不同笼养密度和饲粮对蛋用型公鸡精液品质及受精率的影响

<正> 许多试验和生产均已证明,笼养鸡人工授精生产种蛋,可以减少种公鸡的饲养数量,节省饲养成本,而且可以获得高而稳定的受精率。因此在人工授精技术中,怎样饲养管理公鸡是一个重要课题,其中公鸡笼养密度,饲粮营养水平,对保证公鸡健康,生产质优量高的精液尤为重要。     

日粮中添加蜂花粉对新扬州鸡公鸡生殖机能的影响

44只48周龄健康新扬州公鸡随机分成4组,每组11只,其中对照组饲喂基础日粮,试验组分别在基础日粮中添加0.5%、1.0%和1.5%的蜂花粉.在常规条件下饲养4周,探讨蜂花粉作为饲料添加剂对新扬州公鸡生殖机能的影响.结果表明,①外界环境因素例如高温等在一定程度上可导致鸡体重下降,蜂花粉的添加可缓解此现象.②与对照组相比,日粮中添加蜂花粉虽不能明显提高精液量,但可以有所改善.③试验组鸡精子密度分别比对照组提高了25.68%、31.44%和33.47%,即添加1.5%蜂花粉效果最佳.④试验组鸡的精子畸形率分别比对照组降低了24.83%、34.07%和46.1%,说明日粮中以添加1.0%～1.5%蜂花粉为宜.⑤日粮中添加不同量的蜂花粉对精液pH几乎没有影响.     

公鸡精液品质及血浆睾酮含量的测定

1 前言关于公鸡的精液品质及血浆睾酮含量,不少学者作了大量的报道,但由于种种原因,所得结果差异较大。本实验对“伊莎”公鸡的精液品质及不同日龄“伊莎”公鸡的血浆睾酮含量进行了测定,现报道如下。     

光照对公鸡生长发育及精液品质影响的研究

将114只15日龄“伊莎”公鸡,随机分为两组(实验和对照组),每组57只。实验组以15勒克斯的照度,9小时明;3小时暗:5小时明:7小时暗的间歇光照周期补加光照,使每天的光照时间达14小时,对照组仅接受自然光照。结果表明:不同日龄实验组鸡的体重均大于相应的对照组,而且在55日龄和75日龄时两组鸡的体重间相差极显著;各日龄段,实验组鸡群的料肉比均略低于相应的对照组;实验组鸡的射精量、精子密度略高于对照组,一次射精的精子总数显著的多于对照组,而死精子百分数低于对照组。     

种公鸡体重和体躯结构对精液品质及受精率的影响

１材料和方法１ １试验动物和试验设计每组种公鸡对应设置一组随机抽取的笼养种母鸡１５０只 ,进行人工授精。１ ２精液品质的测定包括精液量、ｐＨ值、精子活力、精子密度、精子数。１ ３每隔５ｄ人工授精一次通过标记种蛋 ,并同机孵化 ,１１ｄ照蛋 ,检出无精蛋。１ ４试验过程中进行日常饲养管理。２结果与讨论２ １体重对种公鸡精液品质和受精率的影响由表１可知 :１３６日龄种公鸡体重在２．０５～２．５０ｋｇ时 ,射精量多 ,精子活力和精液密度大 ,受精率较高。３６８日龄种公鸡体重在２．７５～２．９５ｋｇ内 ,精液品质较好 ,受精率…     

蜂花粉对公鸡体重和精液品质的影响

试验选用44只48周龄的新扬州公鸡，随机分成4组，每组11只，对照组饲喂基础日粮，试验I、Ⅱ、Ⅲ组分别在基础日粮中添加0.5、1.0、1.5%的蜂花粉。探讨蜂花粉对种公鸡体重和精液品质的影响，试验结果表明：日粮中添加1.0、1.5%的蜂花粉后，显著提高公鸡的精液量、精子活力和精子密度，显著降低精子畸形率，而对精液的PH值影响不明显；同时可以缓解高温应激造成的鸡体重下降的现象。     

种公鸡精液品质的快速检测法

种公鸡精液品质的优劣是影响受精率的一个重要因素，其品质在个体之间存在很大差异，据统计只有1／3～1／2的公鸡其精液品质才是良好的，所以对精液质量的检测，挑选优秀种公鸡用于生产，是种鸡正常生产的重要保证。然而实验室检测方法比较复杂，设备要求相对较高，速度比较慢，在实际生产中应用较少，很多的种鸡场往往难以做到。在此     

