Most of the eggs for consumption are produced in a conventional housing system although the demand for organic eggs is increasing because consumers assume better nutritional characteristics. This study was conducted to compare the quality of organic eggs and enriched cage eggs. A total of 409 organic eggs and 385 eggs from hens housed in enriched cages were directly collected from 15 different farms, located in Spain and were analyzed within 4 days after laying. The differences in quality by removing the time bias that can be caused by marketing time were thus determined. All the hens were of three different lines, 47–50 weeks old and consumed commercial feed with the same nutritional composition. The quality traits evaluated were egg weight (EW g), egg shape index (SI), shell thickness (ST), shell percentage (SP), Haugh units (HU), dense albumen percentage (DAP), total albumen percentage (TAP), yolk color (YC), yolk percentage (YP), Roche scale (RS), moisture (M), ash content (AC), total protein (TP), total yolk carotenoids (TYC), total fat (TF), saturated fatty acids (SFA), monounsaturated fatty acids (MFA), and polyunsaturated fatty acids (PFA). Estimates of differences were obtained by generalized least squares using housing system, genetic line and their interaction as factors. Significant differences were observed for EW (65.3 vs 62.9), SI (77.60 vs 76.10), HU (83.60 vs 81.80), TAP (66.5 vs 64.17), YC (3.11 vs 1.89), RS (11.79 vs 9.48), TP (9.99 vs 8.55), TYC (4.188 vs 2.650), SFA (32.20 vs 30.00) and MFA (53.40 vs 44.20) in favor of the enriched cage system. In the organic system, the quality parameters that had higher and significant values were ST (0.34 vs 0.32), SP (10.52 vs 9.41), YP (25.20 vs 24.30), AC (1.12 vs 0.93) and PFA (26.00 vs 14.00). Significant interactions between the housing system and the hen line followed the same pattern observed for fixed effects. Organic eggs were lighter, less rounded with better shell quality and therefore showed lower Haugh unit values and a lower albumen percentage. Total protein, total fat, and lipid profile were within the usual average values for commercial eggs, although the proportion of polyunsaturated fatty acids, which are beneficial for consumers, was higher in organic eggs.

Calcium content in the diet can affect egg quality and production in aged birds. Calcium pidolate is a new form of calcium supplementation in poultry diets, which favours the absorption of this mineral. The current study was conducted to evaluate the effect of dietary calcium pidolate concentration in the diets of aged laying Japanese quails. A total of 120 female quails (27 weeks old) were assigned to four treatment groups, each with six replicates of five quails per pen. In the 10-week trial, quail diets were supplemented with calcium pidolate at four concentrations (0, 0.25, 0.50 and 1.00 g/kg), providing 25.1, 25.4, 25.8 and 26.5 g/kg calcium, respectively. As a result of this study, body weight, feed intake and feed conversion ratio did not change with the concentration of calcium pidolate (P > 0.05). In contrast, albumen and yolk index decreased as calcium pidolate level increased (P < 0.05). Moreover, calcium pidolate at a concentration of 0.50 g/kg resulted in the greatest egg production, eggshell breaking strength and eggshell thickness (P < 0.05), while above these levels the factors studied were negatively affected. According to these results, the optimal concentration of calcium pidolate in the diets of aged laying quails was 0.50 g/kg.

Low and variable egg quality remains a major issue in aquaculture impeding a reliable and continuous supply of larvae, particularly in emerging species, such as pikeperch, Sander lucioperca. We assessed the influence of batch-specific egg parameters (fatty acid (FA) profiles, cortisol content) on embryo life-stages until hatching (survival at 2, 24, 48, 72 h post fertilization (hpf), hatching rate) in an integrated study under commercial hatchery conditions (44 egg batches). Embryo mortality was elevated until 48 hpf (average 9.8% mortality between 2 and 48 hpf). Embryos surviving until 48 hpf were very likely (98.5%) to hatch successfully. The inherent egg FA composition was variable in-between batches. Total FA content ranged form 66.1 to 171.7 µg/mg (dry matter) total FA. Whereas specific FA ,18 : 0 and 20 : 5(n-3) (eicosapentaenoic acid) of the polar fraction and the ratio of 22 : 6(n-3) (docosahexaenoic acid) to 20 : 5(n-3) within the neutral fraction, were significantly correlated with early embryo development, contents of the respective FA did not differ between high (>90% hatching rate), mid (70% to 90% hatching rate) and low (<70% hatching rate) quality egg batches. Late embryo development and hatching were relatively independent of the FA profiles highlighting stage-dependent influences especially during early embryogenesis. Cortisol levels ranged from 22.7 to 293.2 ng/ml and did not directly explain for mortalities. However, high cortisol was associated with a lower content of specific FA, in particular highly unsaturated FA. These results demonstrate the magnitude of inter-individual differences in the batch-specific biochemical egg composition under stable hatchery conditions and suggest a stress-mediated lack of essential FA, which in turn affects early embryo survival. Surprisingly, embryos are able to cope well with a broad range of inherent egg parameters, which limits their predictive potential for egg quality in general. Still, specific FA profiles of high quality egg batches have potential for formulating species-specific broodstock diets and improving reproductive management in pikeperch.

