初生和有效乳头数与生产性状之间的相关性分析

本研究旨在评价在独立淘汰方法下初生和终测(有效)乳头数性状是否受到其他生产性状选择的影响。实验选取某大白猪核心育种场约6年的乳头数性状和主要生产性状数据,利用DMU软件和单/双动物模型计算乳头数性状的遗传力及其与主要生产性状之间的遗传相关,并作遗传趋势图。结果表明:在独立淘汰法下,初生乳头数可能因表型收集不准确而存在隐患;初生和有效乳头数遗传力分别为0.38和0.23,为中等遗传力性状;总产仔数和健仔数与乳头数性状呈弱遗传负相关(约-0.15左右),对产仔数性状高强度选择会对乳头数呈不利影响;对背膘厚和体长的选择会对乳头数有利。因此,从长远来看,在母系猪育种中,可能会由于对产仔数性状的高强度选育使母猪泌乳性能降低,提高仔猪饲养难度。     

猪乳头数性状遗传育种的研究进展

在猪生产中，需要保证母猪足够的猪乳头数以满足仔猪营养需要。乳头数是一个受微效多基因控制的具有品种特性的数量性状，影响仔猪的断奶成活率、断奶窝重及窝均匀度，解析其遗传机制对于选育优良种猪具有重要意义。近年来有许多研究一直关注于猪乳头数性状的改良，相关的分子标记和候选基因被相继报道。本文主要对猪乳头数与数量性状之间的联系、影响乳头数的因素以及QTL定位和GWAS鉴别候选基因等方面的研究进展进行综述，为后续乳头数的选育提供理论基础。     

大白猪乳头数对繁殖性状的影响及其遗传参数估计

本研究主要对大白猪的繁殖性状和乳头数进行遗传参数估计，评估遗传趋势和表型趋势，并探究乳头数对母猪繁殖性状的影响。将乳头数作为繁殖性状的固定效应，对影响大白猪繁殖性状的固定效应进行方差分析，运用DMU软件的DMUAI和DMU4模块，利用单/多性状动物模型估计大白猪繁殖性状和乳头数的遗传参数，并评估这些性状的遗传趋势和表型趋势。结果发现，乳头数对校正21日龄窝重的影响在P<0.05水平显著，对校正21日龄均重的影响在P<0.001水平显著；大白猪乳头数的遗传力为0.156±0.023，属于中等遗传力性状，各繁殖性状的遗传力范围为0.010～0.092，属于低遗传力性状；各繁殖性状遗传相关的范围为-0.306～0.978，表型相关的范围为-0.055～0.970；各繁殖性状的遗传趋势和表型趋势均为先下降后上升，表明该群体的繁殖性状早期选育成效不佳，但在选育后期有所提升。乳头数和校正21日龄均重的遗传趋势和表型趋势波动比较大，表明这2个性状在该群体中并未被选育，在后期选育时，该群体应注重乳头数的选育，以提高大白母猪的繁殖性能。     

猪乳头数性状的观察及其与产仔数关系的研究

对种猪24头、仔猪487头的乳头数性状的遗传规律及其与产仔数的关系进行了调查与分析，用SAS软件对数据进行处理。结果表明：猪的乳头数具有相对稳定的遗传性，接近于父母代的群体均值，且具有一定的集中性；乳头数目不同的父母代组合其后代的乳头数目趋向于父母代的群体均值；父系乳头数与窝平均产仔数呈正相关，母系乳头数与窝平均产仔数呈弱负相关；采用父系半同胞相关法估测猪乳头数性状的遗传力为0.26，属中等遗传力。     

撒坝猪乳头数遗传力及其与繁殖性能关系的研究

本研究对 4个世代共 577头撒坝猪的乳头数进行了分析 ,并用HARVEY程序对乳头数的遗传力进行了估计 ,同时利用 1 2 8头有繁殖性能记录的母猪资料对乳头数与繁殖性状的关系进行了分析。结果表明 ,各世代的乳头数存在着显著差异 ,且逐代均有显著提高 ;乳头数的遗传力为 0 .331 ;乳头数与总产仔数和活产仔数间遗传相关和表型相关均为负值 ,与初生窝重、2 0日窝重、断奶仔数和断奶窝重间则存在着正的遗传相关和表型相关 ;乳头数与所有繁殖性状的环境相关都较弱 ( -0 .0 0 2～ 0 .0 94 )     

