不同剂量半胱胺对东北细毛羊生产性能影响的研究

本试验采用东北细毛羊羔羊32只，均为雌性，随机分成4组，其中一组为对照组，饲喂基础日粮，其余3组分别在日粮中添加半胱胺75、125、175 mg/kg。试验结果表明，添加125 mg/kg的试验组最佳，使羔羊平均日增重提高20.96%（P≤0.01），平均毛长增长提高31.51%（P≤0.01），料肉比降低15.79%（P≤0.01），平均日收入提高66.07%（P≤0.01）。     

Influence of MHS genotype and feeding regime on allometric and temporal growth of pigs assessed by magnetic resonance imaging

A total of 68 barrows, 4-way-crosses with a Piétrain × Hampshire sire and a Large White × German Landrace dam were used in this study. The pigs were divided into 4 groups regarding the MHS (malignant hyperthermia syndrome) genotype (NN and Nn) and feeding regime (intensive and restrictive). The piglets were genotyped by DNA test; data on muscle and fat growth were obtained by repeated measurements of body composition at 4 weeks intervals by magnetic resonance imaging (MRI). Differential growth analysis showed that muscle tissue grew proportionally with the increase of live weight (allometric coefficient, b ≈ 1); fat grew faster in relation to live weight (b > 1) in all investigated groups of pigs. Significant differences in growth coefficients for fat were found only between feeding groups. The analysis by asymmetric S-function showed different patterns of live weight growth of pigs from two feeding regimes. Within the feeding regimes, no significant differences in live weight growth patterns between the pigs of different MHS genotype (NN and Nn) were found. Muscle growth pattern significantly differed between the groups of investigated pigs: Nn pigs from the intensive feeding group were significantly superior to NN pigs in the same group and to Nn pigs fed restrictively (p < 0.05), but only in the phase of progressive growth (b-coefficient of the S-function). In this respect Nn pigs performed better under intensive feeding than under restrictive feeding regime, while no difference was found between NN pigs from two feeding regimes. By combining information on live weight and muscle growth, the optimal slaughter weight of pigs was calculated: 130 and 126 kg for intensively fed NN and Nn pigs, respectively, and about 114 kg for both genotypes from the restricted group of pigs. From fat growth analysis by asymmetric S-function, no influence of genotype on fat deposition in both feeding systems could be observed. Growth patterns of fat differed significantly only between the feeding groups. This study showed that the growth of body components fits a sigmoid curve and that the asymmetric S-function proved to be a more accurate and informative model than a simple allometric function, providing a base for important decisions in fattening of pigs. A practical consequence of this study is that the more cost-effective restrictive feeding regime can be recommended as more appropriate in fattening of pigs, since intensive feeding generally failed to improve their growth traits. Similarly, inclusion of MHS-gene did not enhance muscle growth characteristics of investigated pigs, so MHS-negative pigs (NN) can be considered as more desirable fatteners, especially when fed restrictively.     

活性氧(ROS)对小鼠早期胚胎染色体相对长度的影响

通过对小鼠体内发育的囊胚、扩张囊胚和从1-细胞期取出在CZB培养液中培养的囊胚、扩张囊胚的染色体相对长度进行统计分析,在各号染色体相对长度出现显著性差异的同时,发现体外培养的比体内发育的染色体相对长度短;体外CZB培养的不同时期添加外源性过氧化氢,发育至囊胚、扩张囊胚阶段,制作胚胎标本,观察胚胎的染色体相对长度。结果表明:不同时期添加外源性过氧化氢组比对照组的染色体相对长度短。说明经过氧化氢处理之后存活下来的胚胎染色体相对长度发生了变化。     

复州牛成年母牛体重与体尺指标的相关与回归分析

以辽宁省两个复州牛保种场104头母牛2004年体尺数据为基础材料,对复州牛体重与年龄、体长、体高、胸围、管围的相关系数进行了分析,同时建立了估测复州牛成年母牛体重的回归模型。结果表明:复州牛体重与体高、体长、胸围、管围、年龄之间的相关系数分别为0．798、0．644、0．678、—0．167、0．406,经检验,除管围与体重的相关系数不显著外(P＞0．05),其它四个相关系数均达到极显著水平(P＜0．01);两个估测体重的回归模型估测值与实测值之间的相关程度分别为0．923和0．922,达到极显著水平(P＜0．01)。     

Mapping of expressed sequence tag markers with a cDNA-amplified fragment length polymorphism method in Japanese quail (Coturnix japonica)

In our previous study, a Kobe‐NIBS Japanese quail (KNQ) linkage map was constructed mainly using amplified fragment length polymorphism (AFLP) markers. In order to compare chicken and quail chromosomes, we developed expressed sequence tag (EST) markers derived from cDNA‐AFLP fragments and localized these markers on the linkage map. Using a total of 128 AFLP primer combinations, 24 polymorphic bands were obtained between a neurofilament‐deficient mutant quail line male and a muscular disorder quail line female, which were the parents of the KNQ resource family. Nine of the 24 markers were mapped by linkage analysis. These markers were mapped to seven linkage groups, namely 1, 2, 3, 6, 8, 15 and 42. A subsequent homology search using chicken genome sequences strongly suggests that these linkage groups correspond with chicken chromosomes 1, 2, 3, 5, 15, 23 and 26.     