The fruit of Ligustrum lucidum (FLL, Nuzhenzi in Chinese) is an important traditional medicine, and have attracted significant research attention because of their various biological activities. However, there are few research reports available on the use of FLL as a feed additive in livestock nutrition, particularly in layers. This study was conducted to determine the effects of supplementation of the diet of laying hens with FLL on laying performance, egg quality and blood metabolites. A total of 360 72-week-old hens were allocated to three dietary treatments (eight replications of 15 hens/treatment group) and were fed either a control diet or a diet supplemented with an inclusion level of 0.25% or 0.50% of FLL powder in the final feed, until 78 weeks of age. Hens were housed in a three-tier cage system. Feed and water were provided ad libitum. Blood samples and eggs were collected at the end of the experiment. The results showed that dietary supplementation with FLL did not affect egg weight, feed conversion ratio, eggshell thickness, albumen height, egg yolk color, eggshell breaking strength or egg shape index. However, FLL supplementation significantly decreased (P<0.001) mortality, cracked-egg rate and blood serum levels of cholesterol, low-density lipoprotein cholesterol, triglycerides and alanine aminotransferase, and increased (P<0.001) blood serum levels of high-density lipoprotein cholesterol. No differences in serum levels of total protein, albumin, glucose, calcium, aspartate aminotransferase or alkaline phosphatase were observed in hens fed FLL compared with the control group. It can be concluded that FLL, at a supplementation level of 0.25% final feed, can be used as an effective feed additive to improve the performance of laying hens during the late laying period.

Since 2006, when the European Union imposed a total ban on the use of antibiotic growth promoters, scientific interest has focused on natural feed additives that might be positive to both production performance and animal health. Inulin is a prebiotic, which occurs naturally in many plants as a storage material. The specific structure of inulin underlies the fact that it is not digested by the host digestive enzymes. Unchanged, the prebiotic reaches the large intestine, where it undergoes fermentation and becomes a substrate for some strains of healthy bacteria. Current literature contains information on the effects of inulin on broiler performance and laying performance of hens. It may be concluded from data available that inulin is beneficial in the production of poultry meat and eggs. Inulin may improve feed intake and conversion, stimulate weight gains, strengthen the skeletal system, improve carcass yields and the production and quality of eggs. However, reports on the subject are scarce, and the results they present vary substantially. The mode of action of inulin appears to be complex, multidirectional and is not yet fully understood. The ambiguous character of inulin may result from the fact that its effectiveness in poultry nutrition depends on a number of factors. Despite these unresolved issues, the positive properties of inulin may be of benefit to the poultry industry.