山西黑猪乳头性状的研究

<正> 母猪的有效乳头数与繁殖性能各性状间呈较强的遗传,表型相关(张文灿,1981)。在山西黑猪中存在丁香型和葫芦型两种乳房类型,从南方到北方的群众有偏爱丁香型乳头的习惯。瞎乳头属于单对基因制约的质量性状(陈幼春等,1982)。因此,对于山西黑猪的乳头数与猪繁殖性状相关的研究,乳头类型对繁殖性能影响的研究,瞎乳头的基因频率及基因型频率的研究对于选育提高山西黑猪繁殖性能有着重要的意义。     

猪乳头性状的遗传及其影响因素（综述）

猪乳头性状的遗传及其影响因素（综述）刘文忠，周忠孝（山西农业大学，０３０８０１）猪的育种和生产工作者通常将猪的乳头性状作为重要的繁殖性状。习惯上选留乳头多的公母猪留种，乳头数不足和乳头缺陷是淘汰猪的主要原因之一。本世纪５０年代以前，猪的育种工作已经开...     

猪乳头数遗传规律及其与产仔性能的关系

不管是在育种场,还是在生产场,猪的乳头常常是一个重要的常规选择性状.因为乳头数目关系到带仔的能力.一般认为,猪的乳头数比其它某些经济特征更强烈地受遗传性制约,而不易受饲养管理条件的影响发生变异。有研究表明:纯种二花脸仔猪乳头数介于双亲之间,仔猪乳头数受父母双方影响.此外,群众认为乳头数多的母猪产仔数多,乳头数少的猪生长速度快.本文采用二花脸猪和外来瘦肉型猪种纯繁、杂交资料,来探讨杂交情况下乳头数的遗传规律,亲代乳头数对后代的影响以及乳头数与产仔性能的关系,为商品肉猪生产和利用母本杂交优势提供依据.     

在母猪上找出有助于仔猪存活的基因

正母猪每窝成功地生产出显著较多的活仔,意味着养猪生产者对母猪的哺育能力需要给予更多的关注。由于有时选择指数已经设计好,因此窝产活仔数的增加和母猪乳头数的增加相称的。遗传学和基因组研究平台的里程碑式研究,正在使得研究人员深入了解遗传是如何影响母猪乳头数进行的。Maren van Son的办公室位于挪威Hamar,他对此课题已经研究了18个月。他说:"母猪的乳头数是一个很容易测量的性状,因此我们     

大白和长白猪大样本群体的繁殖性状遗传参数估计及影响因素分析

旨在解析不同因素对大白和长白猪大样本群体繁殖性能的影响。同时估计大白和长白猪繁殖性状的遗传参数。本试验选取温氏2013-2018年5年间大白共65 546窝母猪繁殖记录、长白共9 552窝母猪繁殖记录进行研究。采用SAS软件GLM过程对母猪8个繁殖性状进行分析,解析母猪分娩胎次、出生胎次和情期3个因素对其繁殖性能的影响。同时利用DMU软件估计这些性状的遗传力、遗传相关和表型相关。结果表明:1)在影响因素分析中:在两个品种中,母猪分娩胎次对所有繁殖性状都有极显著影响(P0.001);在大白猪中,母猪出生胎次对5个繁殖性状影响显著(P0.05),情期对所有繁殖性状影响均不显著;而在长白猪中,母猪出生胎次对弱仔数和出生窝重有显著影响(P0.05),情期对5个繁殖性状影响显著(P0.05)。2)在遗传参数估计中:在大白猪中,出生窝重遗传力最高,为0.281,总仔数、活仔数、健仔数、弱仔数和死胎数的遗传力在0.117～0.179范围内;而在长白猪中,总仔数遗传力最高,为0.190,活仔数、健仔数、弱仔数和出生窝重的遗传力在0.100～0.176范围内;在遗传相关和表型相关上,大白猪的总仔数与活仔数、总仔数与健仔数、活仔数与健仔数、健仔数与出生窝重等遗传相关均在0.738以上,其表型相关在0.717以上,长白猪的总仔数与活仔数、总仔数与健仔数、活仔数与健仔数的遗传相关在0.895以上,表型相关在0.791以上。本研究结果为提高母猪的繁殖性能和加速繁殖性状的遗传进展提供了试验数据和理论基础。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.     

Mechanism of Action of Probiotic Function of Lactobacilli

乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制.     

Evaluation of serum concentrations of biomarkers of skeletal metabolism and results of radiography as indicators of severity of osteochondrosis in foals

OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis.