屠宰母牛卵巢卵母细胞体外受精与发育的研究

将从屠宰母牛卵巢采得的卵母细胞用含有LH或hCG的M199培养24～26小时,然后用经钙离子载体Ionophore A23187诱导获能的牛新鲜或冷冻精子进行授精处理。授精6～7小时后再用含有乳酸钠和EDTA的M199培养至48～60小时后观察受精及受精卵的发育情况。结果表明,卵子的受精率及受精卵的发育率与卵母细胞成熟用培养基、授精用精子(新鲜或冷冻)以及供卵牛的品种均有关系。将用含有hCG的M199培养成熟的卵子,以获能处理过的新鲜精子授精后,其受精率和受精卵子中单精子受精并发育为2～8细胞期胚的比率在蒙古牛为91.4％(265/200)和19.6％(52/265),在黑白花奶牛为69.7％(62/89)和4.8％(3/62)。     

"十五"期间我国林木产品进出口前景可观

就林木产品一般概念而言 ,主要包括 6个大类品种 ,即原木、胶合板、锯材、单板、纸浆和纸。80年代初期 ,我国林木产品进口总额仅为 1 1亿美元左右 ,到“九五”末期 ,已升至 80多亿美元 ,增长了 7倍多 ,跃居各种进口商品之首 ,成为当前以至今后一个时期我国最主要的进口商品之一 ,其发展前景十分可观。我国林木产品进口贸易之所以如此火旺 ,其主要原因在于 :其一 ,由于国内经济发展迅速 ,特别是与木材需求有直接关系的建筑、装修、农具制造、造纸业等升温 ,牵动木材消费比重逐年加大 ,从而在目前中国消费市场已占有重要地位。其二 ,我国林木…     

饲粮稀释对肥育期肉仔鸡生长性能和胴体品质的影响

试验研究了饲粮稀释对肥育期肉仔鸡生长性能和胴体品质的影响。60只29日龄艾维因肉仔鸡被随机分成2组,每组30只鸡。对照组基础饲粮根据NRC营养水平配制,试验组饲粮在基础饲粮中添加10%的稻壳粉进行稀释。试验期从肉仔鸡29日龄开始到49日龄结束。试验结果表明:与对照组相比,饲粮稀释对肉仔鸡上市体重、饲料效率、胴体和胸肌重量没有显著影响(P>0.05),但是减少腹脂重量(P<0.05)。     

The Construction of the Goat Ovary Melatonin Signal Specific Vectors pcDNA3.1-Pro/GDF9-ASMT and pcDNA3.1-Pro/Cyp17-MTNR1A and MTNR1B

This study intended to construct an oocyte-specific expression vector (GDF9-ASMT) for melatonin (MLT) synthetase acetylserotonin methytransferase (ASMT),and granule (luteal) cell-specific expression vector (Cyp17-MTNR1A,MTNR1B) for MLT receptors MTNR1A and MTNR1B,the construction of the above vectors provided carrier materials for further production of transgenic sheep with high fertility.First,the goat GDF9 and Cyp17a1 promoter sequences were amplified separately.Then,the full-length CDS sequences of ASMT,MTNR1A and MTNR1B genes were amplified,and ASMT gene was connected to the downstream of GDF9 promoter by enzyme-cutting,with MTNR1A and MTNR1B respectively connected to the downstream of Cyp17a1 promoter to prepare Pro/GDF9-ASMT,Pro/Cyp17-MTNR1A and Pro/Cyp17-MTNR1B expression elements.Finally,the above-mentioned expression elements were integrated into the pcDNA3.1(+) vector by enzyme digestion,thereby constructing pcDNA3.1-Pro/GDF9-ASMT,pcDNA3.1-Pro/Cyp17-MTNR1A and pcDNA3.1-Pro/Cyp17-MTNR1B eukaryotic expression vectors.After sequencing verification,the GDF9 and Cyp17a1 promoters amplified in this study were 2 496 and 2 497 bp in length respectively,and they were 98% homologous to the 2 500 bp region upstream of the start codons of the goat GDF9 and Cyp17a1 genes in GenBank database.The amplified ASMT,MTNR1A and MTNR1B CDS sequence lengths were 1 037,1 100 and 1 130 bp,and the homology with the standard sequences submitted by GenBank were 98%,98% and 99%.The amino acid sequence homologies was 97%,98%,99% respectively.The construction of the above vectors provided references for further production of melatonin transgenic sheep with high fertility.     

Transcatheter intravascular stent placement to relieve supravalvular pulmonic stenosis

Valvular pulmonic stenosis has been successfully treated in dogs via minimally invasive transcatheter balloon dilation procedures for almost 20 years. Supravalvular pulmonic stenosis however is not amenable to balloon dilation procedures. Although several surgical procedures are described for treatment of pulmonic stenosis, the morbidity and mortality of these procedures are significantly higher than for transcatheter approaches.Two cases of supravalvular pulmonic stenosis are presented, one acquired and one congenital, which were successfully treated with transcatheter intravascular stent placement. The procedure alleviated the stenotic lesion and resolved clinical signs.     

Effect of feeding on plasma antibiotic concentrations in Greyhounds given ampicillin and amoxycillin by mouth

In a cross-over study, six Greyhounds were dosed by mouth with ampicillin and amoxycillin at 20 mg/kg, using three different feeding regimens (no food, canned food prior to dosing, and dry food ad lib ) with each drug. Antibiotic levels in plasma were determined by microbiological assay at intervals after dosing.
Plasma ampicillin concentrations tended to be lower in fed than in starved Greyhounds, but amoxycillin levels were relatively unaffected by feeding. In starved Greyhounds, ampicillin gave higher early levels than amoxycillin.