共查询到20条相似文献，搜索用时 218 毫秒
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《畜牧兽医学报》2020,(1)
蛋产品安全一直是人们重点关注的问题,也是研究的热点。随着福利养殖的推广,鸡蛋被微生物污染的机率增大。除了加强饲养管理之外,强化鸡蛋自身保护屏障从而抵抗细菌入侵也十分重要。胶护膜是蛋壳最外层覆盖的无色透明膜,鸡蛋产出前1.5～2.0h于子宫部形成,是蛋抵御微生物污染的重要屏障,研究表明胶护膜较厚的蛋不易被细菌入侵。鸡蛋蛋壳胶护膜主要由糖蛋白(90%)、多糖(4%)、脂质(3%)和以羟基磷灰石晶体形式存在的无机磷(3%)组成。胶护膜中含有溶菌酶C、卵转铁蛋白、ovocleidin-32等多种抗菌蛋白,可有效地阻碍细菌跨壳污染。此外,胶护膜能终止蛋壳矿化、帮助蛋产出前在子宫中翻转、调节水气交换以延长鸡蛋的保存时间。本文对胶护膜的结构、生物学功能、胶护膜品质评价方法及胶护膜质量的影响因素等方面进行了阐述,并对尚待解决的问题展开了探讨。 相似文献
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种蛋处理与贮存的最佳时间与条件（下）韩枫（美国爱拔益加育种公司中国办事处）三、种蛋产出后的变化过程根据上述信息，可以归纳出种蛋产出后可能会发生的变化过程。产蛋时，胶护膜处于潮湿状态，并从结构上可使水分自由通过。一些细菌可以穿过胶护膜接触蛋壳，尔后胶护... 相似文献
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蛋产出母体时会被泄殖腔排泄物污染,接触到产蛋箱垫料和粪便时,被进一步污染.因此,蛋壳上附着很多细菌,并随着时间的推移数量迅速增加,如蛋刚产出时,细菌数为100～300个,15分钟后为500～600个,1小时后达到4000～5000个,有些细菌通过蛋壳的气孔进入蛋内.细菌繁殖速度与蛋的清洁程度、气温高低和湿度大小有关.虽然种蛋有胶质层、蛋壳和内外壳膜等几道自然屏障,但他们都不具备抗菌性能,所以细菌仍可进入蛋内,这对孵化率与雏禽质量构成威胁.因此,必须对种蛋进行认真消毒.消毒的原则:要对实行消毒的工作人员无害,不损伤鸡蛋胚胎,杀灭细菌和病毒要干净、彻底. 相似文献
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<正>鸡蛋是国民餐桌上不可或缺的食物,市场对鸡蛋的需求量巨大,了解鸡蛋的形成过程及其相关的影响因素,对提高蛋鸡养殖产业的经济效益十分重要。鸡蛋主要由蛋黄、蛋清、蛋壳膜和蛋壳等几部分组成。蛋壳膜可分为壳内膜和壳外膜两层,在蛋壳最外层又覆盖一层蛋白质透明薄膜,称为角质膜（胶护膜）,具有重要的保护和调节功能。蛋壳膜是影响鸡蛋品质的重要因素之一, 相似文献
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JohnT.Brake 《中国家禽》2004,26(21):39-46
临产前，蛋壳表面有一层透明的保护膜，称为胶护膜。在子宫中，液体和溶质可透过湿的胶护膜，产出后，胶护膜的结构紧缩，防止随后有微生物进入。但是，在刚刚产出、胶护膜尚未干燥之前和此后任何时间胶护膜重新弄湿时，有些微生物仍可穿透胶护膜。贮存时间的 相似文献
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无壳蛋。蛋鸡产出的无壳蛋指的就是没有蛋壳而仅有蛋黄和蛋白的鸡蛋。实际生产工作中蛋鸡群产出这种鸡蛋有以下五种原因：鸡群饲料中长期含有的少量的钙，而且骨骼中含有的血钙不可以再度调使用的时候，会导致无壳蛋的产出；大肠杆菌或者是沙门氏杆菌侵入鸡群，消化道内有很多病原菌进行繁殖，导致肠道的吸收功能降低，从而引起鸡只吸收钙含量极少；病毒将蛋壳腺细胞破坏使其变形，导致蛋壳很难成型；钙盐在鸡只体内不可以被有效的利用，产蛋鸡一旦服用了金霉素等药物以后，会在体内于血钙溶合，形成钙盐并且很难溶解然后排到体外，形成蛋壳的过程在根本上就受到了影响；鸡蛋会在输卵管子宫部中停留，但是如果停留的时间太短，比如因为急性应激反应的刺激，使蛋鸡所产出的前一枚鸡蛋太长时间的停留在子宫部，会导致许多多余的钙沉积，使得要产出的蛋推迟进入子宫部的时间而过晚的形成蛋壳。 相似文献
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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. 相似文献
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Richards PD Botha A Richards PA 《Journal of the South African Veterinary Association》2002,73(1):13-22
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. 相似文献
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《The Journal of Applied Poultry Research》2014,23(1):59-70
The shell of the egg is essential in providing shape to the egg and ensuring safe packaging of the internal contents; however, shell defects have been shown to increase the risk of microbial contamination of eggs. Eggs were collected from commercial cage and free-range flocks at the ages of 25, 35, 45, 55, 65, and 75 wk. From each collection per flock, 30 eggs were processed for the eggshell and egg internal quality determination, 30 eggs for cuticle estimation, 30 eggs for mammillary layer ultrastructural features scoring, and 60 eggs for egg microbial enumeration. Translucency score and shell reflectivity were significantly higher in free-range eggs and increased with flock age in both production systems. Egg weight, shell weight, percentage shell, shell thickness, albumen height, Haugh unit, and yolk color were higher for cage eggs. The amount of cuticle was higher in cage eggs and fluctuated with flock age in both