Changes In Egg Quality Research Articles

Differential Investment in Eggs by Arctic-breeding Glaucous Gulls (Larus hyperboreus) Exposed to Persistent Organic Pollutants

Abstract.— Although egg size is a widely studied life-history trait in evolutionary ecology, it is largely unknown whether exposure to persistent organic pollutants (POPs) can influence the allocation of resources to avian eggs and, if so, how. It is well established that female birds exposed to POPs transfer these compounds to their eggs. However, little is documented with regard to contaminant-related changes in egg quality, such as egg mass, albumen mass, yolk mass, lipid, and water content. We report positive correlations between the concentrations of several major classes of POPs (organochlorines, brominated flame-retardants, and metabolically derived products) in plasma of Arctic-breeding Glaucous Gulls (Larus hyperboreus) and in the yolk of the last-laid egg of their clutches. The contributions of the different POP classes to the summed POP concentration were also positively correlated between female plasma and egg yolk. In addition, Glaucous Gulls with a relatively high concentration of sum (Σ) ch...

Edible Coatings for Enhancing Microbial Safety and Extending Shelf Life of Hard‐Boiled Eggs

Hard-boiled eggs were coated with chitosan-lysozyme (CL), whey protein isolate (WPI), or Bake sheen (BS), inoculated with Listeria monocytogenes or Salmonella enterica Ser. Enteritidis at 10(4) CFU/g, and stored for 4 wk at 10 degrees C. Microbial populations were enumerated weekly. Two nonchallenge studies were also conducted with hard-boiled eggs: coated shell-on eggs packaged in plastic containers or peeled eggs coated and vacuum-packaged. Total plate counts (TPC), coliforms, yeasts, molds, weight loss, pH, and color of eggs were determined during the 10-wk storage at 10 degrees C. Uncoated eggs served as controls. All the coatings were not effective in inhibiting the growth of L. monocytogenes, but CL coating controlled the growth of S. Enteritidis. At the end of 4-wk storage, the numbers of S. enteritidis on CL-coated eggs were about 4-log(10) CFU/g less than that of the controls. Coatings reduced (P < 0.05) the populations of coliforms and TPC, and completely inhibited mold growth during the 10-wk storage. Coatings also reduced (P < 0.05) the weight loss of eggs, 4.1% to 4.8% on coated eggs compared with 7.5% in uncoated ones at the end of 10-wk storage. The pH of CL-coated eggs remained stable throughout the storage period, while the control eggs increased from 7.6 to 8.6. Color changes in CL- and WPI-coated eggshells were less (P < 0.05) than those of BS-coated and the control. The CL coating effectively suppressed the numbers of TPC, coliforms, yeasts, and molds on peeled eggs during the 6-wk storage (P < 0.05). The results suggest that CL coating on hard-boiled eggs can control the growth of S. Enteritidis and reduce undesirable changes in the interior quality of eggs.

The effects of conjugated linoleic acid (CLA) and canola oil on the fatty acid composition and quality of eggs from laying hens

Dietary conjugated linoleic acid (CLA) causes adverse effects on quality of eggs by modifying the fatty acid composition of the yolk. Supplementing oils prevent CLA-induced changes, but cause a decrease in the level of egg CLA. The objective of the study was to investigate the incorporation of CLA into the egg and its effect on the fatty acid metabolism when laying hens were fed diets containing different levels of canola oil. Hens (15 per group) were assigned to six groups and were fed for 50 days diets containing 0.5% canola oil (Group A), 0.5% CLA (Group B), 0.5% CLA plus 1.25% canola oil (Group C), 0.5% CLA plus 2.5% canola oil (Group D), 0.5% CLA plus 5% canola oil (Group E) or 0.5% CLA plus 10% canola oil. Eggs were collected daily. Three eggs per group were used for fatty acid analysis. Eggs laid on days 1 to11 were stored at 4 °C or room temperature for 30 days, and were separated into yolk and albumen for pH analyses. Yolk from Group B had increased concentrations of C16:0 and C18:0 and decreased concentrations of C18:1(n-9) compared to Group A. Adding 5% or 10% canola oil (Groups E or F) to the diet prevented an increase in C16:0 and C18:0 and a decrease in C18:1(n-9) concentrations. Relative amounts of CLA in eggs from Groups A, B, C, D, E and F were 0, 2.38, 2.33, 1.68, 1.36, and 1.17%, respectively. The concentrations of C18:3(n-3) in Groups A, B, C, D, E and F were 0.23, 0.25, 0.61, 0.70, 1.23 and 1.58%, respectively. The ratios of UFA/SFA in the eggs from Groups B, C and D decreased. When the eggs were stored at 4 °C, the yolk from Groups B, C and D had higher pH values than the other treatments, while the albumen pH of eggs from Groups B, C and D were lower. However, when eggs were stored at room temperature, no abnormal pH changes were observed in the yolk or albumen. This study suggested that adding a certain level of canola oil rich in n-3 fatty acids restored the level of egg yolk SFA to UFA, prevented CLA-induced abnormal changes in egg quality and thus led to a higher level of C18:3(n-3) and CLA in the egg. Keywords : Conjugated linoleic acid; unsaturated fatty acids; egg yolk and albumen pH; chickens South African Journal of Animal Sciences Vol. 35 (3) 2005: pp.172-179

