二花脸猪染色体的G－带、C－带研究

以二花脸猪为材料，采用外周血淋巴细胞短期培养及Ｇ—带、Ｃ—带技术对其体细胞染色体进行分带研究．结果表明，不同细胞在Ｇ—带带型上呈现出带纹宽窄和染色深浅的变化，但每一对同源染色体及Ｘ、Ｙ性染色体都有其特殊的Ｇ—带核型；而Ｃ—带带型呈现出异形性；本文同时还分析了Ｃ—带异形性对品种鉴别的意义     

关于“贝种退化”问题的探讨

据称合浦珠母贝在养殖场“退化了”,“变小了”,是“近亲交配”引起的,这种说法已颇为流行,影响也很大。但是,在理论上还说明不了,也未曾见过有合浦珠母贝退化的研究报告。而且,在养殖场的人工育苗生产中,实际上已极大限度地避免了近亲交配,防止了近亲交配引起退化的可能性。所以,这种所谓“近亲交配”引起“退化”的说法,还缺少严格的科学实验根据。事实证明了,养殖的合浦珠母贝同野生个体的生长一样快,但生活环境不同对生长的影响较大,而在管养条件不良时生长最差。因此建议在生产中加强管养工作,育壮苗、养大贝、出好珠,也要加强基础科学知识的教育,促进合浦珠母贝养殖珍珠生产更好更快地发展。     

环腺苷酸制剂对生长育肥猪生长性能和肉脂品质的影响

选用 2 0 kg左右的“杜长”元杂交猪 2 4头 ,随机分成 1个对照组、 3个试验组 ,试验组分别添加环腺苷酸制剂 (二丁酰 c AMP) 10 mg/kg(试验 1组 )、 2 0 mg/kg(试验 2组 )、 30 mg/kg(试验 3组 ) ,进行饲养试验、屠宰试验和肉的品质测定。结果表明 :添加二丁酰 c AMP,能提高生长育肥猪的生长性能和改善肉脂品质。以添加二丁酰 c AMP2 0 mg/kg效果最好 ,与对照组相比 ,日增重提高 11.80 % (P <0 .0 1) ,料重比降低 16 .4 % (P <0 .0 1) ,胴体瘦肉率提高 8.12 % (P <0 .0 5 ) ,眼肌面积增加 11.98% (P <0 .0 5 ) ,平均背膘厚下降 18.90 % (P <0 .0 1) ;大理石纹评分提高 11.6 6 % (P <0 .0 1) ;肌肉间脂肪含量提高 2 8.88% (P <0 .0 1)。     

细胞型和染色体型与群体细胞遗传学

根据细胞遗传标记的特点，提出了细胞型和染色体型、平均细胞型和平均染色体型的概念及其频率的估计方法．通过对猪Ａｇ－ＮＯＲｓ（ｒＲＮＡ）基因的分析，发现（平均）细胞型频率和（平均）染色体型频率之间存在着类似于ＨａｒｄｙＷｅｉｎｂｅｒｇ定律的相互关系．平均染色体型频率的功用类似于基因频率，可用来表示群体的细胞遗传结构并进行群体间的遗传相似性分析．因此，建议在此基石出上开展动物的群体细胞遗传学研究．     

太湖猪淋巴细胞和小鼠骨髓瘤细胞杂交细胞的建立

以我国优良猪种小梅山（属太湖猪种）的脾淋巴细胞和小鼠骨髓瘤细胞（ＳＰ２／０）作亲本，经聚乙二醇（ＰＥＧ）促融，ＨＡＴ培养基选择培养，先后得到２５株杂种细胞，并对杂种细胞进行染色体分析和同工酶电泳等研究。结果显示，杂种细胞系含有全部小鼠骨髓瘤细胞染色体，而猪染色体丢失迅速，仅保留猪的４号、５号、７￣１０号、１２号、１３号、１５号和１７号等部分染色体，杂种细胞内能检测到全部小鼠同工酶活性，但仅能检测到     

SPATIAL DYNAMICS OF TWO HARVESTED WILD PIG POPULATIONS

ABSTRACT. Simple one- and two-dimensional spatial models are developed for the harvesting of wild pigs in North Sulawesi, Indonesia. The models are used to explore the effects of changes in biological and economic parameter values on the spatial persistence of harvested populations, when off-take must be transported to market. A two-species model shows that the relative catchability of species harvested together strongly affects the distance from market at which each species persists. Due to strong positive feedback, travel costs are a major determinant of the length of the regions where pigs are extinct and exploited.     

A projection method of estimation for a subfamily of exponential families

Summary This paper is concerned with estimation for a subfamily of exponential-type, which is a parametric model with sufficient statistics. The family is associated with a surface in the domain of a sufficient statistic. A new estimator, termed a projection estimator, is introduced. The key idea of its derivation is to look for a one-to-one transformation of the sufficient statistic so that the subfamily can be associated with a flat subset in the transformed domain. The estimator is defined by the orthogonal projection of the transformed statistic onto the flat surface. Here the orthogonality is introduced by the inverse of the estimated variance matrix of the statistic on the analogy of Mahalanobis's notion (1936,Proc. Nat. Inst. Sci. Ind.,2, 49–55). Thus the projection estimator has an explicit representation with no iterations. On the other hand, the MLE and classical estimators have to be sought as numerical solutions by some algorithm with a choice of an initial value and a stopping rule. It is shown that the projection estimator is first-order efficient. The second-order property is also discussed. Some examples are presented to show the utility of the estimator.     

电感耦合等离子质谱法测定染铅猪仔的血铅、尿铅含量

利用电感耦合等离子质谱法测定染铅猪仔的血铅、尿铅含量.铅元素校正曲线的相关系数达到0.9999,方法检出限为0.08 μg/L.用冻干牛血铅、镉成分分析标准物质和冻干人尿铅成分分析标准物质验证了方法的准确性和重复性,分析结果表明,测定值与标准值基本吻合,测定值的相对标准偏差＜3.4％.用此方法分析了染铅猪仔不同时段的血...     

Estimation of N Absorption and Secretion by Digesta Exchange between 15N Labelled and Unlabelled Pigs

Abstract

Three female pigs (LW～30 kg) were fitted with re-entrant cannulas in the duodenum and the ileum and with bladder catheters. Animal No. 1 was labelled by continuous infusion of [¹⁵N]leucine via a catheter into the vena jugularis. After reaching a steady state in the level of endogenous N (4–5 d after beginning of the infusion) the digesta of the labelled animal No. 1 and the two unlabelled animals were exchanged in a 3 day experiment. During this time the course of transit rates of digesta, digesta N and ¹⁵N through duodenum and ileum as well as the proportion of endogenous N: exogenous N were estimated. Using these data it was possible to calculate the secretion and absorption rates of endogenous and exogenous N in the three segments of the digestive tract: mouth-duodenum, duodenum-ileum, ileum-anus and in addition the reabsorption (intestinal recycling) of the endogenous N during its passage through the gut could be computed.     

普通群体与近交群体的对比分析

对普通群体与近交群体的有关概念、性质、影响因素、基因型频率的动态趋势以及随机交配率与随机交配指数对基因型频率的影响进行分析.结果表明:普通交配与近交的概念不同;随机交配率与随机交配指数性质不同;普通群体3种基因型频率在世代间的动态逐渐趋于平衡,近交群体3种基因型频率的动态趋于近交系数等于1的状态;随机交配率与基因型频率呈曲线相关,近交系数与基因型频率呈直线相关.