功报道的根据存在于pCS1质粒和环腐菌染色体中一个1.3 kb的插入因子IS1121、高度重复的DNA片段设计的环腐病菌亚种特异性引物序列合成出引物对CMSIF1-CMSIR1和引物对CMSIF2-CMSIR2。以环腐标准菌株、黑龙江省环腐菌株以及马铃薯上其它主要的细菌病原菌(青枯病、软腐病、黑胫病)为试验材料进行直接PCR和嵌套式PCR扩增,结果只有环腐标准菌株和黑龙江省环腐菌株出现特异性片段(直接PCR扩增出1046 bp的片段,嵌套式PCR扩增出864 bp的片段)。将环腐菌纯菌种菌悬液稀释成浓度梯度并与马铃薯组织液混合进行直接PCR和嵌套式PCR检测灵敏度比较,结果表明嵌套式PCR检测灵敏度比直接PCR检测灵敏度提高了100￣1000倍。以明显感病症状的块茎、无明显感病症状的块茎和健康块茎为试验材料进行直接PCR和嵌套式PCR,结果除明显感病症状块茎外,所有无明显感病症状的块茎也均被检测出带有环腐病菌。     

Phenotypic and genetic parameters for body traits in the giant freshwater prawn (Macrobrachium rosenbergii) in India

Phenotypic and genetic parameters were estimated for three body traits (harvest weight, carapace length and standard length) and for adult male morphotypes of the giant freshwater prawn Macrobrachium rosenbergii in a fully pedigreed synthetic population in India. The data set included 9,173 progeny produced over four generations from 162 sires and 234 dams. Variance components and genetic parameters were estimated fitting an animal model using the residual maximum‐likelihood methodology. The heritabilities for harvest body weight (HW), carapace length (CL) and standard length (SL) were moderate (0.22 ± 0.056, 0.22 ± 0.055 and 0.25 ± 0.059 respectively). The common environmental effects for HW, CL and SL were 0.10 ± 0.020, 0.08 ± 0.018 and 0.10 ± 0.021 respectively. As M. rosenbergii is sexually dimorphic, we estimated heritabilities within each sex. Heritability of HW in females (0.27 ± 0.068) was greater than that in males (0.15 ± 0.057). CL and SL followed the same pattern. The occurrence of male morphotypes is a unique characteristic of adult populations of M. rosenbergii. Populations from culture ponds exhibit a wide range of sizes. To examine whether there was a heritable component in male morphotype frequencies, we treated male morphotypes as traits. The additive genetic variance (and hence the heritability) was zero for male morphotype, indicating that selective breeding to increase the proportion of desirable male morphotypes would not be effective. The genetic correlations among body traits were all positive, high and approaching unity. The results are discussed in relation to selection plans for the giant freshwater prawn.