Influence of the microstructure on the shell strength of eggs laid by hens of different ages

1. The eggshell is a bioceramic material constructed of columnar calcite crystals preferentially oriented with their c-axis perpendicular to the shell surface. 2. The influence of microstructure (crystal size, shape and crystallographic orientation of crystal grains) on the mechanical properties of eggshells (shell strength) was investigated using eggs from hens of different ages. 3. There was a strong correlation between crystallographic texture and the strength of the eggshell in the case of eggs laid by young hens. The strength of eggshells increased as the preferential orientation of the crystals constituting the eggshell decreased. 4. By comparing two age populations, the effect of hen age on eggshell properties was evaluated. In general, eggshells from aged hens had a lower breaking strength (less than half that of those laid by young hens) and showed a greater variability in their structural properties such as thickness, grain morphology and crystallographic texture. 5. Texture analysis revealed that shells from eggs laid by aged hens have two preferred crystal orientations, after (001) and (104), compared with mainly one, after (001), in eggs laid by young hens. 6. These observed changes in eggshell properties could be due to changes in the organic matrix of the eggshell associated with ageing of the hens.     

Changes in eggshell mechanical properties, crystallographic texture and in matrix proteins induced by moult in hens

The effect of moult on eggshell mechanical properties, on composition and concentrations of organic matrix components and on eggshell microstructure was investigated. The observed changes were studied to understand the role of organic matrix and eggshell microstructure in eggshell strength. Moult was induced by zinc oxide (20 g zinc/kg diet) in 53 ISA Brown laying hens at 78 weeks of age. No difference was observed for egg or eggshell weights after moult. In contrast, moult improved the shell breaking strength (28.09 vs 33.71 N). After moult, there was a decrease in the average size of calcite crystals composing the eggshell and in their heterogeneity, whereas crystal orientation remained basically the same. After moulting, the total protein concentration in eggshell increased slightly. The comparisons of SDS-PAGE profiles of the organic matrix constituents extracted before and after moulting showed changes in staining intensity of certain bands. After moult, bands associated with main proteins specific to eggshell formation (OC-116 and OC-17) showed higher staining intensity, while the intensity of the egg white proteins (ovotransferrin, ovalbumin and lysozyme) decreased. ELISA confirmed the decrease in ovotransferrin after moult. Its concentration was inversely correlated with breaking strength before moult. These observations suggest that changes in eggshell crystal size could be due to changes in organic matrix composition. These changes may provide a mechanism for the improvement in shell solidity after moulting.     

蛋壳质量与元素组成、超微结构关系的研究

为探寻蛋壳质量与元素组成、超微结构的关系,分别用常规方法和X射线能谱仪测定了同日产65枚蛋的蛋壳质量、蛋壳结构属性与蛋壳元素相对含量,并用环境扫描电子显微镜观察蛋壳超微结构.结果表明,不同强度蛋壳元素相对含量差异不显著,而蛋壳乳突层有效厚度和乳突间隙组间差异显著,高强度组乳突层有效厚度和乳突间隙分别比中强组低23.01%(P<0.01)和14.94%(P<0.05)、比低强度组低73.43%(P<0.01)和25.06%(P<0.05).由此得出,蛋壳超微结构致密度直接影响蛋壳质量,而蛋壳元素组成与蛋壳质量间则无显著关联.     

赤水乌骨鸡不同产蛋期SPIA1基因的差异表达研究

为了探究SPIA1基因的表达量与蛋壳绿色深浅之间的规律性,本试验以赤水乌骨鸡母鸡为试验动物,利用双重PCR技术进行基因分型,根据基因型(纯合型、杂合型)和蛋壳颜色(深绿色、浅绿色、淡绿色)进行分类.采集300日龄赤水乌骨鸡的蛋壳腺进行转录组测序,结果发现SPIA1基因为蛋壳绿色的上调基因,为了验证测序结果,随机选取不同...     

Genetic properties of egg quality traits and their correlations with performance traits in Japanese quail

1. Performance traits were measured on 1908 Japanese quail and egg quality traits assessed on 1800 eggs at 10?wk of age.

2. Genetic and phenotypic correlations were estimated using a bivariate animal model with restricted maximum likelihood using ASREML software.

3. Body weight at different ages showed positive genetic correlations with egg weight and most of the internal egg quality traits, whereas their genetic correlations with eggshell thickness, eggshell strength and eggshell percentage were negative.

4. Genetic correlations of age at sexual maturity and egg number with most of external and internal traits were negative.