Flaxseed is a rich source of α-linolenic acid and phytoestrogens, mainly lignans, whose metabolites (enterodiol and enterolactone) can affect estrogen functions. The present study evaluated the influence of dietary flaxseed supplementation on reproductive performance and egg characteristics (fatty acids, cholesterol, lignans and isoflavones) of 40 Hy-Line hens (20/group) fed for 23 weeks a control diet or the same diet supplemented with 10% of extruded flaxseed. The flaxseed diet had approximately three times the content of lignans (2608.54 ng/g) as the control diet, mainly secoisolariciresinol diglucoside (1534.24 v. 494.72 ng/g). When compared with the control group, hens fed flaxseed showed a similar deposition rate (72.0% v. 73.9%) and egg yield. Furthermore, there was no effect of flaxseed on the main chemical composition of the egg and on its cholesterol content. Estradiol was higher in the plasma of the control group (1419.00 v. 1077.01 pg/ml) probably due to the effect of flaxseed on phytoestrogen metabolites. The plasma lignans were higher in hens fed flaxseed, whereas isoflavones were lower, mainly due to the lower equol value (50.52 v. 71.01 ng/ml). A similar trend was shown in eggs: the flaxseed group had higher level of enterodiol and enterolactone, whereas the equol was lower (198.31 v. 142.02 ng/g yolk). Secoisolariciresinol was the main lignan in eggs of the flaxseed group and its concentration was three times higher then control eggs. Flaxseed also improved the n-3 long-chain polyunsaturated fatty acids of eggs (3.25 v. 0.92 mg/g egg), mainly DHA, however, its oxidative status (thiobarbituric reactive substances) was negatively affected. In conclusion, 10% dietary flaxseed did not affect the productive performance of hens or the yolk cholesterol concentration, whereas the lignans and n-3 polyunsaturated fatty acid content of eggs improved. Further details on the competition between the different dietary phytoestrogens and their metabolites (estrogen, equol, enterodiol and enterolactone) should be investigated.

Exposure of laying hens to chronic heat stress results in loss of egg production. It should be possible to improve hen resilience to chronic heat stress by genetic selection but measuring their sensitivity through internal temperature is time consuming and is not very precise. In this study we used infrared thermography to measure the hen’s capacity to dissipate heat, in a commercial line of laying hens subjected to cycles of neutral (N, 19.6°C) or high (H, 28.4°C) ambient temperatures. Mean body temperatures (BT) were estimated from 9355 infrared images of wing, comb and shank taken from 1200 hens. Genetic parameters were estimated separately for N and H temperatures. Correlations between BT and plumage condition were also investigated. Wing temperature had low heritability (0.00 to 0.09), consistent with the fact that wing temperature mainly reflects the environmental temperature and is not a zone of heat dissipation. The heritability of comb temperature was higher, from 0.15 to 0.19 in N and H conditions, respectively. Finally, the shank temperature provided the highest heritability estimates, with values of 0.20 to 0.22 in H and N conditions, respectively. Taken together, these results show that heat dissipation is partly under genetic control. Interestingly, the genetic correlation between plumage condition and shank and comb temperatures indicated that birds with poor condition plumage also had the possibility to dissipate heat through featherless areas. Genetic correlations of temperature measurements with egg quality showed that temperatures were correlated with egg width and weight, yolk brightness and yellowness and Haugh units only under H conditions. In contrast, shell colour was correlated with leg temperature only at thermo-neutrality.

The objective of the present study was to investigate the effect of feeding two transgenic corn lines containing the mCry1Ac gene from Bacillus thuringiensis strain (BT-799) and the maroACC gene from Agrobacterium tumefaciens strain (CC-2), respectively, on growth, egg quality and organ health indicators. Expression of the mCry1Ac gene confers resistance to Pyrausta nubilalis and the maroACC gene confers tolerance to herbicides. Healthy hens (n=96 placed in cages; 3 hens/cage) were randomly assigned to one of four corn–soybean meal dietary treatments (8 cages/treatment) formulated with the following corn: non-transgenic near-isoline control corn (control), BT-799 corn, CC-2 corn and commercially available non-transgenic reference corn (reference). The experiment was divided into three 4-week phases (week 1 to 4, week 5 to 8 and week 9 to 12), during which hens were fed mash diets. Performance (BW, feed intake and egg production) and egg quality were determined. Following slaughter at the end of 12 weeks of feeding (n=8/treatment), carcass yield and organ weights (heart, liver, spleen, lung, kidneys, stomach and ovary) were recorded; organs and intestines were sampled for histological analysis. Analysis of serum biochemistry parameters to assess the liver and kidney function were performed. No differences in BW, egg production and production efficiency were observed between hens consuming the control diet and hens consuming the BT-799 or CC-2 diet. Haugh unit measures and egg component weights were similar between the control and test groups. Carcass yield was not affected by the diet treatment. Similar organosomatic indices and serum parameters did not indicate the characteristics of organ dysfunction. All observed values of the BT-799 and CC-2 groups were within the calculated tolerance intervals. This research indicates that the performance, egg quality, organ health and carcass yield of laying hens fed diets containing the BT-799 or CC-2 corn line were similar to that of laying hens fed diets formulated with the non-transgenic near-isoline corn with comparable genetic backgrounds.

