Physical and mechanical properties of eggshell as affected by chicken breed and flock age

ABSTRACT

1. A study was conducted to evaluate the relationship among physical and mechanical properties of the eggshell, as affected by breed and hen’s age.

2. Data on eggshell quality (external characteristics and derived measurements) were obtained from 322 laying hens, from three breeds (Fayoumi, Dandarawi and Hy-Line Brown) during the laying cycle, starting from 38 wks of age for four experimental periods (38, 46, 54 and 62 wks).

3. Eggs obtained from the Fayoumi breed exhibited the highest shell thickness and breaking force. There was a linear improvement in eggshell quality attributes associated with hen’s age up to 54 wks, thereafter a deterioration was found for all breeds.

4. Generally, eggs laid by native breeds (Fayoumi and Dandarawi) had better mechanical properties compared to those produced by the commercial strain (Hy-Line Brown). In addition, the interaction between breed and hen’s age was not significant for any physical property or mechanical attribute. There was a highly significant (P ≤ 0.01) positive correlation between the breaking force and either eggshell toughness or shell thickness, and regression analyses suggested that eggshell toughness was the best predictor for breaking force, followed by shell thickness.     

The method of chicken whole embryo culture using the eggshell windowing,surrogate eggshell and ex ovo culture system

1. The unique accessibility of the avian embryo have made them an ideal model for the study of development and genome editing. Chicken whole embryo culture has provided important insights into toxicity tests, gene manipulation, clarifying gene functions, cell transplantation and cell tracking.

2. A simple technique for chicken manipulation is eggshell windowing, without or with seal, the latter having demonstrated some improvement in hatching rates.

3. Likewise, a surrogate eggshell system provides an accessible model for manipulation during chicken and quail development, with a higher hatchability compared to the simple windowing method.

4. The development of the chicken ex ovo culture systems in a synthetic environment as an efficient technique for imaging and microsurgery applications has enabled the study of important events of live chicken embryos at a specific time point.

5. This short review illustrates recent applications of well-designed whole embryo culture systems as a robust model for research into numerous biological mechanism, drug discovery, gene manipulating and production of functional proteins.     

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.     

傅立叶变换近红外光谱技术快速测定玉米DDGS营养成分

为实现玉米DDGS营养指标的快速检测,本实验采用傅立叶变换近红外光谱技术,建立玉米DDGS水分、粗蛋白质、粗脂肪、粗灰分和氨基酸定量分析模型。收集全国范围内230个玉米DDGS样品,随机分为215个校正样品和15个验证样品,通过对不同组分独立进行光谱的预处理、交互检验计算和优化定标,得到的水分、粗蛋白质和粗脂肪定标方程决定系数R~2均在0.9以上,交互验证均方根误差(RMSECV)在0.30以内,相对分析误差RPD>3;粗灰分R~2为0.81,RMSECV为0.12,RPD为2.3,盲样验证结果均满足GB/T 18868要求,模型均有较好的准确性和稳定性;氨基酸组分建模和验证效果也较好。结果表明,采用傅立叶变换近红外光谱技术能够实现对玉米DDGS的快速检测。     

Negative staining method with nigrosin for the detection of cryptosporidial oocysts: a comparative study

A comparison was made between two methods for the detection of cryptosporidial oocysts in human faecal sediments of formalin-ether concentrates: a cover-slipped, wet method (containing Gram's iodine) and an air-dried, negative staining method using nigrosin solution. A modified Ziehl-Neelsen technique was used as a reference method. The negative staining method with nigrosin gave a positive diagnosis more often than the cover-slipped wet method. A comparison of the nigrosin method with the modified Ziehl-Neelsen method gave almost identical results. Restaining the nigrosin slides with the modified Ziehl-Neelsen technique showed that the round, refractile bodies were cryptosporidial occysts.     

