Porcine CD5 gene and gene product identified on the basis of inter-species conserved cytoplasmic domain sequences

Analysis of published CD5 amino acid sequences identified conserved sequences with potentially immunogenic epitopes. To obtain anti-porcine CD5, synthetic peptides representing conserved sequences identified in mouse, human, cattle and sheep CD5 cytoplasmic tail domains were linked to KLH and used to immunize rabbits. Anti-synthetic peptide serum reacted with an antigen extracted from porcine lymphocyte membrane which was consistent in size (67 kDa) with CD5. Murine monoclonal anti-porcine wCD5 (b53b7) and the anti-CD5 synthetic peptide serum react with the same ligand confirming that porcine wCD5 has conserved amino acid sequences similar to those of CD5 of several species. Analysis of porcine genome for CD5 gene sequences by PCR was conducted to verify the presence of CD5-like genes. Oligomeric primers were designed to identify CD5-like sequences by polymerase chain reaction in pigs and other species. Amplified DNA similar in size to that predicted for CD5 elements were amplified from a variety of animal genomes including that of pig. The porcine-derived fragment was cloned and shown to be 96% similar to mouse CD5. The use of published CD sequences for prediction of immunogenic peptides has provided a complimentary alternative to the more traditional approaches to production of CD-specific antibodies.     

Bt星光4号虫体连续传代及增效作用的研究

为了保持和提高星光4号菌株的优良特性,在5～6龄的马尾松毛虫上进行连续接种传代试验。结果表明:不同虫体及不同传代数的分离物之间的毒力差异明显,其中第九代分离物较之原始菌株毒力提高了19.6％。因而,生产上的复壮所采用的菌株代数,必须经过严格的毒力测定后才能确定。该菌株与某些农药混合使用有增效作用,其中与溴氰菊酯混合使用经共毒系数分析,毒力增加了1.81倍。     

15N标记绿肥喂猪后还田的转化和效益的研究

本文用１５Ｎ标记绿肥与无Ｎ淀粉配制成饲料喂猪，猪体平均回收饲料１５Ｎ２３．５１％；猪粪回收１５Ｎ２３．８５％，猪尿回收１５Ｎ２８．７６％；饲料绿肥Ｎ的总回收率为７６．１２％。猪粪，尿还田，水稻全株对Ｎ的回收分别相当于饲料绿肥Ｎ的３．７５％和７．．２５％。其中转化至稻谷的分别为２．５１％和４．８２％。以经济产品计算，猪体和稻谷共回收饲料绿肥１５Ｎ３０．８４％，比１５Ｎ绿肥与尿素配施还田稻回收的绿肥Ｎ     

我国养猪生产的发展方向

我国养猪生产正处在由传统生产向现代化生产转化阶段。在这个阶段中，养猪生产所面临的主要任务是工作重心由城郊转向农村；引导养猪生产向产业化方向发展；提高宏观调控能力，做到可持续发展。     

Patterns of Cytosine Methylation in Parental Lines and Their Hybrids of Large White and Meishan Reciprocal Crosses

The extent and patterns of cytosine methylation in blood DNA were assessed, using the technique of methylation-sensitive amplified polymorphism(MSAP),in Meishan, Large White pigs and hybrids of their reciprocal crosses. In all, 1 508 fragments, each representing a recognition site cleaved by either or both of the isoschizomers, MspI and HpaII, were amplified using 20 pairs of selective primers. 10.3% of CCGG sites were methylated in Meishan pigs, 10.5% in Large White pigs, and 10.2% in the hybrids. Cytosine methylation was not significantly different among parental lines and hybrids of reciprocal crosses. Four classes of patterns were identified in a comparative assay of cytosine methylation in the parents and hybrids: (1) the same level of methylation in both parental lines and the hybrids; (2) the same level of methylation in either parent or hybrid; (3) an increased level of methylation in the hybrids compared to the parents, and (4) a decreased level of methylation in the hybrids. 11 crossspecific methylation sites were detected in F1 hybrids of Large White×Meishan, and 10 crossspecific methylation sites in the hybrid of Meishan×LargeWhite. In conclusion, (1) the whole methylation status between parental lines and hybrids was not different, but specific sites were differentially methylated; (2) specific sites were differentially methylated between reciprocal crosses; (3) demethylation and hypermethylation of many sites accounted for mostly (more than 50%) methylated sites in the hybrids compared to parental lines.     

增瘦剂对长—巴猪(F_1)银染核仁组成区Ag—NoR_s影响的研究

本文以西北农业大学畜牧场埋植(或添加)增瘦剂的长—巴F_1杂种肥育猪为研究对象,采用微量外周血淋巴细胞培养以及银染色技术,对14头个体染色体银染核仁组成区(Ag-NoRs)的数目、分布以及其联会进行了详细的分析,以检验增瘦剂实用于生产实践的可靠性。结果表明,对照组、埋植组和喂药组(分两个剂量)二倍体细胞染色体Ag-NoRs的平均数分别为1.98、1.99、2.00和1.98,组内个体Ag-NoRs的众数均为2,Ag-NoRs联会的频率分别为1.41％、0.49％、0.65％和0.59％:与对照组相比,试验组的Ag-NoRs平均数及联会频率均未出现显著的差异。从而证明,在细胞遗传学的Ag-NoRs指标上,二增瘦剂对长——巴(F_1)肥育猪具有安全性,可以在生产上加以应用。     

实验性猪缺硒病的病理形态学观察

用低硒地区所产饲料作为基础日粮，以妊娠母猪和初生仔猪为实验猪，通过肉眼观察和组织学变化得知，硒缺乏病病理变化具有规律性。其中初生仔猪的骨骼肌具有全身肌肉群呈弥散性变性变化，主要特点是肌肉苍白呈鱼肉样。哺乳仔猪的骨骼肌，病变出现的肌群广泛，受害面积大，可为某一肌群的全部或某一肌群的某块肌肉出现灰白色条纹状病变。病变出现的范围不同，可能是不同月份的个体与硒的耐受力有关。     

淮猪新品系二世代母猪泌乳性能的研究

[目的]为了研究淮猪新品系的生理特性,加速其开发利用,健全其科学饲养措施。[方法]选取淮猪新品系二世代健康母猪4头,测定其泌乳力。在28 d内,分7次进行泌乳测定,每次测定持续时间24 h,每隔2小时测定每次,测定时以该窝仔猪的前后两次的体重之差记为母猪的该次泌乳量,24 h(12次)测定的泌乳量为该母猪该天的泌乳量。[结果]结果表明:淮猪新品系二世代母猪泌乳量在泌乳期内呈先上升后下降,然后上升并达到最大值的变化趋势;28 d母猪泌乳期总泌乳量为163.24 kg,每头日平均泌乳量为1.458 kg,每天每头母猪泌乳量最高达1.817 kg/d;在12:00~18:00时间段内,淮猪新品系二世代母猪的泌乳量高于其他时间段,且在0.01水平显著高于0:00~6:00和18:00~0:00两个时间段。[结论]该研究为淮猪新品系的推广与应用提供了理论依据。