Oogenesis and relevant changes in egg quality of abalone Haliotis discus hannai during a single spawning season

Oogenesis of abalone Haliotis discus hannai was examined histologically during a single spawning season using broodstock of various maturation conditions, which were controlled by effective accumulative temperature (EAT). The quality of eggs spawned was determined in relation to oogenesis. For histological examinations, three to five females were sacrificed at 300, 600, 850, 1050, and 1150 °C days EAT, without induction of artificial spawning. Other females were successfully induced to spawn at 700 °C days EAT and were reared following spawning. Three of these females were then sacrificed every 200 °C days EAT until 1300 °C days EAT. Gonad histology showed that two oocyte cohorts matured in H. discus hannai ovaries during a single spawning season. One mature oocyte cohort could be spawned in multiple times. The second oocyte cohort started developing after the first oocyte cohort had been spawned or reabsorbed, and became fully mature 400 °C days EAT after the first cohort was depleted. For egg quality measurements, three to five females were successfully induced to spawn at 850, 1050, 1150, 1900, and 2350 °C days EAT (Experiment 1). Three females were induced to spawn twice, at 700 and 1500 °C days EAT, resulting in two batches of eggs from the same individuals (Experiment 2). Total lipid and protein content of eggs were measured and were greater in eggs from the second cohort than in eggs from the first cohort. No carbohydrates were detected in eggs and there was no difference in cytoplasm volume between the two cohorts. In hatcheries producing H. discus hannai, it is important to increase post-larval starvation tolerance by increasing the quality of eggs, to yield higher and more consistent survival. The results of this study suggest that H. discus hannai hatcheries should use eggs from the second oocyte cohort, which are of higher quality, rather than eggs from the first oocyte cohort.

The Influence of Conjugated Linoleic Acid Enriched Tallow on Egg Hatchability and Quality in Chicken

Dietary conjugated linoleic acid (CLA) was shown to increase the level of saturated fatty acids in egg yolk, alter interior egg quality, and induce embryo mortality in fertile eggs. Since CLA may soon be used as an animal feed supplement, the objective of this study was to determine if feeding chickens tallow from beef cattle fed a CLA-supplemented diet would induce embryo mortality and cause changes in egg quality. Single Comb White Leghorn laying hens (10 per treatment) were fed a diet containing 0.5% canola oil (CO), 0.5% CLA (CLA), 10% regular tallow (RT), 9.5% regular tallow plus 0.5% CLA (RT+CLA), 10% tallow from beef cattle fed 1% CLA (TCLA1), or 10% tallow from beef cattle fed 2.5% CLA (TCLA2.5) for 18 d. For hatchability studies, hens were artificially inseminated weekly. Eggs were collected daily, stored at 15EC for 24 h, and then incubated. Twenty eggs per treatment were stored at 4EC for 30 d and analyzed for pH. After 18 d of feeding, 3 hens per group were euthanized with carbon dioxide exposure and liver and adipose tissue samples were obtained. Fat from yolk, liver and adipose tissue were extracted for fatty acid analysis. After the 8th d of feeding, embryo mortality was 100% in CLA group versus 7, 9, 5, 6, and 7% in CO, RT, RT+CLA, TCLA1, and TCLA2.5, respectively. Relative CLA levels (% of fatty acids) of yolk from CO, CLA, RT, RT+CLA, TCLA1, and TCLA2.5 were 0, 2.31, 0.99, 1.67, 1.18, and 1.35%, respectively. Diets containing CLA and RT+CLA resulted in increased C16:0 and C18:0 and decreased C16:1(n-7) and C18:1(n-9) in the egg yolk. The CLA but not TCLA1 or TCLA2.5 diet resulted in decreased levels of C20:4(n-6) in yolk and liver compared to CO. Yolk pH increased and albumen pH decreased in the eggs from the CLA relative to CO (8.09 and 8.63 versus 6.13 and 9.04, respectively). Abnormal pH changes did not develop in the eggs from CO, RT, RT+CLA, TCLA1 and TCLA2.5. These results showed that tallow from beef cattle fed CLA or tallow supplemented with CLA had no adverse effects on hatchability and egg quality.