The objective of this experiment was to replace soya bean oil with glycerol in laying hen diets and assess the change’s effect on performance, parameters of egg quality and the egg fatty acid profile. A total of 60 44-week-old Hy-Line W36 laying hens were distributed according to a completely randomised experimental design into four treatments consisting of glycerol substitutions for soya bean oil dietary at varying inclusion levels (0%, 25%, 50% and 75%), with five replicates of three birds each. Dietary treatments had no significant effect on BW change, egg production, feed intake, feed conversion ratio, egg weight and egg mass of laying hens. The inclusion of glycerol in the diet of laying hens had no significant effect on egg specific gravity, eggshell breaking strength, eggshell weight, eggshell thickness, egg shape index, albumen index, yolk index, haugh unit, albumen pH, yolk pH and egg yolk colour values. The inclusion of glycerol in the diet of laying hens had no significant effect on palmitic, palmitoleic, stearic, oleic and linolenic acid contents of the egg yolk. The linoleic acid and polyunsaturated fatty acid contents of the egg yolk significantly decreased with the higher levels of dietary glycerol supplementation (P<0.05). The results of this study show that it is possible to replace 75% of soya bean oil (4.5% in diet) with glycerol.

Nutrients such as minerals and vitamin D have clear roles in skeletal metabolism. Boron (B) has been examined as a possible essential nutrient in the metabolism and utilisation of several micro nutrients and hence could have an influence on bone mineral density and eggshell quality. However, there have been few direct studies to examine the dietary response to B in chicken and layer hen models, although there is evidence that both compositional and functional properties of bone are affected by dietary boron status in other model animals and humans. Bone integrity, skeletal problems in chickens and eggshell quality in laying hens are important economic, welfare and health issues for the poultry industry. Therefore, better understanding of certain role of B on mineral availability in chickens and layer hens is important to enhance productivity and improve animal welfare. The following review examines the published data relating to these aspects of B in poultry feed.

Improper activation and swelling of in vitro produced eggs of European eel, Anguilla anguilla, has been shown to negatively affect embryonic development and hatching. We investigated this phenomenon by examining the effects of salinity and sea salt type on egg dimensions, cell cleavage patterns and egg buoyancy. Egg diameter after activation, using natural seawater adjusted to different salinities, varied among female eels, but no consistent pattern emerged. Activation salinities between 30–40 practical salinity unit (psu) produced higher quality eggs and generally larger egg diameters. Chorion diameters reached maximal values of 1642 ± 8 μm at 35 psu. A positive relationship was found between egg neutral buoyancy and activation salinity. Nine salt types were investigated as activation and incubation media. Five of these types induced a substantial perivitelline space (PVS), leading to large egg sizes, while the remaining four salt types resulted in smaller eggs. All salt types except NaCl treatments led to high fertilization rates and had no effect on fertilization success as well as egg neutral buoyancies at 7 h post-fertilization. The study points to the importance of considering ionic composition of the media when rearing fish eggs and further studies are encouraged.

Coastal and rural parts of Odisha are home to indigenous ducks, which are mostly reared for meat and egg production. Cross performance of the indigenous duck with exotic breeds, along with the suitability of crossbreeds for commercial rearing in the region are highlighted in this review paper. The crossbreeds perform comparatively better for most economic traits compared to the indigenous duck. The cross of the indigenous duck (male) with the Khaki Campbell (female) perform better in respect to different growth and production traits. Indigenous ducks in combination with White Pekin perform better in respect to juvenile growth, carcass quality and egg production. Most of the economic traits have showed desirable heterosis in crossbreds. The performance of indigenous ducks kept under free range conditions, molecular characteristics, mortality pattern and disease incidence, nutritional, and haematological studies are included in this review.