种公鸡体形外貌及精液品质性状的聚类分析

本研究对种公鸡的体形外貌及精液品质共14个性状，用统计分析软件SPSS(Ver．11．0)进行了聚类分析，结果表明：在SPSS提供的聚类分析方法中，沃特氏(Ward’s method)聚类分析法把这些性状分为5类，能较全面反映性状实际情况。这一结果为种公鸡的体形外貌、精液品质的选育提供了科学依据。     

精液质量分析系统在公鸡精液品质检测中的初步应用

公鸡精液品质检测是人工授精重要的基础检查工作.生产上,一般通过肉眼观察精液颜色和浓稠度进行大概的估测,然后粗略稀释,借助普通显微镜进行观测,主要观察精子活力和精子密度两项指标,结合经验评定每只公鸡精液品质好中差等级,这种测定方法受人为因素影响大,不同人员测定结果缺乏对比性,因此对于正规的育种公司而言要专门选择提高公鸡的精液品质需要一个客观、快速并具有较高准确性的工具.     

Heritability and genetic correlation estimates of semen production traits with litter traits and pork production traits in purebred Duroc pigs

We estimated heritabilities of semen production traits and their genetic correlations with litter traits and pork production traits in purebred Duroc pigs. Semen production traits were semen volume, sperm concentration, proportion of morphologically normal sperms, total number of sperm, and total number of morphologically normal sperm. Litter traits at farrowing were total number born, number born alive, number stillborn, total litter weight at birth, mean litter weight at birth, and piglet survival rate at birth. Litter traits at weaning were litter size at weaning, total litter weight at weaning, mean litter weight at weaning, and piglet survival rate from birth to weaning. Pork production traits were average daily gain, backfat thickness, and loin muscle area. We analyzed 45,913 semen collection records of 896 boars, 6,950 farrowing performance records of 1,400 sows, 2,237 weaning performance records of 586 sows, and individual growth performance records of 9,550 animals measured at approximately 5 mo of age. Heritabilities were estimated using a single-trait animal model. Genetic correlations were estimated using a 2-trait animal model. Estimated heritabilities of semen production traits ranged from 0.20 for sperm concentration to 0.29 for semen volume and were equal to or higher than those of litter traits, ranging from 0.06 for number stillborn and piglet survival rate at birth to 0.25 for mean litter weight at birth, but lower than those of pork production traits, ranging from 0.50 for average daily gain to 0.63 for backfat thickness. In many cases, the absolute values of estimated genetic correlations between semen production traits and other traits were smaller than 0.3. These estimated genetic parameters provide useful information for establishing a comprehensive pig breeding scheme.     

Genetic parameters for semen production traits in Swiss dairy bulls

Variance components (VC) were estimated for the semen production trait ejaculate volume, sperm concentration and sperm motility in the Swiss cattle breeds Brown Swiss (BS), Original Braunvieh (OB), Holstein (HO), Red‐Factor‐Carrier (RF), Red Holstein (RH), Swiss Fleckvieh (SF) and Simmental (SI). For this purpose, semen production traits from 2,617 bulls with 124,492 records were used. The data were collected in the years 2000–2012. The model for genetic parameter estimation across all breeds included the fixed effects age of bull at collection, year of collection, month of collection, number of collection per bull and day, interval between consecutive collections, semen collector, bull breed as well as a random additive genetic component and a permanent environmental effect. The same model without a fixed breed effect was used to estimate VC and repeatabilities separately for each of the breeds BS, HO, RH, SF and SI. Estimated heritabilities across all breeds were 0.42, 0.25 and 0.09 for ejaculate volume, sperm concentration and sperm motility, respectively. Different heritabilities were estimated for ejaculate volume (0.42; 0.45; 0.49; 0.40; 0.10), sperm concentration (0.34; 0.30; 0.20; 0.07; 0.23) and number of semen portions (0.18; 0.30; 0.04; 0.14; 0.04) in BS, HO, RH, SF and SI breed, respectively. The phenotypic and genetic correlations across all breeds between ejaculate volume and sperm concentration were negative (?0.28; ?0.56). The other correlations across all breeds were positive. The phenotypic and genetic correlations were 0.01 and 0.19 between sperm motility and ejaculate volume, respectively. Between sperm motility and sperm concentration, the phenotypic and genetic correlations were 0.20 and 0.36, respectively. The results are consistent with other analyses and show that genetic improvement through selection is possible in bull semen production traits.     

