基于畜禽粪便养分含量的畜禽承载力研究

为了减少畜禽养殖带来的环境污染,许多发达国家规定畜牧场周围必须配备农田来消纳畜禽粪便,同时也有成熟的畜禽承载力的研究方法。根据我国区域养殖畜种较多、农田分散、农牧脱节等情况,本研究确定了适合我国国情的用特定地理区域范围消纳畜禽粪便氮(N)、磷(P2O5)能力的方法来确定畜禽承载力。本研究根据不同畜种平均每头(只)存栏动物每年的粪便养分产生量、每公顷作物每年的养分移走量,计算出每公顷大田作物地、蔬菜地和园地每季所能承载的各种畜禽数量,然后根据各地区的复种指数估算出作物地每年承载的畜禽数量。结果表明:牛、羊的年产粪便N/P2O5较大,禽类比值较小,其他畜种比值居中;蔬菜地可以承载的畜禽数量最多,大田作物地次之,园地承载的最少;以N作为承载标准时,农用地所承载的畜禽数量比以P2O5作为标准时多(最高为6.6倍)或者两者持平。可以根据区域需要,通过提高作物对肥料的利用率、调整化肥与粪肥用量、调整种植结构等方式改变畜禽承载力的大小。     

德本F1蓝本F1牛适应性分析研究

研究了德国黄牛和比利时蓝牛的杂种后代德本F1、蓝本F1牛在甘肃省陇东地区肉牛带的适应性能,主要包括生长发育、增重、抗病性和繁殖性能等因素。结果表明德本F1、蓝本F1牛在试验期内（0～12月龄）的各项指标均优于本地牛,对当地饲养条件和环境条件表现出了良好的适应能力,可以在当地推广应用。     

口蹄疫病毒VP1基因密码子偏好性分析

VP1蛋白是口蹄疫病毒(FMDV)的主要结构蛋白,可诱导机体产生中和抗体以及激发保护性免疫应答。为探究VP1基因密码子偏好性,筛选出其最佳体外表达系统,使用Visual Gene Developer、CodonW、GraphPad Prism等软件,对VP1基因进行密码子偏好性分析,同时将VP1基因密码子使用频率与大肠杆菌、毕赤酵母、昆虫杆状病毒和哺乳动物细胞表达系统作了比较。结果显示,VP1基因的CAI为0.21,ENC为55.43,GC3S为65.26%,表明该基因密码子使用偏好较弱并且密码子偏好以G/C碱基结尾。结合VP1基因与各表达系统密码子使用频率比值,发现其与昆虫杆状病毒表达系统频率比值差异最小且CAI最大,因此推断昆虫杆状病毒表达系统是FMDV VP1基因最适体外表达系统。本研究为FMDV亚单位疫苗研制等提供了技术基础。     

乳牛口服过量维生素A对维生素D3及钙磷代谢的影响

从北京郊区某农场选取１０头健康成年黑白花乳牛，随机分为试验（５头，每周每头口服维生素Ａ１００万单位）和对照（５头，不作任何处理）两组。８周以后检测发现，试验组血清钙和无机磷水平呈下降趋势；尾椎骨皮质变薄，密度下降，呈现骨质吸收现象；血清碱性磷酸酶显著下降（Ｐ＜０．０５）；其活性代谢产物２５－羟维生素Ｄ３（２５－ＯＨ－Ｄ３）极显著下降（Ｐ＜０．０１）；１，２５－二羟维生素Ｄ３［１，２５－（ＯＨ）２－     

The T allele at the g.1471620G>T in the EDG1 gene associated with high marbling in Japanese Black cattle is at a low frequency in breeds not selected for marbling

Our previous study detected a single nucleotide polymorphism (SNP), g.1471620G > T , in the 5' flanking region of the endothelial differentiation sphingolipid G-protein-coupled receptor 1 ( EDG1 ) gene, which has been considered as a positional functional candidate for the gene responsible for marbling, and showed association of the g.1471620G > T SNP with marbling in Japanese Black beef cattle. In the present study, we investigated the allele frequency distribution of the g.1471620G > T SNP among the 5 cattle breeds, Japanese Black, Japanese Brown, Japanese Short Horn, Holstein, and Brown Swiss breeds. The T allele at the g.1471620G > T SNP associated with high marbling was found at high frequency in Japanese Black breed that has been subjected to a strong selection for high marbling, while the allele was absent or at very low frequencies in the other breeds that have not been strongly selected for high marbling. Based on this finding, we hypothesized that the pressure of the strong selection for high marbling in Japanese Black breed has increased the frequency of the T allele at the g.1471620G > T SNP in the EDG1 .     

MDCC—MSB1培养基上清液中DNA活性的定性研究

将 Ｍ Ｄ Ｃ Ｃ Ｍ Ｓ Ｂ１ ４８ 小时培养物 １０００ｒ／ｍ ｉｎ 离心的上清液分别用 Ｒ Ｎ Ａ 酶、 Ｄ Ｎ Ａ 酶和蛋白酶 Ｋ 处理后,进行体外试验。结果表明,只有 Ｄ Ｎ Ａ 酶处理后的上清液失去了体外抑制 Ｍ Ｄ Ｖ“８１４”增殖的作用。将该上清液 １００００ｒ／ｍ ｉｎ 离心所得的沉淀分别用上述酶处理后进行体内试验。结果表明,只有 Ｄ Ｎ Ａ 酶处理的样品失去了体内促进 Ｍ Ｄ Ｖ 京１ 株致瘤的作用。同时,电泳分析结果证明,该上清液中确实存在 Ｄ Ｎ Ａ。     

The influence of temperature and age on the T1 relaxation time of the equine distal limb

The extent of fat suppression using short tau inversion recovery (STIR) imaging is variable between horses. Our aim was to determine if patient's age and/or hoof temperature have an influence on the T(1) relaxation time of bone marrow in the equine distal limb, thereby affecting the suppression of fat signal. Magnetic resonance imaging was conducted on standing horses and cadaver samples using a low-field magnet (0.27 T). The hoof temperature was measured at the lateral side of the coronary band. A modified inversion recovery fast spin-echo (IR-FSE) sequence was used to measure the signal intensity for a range of inversion times (TIs) at six different regions of interest (ROI): (1) distal aspect of the proximal phalanx, (2) proximal aspect of the middle phalanx, (3) distal aspect of the middle phalanx, (4) navicular bone, (5) proximal aspect of the distal phalanx, and (6) distal aspect of the distal phalanx. The T(1) of the bone marrow in the equine distal limb was calculated from the results and was found to increase by 3.13 ± 0.08 (SE) ms/°C. There was no significant effect of age (2-16 years) but the T(1) values measured from the limbs of young (< 1 year) animals were considerably longer (32.6 ± 1.7 (SE) ms). Similar effects of temperature and age were found for all measured ROIs but there were significant differences in the mean values of T(1) , ranging from +7.7 (distal aspect of the distal phalanx) to -13.2 ms (distal aspect of the proximal phalanx).     

鸡X期胚盘细胞电转染外源基因条件的探索

以EGFP为报告基因体外电穿孔转染鸡X期胚盘细胞,探讨适宜电转染条件以及影响鸡ES细胞存活率和转染率因素。分离鸡X期胚盘细胞进行培养、传代及鉴定,二代细胞设定不同的电压、脉冲时间、质粒浓度、细胞密度及孵育温度等条件转染。电击后10 min,0.4%台盼蓝染色,血细胞计数板计数,计算存活率。48 h后在荧光显微镜下计绿色荧光细胞数和总细胞数,计算转染率。结果表明:电转染鸡ES细胞的最优化电压为280 v,脉冲时间为75μs,质粒浓度为20μg/mL,转染前4℃、转染后25℃(室温)或4℃各静置10 min,细胞密度调整在1×105个/mL×106个/mL,尽量使细胞处于对数生长期。电穿孔法转染鸡ES细胞是简便有效的方法,利用优化条件转染ES细胞,可以满足进一步实验的要求。