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PubMed2000

Extraction and quantification by ELISA of eggshell organic matrix proteins (ovocleidin-17, ovalbumin, ovotransferrin) in shell from young and old hens.

The eggshell matrix is mainly composed of proteins that are thought to influence shell formation and calcification and, thus, modify the resulting properties of the shell. We investigated the potential of some of these proteins as biomarkers of eggshell quality by developing a competitive indirect ELISA for quantifying ovotransferrin, ovalbumin, and ovocleidin-17 in eggshell extract. Eggshell fragments were demineralized in acetic acid (20%) and freeze-dried. The micro-extraction yield was markedly increased (>50%) when Tween 20 was added to the subsequent extraction and dialysis milieus. Microplates were coated with ovotransferrin and ovalbumin in a 0.1M carbonate-bicarbonate buffer, but ovocleidin-17 was fixed with acetone (-20 C, 20 min). Optimal dilutions of the monoclonal (ovotransferrin) and polyclonal (ovalbumin and ovocleidin-17) antibodies were 1/3,000, 1/25,000 and 1/4,000, respectively. The inhibition curves were optimized by preincubating the antibodies and proteins overnight. The intraassay coefficient (<5%), parallelism of the standards and samples curves, and recovery (101%) were satisfactory for ovotransferrin. Measurements of ovalbumin were less precise because of higher interassay variation and differences between the slopes of standard and sample inhibition curves. Ovocleidin-17 assays showed similar slopes for standard and eggshell extracts. Although the total protein in soluble matrix extracts was not affected by age, the concentrations of these proteins were higher in eggshell extracts from older hens compared with those from young hens: 1.98x for ovotransferrin, 1.86x for ovalbumin, and 1.58x for ovocleidin-17. The quantification of specific eggshell matrix proteins in shell of differing quality is, therefore, a promising tool for analyzing the origin of eggshell faults and may provide useful information for breeding programs.

Aging↗

PubMed2004

Determination of cooling rates and carbon dioxide uptake in commercially processed shell eggs using cryogenic carbon dioxide gas.

The ability to rapidly cool shell eggs to 7 degrees C is important in the prevention of Salmonella Enteritidis (SE) growth. In addition, quality may also be maintained longer from rapid cooling of shell eggs. A commercial cryogenic CO2 egg cooling unit was designed and installed in a commercial egg processing facility. This unit was installed on a packer head to rapidly cool eggs individually prior to packaging. The objective of this study was to determine cooling rates and CO2 gas changes that result from rapidly cooling eggs using this commercial cryogenic egg cooling system and subsequent storage for 15 wk. Results indicated that cryogenic CO2 cooling quickly cooled shell eggs in approximately 45 min, whereas traditional cooling required from 19 to 116 h. CO2 uptake into the albumen was greater in cryogenically cooled eggs (2.11 mg/g) than in traditionally cooled eggs (1.81 mg/g) immediately after processing. No differences were observed in albumen CO2 content after 2 wk of storage; at 10 wk statistically greater CO2 content remained in the cryogenically cooled eggs (1.75 mg/g) compared with the traditionally cooled eggs (1.60 mg/g). These results suggest that a large amount of CO2 enters the egg during the cryogenic cooling process but is quickly lost during storage. Beyond 10 wk of storage, the albumen CO2 content in cryogenically cooled eggs was higher than in the traditionally cooled eggs suggesting chemical changes may have occurred in the albumen.

Animals↗

PubMed2004

Microbial contamination in inoculated shell eggs: II. Effects of layer strain and egg storage.