Determining storage related egg quality changes via digital image analysis

The present study was carried out to determine some egg quality characteristics and storage related changes using computer assisted digital image analysis (CADIA) in an 18-month old moulted brown layer (Lohmann Brown) flock. A total of 150 newly laid eggs was randomly divided into two groups: eggs from the control group were broken immediately, while the remainder were stored at 18 o C and 55% RH for seven days. Area and length measurements related to exterior and interior egg quality were determined by digital image analysis. In general, excluding the outer thin albumen area, all of the area measurements such as total egg content area and inner thick albumen area were larger in stored eggs than in fresh eggs (52.28 vs. 49.37 cm 2 , 114.36 vs. 137.13 cm 2 , and 62.08 vs. 87.76 cm 2 , respectively). Phenotypic correlations between some exterior and interior egg quality characteristics were also determined. Key Words: Egg quality, Moulted brown layer, Storage, Digital image analysis SA Jnl Animal Sci Vol.34(2) 2004: 70-74

Nutritional and physiological effects of flax seed in diets for laying fowl

Dietary flax seed may prove to be a key feed ingredient in establishing the egg as a food useful for promoting cardiovascular health in humans. Yolk linolenic acid (LNA; 18:3n-3) increases in a linear fashion in response to graded levels of ground flax seed and whole flax seed if grit is provided in the feed to promote in vivo seed grinding. In contrast, the metabolic derivatives of LNA, eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), are deposited only in limited amounts regardless of the level or form of flax seed fed. The distribution of the omega-3 polyunsaturated fatty acids (n-3 PUFA) in egg yolk lipid classes varies between laying stocks and these differences appear to influence the oxidative and sensory qualities of the product. Dietary flax seed results in apparently benign fluctuations in body weight of mature laying hens. Undesirable changes in egg production have only been reported for young birds early in their reproductive cycles. Changes in egg quality include reduced shell weight and decreased yolk weight. It is proposed that yolk weight reduction is related to changes in circulating oestradiol brought about by either n-3 PUFA or the phyto-oestrogens characteristic of flax seed.

Induced ovulation of Japanese flounder (Limanda yokohamae) with human chorionic gonadotropin and salmon gonadotropin, with special reference to changes in quality of eggs retained in the ovarian cavity after ovulation.

This study was undertaken to determine the effects of delay between ovulation and stripping on egg quality in the Japanese flounder. Post-ovulatory eggs were divided into 2 categories. Eggs in stage I were normal, whereas those in stage II were over-ripened and observed to be 3 to 5 days affer ovulation. In HCG-treated fish the percentages of successful fertilization and hatching indicatied were maximal one day after ovulation, followed by a rapid decrease, whereas in SG-G100-treated fish the fertilization rate was maximal 2 days after ovulation, followed by a more gradual decrease. It is shown that flounder eggs remain in good condition for 2 or 3 days depending upon the type of hormone used to induce ovulation. Changes in body weight, water and sodium contents of the eggs are discussed in relation to the over-ripening phenomenon.

Hemagglutination-Inhibition Antibodies against an Adenovirus (Virus-127) in White Pekin Ducks in the United States

A new disease syndrome affecting egg production in chickens about 6 to 8 months old was recently described by workers in the Netherlands and Great Britain (2-7). The condition has been called egg-drop syndrome. Because it was first described in 1976, the acronym EDS-76 has been used to identify the specific entity. Affected flocks characteristically fail to reach expected peak egg production or undergo a sudden drop in production of 30 to 50% or more. Just before the drop or during the first 1-3 weeks of severe drop, the egg quality changes transiently: Brown eggs may have pale shells, and eggs may be thin-shelled or shell-less. Some workers (6,7) have also observed watery and cloudy thin albumen in affected eggs. EDS-176 is caused by an adenovirus, of which isolates 127 and BC-14 are representative (2-5). This virus shows partial sharing of the group-specific antigen common to fowl adenoviruses, although there is no apparent serologic relationship between Virus 127 and the known serotypes of chicken or turkey adenoviruses (3). The EDS-76 agent, unlike other adenoviruses isolated from chickens, agglutinates fowl erythrocytes, which permits a hemagglutination-inhibition (HI) test to be used for detecting specific antibodies in sera (4). The observation of an in vitro preference for duck over chicken cells by virus-127 (2), coupled with the demonstration of HI antibodies against the agent in duck flocks in the United Kingdom (W. Baxendale, personal communication), suggested that ducks might be a natural host for the agent. That prompted examination of sera from commercial d'uck flocks for HI antibodies, as reported here. Additionally, because some commercial egg-laying flocks in New York State have problems in egg production (although without the egg quality changes seen with EDS-76), it was also of

Studies on the Changes of Egg Quality. Part V.