Identification of new semen trait-related candidate genes in Duroc boars through genome-wide association and weighted gene co-expression network analyses

Semen traits are crucial in commercial pig production since semen from boars is widely used in artificial insemination for both purebred and crossbred pig production. Revealing the genetic architecture of semen traits potentially promotes the efficiencies of improving semen traits through artificial selection. This study is aimed to identify candidate genes related to the semen traits in Duroc boars. First, we identified the genes that were significantly associated with three semen traits, including sperm motility (MO), sperm concentration (CON), and semen volume (VOL) in a Duroc boar population through a genome-wide association study (GWAS). Second, we performed a weighted gene co-expression network analysis (WGCNA). A total of 2, 3, and 20 single-nucleotide polymorphisms were found to be significantly associated with MO, CON, and VOL, respectively. Based on the haplotype block analysis, we identified one genetic region associated with MO, which explained 6.15% of the genetic trait variance. ENSSSCG00000018823 located within this region was considered as the candidate gene for regulating MO. Another genetic region explaining 1.95% of CON genetic variance was identified, and, in this region, B9D2, PAFAH1B3, TMEM145, and CIC were detected as the CON-related candidate genes. Two genetic regions that accounted for 2.23% and 2.48% of VOL genetic variance were identified, and, in these two regions, WWC2, CDKN2AIP, ING2, TRAPPC11, STOX2, and PELO were identified as VOL-related candidate genes. WGCNA analysis showed that, among these candidate genes, B9D2, TMEM145, WWC2, CDKN2AIP, TRAPPC11, and PELO were located within the most significant module eigengenes, confirming these candidate genes’ role in regulating semen traits in Duroc boars. The identification of these candidate genes can help to better understand the genetic architecture of semen traits in boars. Our findings can be applied for semen traits improvement in Duroc boars.     

Genetic and phenotypic parameters for conformation and yield traits in three Swiss dairy cattle breeds

This study presents genetic parameters for conformation traits and their genetic and phenotypic correlations with milk production traits and somatic cell score (SCS) in three Swiss dairy cattle breeds. Data on first lactations from Holstein (67 839), Brown Swiss (173 372) and Red & White breeds (53 784) were available. Analysed conformation traits were stature and heart girth (both in cm), and linear scores of body depth, rump width, dairy character or muscularity, and body condition score (only in Holstein). A sire model, with relationships among sires, was used for all breeds and traits and variance components were estimated using AS‐REML. Heritabilities for stature were high (0.6–0.8), and for the linear type traits ranged from 0.3 to 0.5, for all breeds. Genetic correlations with production traits (milk, fat and protein yield) and SCS differed between the dairy breeds. Most markedly, stronger correlations were found between SCS and some conformation traits in Brown Swiss and Red & White, indicating that a focus on a larger and more ‘dairy’ type in these breeds would lead to increased SCS. Another marked difference was that rump width correlated positively with milk yield traits in Holstein and Red & White, but negative in Brown Swiss. Results indicate that conformation traits generally can be used as predictors for various purposes in dairy cattle breeding, but may require specific adaptation for each breed.     

三穗鸭体型外貌观察与生长发育分析

为制定三穗鸭的地方标准,试验测定了210只0～17周龄原种三穗鸭的平均周增重,并于17周龄(120日龄)进行了体尺测定和相关分析。结果表明,1～17周龄公鸭的绝大多数周增重之间无显著性差异(P>0.05);公母鸭间的体斜长、半潜水长、龙骨长、胫围、胸宽、胸深极显著高于母鸭(P<0.01);公母鸭间的胫长和骨盆宽差异不显著(P>0.05)。与1991年制定的三穗鸭地方标准比较,在120日龄体重方面表现出一定的差异,外貌与体尺符合三穗鸭的品种特征。     

Effects of breed proportion and components of heterosis for semen traits in a composite cattle breed