Three Ottawa control strains and a current commercial laying stock were reared and housed in the same environment. Eggs were collected at 5 different hen ages throughout the 2 production cycles of the flock. The eggs were inoculated with Salmonella Enteritidis (SE), Pseudomonas fluorescens (PF), a combination of the 2, or sterile buffered peptone water and stored up to 5 wk. After storage at room temperature, contamination levels were determined for the exterior surface, air cell, egg contents, and within the shell. Interior, egg contents, and shell contamination levels of SE and PF increased with storage time. There were no apparent increases in the infectivity of SE or PF in the presence of the other organism. PF was a poor survivor on the shell surface under these storage conditions. Throughout the 5-wk storage, eggs from control strain 10 maintained their microbial integrity more effectively. Eggs from control strain 5 and the current commercial stock were more easily contaminated than the other strains. These data suggest that genetic selection has altered microbiological defenses of the eggs produced.

Animals↗

PubMed1980

Localization of lysyl oxidase in hen oviduct: implications in egg shell membrane formation and composition.

Lysyl oxidase activity was found in the isthmus (the membrane-forming region) of the hen's oviduct in a copper-rich region proximal to the shell gland. Desmosine and isodesmosine, cross-linking compounds associated with mature elastin, were found in hydrolysates of the shell membrane, confirming the necessity for lysyl oxidase in its biosynthesis. Shell membranes from hens fed a copper-deficient diet or a diet supplemented with beta-aminopropionitrile had a reduced content of desmosine and isodesmosine.

Amino Acid Oxidoreductases↗

PubMed1978

Role of shell diffusion area in incubating eggs at simulated high altitude.

Embryonic development is inhibited when eggs are incubated at 9,100 m (0.3 atm) despite a normoxic environment. The problem apparently relates to respiratory gas exchange occurring by diffusion through gas-filled pores in the shell. Gaseous flux is therefore inversely proportional to ambient pressure and is affected by the physical characteristics of the ambient gas (Chapman-Enskog equation). Excess loss of H2O and CO2 occurs in eggs incubating at altitude and could be detrimental. Such increased loss should be correctable by decreasing diffusion area. This was tested by progressively increasing coverage of the shell with paraffin and incubating at simulated 0.3 ATA (225 Torr) in 100% O2. Uncoated eggs failed to hatch, but numbers of chicks increased with increased coverage. Maximum hatch was an extrapolated 90% of controls at 69% shell coverage. With further coverage, hatch size decreased. Egg weight loss, and estimate of H2O diffusion, was around three times controls in uncoated eggs but decreased linearly with paraffin coverage, reaching near normal at maximum hatch. Reduction of diffusion area to 0.3 normal at maximum hatch generally balanced the increased flux predicted for 0.3 ATA.

Adaptation, Physiological↗

PubMed1993

Tissue-specific regulation of shell gland calbindin D28K biosynthesis by estradiol in precociously matured, vitamin D-depleted chicks.

Provision of Ca2+ for egg shell calcification in the avian uterus [egg shell gland (ESG)] derives mostly from vitamin D-dependent intestinal Ca2+ absorption from the diet. Ca2+ absorption is strongly linked to the intestinal vitamin D-dependent calbindin D28K (D28K) concentration. The laying hen ESG also contains D28K, and again, Ca2+ transport into the shell appeared to be linked to the ESG D28K concentration. However, evidence is now presented that ESG D28K synthesis may be estradiol (E2) dependent and vitamin D independent under certain conditions. One-day-old female chicks fed a vitamin D-free diet for as long as 6 weeks and then repeatedly injected im with E2 for up to 3 more weeks developed frank rickets, but possessed precociously matured reproductive tracts. While the tiny presumptive ESGs of nonestrogenized vitamin D-depleted chicks were devoid of D28K, the highly developed ESG, including the isthmus, of estrogenized chicks contained D28K. The ESGs of nonestrogenized, vitamin D-replete chicks also exhibited no development or detectable D28K. Regardless of whether vitamin D depleted or replete, estrogenized chick ESG contained similar D28K and D28K mRNA concentrations. Immunohistochemical techniques showed that the endometrial cellular localization of both D28K and Ca(2+)-ATPase (Ca2+ pump) in estrogenized chicks was similar to that in mature laying hens. There was no trace of D28K, nor was there any stimulation of Ca2+ absorption, in duodenum of vitamin D-free, immature chicks regardless of E2 treatment. As expected, both D28K and D28K mRNA were present in vitamin D-replete chick duodenum. We conclude that in E2-treated chicks, ESG D28K gene expression may be vitamin D independent and E2 dependent. This is the first clear demonstration of hormone-dependent tissue-specific D28K gene expression in the chick.