5. It was concluded that selection for higher body weight will result in heavier and better quality eggs. Because of the negative genetic correlation between BW and egg shell quality, a selection index including BW and eggshell strength would be the best breeding strategy for genetic improvement of egg quality in Japanese quail.     

鸡蛋壳质量与超微结构关系的研究

研究使用常规方法测定蛋形指数、蛋壳相对重量、蛋壳强度和蛋壳厚度等蛋壳质量指标,使用X射线能谱仪测定蛋壳断面各层钙的相对含量,使用环境扫描电子显微镜观察蛋壳断面各层和内外表面的超微结构。结果表明:蛋壳强度与蛋壳相对重量、蛋壳强度与蛋壳厚度以及蛋壳相对重量与蛋壳厚度之间相关分别达到0.444(P<0.01)、0.700(P<0.01)和0.611(P<0.01),各相关系数不在同一水平。蛋壳各层钙的相对含量分别达到32.68%±8.62%、33.13%±6.58%和32.35%±.97%,之间差异不显著(P>0.05),几近匀质。环境扫描电子显微镜的观察发现不同强度的蛋壳,其各层和内外表面超微结构存在明显差异。由此得出:蛋壳超微结构的差异是蛋壳质量变化的重要影响因素。     

Quality assessment of chicken eggshell cuticle by infrared spectroscopy and staining techniques: a comparative study

1. The cuticle is a very thin organic layer that coats the eggshell surface and plugs the eggshell pores preventing bacterial penetration. It also reduces eggshell permeability which is important to maintain internal quality of the egg. Thus, the eggshell cuticle quality is crucial to ensure the food safety and quality of eggs.

2. A new methodology to assess eggshell cuticle quality, based on attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), is compared with a more traditional method based on cuticle staining techniques.

3. Both techniques are useful to determine the amount of cuticle; however, the ATR-FTIR technique is independent of egg colour, more sensitive and provides complete information about the cuticle and its composition. Additionally, it provides information about eggshell permeability.

4. The methodology for cuticle quality assessment described in this work can be very useful for genetic selection programmes aimed to improve the safety and quality of eggs.     

Electrochemical synthesis of highly ordered Ni nanowire arrays through AAO templates

One-dimensional Ni nanowires arrays were fabricated successfully by the electrochemical deposit in porous anodic alumina oxide(AAO)templates.The microstructure of nanoarrays was respectively observed by scanning electron microscope s(SEM)and transmission electron microscopes(TEM).The results show that the obtained Ni nanowires are arranged orderly and the diameter is about 200nm.Crystallization way was observed by X-ray diffraction(XRD).The results show that Ni nanowire is face-centered cubic structure     

Measuring the eggshell strength of 6 different genetic strains of laying hens: techniques and comparisons

1. Eggshell quality was compared in 6 different strains of laying hens. Three strains were commercial; the three others were experimental. 2. Four different variables describing the strength of eggshells were investigated. Three of them were the classical ones eggshell thickness, shell stiffness measured during quasi-static compression and breaking force. Dynamic stiffness, introduced by Coucke (Ph.D. Thesis, KU Leuven, 1998), was the 4th. The fact that this measurement is dynamic could be helpful in genetic selection for eggshell breakage, because forces applied to the egg in practice are dynamic, rather than static. 3. Hisex White hens produce eggs with the strongest eggshell, in terms of all 4 eggshell variables. However, their shell quality in terms of breaking force did not remain constant over the laying period, unlike 4 other strains. 4. All strains showed a decline in quasi-static stiffness over time. 5. The eggshell thickness of three strains showed a decline over time. 6. Dynamic stiffness remained constant or improved in all strain. 7. All variables describing the mechanical eggshell strength gave different information.     

Morphological and histochemical observations of the organic components of ostrich eggshell

The organic component of the avian eggshell can be divided into 3 portions, the shell membranes, the matrix and the cuticle. These have been well characterised in the chicken but little has been published with regard to the ostrich (Struthio camelus). A number of recent studies have indicated that the cause of intra-shell embryonic deaths in the ostrich is similar to intra-shell embryonic deaths that occur in the chicken. These deaths in the chicken are associated with the loss of or damage to the waxy cuticle and other organic components of the eggshell, which is reported to be absent in the ostrich eggshell. In this study, preliminary morphological and histochemical analyses, at the level of the light and electron microscope, have characterised the various organic components of the ostrich eggshell. The results of the histochemical and electron microscopical analyses suggest that there may only be 1 shell membrane in this species, which could play a major role in the limitation of bacterial penetration to the embryonic chamber The shell membrane has a distinct elemental profile as determined by EDS analysis. The matrix is shown to decrease in mesh size from the mammillary layer to the vertical crystal layer. The closer packing of the mesh may indicate the presence of a morphologically discernible termination signal to calcification or the remnants of an evolutionary calcified cuticle. The matrix of the pores may also form a defensive barrier against bacterial invasion, which could be damaged as a result of dipping the eggs before incubation.     