The aim of this study was to estimate the non‐additive genetic effects of the dominance component of heterosis as well as epistatic loss on semen traits in admixed Swiss Fleckvieh, a composite of Simmental (SI) and Red Holstein Friesian (RHF) cattle. Heterosis is the additional gain in productivity or fitness of cross‐bred progeny over the mid‐purebred parental populations. Intralocus gene interaction usually has a positive effect, while epistatic loss generally reduces productivity or fitness due to lack of evolutionarily established interactions of genes from different breeds. Genotypic data on 38,205 SNP of 818 admixed, as well as 148 RHF and 213 SI bulls as the parental breeds were used to predict breed origin of alleles. The genomewide locus‐specific breed ancestries of individuals were used to calculate effects of breed difference as well as the dominance component of heterosis, while proxies for two definitions of epistatic loss were derived from 100,000 random pairs of loci. The average Holstein Friesian ancestry in admixed bulls was estimated 0.82. Results of fitting different linear mixed models showed including the dominance component of heterosis considerably improved the model adequacy for three of the four traits. Inclusion of epistatic loss increased the accuracy of the models only for our new definition of the epistatic effect for two traits, while the other definition was so highly correlated with the dominance component that statistical separation was impossible.     

Secondary sexual traits and semen characteristic of chicken germline chimeras

Birds obtained by embryo engineering are used to study embryo development and to produce transgenic birds. As this method of producing birds still generate strong emotions of the public opinion head ornaments, testes and semen characteristics of sex chimera roosters were examined to check whether they differ from chickens obtained by non‐manipulated methods. Measurements of head ornaments, testes and semen were correlated with each other. Semen quality factor (SQF) was calculated, as well as the level of fluctuating asymmetry (FA) of bilateral traits (wattles and testes). Positive correlation was found for comb width and wattle length and comb thickness and sperm concentration. Semen characteristics and FA did not exceed the level encounter in other chicken lines. Results obtained indicate that germline chimeras are similar in appearance of secondary sexual traits, and semen and testes characteristics to chickens produced in non‐manipulated way.     

斗鸡及其杂交鸡肉质性状的研究

对斗鸡、艾维菌肉鸡及其杂交一代鸡８周龄和１２周龄胸腿肌肉品质分析的结果表明：遗传因素对肉质性状有较大影响,斗鸡、艾维菌肉鸡及其杂交一代鸡的肌肉水分、蛋白南、脂肪、微量元素等有显著差异、肌纤维直径、ＰＨ值和熟肉率也有所不同,斗鸡的肉质性状及感官评定结果最优,其次是杂交一代鸡,艾维茵肉鸡最差,胸腿部位间多数指标存在显著差异,而性别和周龄对肉质性状的影响较小。     

Relationship between sperm quality traits and field-fertility of porcine semen

An investigation involving seven boars, active in artificial insemination, and 1,350 multiparous sows was conducted at a private farm and aimed at examining the relationship between sperm quality traits and boar fertility in terms of farrowing rate and litter size. This experiment was done for 6 months. The semen samples were evaluated for subjective sperm motility and concentration. Ejaculates with at least 1 × 10⁸ sperm/mL and 70% sperm progressive motility were extended with a commercial medium to 30 × 10⁶ sperm/mL and used for artificial insemination (AI). AI dose was 100 mL semen containing 3 × 10⁹ spermatozoa. Aliquots of diluted semen were assessed for live morphologically normal spermatozoa (LMNS, eosin-nigrosin stain exclusion assay) and sperm chromatin instability (SCI, acridine orange assay). Farrowing rates according to different boar sperm varied (p < 0.001) from 59.3 to 88.92%. The mean values of LMNS (47.2~76.5%) and SCI (0.16~4.67%) differed significantly among boars. LMNS (r = 0.79, p < 0.05) and SCI (r = -0.90, p < 0.02) accounted for 62.2 and 81.7% of the variability in farrowing rates, respectively. After the combination of sperm traits, the relationship between percentage of LMNS with stable chromatin structure and farrowing rate was significant (r = 0.86, p < 0.05). The number of live piglets per parturition was not significantly correlated with sperm quality attributes. In conclusion, boar fertility after AI with freshly diluted semen can be predicted based on the evaluation of sperm morphology and chromatin integrity.