Animals↗

PubMed2005

Sodium and anion transport across the avian uterine (shell gland) epithelium.

The uterine (shell gland) epithelium from the domestic chicken was mounted in Ussing chambers, bathed in symmetric avian saline solution on both apical and basolateral aspects and voltage clamped at 0 mV. The epithelium exhibited a basal short circuit current (I(sc)) that was partially inhibited by the epithelial Na(+) channel (ENaC) blockers, amiloride and benzamil (IC(50) values of 0.8 and 0.12 micromol l(-1), respectively). Inhibition of basal Na(+) absorption by 10 micromol l(-1) amiloride was confirmed by measurements of transepithelial Na(+) and Cl(-) fluxes, where inhibition of the apical-to-basolateral and net Na(+) flux occurred, but no significant effects on Cl(-) fluxes were detected. The amiloride-insensitive portion of the basal I(sc) was both Cl(-) and HCO(3)(-) dependent and was inhibited by the Cl(-) channel blocker, diphenyl-2-carboxylate (DPC; 100 micromol l(-1)). Stimulation with 8-(4-chlorophenylthio)-cyclic 3'-5', adenosine monophosphate (8-cpt cAMP) produced a sustained increase in I(sc) that was dependent on both Cl(-) and HCO(3)(-). The magnitude of the amiloride-sensitive I(sc) was approximately twofold greater in birds where shell formation was complete, but oviposition had not yet occurred. In addition, the amiloride-sensitive I(sc) was greater in hens over the age of 55 weeks and in molting birds. The anion-dependent component of the basal I(sc) was reduced in older birds, and electrogenic HCO(3)(-) transport was nearly absent in molting birds. These results demonstrated that electrogenic Na(+) transport in avian shell gland was similar to the mammalian uterine epithelium and increased with age and during molting. Electrogenic Cl(-) and HCO(3)(-) transport were coupled under basal and cAMP stimulated conditions and basal anion transport decreased with age and during molting.

Aging↗

PubMed1989

Respiratory gases and acid-base balance in shell-less avian embryos.

1. The PCO2 and PO2 levels of oxygenated and deoxygenated embryonic blood were measured in normal and shell-less cultured embryos. 2. Embryos in shell-less culture were both hypoxic and hypocapnic, suggesting that wetting the respiratory membranes and the reduction in their functional area is distorting their normal function. 3. Despite this hypocapnia, there was evidence for an increase in base excess during incubation. This suggests that plasma bicarbonate is derived from renal sources rather than by resorbing the eggshell calcium carbonate, which is, of course, absent from shell-less cultures.

Acid-Base Equilibrium↗

PubMed2006

The magnum-isthmus junction of the fowl oviduct participates in the formation of the avian-type shell membrane.

Avian eggs possess a shell membrane in the shape of an asymmetrical ellipsoid and with a limiting membrane that is a smooth layer of homogeneous, dense materials. We describe the role of the magnum-isthmus junction (MIJ) of the oviduct in the formation of the avian-type shell membrane in the domestic fowl Gallus domesticus. The narrow width of the lumen at the MIJ indirectly participates in the determination of the asymmetrical ellipsoid shape of eggs that are encased by the egg-white layer and subsequently by the peri-albumen layer (PL) and the shell membrane. The PL reacts with Alcian blue and exists between the egg white and the limiting membrane. It is added to the ovulating egg at the MIJ and covers the outermost surface of the egg-white layer. The function of the PL is to provide a smooth surface by covering the irregular surface of the egg-white layer. The materials of the PL consist of an Alcian blue-positive polysaccharide (or glycoprotein) of 240 kDa and five proteins of 135, 116, 72, 49, and 46 kDa. The isolated materials have an affinity to bind with the egg-white mass. An antiserum against quail PL materials stains the domestic fowl PL and secretory cells of the luminal epithelium at the MIJ, and cross-reacts with the molecules of 240, 135, and 116 kDa.