[in Japanese]

Effects of Management, Strain and Truck Shipment on Albumen Quality of Eggs

VERY little has been reported on changes in quality of eggs during shipment. Gwin (1952) reported a study involving more than a billion eggs purchased by the Armed Forces of the United States. U. S. Grades were determined by candling and inspection by trained inspectors from the Army Veterinary Corps and the U. S. Department of Agriculture. Quality loss was shown to be related to time in transit, distance or miles in transit and seasonal influences. No data were reported as to the relation of varying physical conditions during transit or position effects within the rail cars. Adams and Milam (1960) studied the effects of international shipping of eggs from Lincoln, Nebraska to Rio de Janeiro, Brazil, using the Haugh unit score as a measure of internal quality. In this study eggs were transported from Lincoln, Nebraska to New Orleans by auto truck and thence to Rio de Janeiro by…

Studies on the Changes of Egg Quality. Part IV.

[in Japanese]

Studies on the Changes of Egg Quality. Part III.

[in Japanese]

Effects of Vibration for the Changes of Egg Quality

Effects of Vibration for the Changes of Egg Quality

Studies on the Changes of Egg Quality. Part I

[in Japanese]

The Influence of Season and the Age of Layers on Egg Weight, Shape Index, Albumen Quality and Shell Thickness

IN RECENT years an increasing number of poultrymen have been keeping layers for a second year of production. While adequate information is available on changes in egg quality during the pullet year, experimental evidence on the effect of age on egg quality during the second year of production is, with the exception of egg weight, relatively limited.Romanoff and Romanoff (1949) reviewed the literature on the changes in egg weight as the age of layers increases. They state that in spring hatched pullets egg weight increases from October to February or March, then declines somewhat until midsummer, but subsequently increases until it approximates that of two year old hens in October or November. According to these authors two year old hens lay their largest eggs in December or January and their smallest eggs in May, June and July.Benjamin (1920) in an experiment with Single Comb White Leghorns, found no …

Seasonal Variations in Quality of Eggs as Measured by Physical and Functional Properties

PARKER, Gossman and Lippincott (1926) and Parker (1927) appear to be the first investigators to study the seasonal changes in egg quality. They found no definite trend in yolk color. These observations were later substantiated by Hunter, Van Wagenen and Hall (1936) and Wilhelm and Heiman (1938).Hunter, Van Wagenen and Hall (1936) observed the interior quality of fresh eggs produced by a flock of Single Comb White Leghorns hens under constant management conditions. They found that the eggs of highest quality were produced between November and March and that there was a seasonal trend in interior quality showing a decline beginning with March or April and continuing through the summer.Wilhelm and Heiman (1938), using albumen index and yolk index as criteria of quality, found a consistent drop in egg quality from the time the hens came into production until a low point was reached in July, there then …

Methods of Measuring Changes in Egg Quality in Terms of Physical Grade and Economic Value

THE great interest in egg quality changes shown by egg marketing researchers and members of the egg trade have suggested a need for an examination of various measures of changes in egg quality. The authors have used, as a basis, the various methods of measuring changes that have been used at the Michigan station. We do not, in this paper, expect to explore all of the alternative methods of measuring egg quality. The discussion in this paper is limited to changes in egg quality as reflected by changes in individual eggs from one U. S. grade level to another. No effort was made to analyze here the information pertaining to various factors affecting changes in egg quality. It is expected, however, that much of the procedure suggested in this paper could be adapted readily to other systems of grading eggs and egg quality.To facilitate comparison, the quality changes in .

The Changes in Egg Quality Resulting from Force Molting White Leghorn Yearling Hens

THE practice of forcing White Leghorn yearling hens to molt during the late spring or early Summer, for the purpose of securing greater production of higher quality eggs during the period of peak fall egg prices, is quite widely followed by the commercial poultrymen of Washington. That the practice of force molting, as conducted by the poultrymen, can be successful is indicated by the increasing number of poultrymen each year who are following the procedure and are continuing to do so year after year.The poultrymen who have successfully force molted yearling hens have claimed that flocks which are force molted not only produced more eggs but also produced eggs of improved grades during the fall months, than do flocks which are permitted to lay and molt normally. The authors, who had been studying shell and albumen quality, were interested in these claims of improved egg grades following the forced .

Seasonal Changes in Interior Egg Quality of Single Comb White Leghorn Hens

CONSIDERABLE effort has been expended in recent years to discover just what quality is in reference to the contents of an egg, to set up and to standardize ways of improving and maintaining it at a high level. But there has been little work to show differences in the initial quality of eggs, as determined by present day measures, that occur with season. Parker, Grossman and Lippincott (1926) concluded that there is no seasonal effect on the color of the yolks of eggs. Almquist (1933) states that, “eggs are not all ‘created equal’ or, if they are, they do not long remain so. Initial quality and keeping quality may vary greatly from egg to egg, but are found to vary to a relatively small extent in eggs from the same hen.” This paper considers the seasonal changes in the interior quality of eggs laid by a flock of S.C. White .