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At least 271 records · Page 15Linked to original sources

PubMed1995

Powdered eggshell: a pilot study on a new bone substitute for use in maxillofacial surgery.

The present study is a preliminary report on the use of hen's eggshell as a possible bone substitute. In the first part of the study, particles ranging from 400 microns to 600 microns in diameter were bioassayed in an intramuscular pouch in rodents. This material was found to be biocompatible, but appeared not to have osteoinductive capacities. In the second and third part of the study, this material was used as an interpositional graft material in critical-size defects of rat mandibles and rabbit skulls. At 2 months, a morphologic restoration was obtained using the graft, but the healing was only achieved by fibrous union. In the fourth part of the study, the material was experimented on as an onlay bone graft on rabbit mandibles. A 6-month follow-up of the implant confirmed its stability. In conclusion, the use of this safe and inexpensive material is suggested for filling limited bone defects in non-weight-bearing areas. The use of eggshell powder for bone augmentation may also be considered, after further studies, to assess its long-term stability.

Animals↗

PubMed2002

Aspartame optical biosensor with bienzyme-immobilized eggshell membrane and oxygen-sensitive optode membrane.

An aspartame optical biosensor has been fabricated by employing a bienzyme system composed of alpha-chymotrypsin and alcohol oxidase immobilized onto an eggshell membrane and an oxygen-sensitive optode membrane as the transducer. The detection schemes involve the enzymatic reactions of aspartame leading to the depletion of the oxygen level of the medium with a concomitant enhancement of the fluorescence intensity of the oxygen-sensitive membrane. The scanning electron and transmission electron micrographs show the microstructure of the eggshell membrane which is successfully immobilized with bienzyme. Using this novel immobilization technique, the aspartame biosensor shows extremely good stability with a shelf life of at least 8 months. The rate change of the fluorescence intensity in 4 min is found to be linearly related to the concentration of aspartame. The useful analytical working range of the biosensor is from 0.056 to 3.07 mM aspartame. The effects of temperature, pH, and ionic strength on the response of the aspartame biosensor are investigated in detail. Citric acid, cyclamic acid, D-fructose, D-galactose, D-glucose, hydrogen peroxide, DL-malic acid, L-phenylalanine, saccharin, sodium benzoate, and sucrose show no interferences but ethanol interferes strongly. The aspartame biosensor has been applied to determine aspartame contents in some commercial products.

Animals↗

PubMedDate not supplied

Purification and characterization of a vaterite-inducing peptide, pelovaterin, from the eggshells of Pelodiscus sinensis (Chinese soft-shelled turtle).

Proteins play a crucial role in the biomineralization of hard tissues such as eggshells. We report here the purification, characterization, and in vitro mineralization studies of a peptide, pelovaterin, extracted from eggshells of a soft-shelled turtle. It is a glycine-rich peptide with 42 amino acid residues and three disulfide bonds. When tested in vitro, the peptide induced the formation of a metastable vaterite phase. The floret-shaped morphology formed at a lower concentration ( approximately 1 microM) was transformed into spherical particles at higher concentrations (>500 microM). The solution properties of the peptide are investigated by circular dichroism (CD), fluorescence emission spectroscopy, and dynamic light scattering (DLS) experiments. The conformation of pelovaterin changed from an unordered state at a low concentration to a beta-sheet structure at high concentrations. Fluorescence emission studies indicated that the quantum yield is significantly decreased at higher concentrations, accompanied by a blue shift in the emission maximum. At higher concentrations a red-edge excitation shift was observed, indicating the restricted mobility of the peptide. On the basis of these observations, we discuss the presence of a peptide concentration-dependent monomer-multimer equilibrium in solution and its role in controlling the nucleation, growth, and morphology of CaCO(3) crystals. This is the first peptide known to induce the nucleation and stabilization of the vaterite phase in solution.

Amino Acid Sequence↗

PubMed1999

Ostrich eggshell as a bone substitute: a preliminary report of its biological behaviour in animals--a possibility in facial reconstructive surgery.