Animals↗

PubMed1984

The effect of cyclic and constant ambient temperatures on feed consumption, egg production, egg weight, and shell thickness of hens.

Groups of 18 hens, 230 days of age, were housed in each of three climatic chambers with light schedules of 14L:10D. One was maintained at a constant temperature of 23.9 C, the second was cycled between 15.6 and 37.7 C (mean, 26.7 C), and the third was cycled between 21.1 and 37.7 C (mean, 29.4 C). In Experiment 1, the high temperature peaked during the dark period at 0200 hr and in Experiment 2, the high temperature peak was at 1400 hr during the light period. The birds had free access to a commercial breeder feed in these two experiments. The results from three 2-week observation periods indicated no significant differences in percent hen-day production, grams of feed per gram of egg mass, or overall body weight change but feed intake per day, egg weight, and shell thickness were significantly reduced by mean temperatures of 26.7 and 29.4 C in cycling chambers. The pair-feeding of birds in the 23.9 C constant chamber compared with those in the cycling 29.4 C chamber resulted in production of significantly heavier eggs with thicker shells without significantly influencing any of the other parameters. The reductions in egg weight and shell thickness observed at cyclic temperatures were not simply a result of a reduction in nutrient intake at high temperatures but also the direct effect of heat stress on the hens. In the 23.9 C constant temperature chambers, a reduction in AME of the feed for the hens fed ad libitum was observed but not for hens pair-fed to hens in the 29.4 C cyclic chamber.

Animals↗

PubMed1985

The effect of marginal levels of calcium, fish meal, torula yeast and alfalfa meal on feed intake, hepatic lipid accumulation, plasma estradiol, and egg shell quality among laying hens.

In two 2 X 3 factorial-design experiments, Single Comb White Leghorn (SCWL) laying hens were fed either a corn-soy (CS) diet or one containing 5% each of fish meal, alfalfa meal, and torula yeast (FAY), each with 2.0, 2.75, or 3.5% calcium in Experiment 1 and 2.5, 3.5, or 4.5% in Experiment 2. Duration of the experiments were 6 and 8 weeks, respectively. Low dietary calcium resulted in decreased efficiency of energy utilization in both experiments and significantly elevated energy consumption in Experiment 2. Liver lipids and body weight were unaffected by dietary calcium level, and declines in both egg production and shell quality were observed in both studies. In Experiment 1, overall plasma estradiol and tibial bone ash were significantly reduced with lowered dietary calcium, but this was not observed in Experiment 2. Egg weight was significantly increased by decreased dietary calcium in Experiment 1. Plasma calcium was not affected by dietary calcium in either trial. Feeding FAY resulted in significantly lower liver lipid than feeding CS in both experiments, and similar but nonsignificant trends were realized for plasma estradiol. Tibial bone ash and egg-breaking strength were significantly higher for hens fed FAY in Experiment 1. In Experiment 2, plasma total calcium was lower and the percent shell was higher in hens fed FAY with 3.5% calcium than in hens fed CS with 3.5% calcium. No differences were observed between CS and FAY in feed consumption, body weight, or egg production. These studies indicate that feeding a more complex diet to laying hens may change calcium metabolism and improve shell quality at marginal levels of calcium compared with feeding a simplified CS diet.

Animal Feed↗

PubMed1985

Magnesium, calcium, and phosphorus content of shells from hatching and nonhatching turkey eggs.