Prediction of chemical composition and peroxide value in unground pet foods by near‐infrared spectroscopy

The massive development of the pet food industry in recent years has lead to the formulation of hundreds of canine and feline complete extruded foods with the objective of meeting both the needs of the animals and numerous demands from pet owners. In the meantime, highly variable raw material compositions and the industry's new production techniques oblige manufacturers to monitor all phases of the extrusion process closely in order to ensure the targeted composition and quality of the products. This study aimed at evaluating the potential of infrared technology (visible and near‐infrared spectrophotometer; 570–1842 nm) in predicting the chemical composition and peroxide value (PV) of unground commercial extruded dog foods. Six hundred and forty‐nine commercial extruded dog foods were collected. For each product, an unground aliquot was analysed by infrared instrument while a second aliquot was sent to a laboratory for proximate analysis and PV quantification. The wide range of extruded dog food typologies included in the study was responsible for the wide variability observed within each nutritional trait, especially crude fibre and ash. The mean value of the 208 pet foods sampled for PV quantification was 17.49 mEq O₂/kg fat (min 2.2 and max 94.10 mEq O₂/kg fat). The coefficients of determination in cross‐validation of NIRS prediction models were 0.77, 0.97, 0.83, 0.86, 0.78 and 0.94 for moisture, crude protein, crude fat, crude fibre, ash and nitrogen‐free extract (NFE) respectively. PV prediction was less precise, as demonstrated by the coefficient of determination in cross‐validation (0.66). The results demonstrated the potential of NIRS in predicting chemical composition in unground samples, with lower accuracy for moisture and ash, while PV prediction models suggest use for screening purposes only.     

动物源性食品质量安全因素和控制

随着动物源性食品在人民膳食结构中所占比重的增大,动物源性食品质量安全成了很重要的公共卫生问题.本文对引起动物源性食品安全问题的因素及预防控制措施做了综述.     

Continuous and non-invasive study of brain oxygenation in the calf by near infrared spectroscopy

Near infrared spectroscopy (NIBS) was used to detect changes in brain oxygenation in five tranquilised calves that were placed on a hypoxic gas mixture (10 per cent O₂/90 per cent N₂) and hyperoxic gas mixture (30 per cent O₂/70 per cent N₂) for five minutes at each concentration. A NIRO 500 (Hamamatsu, Japan) was used for the NIBS, with the incident light source and separate detector (optodes) placed on shaved skin on the most dorsal surface of the frontal bone. Sequential arterial blood gas sample analyses provided confirmation of the appropriate change in systemic oxygenation status. By the end of the five-minute-period of breathing 10 per cent oxygen, NIBS of the calf head detected highly significant changes in haemoglobin oxygenation reflective of hypoxaemia, with oxyhaemoglobin decreasing by 23·5 units (P<0·01) and deoxyhaemoglobin increasing by 45·6 units, (P<0·01) from the baseline of breathing room air. Total haemoglobin (oxyhaemoglobin + deoxyhaemoglobin) showed a significant increase of 22·1 units (P<0·05) but there was no significant change in LAIRS determined cytochrome aa₃ oxygenation. Concomitant blood gas alterations included significant decreases in Pa)₂ (−27·8 mmHg, P<0·01), haemoglobin saturation (−29·0 per cent, P<0·05), and PaCO₂ (−7·8 mmHg, P<0·05) and significantly increased blood pH (0·059, P<0·05). At the end of the five minutes of breathing 30 per cent oxygen NIBS of the calf head detected significantly increased oxyhaemoglobin (13·1 units, P<0·01) and decreased deoxyhaemoglobin (−13·7 units, P<0·05) when compared with baseline breathing of room aim. Total haemoglobin and cytochrome aa₃ were unchanged from baseline. The accompanying arterial blood gas changes included significant increases in PaO₂ (30·9 mmHg, P<0·05), arterial O₂ saturation (11·7 per cent, P<0·05), and significantly decreased pH (−0·026, P<0·05), This study showed that NIRS can be used to continuously and non-invasively detect cerebral oxygenation changes in the live calf in response to both increased and decreased systemic arterial oxygen. Additionally, despite induction of profound hypoxaemia, cytochrome aa₃ in the brain did not appear to become reduced.     

Counting coccidial oocysts in chicken faeces: a comparative study of a standard McMaster technique and a new rapid method

For the assessment of coccidial oocyst production by chickens, some modified form of the McMaster counting method is commonly used. The objective of this study was to evaluate a standard method and to compare it to a new, faster method, in which all the preparative stages before counting are carried out in the same container into which the original faecal sample was collected. A stock suspension containing purified oocysts of all seven valid Eimeria species that parasitize chickens was prepared, from which seven concentrations of oocyst suspensions were made. Since the faecal material in a sample influences the ability of oocysts to float up in a McMaster chamber, the new method was tested to establish the optimal amount of faeces in the original sample. Control oocyst suspensions containing no faeces were also tested, and three series of counts using the new method were compared with the standard McMaster method. The results were statistically analysed by agreement analysis. Repeatability and between-operator variation of both methods were also tested by agreement analysis. Counting by the standard McMaster method underestimated the true number of oocysts. The new method gave counts in agreement with the true number of oocysts if using 1 g of faeces per sample. With 2 g of faeces, counts were obtained that agreed with counts by the standard McMaster method. Both methods showed agreement between repeated measurements. The new method used on a sample containing 2 g of faeces provides a convenient alternative to the standard modified McMaster method. A 1-g faecal sample increases agreement with the true numbers of oocysts. Processing of a sample with the new method is about nine times faster than with the standard method.     