The aim of this study was to assess the biological behaviour of an implant of ostrich eggshell in various animal models of facial bone reconstruction. The implant was first bioassayed in a rat muscle pouch (n=10), and then tested as an interpositional graft in rat (n=10) and rabbit (n=5) cranial defects. It was finally used as an onlay graft on rabbit mandibles (n=5). Animals were killed after two months in the bioassay, three months in the interpositional model, and six months in the onlay model. The specimens were studied by contact radiography and standard histological techniques. All animals showed normal wound-healing. In the bioassay, the implants produced only a minimal inflammatory reaction. In the interpositional model, the implants maintained a good contour, but there was no sign of graft-remodelling. In the onlay model, the grafts were stable and partly osteointegrated. The onlay graft model gave the most promising results. Because ostrich eggshell is inexpensive and has good mechanical properties, it deserves further study. Long-term studies will clarify its possible role in maxillofacial surgery.

Animals↗

PubMed1977

Reduction of pore area of the avian eggshell as an adaptation to altitude.

Standard measurements of water vapor conductance in units of mg of H(2)O . day(-1) . torr(-1) (SI equivalent is mg of H(2)O . day(-1) . pascal(-1)) of fresh eggs of the red-winged blackbird (Agelaius phoeniceus) and the native chicken of India (Gallus gallus) collected at altitude are significantly less than those of eggs of the same species collected near sea level. This decrease is caused by a reduction of the total effective pore area of the eggshell at altitude. It appears to be proportional to the reduction in barometric pressure and the simultaneous increase in the diffusion coefficient of water vapor. Thus, reduction in pore area offsets increased diffusivity at altitude, and water vapor loss through the eggshell at any altitude remains the same as at sea level. The data suggest a structural adaptation of the shell to altered diffusivity of gases at altitude in order to prevent excessive water loss of eggs during natural incubation.

Journal Article↗

PubMed2004

Crystal structure of ovocleidin-17, a major protein of the calcified Gallus gallus eggshell: implications in the calcite mineral growth pattern.

Ovocleidin-17 (OC17) from Gallus gallus is one of the best candidates to control and regulate the deposition of calcium carbonate in the calcified eggshell layer. Here, the crystal structure of monomeric OC17, determined at a resolution of 1.5 A, was refined to a crystallographic R-factor of 20.1%. This is the first protein directly involved in a non-pathological biomineralization process resolved by x-ray diffraction to date. The protein has a mixed alpha/beta structure containing a single C-type lectin-like domain. However, although OC17 shares the conserved scaffold of the C-type lectins, it does not bind carbohydrates. Nevertheless, in vitro OC17 modifies the crystalline habit of calcium carbonate (CaCO3) and the pattern of crystal growth at intervals of 5-200 microg/ml. Determining the three-dimensional structure of OC17 contributes to a better understanding of the biological behavior of structurally related biomolecules and of the mechanisms involved in eggshell and other mineralization processes.

Amino Acid Sequence↗

PubMed2005

Bacterial eggshell contamination in conventional cages, furnished cages and aviary housing systems for laying hens.

The influence of housing system on the initial bacterial contamination of the eggshell was studied. Two long-term experiments were performed. Bacterial eggshell contamination, as expressed by total count of aerobic and Gram-negative bacteria, was periodically analysed for eggs from a conventional cage, a furnished cage with nest boxes containing artificial turf or grids as nest-floor material and an aviary housing system. Results were log-transformed prior to statistical analyses. For both experiments no systematic differences were found between the conventional cage and furnished cage. The type of nest-floor material in the nest boxes of the furnished cages also did not systematically influence the bacterial contamination. A possible seasonal influence on contamination with a decrease in the winter period (up to > 0.5 log cfu/eggshell) of total count of aerobic and Gram-negative bacteria was observed in the first experiment. The contamination with total aerobic flora was higher (more than 1.0 log) on eggs from the aviary housing system compared to the conventional and the furnished cage systems. For Gram-negative bacteria this was not the case. During the entire period of both experiments, independent of housing system, shell contamination was not influenced by age of hens or period since placing the birds in the houses. For the total count of aerobic bacteria a restricted positive correlation (r2 = 0.66) was found between the concentration of total bacteria in the air of the poultry houses and initial shell contamination.