Genetic correlations between body condition scores and fertility in dairy cattle using bivariate random regression models

Genetic correlations between body condition score (BCS) and fertility traits in dairy cattle were estimated using bivariate random regression models. BCS was recorded by the Swiss Holstein Association on 22,075 lactating heifers (primiparous cows) from 856 sires. Fertility data during first lactation were extracted for 40,736 cows. The fertility traits were days to first service (DFS), days between first and last insemination (DFLI), calving interval (CI), number of services per conception (NSPC) and conception rate to first insemination (CRFI). A bivariate model was used to estimate genetic correlations between BCS as a longitudinal trait by random regression components, and daughter's fertility at the sire level as a single lactation measurement. Heritability of BCS was 0.17, and heritabilities for fertility traits were low (0.01-0.08). Genetic correlations between BCS and fertility over the lactation varied from: -0.45 to -0.14 for DFS; -0.75 to 0.03 for DFLI; from -0.59 to -0.02 for CI; from -0.47 to 0.33 for NSPC and from 0.08 to 0.82 for CRFI. These results show (genetic) interactions between fat reserves and reproduction along the lactation trajectory of modern dairy cows, which can be useful in genetic selection as well as in management. Maximum genetic gain in fertility from indirect selection on BCS should be based on measurements taken in mid lactation when the genetic variance for BCS is largest, and the genetic correlations between BCS and fertility is strongest.     

矿质营养与植物生长调节剂对澳洲坚果花粉生活力的影响

以6年生的澳洲坚果为试材,研究温度、蔗糖浓度、矿质营养和植物生长调节剂对花粉萌发和花粉管伸长的影响.结果表明25℃和10%的蔗糖浓度对花粉的萌发和生长最为有利;植物生长调节剂GA3为20mg/L时能显著促进花粉的萌发,而IAA和2,4-D对花粉萌发的促进作用不显著;矿质营养最有利于花粉萌发的浓度分别是Zn10mg/L、Mo5mg/L、B10mg/L、Mn40mg/L、Ca30mg/L.     

Sequence and polymerase chain reaction–restriction fragment length polymorphism analysis of the large subunit rRNA gene of bivalve: Simple and widely applicable technique for multiple species identification of bivalve larva

ABSTRACT:   One of the biggest and long-standing difficulties in investigation of larval ecology in the field is species-level identification. In the present study, we developed polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) analysis based on the large subunit (LSU) rRNA gene (rDNA) D1/D2/D3 region for identification of multiple species of bivalve larvae using 14 species of bivalve collected from Maizuru Bay. The LSU rDNA D1/D2/D3 region of all analyzed species could be amplified by PCR using bvD1f/bvD3r primers, and RFLP analysis by Hae III digestion on the PCR products showed species-specific fragment patterns. Furthermore, this analysis applied to single bivalve larvae in Maizuru Bay revealed efficient amplification of the target region and the species-specific pattern from 80% of the larvae, 75% of which showed a pattern that matched a certain pattern of the adult bivalves. In addition, the analysis of inter- and intraspecies variation of the LSU rDNA D1/D2/D3 region using the sequence data of the genus Crassostrea from the DDBJ database showed high applicability of this RFLP analysis on closely related species. Because of the wide applicability and technical simplicity, this method can become the standard for the identification of bivalve larvae species once the sequence data of the LSU rDNA D1/D2/D3 region of many bivalve species have been accumulated.     

Molecular cloning of Yersinia ruckeri aroA gene: a useful taxonomic tool

The aroA gene of Yersinia ruckeri , which encodes 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase was cloned by complementation of the aroA mutation in Escherichia coli AB2829 by using pUC18 plasmid as a vector. Nucleotide sequence of the aroA gene revealed an open reading frame of 427 amino acids showing a high degree of homology to other bacterial AroA proteins. A pair of primers with 23 and 20 nucleotides were selected from the 5' and 3' termini, respectively, and formed the basis of a specific polymerase chain reaction (PCR) assay. A 1165-bp deoxyribonucleic acid (DNA) fragment was amplified from all lysed Y. ruckeri strains. An identical size fragment was also amplified from lysed Y. pseudotuberculosis , Y. aldovae , Salmonella enteritidis and E. coli , but not from other enterobacteria. Alu I restriction fragment length polymorphism (RFLP) of the PCR amplified products allowed for differentiation between Y. ruckeri and the other bacteria. Specificity and sensitivity make this PCR assay a useful method for rapid identification and diagnosis of Y. ruckeri infections.     

Shell growth and age determination of the brackish water bivalve Corbicula japonica in Lake Shinji, Japan

ABSTRACT:   Shell growth and age determination of Corbicula japonica were investigated from samples collected monthly at two sites and field growth experiments from November 1999 to November 2000 in Lake Shinji. Both specimens did not grow in winter when the water temperature was below 11°C, but grew rapidly from spring to early summer when the water temperature rose from 15°C to 30°C, before further growing slowly from summer to autumn after the main breeding period. The monthly marginal growth distribution of the samples indicated that the concentric groove on the shell surface was an annual growth ring. It is concluded that the age of C .  japonica in the i -ring group when the shell growth resumed in spring was i  + 0.5 ( i  = 1, 2, · · ·), because the first true growth ring was formed at 0–2 mm in shell length, which then faded with growth. Lee's phenomenon was observed in the age determination results, and thus the growth coefficient and the asymptotic shell length of the von Bertalanffy growth equation were not estimated from the samples. However, these parameters were estimated from the annual shell length increments of the experimental individuals, which were 0.331/year and 28.2 mm, respectively.