Organic matrix composition and ultrastructure of eggshell: a comparative study.

1. The avian eggshell is a biomineralised composite ceramic consisting of calcium carbonate embedded in an organic matrix. Matrix components are supposed to be involved in the control of mineralisation, crystallographic texture and biomechanical properties of eggshell. 2. The structure and eggshell matrix composition of various domesticated bird species were compared to gain insight into the universality of the eggshell mineralisation process. 3. The SDS-PAGE profiles of soluble eggshell matrix were specific within groups of birds (a: laying hen, breeder hen, quail, pheasant and possibly turkey; b: guinea fowl; c: duck and goose) but some of the protein bands were common to all groups. 4. Analogies between species were confirmed by Western blotting using hen protein antibodies. Ovocleidin-17 (OC-17) and ovalbumin were revealed in all species (except quail for OC-17). Lysozyme was present only in hen eggshell. Another egg white protein: ovotransferrin showed a positive signal in hens, turkey and quail. Osteopontin was observed in laying and breeder hens and quail. 5. Different proteoglycans were localised to discrete regions within the eggshell. Dermatan sulphate was observed within the matrix of the calcified shell of all species except quail which contained chondroitin-6-sulfate. Keratan sulphate was observed in mammillary bodies of breeder and laying hen, quail, pheasant and turkey while chondroitin sulphate was also present in guinea fowl and duck. 6. The general structural organisation of the different avian eggshells was similar but specific differences were observed in the ultrastructure of the mammillary layer. Species of the same taxonomic family could be grouped according to their structural analogies: breeder hen, turkey and pheasant resembled that of the domestic fowl. Guinea fowl was unique. Goose and duck were quite similar with large and confluent mammillary bodies. 7. Some matrix components are therefore common to eggshells of various species but more information is needed to relate differences in matrix composition between taxonomic groups with differences in ultrastructure.     

中国6个地方鸡种蛋壳质量和超微结构的比较

实验测定和观察比较同一饲养条件下6个地方鸡种同一天所产的各30枚蛋的蛋重、蛋形指数、蛋壳颜色、蛋壳厚度、蛋壳强度和蛋壳超微结构。结果表明:蛋形指数以茶花鸡、藏鸡和金湖乌凤鸡较合适,基本维持在1.32~1.34;金湖乌凤鸡的蛋壳厚度和蛋壳强度分别为0.33 mm和4752.20 g/cm2;6品种蛋鸡蛋壳质量由高到低依次为金湖乌凤鸡、边鸡、泰和鸡、北京油鸡、藏鸡和茶花鸡。泰和鸡蛋壳外表面裂隙数分别比金湖乌凤鸡、边鸡、茶花鸡、藏鸡和北京油鸡多4.37%、11.87%、28.75%、43.75%和32.50%;而金湖乌凤鸡蛋壳外表面裂隙宽仅有0.88μm;藏鸡蛋壳栅栏层厚度所占百分比为63.30%;金湖乌凤鸡蛋壳的乳头数和乳头宽分别为10.67个/μm2和36.32μm。蛋壳外表面的裂隙数、乳头层、栅栏层及晶体层厚度百分比和乳头数与蛋壳强度均呈显著或极显著正相关,而裂隙宽和乳头宽与蛋壳强度呈极显著负相关。     

规模化鸡场蛋壳质量的影响因素与调控措施

蛋壳的质量是评定鸡蛋品质的一项重要指标,蛋壳质量的好坏对蛋的运输、贮存、加工、消费和孵化都有极大的影响。就影响蛋壳质量因素的钙、磷、维生素、微量元素、电解质、鸡龄、饲养管理、疾病与药物等方面进行了阐述,并综述了提高蛋壳质量的调控措施,以期对广大鸡蛋生产者和经营者提供帮助。     

Identification of the major proteins of the organic matrix of emu (Dromaius novaehollandiae) and rhea (Rhea americana) eggshell calcified layer