Air Microbiology↗

PubMed2005

Effect of environmental enrichment during the rearing phase on subsequent eggshell quality in broiler breeders.

This study set out to investigate if access to an enriched environment during the rearing phase influences subsequent production and eggshell quality in broiler breeders. Broiler breeder pullets were reared under standard rearing conditions (control treatment) or under standard conditions with an environmental enrichment of bales of plastic-wrapped wood shavings (enriched treatment). At 19 weeks of age both groups were transported to a laying facility and housed in standard pens according to treatment type. Egg weight, shape, shell thickness, non-destructive deformation, breaking strength, stiffness and ultrastructural quality were compared at beginning of lay (25 weeks old), peak production (31 weeks old), mid-lay (45 weeks old) and end of lay (57 weeks old). Production and hatchery data were also collected throughout lay. Significant treatment-age interactions were detected for non-destructive deformation, breaking strength and stiffness, such that birds which had received prior enrichment went on to maintain a better shell quality with age. The measurements of total shell thickness, mammillary thickness and effective shell thickness all showed a trend for a treatment-age interaction. Significant age effects were found for weight, shape index, shell thickness, breaking strength and stiffness. All production and hatchery data also demonstrated significant changes with age. It is concluded that early enrichment with bales of wood shavings may provide a novel approach to the maintenance of eggshell quality at a time when calcium metabolism begins to reduce in efficiency.

Aging↗

PubMed2005

Eggshell characteristics and penetration by Salmonella enterica serovar Enteritidis through the production period of a layer flock.

1. Egg weight, shell thickness, number of pores, cuticle deposition and ability of Salmonella enterica serovar Enteritidis (SE) to penetrate the shell were determined for eggs from one layer flock through the entire production period. 2. Penetration was assessed by filling the eggs with a selective medium that allowed visualising Salmonella growth on the inside of the shell and membrane complex. After inoculation of each shell with on average 2.59 log cfu, the eggs were stored for up to 20 d at 20 degrees C and 60% relative humidity (RH). 3. On average 38.7% of the eggshells became penetrated. Mostly penetration occurred on d 3. Although it affected all shell characteristics studied, hen age did not significantly influence eggshell penetration. 4. No correlations were observed between any of the shell characteristics studied and the ability of SE to penetrate the shell. The growth of SE on the shell is of major importance because shell contamination at 20 d of storage and SE penetration were highly correlated.

Aging↗

PubMed1992

Relationship between shell structure and movement of Salmonella enteritidis across the eggshell wall.

1. Ultrastructural analyses of the eggshells of one strain of commercial layers indicated that the cuticular layer is rarely present as an even covering over the shell surface and the paired shell membranes are invariably pitted with holes larger than bacterial dimensions. 2. The above conditions pertain irrespective of the age of the laying bird. 3. Bacterial penetration of the eggshell is independent of pore numbers. 4. In the absence of a functional cuticle and with the shell membranes removed, bacteria are checked in their movement by structural modifications in the mammillary layer.

Age Factors↗

PubMed1998

Organic matrix morphology and distribution in the palisade layer of eggshells sampled at selected periods during lay.

1. 1 cm2 pieces of eggshells from a commercial battery flock were plasma etched to remove the outer shell membranes. 2. They were decalcified using EDTA (200 g/l, pH 6.9 to 7.0) in paraformaldehyde (20 g/l) and 25% gluteraldehyde (20 ml in 0.98 l) in phosphate buffer, then prepared for light and transmission electron microscopy. 3. Light microscopy revealed a differential distribution of matrix material within all 3 regions of the palisade layer at the beginning of lay. 4. Transmission electron microscopy revealed a more even distribution of matrix at the beginning of lay, although morphological differences were observed. At the end of lay all 3 regions showed an increase in % matrix and vesicles/10 cm2 of micrograph compared to the middle and beginning of lay periods. 5. It is hypothesised that matrix vesicles are involved in the regulation of the physiochemical environment within the forming eggshell and that the decline in shell quality associated with the end of lay is related to a concomitant change in matrix quality.