production systems. For the mammillary layer ultrastructural variables, a significant effect of production system and flock age was observed for early fusion, Type A bodies, and Type B bodies, whereas aragonite, depression, erosion, and hole were rarely observed. Variability of mammillary cap size, the incidence of poor mammillary cap quality, incidence of late fusion, alignment, Type A bodies, Type B bodies, and cubic cone formation were greater in the free-range versus cage system and increased with flock age in both production systems. The incidence of confluence and early fusion were greater in cage eggs and decreased with age in both production systems. Significantly lower total microbial load was observed for cage compared with free-range eggs, but the overall bacterial load recorded in this study was low. It can be concluded that cage eggs were better in overall quality when directly compared with free-range eggs. 相似文献
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1. Egg weight, shell thickness, number of pores, cuticle deposition and ability of Salmonella enterica serovar Enteritidis (SE) to penetrate the shell were determined for eggs from one layer flock through the entire production period. 2. Penetration was assessed by filling the eggs with a selective medium that allowed visualising Salmonella growth on the inside of the shell and membrane complex. After inoculation of each shell with on average 2.59 log cfu, the eggs were stored for up to 20 d at 20 degrees C and 60% relative humidity (RH). 3. On average 38.7% of the eggshells became penetrated. Mostly penetration occurred on d 3. Although it affected all shell characteristics studied, hen age did not significantly influence eggshell penetration. 4. No correlations were observed between any of the shell characteristics studied and the ability of SE to penetrate the shell. The growth of SE on the shell is of major importance because shell contamination at 20 d of storage and SE penetration were highly correlated. 相似文献
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1. Scanning electron microscopy was used to assess the relationship between the layers of the eggshell and egg viability. The relative thickness (absolute and %) of the mammillary, palisade, vertical crystal and cuticle layers relative to the total eggshell were measured over a 30-week laying period in 2 broiler breeder lines having different hatchability rates. 2. A significant difference in hatchability of 5.5% between the breeder lines was observed. However, there was no significant difference in either egg viability or fertility between lines. 3. The relative thickness of the individual calcified layers and the cuticle did not differ between lines. Therefore, variations in the thickness of the individual eggshell layers are unlikely to explain the 5.5% difference in hatchability rate between lines. 4. The thickness of the calcified region did not alter as the broiler hen aged. However, the percent contribution of each calcified layer significantly differed over the egg production period. 5. The cuticle was significantly thinner at the beginning and at the end of the laying period compared to 38 weeks of age. 6. No significant correlation was observed between egg viability and the relative thicknesses of the mamillary, palisade or cuticle layers. In contrast, there was a positive relationship between egg viability and the thickness of the vertical crystal layer. 7. The percent contribution of the mammillary and palisade layers was similar in the thinnest and thickest eggshells, suggesting conservation of the proportions of these layers independent of eggshell thickness. 相似文献