Shells of hatching and nonhatching Large White turkey eggs were examined for magnesium, calcium, and phosphorus content. Eggshells containing embryos that hatched contained significantly (P less than .05) more magnesium than shells from nonhatching eggs. No differences were seen in their calcium content. Eggshells from pipped eggs contained significantly (P less than .05) more phosphorus than shells from eggs that were not pipped or those that hatched. Calcium and magnesium in turkey eggshells declined as time in lay increased. Injections of exogenous magnesium both at setting and transfer significantly (P less than .05) depressed hatchability, whereas exogenous calcium injected at transfer significantly (P less than .05) improved hatchability. Injections of exogenous calcium at the time of setting significantly (P less than .05) depressed hatchability. It was concluded that the mineral content of turkey eggshells may influence embryo physiology and hatchability.

Animals↗

PubMed1986

Effects of feeding graded levels of vitamin D3 on egg shell pimpling in aged hens.

Pimpled egg shells are one of the various types of egg shell problems in the industry today. In this study, graded levels of vitamin D3 (D3) (0, 138, 275, 550, 2200, 22,000, 44,000, and 88,000 ICU of D3/kg of feed) were fed in a corn-soy ration to Single Comb White Leghorn hens (78 weeks of age), randomly assigned to one of the eight treatments. Feed consumption, egg production, egg weight, egg specific gravity, and pimple score were determined at weekly or biweekly intervals for a 10-week period. At termination of the experiment, calcium, sodium, potassium, and ash content of the uterus and serum calcium levels were assayed. Results showed that a significant (P less than .05) linear increase in pimple score, uterine ash, and serum calcium occurred as dietary levels of D3 increased. Egg production and egg specific gravity were correlated to D3 level in a quadratic fashion. Uterine sodium levels declined with increased D3 in the diet, while potassium values showed no differences. Calcium levels of uterine tissue tended to increase with increased D3. The lowest (0 ICU/kg) and highest level of D3 (88,000 ICU/kg) significantly decreased feed consumption. It was concluded that egg shell pimpling is directly related to level of cholecalciferol (D3) in the diet.

Aging↗

PubMed1991

Influence of sodium zeolite A with and without pullet-sized limestone or oyster shell on eggshell quality.

To determine whether particle size of CaCO3 influences the hen's response to sodium zeolite A (ZA), two experiments were conducted. In Experiment 1, hens were fed 0, .75, and 1.50% ZA for 6 wk with and without a Na correction. At the end of the 4th wk, pullet-sized limestone was substituted for 50% of the added fine granular limestone in the diet containing no ZA. In Experiment 2, hens were fed diets containing 0, .68, and 1.36 ZA for 8 wk with and without one-half of the added fine granular limestone substituted for oyster shell. No correction for Na was made. A dietary calcium concentration of 2.75% was used in Experiment 1 and 3.5% in Experiment 2. Egg specific gravity, egg production, feed consumption, and egg weight were measured. Sodium zeolite A increased egg specific gravity, and the beneficial effects of ZA were maintained during Weeks 5 and 6 when pullet-sized limestone was added to the control diet containing no ZA (Experiment 1). Oyster shell and ZA improved egg specific gravity in Experiment 2 and the effect was additive. Dietary treatments had no effect on egg production or egg weight in Experiments 1 or 2 and there was no effect on feed consumption (Experiment 1). Feed consumption was reduced by ZA, when hens were fed oyster shell, but not when they were fed ZA with fine granular limestone (Experiment 2). It was concluded that the beneficial effect of ZA on egg specific gravity was independent of particle size of CaCO3 in the diet.

Aluminum Silicates↗

PubMed1991

Effect of dietary boron supplementation on egg production, shell quality, and calcium metabolism in aged broiler breeder hens.