Laying hen rearing systems have been the focus of scientific research for many years. Over the last few decades, new laying hen rearing systems have been rapidly introduced in an effort to harmonise poultry health and welfare with consumer, producer, industry and environmental demands. Given the above situation, the subject matter of this paper was a comparative review of the results obtained by different authors on the effect of rearing system on productive traits (egg production and mortality) and egg quality characteristics (egg weight, proportions of main egg parts, Haugh units, yolk colour and carotenoids) in laying hens. Although productive performance in alternative systems is often lower compared to conventional, intensive layers, eggs from alternative systems have been proven in numerous studies to have better nutritional properties. Moreover, research results indicate differences within rearing systems. In view of this, this overview of the literature on the use of different rearing systems in table egg production can serve as a tool in determining the future direction of research as well as an indicator of its practical application.

Thirty-seven layer performance tests have been conducted at North Carolina State University during the past 53 years. Originally established as the North Carolina Random Sample Layer Test (NCRSLT), all of the test flocks have been hatched and housed at the Poultry Unit of the North Carolina Department of Agriculture and Consumer Service's Piedmont Research Station at Salisbury, North Carolina. In 1988, the NCRSLT name was changed to the North Carolina Layer Performance and Management Test (NCLP&MT) reflecting changes in the testing procedures to include the evaluation of management practices used by commercial egg producers. Strain testing and evaluating the relative egg production of commercially available egg production stocks began in 1911, and the number of such Random Sample Tests in North America peaked at 23 in approximately 1968. The mission for the NCRSLT to provide an unbiased evaluation of the overall performance of strains, evolved to include the effects of various housing and husbandry practices on the performance of the genetic stocks entered into the test. Test results have been distributed to the industry throughout the USA as well as to producers in 22 other countries throughout the world. In addition, the internet site for the NCLP&MT http://poultry.ces.ncsu.edu/layer-performance/ allows the distribution of the results to many other interested university and government officials. This review of the first 37 North Carolina layer tests shows continuing improvements in egg production, reduction in body weight and feed consumption, increases in egg weight and feed conversion, improvements in liveability, and an improvement in egg quality from the commercially available white and brown egg strains. These changes have continued throughout the 50+ year history of the tests, and the changes observed have been brought about primarily by poultry breeding companies applying quantitative genetics for the improvement of the layer stocks used worldwide.

The hen's egg, in the form of table eggs and egg products, forms a staple part of the world's total protein consumption. In the last century, there has been considerable research effort focusing on ways of improving egg production and enhancing the quality of eggs. More recently, and with the development and application of new molecular technologies, our understanding and knowledge of how an egg is formed, what it actually consists of, in terms of its major versus minor components, and what the functional roles of each of these components might be, have been greatly enhanced. For example, new previously unknown molecules with specific activity or functional properties have been discovered in the egg albumen and yolk, some of which have potential uses in pharmaceutical and other food related applications. This review paper, which is the collaborative effort of members of Working Group 4 - Quality of Eggs and Egg Products - of the European Federation of WPSA, describes the scientific research behind a number of these major advances and provides some insight to the focus of current research in this area.

Adding value to eggs, being a very old concept in foods, is practiced for supplementing nutritive values along with provision for ease of handling too. Some of the value-added egg products include tea/century eggs (for extended shelf life of egg products); low cholesterol eggs (preferred by health conscious customers); and ‘super’ eggs produced through use of either herbal supplements, inclusion of drugs, manipulation of dietary protein and energy content, poly unsaturated fatty acids (PUFA), or additional vitamins and minerals in the poultry diet. These are considered helpful in reducing the risk of heart diseases and in some cancerous conditions.

However, the focus of this review is to concentrate on the production of salted eggs and the process of brining. Sales of salted eggs have been quite encouraging for on its own merits. People in many parts of the globe, prepare and market salted eggs as part of their preservative/extra value but very little scientific information has been available regarding the standardised brining technology and storage quality of salted chicken eggs. Apart from this, no information has been available on the hatching performance of salted eggs, subsequent growth performance of progeny, broiler chick quality and their immune-competence against disease. In view of the requirement for information, it was deemed imperative to consolidate the relevant information to determine future research needs.