1. The eggshell is a composite consisting of 95% calcite and an organic matrix. 2. While many proteins of the chicken eggshell matrix have already been identified, little is known about the matrix of other birds. 3. Isolation of the emu and rhea eggshell matrix and analysis of its major constituents showed that the predominant components were C-type lectin-like proteins related to those of ostrich, chicken and goose. 4. Serum albumin, vitelline membrane outer layer protein I (VMO-I) and the turpentine-induced acute phase serum protein 18-B were identified as minor components of the emu shell matrix. Both eggshell matrices also contained a novel proline- and alanine-rich protein. 5. Like ostrich, and unlike chicken and goose, both emu and rhea eggshell matrix contained two different C-type lectin-like proteins as major components, indicating that the occurrence of two proteins of this family may be widespread among ratites.     

Comparison of repeatability and multiple trait threshold models for litter size in sheep using observed and simulated data in Bayesian analyses

Bayesian analyses were used to estimate genetic parameters on 5580 records of litter size in the first four parities from 1758 Mule ewes. To examine the appropriateness of fitting repeatability (RM) or multiple trait threshold models (MTM) to litter size of different parities, both models were used to estimate genetic parameters on the observed data and were thereafter compared in a simulation study. Posterior means of the heritabilities of litter size in different parities using a MTM ranged from 0.12 to 0.18 and were higher than the heritability based on the RM (0.08). Posterior means of the genetic correlations between litter sizes of different parities were positive and ranged from 0.24 to 0.71. Data sets were simulated based on the same pedigree structure and genetic parameters of the Mule ewe population obtained from both models. The simulation showed that the relative loss in accuracy and increase in mean squared error (MSE) was substantially higher when using the RM, given that the parameters estimated from the observed data using the opposite model are the true parameters. In contrast, Bayesian information criterion (BIC) selected the RM as most appropriate model given the data because of substantial penalty for the higher number of parameters to be estimated in the MTM model. In conclusion, when the relative change in accuracy and MSE is of main interest for estimation of breeding values of litter size of different parities, the MTM is recommended for the given population. When reduction in risk of using the wrong model is the main aim, the BIC suggest that the RM is the most appropriate model.     

牛磺酸对中后期蛋鸡蛋壳质量影响的研究

采用单因子随机化设计,将所选的378只体质健康的47周龄海塞克斯褐蛋鸡随机分为6组,每组3个重复,每个重复21只。第1~6组在饲喂基础日粮的基础上分别添加牛磺酸0,20,40,80,160,320 mg/kg。以谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶酶活(SOD)和甲状腺激素(T3、T4)的含量作为血清生化指标,以破壳软壳蛋数、蛋壳钙含量作为蛋壳质量的评定指标,以此来研究牛磺酸是否能提高中后期蛋鸡的蛋壳质量,为牛磺酸在蛋鸡中的应用提供理论基础。结果表明中后期蛋鸡日粮中添加不同水平的牛磺酸,可以提高中后期蛋鸡全血中GSH-PX、血清中SOD两种酶的酶活;提高了血清中的T3含量,降低T4含量;提高了蛋壳钙含量和降低破壳蛋数。     

Effects of electrical field on hatchability performance of eggs from a layer-type breeder

1. Eggs from a layer-type breeder flock (Baladi, King Saud University) between 50 and 63 weeks of age were used in three trials to study the effects of electrical field (EF) during incubation on albumen and yolk heights, incubation temperature, egg weight loss and hatchability traits. The effects of egg size and eggshell characteristics on hatchability traits of eggs incubated under EF were investigated. 2. Eggs were weighed and graded into three weight classes (small, medium, and large). The physical dimensions, eggshell characteristics, and conductance of eggs were examined. The incubator was divided into two compartments for the control and EF treatments. Two aluminium plates were fitted on the inside walls of the EF compartment, face to face, and connected to a step up electric transformer. Eggs were exposed constantly to the EF during the first 18 d of incubation at the level of 30 kV/m, 60 Hz. 3. Egg size influenced the physical dimensions and eggshell characteristics of eggs. Large eggs had higher egg weight, egg surface area, egg volume, eggshell conductance, and eggshell weight and lower yolk weight percentage than medium or small size eggs. Small eggs had lower egg length and higher egg density than large or medium size eggs. Large eggs had higher eggshell thickness than small size eggs. 4. EF incubation of eggs raised incubation temperature by 0.06 degrees C, and increased the percentage of egg weight loss, hatchability, and weight of hatching chicks and reduced the early embryo deaths, and length of incubation by approximately 9.8, 19.6, 1.7, 62.1 and 2.1%, respectively. 5. There was no significant difference between the two incubation treatments in the heights of albumen and yolk of incubated eggs, percentages of late embryo deaths, and pips with live and dead embryos. Hatchability traits were not significantly influenced by egg size. 6. It was concluded that EF incubation of eggs increased hatchability, chick-hatching weight, and reduced the length of incubation of Baladi eggs. Differences in the physical dimensions and eggshell characteristics of eggs did not influence hatchability traits of eggs under EF incubation.     