乳品质量安全追溯体系分析

随着社会的发展和生活水平的提高,人们对乳品质量安全越来越关注.然而,随着乳品供应链的日益延伸和行为参与人的日渐复杂,消费者很难获取到乳品的质量安全信息.乳品质量安全追溯体系作为乳品质量安全管理的有效手段,越来越受到有关部门和广大消费者的关注.本文针对我国乳品质量安全情况阐述建立质量安全追溯体系的必要性,分析推广乳品质量安全追溯体系所面临的问题,研究搭建乳品质量安全追溯体系框架,并针对体系建设提出一些政策建议.     

动物源食品质量安全存在的主要问题及对策

本文浅析了动物源性食品质量安全中存在的主要问题和对社会、人类的影响,并就新形势下如何保障动物食品安全,共建小康社会提出了对策建议.     

近红外光谱法测定DDGS中粗蛋白含量的试验研究

试验建立DDGS粗蛋白含量测定的近红外光谱分析定标模型。采用化学分析法测定72个DDGS样品中的粗蛋白含量,利用FOSS InfraXact型近红外光谱分析仪采集样品光谱,光谱经2,4,4,1导数和标准正常化+散射处理(SNV+Detrend),用改进最小二乘法(MPLS)回归,获得了较好的定标模型,校正决定系数(RSQ)、交叉验证决定系数(1-VR)、校正标准误差(SEC)、交叉验证标准误差(SECV)分别为0.982 5、0.932 8、0.266 2、0.389 5。利用30个验证集的DDGS样品进行外部检验,预测值与真实值之间差异不显著(P>0.05)。结果表明,定标模型的预测性能较好,可以替代化学分析法快速测定DDGS中的粗蛋白含量。     

Quantitation of serum phospholipase A2 by enzyme-diffusion in lecithin agar gels. A comparative study in man and animals

A sensitive gel-diffusion assay for determination of phospholipase A₂ was developed. PLA₂ standards, serum, faecal and pancreas homogenate samples with PLA₂-activity were allowed to diffuse from wells into agar-gels containing lecithin-membranes. The turbidity cleared radially upon PLA₂-activity. The diameters of the cleared zones showed a linear relationship with the log of the enzyme concentration. Serum samples resulted in some turbidity within the cleared zones. This interference originating from serum lipoproteins could be abolished by hydrophobic absorption. The gel-diffusion method was compared with two other methods for PLA₂, titrimetric and radiometric techniques. Analysis on 37 human patients with acute pancreatitis showed close interrelationship between these methods. The phospholipase A₂ activity in sera from man, the dog, the horse, the cow, the pig and the cat were almost equal, but much less than in the albino rat. No significant differences between PLA₂ activities in pancreatic samples were obtained in different animal species. Of the faecal samples, the cow had the lowest PLA₂ activity. Dogs suffering from pancreatic degenerative atrophy (PDA), had significantly reduced PLA₂ activity both in their pancreas and faeces but not in serum.     

Development of an algorithm for assessing the risk to food safety posed by a new animal disease

An algorithm was developed as a tool to rapidly assess the potential for a new or emerging disease of livestock to adversely affect humans via consumption or handling of meat product, so that the risks and uncertainties can be understood and appropriate risk management and communication implemented. An algorithm describing the sequence of events from occurrence of the disease in livestock, release of the causative agent from an infected animal, contamination of fresh meat and then possible adverse effects in humans following meat handling and consumption was created. A list of questions complements the algorithm to help the assessors address the issues of concern at each step of the decision pathway. The algorithm was refined and validated through consultation with a panel of experts and a review group of animal health and food safety policy advisors via five case studies of potential emerging diseases of cattle. Tasks for model validation included describing the path taken in the algorithm and stating an outcome. Twenty-nine per cent of the 62 experts commented on the model, and one-third of those responding also completed the tasks required for model validation. The feedback from the panel of experts and the review group was used to further develop the tool and remove redundancies and ambiguities. There was agreement in the pathways and assessments for diseases in which the causative agent was well understood (for example, bovine pneumonia due to Mycoplasma bovis). The stated pathways and assessments of other diseases (for example, bovine Johne's disease) were not as consistent. The framework helps to promote objectivity by requiring questions to be answered sequentially and providing the opportunity to record consensus or differences of opinion. Areas for discussion and future investigation are highlighted by the points of diversion on the pathway taken by different assessors.     