Animals↗

PubMed1999

Features of eggshell formation in guinea fowl: kinetics of shell deposition, uterine protein secretion and uterine histology.

1. Rate of calcium carbonate deposition, duration of eggshell formation, organic composition of the uterine fluid, morphology of the egg shells and histochemistry of the uterus were studied in guinea fowl to analyse the origin of such thick, strong egg shells. 2. The egg shell was linearly deposited from 6.4 h to 21.8 h after the oviposition of the previous egg. The rate of egg shell deposition was similar to that in laying hens. However, the duration of linear shell deposition was increased by 2.1 h relative to that in hens. This explained the increased egg shell weight observed in the guinea fowl. 3. Intervals between oviposition of intra-clutch eggs were 24 h throughout the laying period. Ovulation occurred just after oviposition of the previous egg in the guinea fowl, as previously observed in hens but the duration of egg white protein deposition, of plumping and of initiation of shell mineralisation were all 1.5 h shorter than in domestic hen. 4. Uterine fluid can only be collected during the growth and terminal phase of shell formation. The electrophoretic profiles of the uterine fluid differed between phases and were somewhat different from those previously observed in the hen. Ovalbumin and ovocleidin-17 were both present in the uterine fluid and also in egg shell extract. Ovocleidin-17 was predominant during the growth phase. 5. The histology of the uterus differed slightly in guinea fowl compared to hens. Ovocleidin and ovalbumin are both secreted by the tubular glands. 6. Examination of radial ultrathin sections of eggshell showed, above the mammillary layer, intricate interlacing of adjacent exospherite in guinea fowl in contrast to the continuous columnar microstructure in hens. 7. The kinetics of egg shell deposition largely explains the increased egg shell weight of guinea fowl. The organic matrix proteins may be associated with the contrast between the structural organisation of the guinea fowl egg shell and that of the hen egg shell.

Animals↗

PubMed2001

The functions of the multiproduct and rapidly evolving dec-1 eggshell gene are conserved between evolutionarily distant species of Drosophila.

The Drosophila dec-1 gene encodes multiple proteins that are required for female fertility and proper eggshell morphogenesis. Genetic and immunolocalization data suggest that the different DEC-1 proteins are functionally distinct. To identify regions within the proteins with potential biological significance, we cloned and sequenced the D. yakuba and D. virilis dec-1 homologs. Interspecies comparisons of the predicted translation products revealed rapidly evolving sequences punctuated by blocks of conserved amino acids. Despite extensive amino acid variability, the proteins produced by the different dec-1 homologs were functionally interchangeable. The introduction of transgenes containing either the D. yakuba or the D. virilis dec-1 open reading frames into a D. melanogaster DEC-1 protein null mutant was sufficient to restore female fertility and wild-type eggshell morphology. Normal expression and extracellular processing of the DEC-1 proteins was correlated with the phenotypic rescue. The nature of the conserved features highlighted by the evolutionary comparison and the molecular resemblance of some of these features to those found in other extracellular proteins suggests functional correlates for some of the multiple DEC-1 derivatives.

Amino Acid Sequence↗

PubMed1997

Improving eggshell quality at high temperatures with dietary sodium bicarbonate.

Two experiments were conducted that confirmed the hypothesis that a dietary bicarbonate supplement will improve eggshell quality in hens at high temperatures as long as feed is consumed during the period of eggshell formation. End-of-lay hens were maintained on continuous light at temperatures of 30 and 35 C. Individual egg weights and shell quality measures for each hen were calculated as a proportion of the initial values determined during an acclimatization period at 25 C. Improvements in shell breaking strength in both experiments were observed as a result of supplementing control diets with 1% sodium bicarbonate (NaHCO3). This response to NaHCO3 was not a reflection of a reduced rate of lay or egg mass output, as these were similar or inferior on the control diets. Similar feed intakes on the control and NaHCO3 diets indicated that the response was not related to differences in calcium intakes. Supplements of zinc methionine and ascorbic acid proved to be inferior to NaHCO3. Improvements in egg weight were associated with the introduction of continuous lighting.