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1. The eggshell cuticle is the proteinaceous outermost layer of the eggshell which regulates water exchange and protects against entry of micro-organisms. In this study, we investigated the hypothesis that the cuticle may also reduce microbial contamination by providing a chemical defence. 2. Outer eggshell and cuticle protein was extracted from domestic chicken (Gallus gallus), duck (Anas platyrhynchos) and goose (Anser anser) eggs by HCl and urea treatment, respectively. Antimicrobial activity of the extracts against Gram-positive and Gram-negative bacteria was evaluated. 3. C-type lysozyme, ovotransferrin and ovocalyxin-32 were identified in all extracts by Western blotting. All extracts from all species demonstrated lysozyme enzymatic activity. Immobilised c-type lysozyme retained some enzymatic activity. Protein extracts demonstrated activity against Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis suggesting the action of antimicrobial proteins in addition to lysozyme. 4. The results suggest that the antimicrobial outer eggshell and cuticle proteins present in a number of avian species may be a mechanism which enhances avian reproductive success. 相似文献
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低聚木糖对蛋鸡的促生长作用及促生长机理研究 总被引：6，自引：0，他引：6
采用生物技术,由天然植物纤维原料提取得到具有生物活性的低聚木糖。在体外严格厌氧条件下,以5.00g/l低聚木糖分别培养两歧双歧杆菌和青春双歧杆菌30h后,两歧双歧杆菌和青春双歧杆菌的菌体浓度可分别增殖1.8倍和4.7倍。因而,该低聚木糖也能够对蛋鸡肠道内的双歧杆菌有效增殖,进而对蛋鸡产生多种保健促生长作用,可显著提高蛋鸡的生产性能。当低聚木糖添加量为饲料重量的0.007%时促生长效果最佳,蛋鸡的产蛋率可提高2.0%￣4.0%,产蛋重可提高4.5%￣6.3%,蛋料比可提高3.6%￣5.7%。蛋鸡饲喂低聚木糖后,对鸡蛋的蛋形和蛋壳、必需氨基酸和微量元素等鸡蛋品质指标没有显著影响。经济分析表明,添加低聚木糖0.007%,1000羽蛋鸡厂一年可增收毛利润17%￣28%,具有良好的社会效益和经济效益。 相似文献
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1. Ultrastructural analyses of the eggshells of one strain of commercial layers indicated that the cuticular layer is rarely present as an even covering over the shell surface and the paired shell membranes are invariably pitted with holes larger than bacterial dimensions. 2. The above conditions pertain irrespective of the age of the laying bird. 3. Bacterial penetration of the eggshell is independent of pore numbers. 4. In the absence of a functional cuticle and with the shell membranes removed, bacteria are checked in their movement by structural modifications in the mammillary layer. 相似文献
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不同周龄母鸡鸡蛋及不同蛋壳质地鸡蛋的蛋品质比较 总被引：1，自引：0，他引：1
本文比较了同一品种不同周龄(26、40周龄和64周龄)母鸡所产蛋的蛋壳品质和蛋品质,包括蛋重、蛋壳相对重、蛋形指数、蛋壳强度、蛋壳厚度、蛋黄颜色、蛋黄指数、蛋黄比率、哈氏单位、蛋清pH值。之后,还比较了该鸡种不同蛋壳质地鸡蛋(正常蛋和砂壳蛋)之间上述指标的差异。结果表明:在不同周龄母鸡所产蛋之间,蛋重、蛋黄指数、蛋黄比率、哈氏单位等均存在显著差异(p<0.05),而蛋壳厚度之间差异不显著(p>0.05)。此外,蛋重、蛋形指数、蛋黄颜色、蛋黄比率随着母鸡周龄的增加呈上升趋势,而蛋壳强度、蛋壳相对重、哈氏单位、蛋黄指数、蛋清pH值呈下降趋势。最后,蛋壳质地不同的鸡蛋(正常蛋与砂壳蛋)之间,蛋重、蛋壳相对重、蛋壳强度、蛋清pH值之间存在极显著差异(p<0.01),而其他参数之间差异不显著(p>0.05)。 相似文献