Three experiments were conducted using aged broiler breeder hens (greater than 60 wk) to investigate the effects of supplemental B on egg production (EP), shell quality, and Ca metabolism. Experiment 1 had a 2 x 2 factorial arrangement of treatments: 1) high Ca (3.5%); 2) high Ca plus B; 3) low Ca (1.5%); and 4) low Ca plus B; using 32 60-wk-old hens. The B levels were basal and 100 ppm supplemental for the first 2 wk of the experiment and reduced to 60 ppm for the remaining 3 wk. Egg production, shell thickness (ST), and egg specific gravity (SG) were recorded weekly. In Experiment 2, 40 60-wk-old hens were divided into two groups: high and low shell quality. Each group was further divided into two subgroups and fed a low-Ca basal diet with or without supplemental B. The level of B supplementation and the experimental period was the same as in Experiment 1. In Experiment 3, 52 75-wk-old hens were force-molted. After molting, 36 hens were fed a commercial layer diet with the remaining 16 hens fed the control diet supplemented with 100 ppm B. Blood samples were taken during the nonlaying and laying periods, respectively. The results showed that B significantly (P less than .05) depressed EP in Experiment 1 but not in Experiments 2 and 3. Supplemental B decreased plasma Ca when hens were fed a diet containing high Ca levels (3.5%). Supplemental B did not affect SG, ST, or Ca retention, but did significantly increase tibial bone ash percentage (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1994

The effects of sex steroid hormones on the pigment accumulation in the shell gland of Japanese quail.

Effects of sex steroid hormones on the accumulation of the superficial pigment of the eggshell in the quail shell gland were investigated. In Experiment 1, 10 or 20 mg/100 g BW of aminoglutethimide (AG) was injected s.c. into laying quail hens 10 h before the expected ovulation. Thirty percent of the hens that received 10 mg/100 g BW and 87% of the hens that received 20 mg/100 g BW failed to ovulate. They had significantly (P < .01) lower concentrations of preovulatory plasma progesterone (P) than the control hens and showed significantly (P < .05) low concentrations of plasma estradiol-17 beta (E) and small amounts of the pigment in their shell glands after oviposition of the preceding egg. In Experiment 2, AG (20 mg/100 g BW) was administered s.c. to quail hens 10 h before the expected ovulation, followed by the administration of P (.05, .1, or .2 mg/100 g BW), E (.1, .2, or 1.0 mg/100 g BW), or testosterone (T) (.5 mg/100 g BW). Significant increases in the accumulated pigment 18 h after oviposition of the preceding egg were found when P was injected. However, administration of E and T had no influence on pigment accumulation. These results suggested that P might affect the accumulation of pigment in the quail shell gland.

Animals↗

PubMed1996

Pasteurization of eggs in the shell.

A small percentage of all eggs may be contaminated with Salmonella enteritidis (SE). To eliminate this hazard from the food supply, procedures for pasteurizing eggs in the shell have been developed. At least four research groups are attempting to devise a process to achieve a pasteurized shell egg. Only one of the groups has reported procedures and results. Sound shell eggs were washed to remove surface contaminants. The clean eggs were then inoculated with high levels of SE cells. The inoculated eggs were then heated by one of several means to a yolk temperature of about 55 C and held at that temperature for varying periods of time. The number of surviving cells was determined. It is possible to obtain a 7 log cycle reduction of SE in inoculated eggs without a significant change in functional or visual quality of the eggs.

Animals↗

PubMed2000

Prevalence of Salmonella spp. in poultry broilers and shell eggs in Korea.

This study was conducted to determine the presence of Salmonella spp. in raw broilers and shell eggs in Korea. In total, 135 dozen shell eggs and 27 raw broilers were tested. None of the egg yolks were found to contain Salmonella organisms but Escherichia coli, Escherichia hermanii, and Citrobacter freundii were isolated from egg shells. Salmonella spp. were detected in 25.9% of raw broilers, and Salmonella serotypes isolated from raw broilers were Salmonella Enteritidis, Salmonella Virchow, and Salmonella Virginia. D-values and antibiotic resistance of Salmonella isolates were also investigated. D-values of Salmonella enteritidis, Salmonella Virginia, and Salmonella Virchow in tryptic soy broth at 55 degrees C were 2.36, 2.13, and 0.70 min and 0.53, 0.37, and 0.20 min at 60 degrees C, respectively. All Salmonella isolates showed multiple antibiotic resistance patterns and were resistant to penicillin and vancomycin. One strain of Salmonella Enteritidis showed resistance to 12 antibiotics used in this study.

Animals↗