高产蛋鸡品系产蛋中后期蛋品质性状遗传规律的研究

为选育改良国产高产蛋鸡产蛋中后期蛋品质,确定合理的饲养周期。本研究选取北京市华都峪口禽业有限责任公司13世代Y1、K1品系蛋鸡,测定56、66、72、80周龄蛋重、蛋壳颜色、蛋壳强度、蛋白高度和蛋黄颜色,采用DMU软件估计遗传参数。结果表明:随着蛋鸡周龄增大,Y1、K1系蛋重显著提高(P0.05),蛋壳强度、蛋白高度和蛋黄颜色极显著下降(P0.01);Y1系和K1系56~80周龄各性状遗传力在0.03~0.52;品系内同一性状不同周龄之间高度遗传相关(0.57~0.99),同一周龄不同性状之间遗传相关(-0.39~0.43)和表型相关(-0.049~0.122)均较低。本研究表明高产蛋鸡纯系产蛋后期蛋品质随周龄增加有所下降,同一性状不同周龄之间高度相关,可以通过前期的选育提高后期蛋品质。     

Mussel shells as an environment enrichment and calcium source for floor-housed laying hens

Feather pecking is still a behavioral problem in laying hen flocks, resulting in impaired welfare and economic losses. Environment enrichment, e.g., providing access to litter, to increase foraging behavior in laying hens has been shown to decrease feather pecking. This study investigated the effect of spreading crushed mussel shells (particle size 10 to 20 mm) in the litter area as an environment enrichment and source of calcium for layers receiving a commercial feed and for layers given a feed with 40% less calcium. These treatments were compared with a control involving hens given the commercial feed, but no mussel shells in the litter. The study included 900 Dekalb White layers housed in a single-tier floor system during a production cycle (20 to 72 wk of age). The mussel shells were consumed to a lower extent than predicted, resulting in calcium deficiency in hens fed the low-calcium diet. This in turn was evident as increased degree of keel bone deviations and lower eggshell breaking strength. Daily addition of crushed mussel shells to the litter for laying hens on a balanced or calcium-deficient diets did not generate any positive effects on bird feather cover, eggshell quality, production performance, or fearfulness. Hence, with the particle size of mussel shells used in this study, there was no indication of improved welfare due to environment enrichment.     

中型褐壳产蛋鸡饲粮钙适宜水平的研究

用 2 0周龄的商品代北京红鸡 1 5 0只 ,按完全随机设计以体重随机分为 5个处理组 ,分别喂以含钙水平为 2 .5 %、3.0 %、3.5 %、4.0 %和 4.5 %及非植酸磷水平均为 0 .2 5 %的玉米 豆粕型饲粮 2 0周 ,研究中型褐壳产蛋鸡在 2 0～ 40周龄产蛋阶段的饲粮钙适宜水平。饲粮钙水平对产蛋率、蛋重、产蛋量、耗料量、饲料效率、蛋形指数、哈夫单位、蛋壳百分率和血浆钙含量无明显影响 (P >0 .1 0 ) ,而显著影响了蛋壳厚度、蛋壳强度、蛋壳重、骨灰及蛋壳钙含量 (P <0 .0 5 )。随着饲粮钙水平的增加 ,蛋壳厚度、蛋壳强度和蛋壳重均呈曲线型增加 ,当饲粮钙水平升至 4.0 %时均增至最大。本次研究结果表明 ,蛋壳厚度、蛋壳强度和蛋壳重是评价中型褐壳产蛋鸡饲粮钙营养需要量的敏感指标 ;北京红中型褐壳产蛋鸡在 2 0～ 40周龄产蛋阶段的玉米 -豆粕型饲粮中钙水平以 4.0 %(实测值为 3.94%,每日钙进食量为 4.1 8g)为宜 ,比美国现行NRC( 1 994)对中型褐壳产蛋鸡饲粮钙建议需要量 ( 3.2 7%钙 ,每日钙进食量为 3.60g)的高