In this study, laying hen welfare is taken into account as part of an overall ‘egg safety and quality concept’. A holistic approach is adopted that encompasses the whole food chain in which responsibility for the production of safe and high quality eggs is shared along the entire food chain. Scientific data on egg quality traits in relation to laying hen welfare in different housing systems are presented. Public concern to improve laying hen welfare and egg quality is widely discussed, partly because it is an area of potential added value for producers, retailers, processors, manufacturers, producer cooperatives. Legislation and legal requirements for the labelling of eggs are described in order to demonstrate the ability to provide sound and scientifically based information on the welfare status of laying hens used to supply particular eggs. The study concludes by highlighting achievements and future aspects on the relationship between hens’ welfare and egg quality.

An adequate supply of all nutrients, including proteins, fats, carbohydrates, vitamins, minerals and water, has to be provided to support maximum productivity of laying hens. Among these nutrients, vitamins are particularly important, since they are essential for optimum health as well as normal physiological functions of the hens. As most vitamins cannot be synthesized by poultry in sufficient amounts to meet physiological demand, they must be obtained from the diet. The absence from feed or impaired absorption or utilization of vitamins can lead to specific deficiency disorders. This review reports on the occurrence and the physiological functions of all vitamins and summarizes research related to the requirements for and the beneficial effects of supplemental vitamins for laying hens. The recommendations for dietary supplementation of vitamins from various organizations are compared and put into perspective of modern poultry genotypes and current husbandry conditions. As there is good evidence that the minimum dietary vitamin levels, required to prevent clinical deficiencies may not support optimum health, performance and welfare of poultry under today's conditions it is recommended to include a safety margin to the vitamin requirements of laying hens.

Except for conventional cages, the most common housing systems for laying hens comprise deep litter, aviaries and more recently furnished cages. Layers in floor systems may also include out-door keeping. Furnished cages will be the only legal form of cages in the EU from 2012 (1999 EU-directive) but have as yet only been installed in significant numbers in Sweden and partly in Norway, Germany and Great Britain. Climate, feed, bird genotype, group size as well as the legal possibility to beak trim or to use certain medical treatments (mainly against endo- and ectoparasites) or not, are all conditions affecting results with different housing systems in different countries. Offering benefits to the bird as regards increase in behavioural repertoire as well as providing more space, all alternatives to conventional cages, require new orspecial knowledge of management. This is due to the fact that these systems often include higher potential risks in production and health of layers. This especially applies to non-cage systems (Petermann, 2003). The main issues to control in largergroup floorhousing are parasitic disorders, outbreak and spreading of cannibalistic pecking, increased feed intake, misplaced eggs, catching of spent hens and airquality (dust and ammonia levels). Many management practices to reduce some of these risks have been presented including rearing method, medication, vaccination, light intensity, genotype, feed composition, beak trimming and – for improved air quality – the use of spraying/fogging with water or oil as well as more frequent manure removal at closerintervals have been practised. Coming in a wide range of models and group sizes, the furnished cages attempt to combine the benefits and reduce the disadvantages of floorkeeping and conventional cages. The most developed models of furnished cages provide similar production results to conventional cages. However, differences still exists e.g. in egg quality traits between models. Design and location of nests, perches and litter are all important factors.

In conclusion, future trends in investments forhousing system in egg production will have to take into account several factors apart from the degree of success from technical development of each system. These will probably involve national directives regarding beak trimming, stocking densities, directives of withdrawal times of medication and occupational safety on one side and national markets and trades fordifferent categories of eggs on the other.

Due to the increasing throughput of modern egg grading machines, which grade up to 120 000 eggs per hour, the visual inspection of eggs by humans (“candling”), becomes a critical bottleneck in the egg sorting chain. In order to assure a high and consistent egg quality, researchers investigated the use of modern sensor technologies to replace the candling operation. During the last decades, several types of sensors were developed, and it is believed that these sensors will replace human candling in the near future. A first class of sensors is based on mechanical techniques and allows investigation of the physical shell quality, such as the presence of cracks and shell strength. A second class is based upon spectroscopic principles and allows the operator to “see” through the egg shell in order to determine the internal quality of the eggs, such as albumen pH and viscosity and the presence of inclusions such as blood and meat spots. A third class of sensors aims at mimicking the human eye by means of a camera and a software platform (“computer vision”). Besides these types of sensors, some others based on ultrasonic, magnetic resonance and electronic nose principles are investigated and discussed. This paper gives an overview of these modern sensor technologies for egg grading.