乳品质量安全法律监管的问题及对策——从麦趣尔“丙二醇”事件切入

法律监管是乳品质量安全的重要防线。麦趣尔集团股份有限公司超范围使用“丙二醇”添加剂事件,再一次凸显了乳品质量安全法律监管问题的严峻性,揭示了我国乳品质量安全法律监管体系存在缺陷、机制存在漏洞、警示效果甚微的问题。这些问题出现的原因在于法律监管意识不强、部门协调性差以及监管手段不完善。通过健全乳品质量安全法律监管体系、加强乳品企业合规建设、提高消费者乳品质量安全意识,能够实现乳品质量安全监管的法治化、现代化以及体系化。     

Implications of Preslaughter Feeding Cues for Broiler Behavior and Carcass Quality

Feed withdrawal management has significant effects on contamination of commercial broiler chickens. The effect of a cue (short period of feed withdrawal) on broiler behavior, carcass yield, and carcass quality (carcass scratches, trimming, condemnations, and fecal contamination) was evaluated using 2,400 female broilers. Cues were applied for 3 consecutive days prior to slaughter by lifting the feeders in each pen for 0, 1, 2, or 4 h. Bird behavior was monitored to determine the effect of the cue on feeding patterns. The effect of the cue on carcass yield and quality (carcass scratches, trimming, condemnations, and internal contamination) at the time of processing was determined.Cueing for 1 (CUE1), 2 (CUE2), and 4 (CUE4) h resulted in an increase in activity at the feeders compared with the control treatment (CUE0); higher activity resulted from longer cues. During the cue, live BW loss was greatest in the CUE4 treatment at 24.8 g. Birds in the CUE1 treatment gained 11.3 g during application of the cue. Uniformity of cecal contents was improved in the CUE4 treatment. No differences in carcass yield among cueing treatments were observed. The incidence of new scratches, a possible entry point for cellulitis infections, was lowest in the CUE0 and CUE4 treatments. Contamination scores were highest in the CUE1 treatment and lowest in the CUE0 and CUE4 treatments.The data suggest that feeding cues of up to 4 h may be used without compromising processing yield or carcass quality. Benefits may be limited to improved uniformity of cecal emptying.     

Risk for interspecies transmission of zoonotic pathogens during poultry processing and pork production in Peru: A qualitative study

Interspecies transmission of pathogens is an unfrequent but naturally occurring event and human activities may favour opportunities not previously reported. Reassortment of zoonotic pathogens like influenza A virus can result from these activities. Recently, swine and birds have played a central role as “mixing vessels” for epidemic and pandemic events related to strains like H1N1 and H5N1. Unsafe practices in poultry markets and swine farms can lead to interspecies transmission, favouring the emergence of novel strains. Thus, understanding practices that lead to interspecies interactions is crucial. This qualitative study aimed to evaluate poultry processing practices in formal and informal markets and the use of leftovers by swine farmers in three Peruvian cities: Lima (capital), Tumbes (coastal) and Tarapoto (jungle). We conducted 80 direct observations at formal and informal markets and interviewed 15 swine farmers. Processors slaughter and pluck chickens and vendors and/or processors eviscerate chickens. Food safety and hygiene practices were suboptimal or absent, although some heterogeneity was observed between cities and chicken vendors versus processors. Both vendors (76%) and processors (100%) sold the chicken viscera leftovers to swine farmers, representing the main source of chicken viscera for swine farms (53%). Swine farmers fed the chicken viscera to their swine. Chicken viscera cooking times varied widely and were insufficient in some cases. Non‐abattoired poultry leads to the sale of poultry leftovers to small‐scale swine farms, resulting in indirect but frequent interspecies contacts that can lead to interspecies transmission of bacterial pathogens or the reassortment of influenza A viruses. These interactions are exacerbated by suboptimal safety and hygiene conditions. People involved in these activities constitute an at‐risk population who could play a central role in preventing the transmission of pathogens between species. Educational interventions on hygiene and food safety practices will be important for reducing the risk of interspecies influenza transmission.