Acclimatization↗

PubMed1998

Effects of dietary fat and eggshell cuticle removal on egg water loss and embryo growth in broiler hatching eggs.

The effects of dietary fat and eggshell cuticle removal on egg water loss, embryo growth, and hatchability were determined in eggs from broiler breeder hens at different ages. Hens were fed isocaloric diets containing one of three different types and levels of added fat. In addition, eggs were either left intact or washed to remove the eggshell cuticle prior to set. Cuticle removal increased egg water loss between 43 and 62 wk. Cuticle removal increased relative wet embryo weight at Week 52 and relative dry embryo weight at 52 and 62 wk. Furthermore, at 62 wk, diet and day of incubation interacted to affect wet embryo weight, and diet variably affected dry embryo weight. No treatment differences were observed for cumulative hatchability, rate of hatch, and relative yolk sac weight at Day 19 of incubation. It was concluded that cuticle removal and the addition of fat to breeder diets may influence embryonic growth without having any subsequent effects on hatchability.

Animal Feed↗

PubMed2000

Paternal influences on turkey embryonic growth in the absence of changes in egg weight and eggshell conductance.

The hypothesis was proposed that embryonic growth could be influenced paternally in the absence of changes in egg weight or eggshell conductance. Sire families were established by selecting 11 sires based on blood sampling of approximately 50 commercial turkey males. Southern blot analysis was used to identify the most distantly related individuals in the subpopulation. Five hen siblings or half-siblings of the males were randomly assigned to each male to randomize effects of egg size and eggshell conductance. Artificial inseminations were performed weekly for 17 wk, using each sire with the assigned hens. Fertilized eggs were collected and set in incubators at biweekly intervals. Offspring were observed at the time of hatching for sex, body weight, and blood glucose concentration. Significant differences among sires were observed at hatching for poult weights and blood glucose concentration, and a significant correlation between the BW and glucose concentration was noted. Progeny of sires with the highest and lowest BW and blood glucose concentrations were subsequently compared. Mean BW of poults from different sires differed by as much as 10 g, although they were hatched from eggs of the same weight. Elevated blood glucose was associated with heavier BW; heavier heart, liver, and muscle weights; a rapid utilization of glycogen at pipping; and increased gluconeogenesis as measured by plasma organic acids and glucose-6-phosphatase activity. We conclude that poult embryonic growth differs even when not mediated by egg size and functional characteristics.

Animals↗

PubMed2000

Mineral, amino acid, and hormonal composition of chicken eggshell powder and the evaluation of its use in human nutrition.

Chicken eggshell powder (ESP) might be an attractive source of Ca for human nutrition. To study its nutritional value, we analyzed minerals, amino acids, and hormones in commercially available Slovakian ESP. The mineral composition was compared with three Dutch ESP samples that differed in feed and housing, a Japanese ESP, refined CaCO3, and an oyster shell supplement. Chicken eggshell powder contains high levels of Ca (mean +/- SD/g EPS: 401+/-7.2 mg) and Sr (372+/-161 microg) when compared with recommended or estimated daily intakes for humans 51 to 70 yr of age. Levels of potentially toxic Pb, Al, Cd, and Hg were very low as were levels of V, B, Fe, Zn, P, Mg, N, F, Se, Cu, and Cr. Large differences in the levels of F, Se, Cu, Cr, and Sr in the Dutch and Slovakian ESP indicated a strong influence of feed and environment. The small protein fraction of ESP contains high levels of Gly and Arg. Furthermore, small amounts of transforming growth factor-beta1 (0.75 to 7.28 ng/g ESP), calcitonin (10 to 25 ng/g ESP), and progesterone (0.30 to 0.33 ng/g ESP) were detected. Estradiol-17beta and calcitriol were below the detection limit of the methods used. Compared with ESP, refined CaCO3 was found to contain increased levels of Cd, and the oyster shell supplement showed increased levels of Al and Cd. Therefore, ESP seems to have a beneficial composition with about 39% of elemental Ca, relevant amounts of Sr, and low levels of Al, Pb, Cd and Hg. It may be used as a Ca source in human nutrition.

Aged↗

PubMed2002

Reduction of eggshell aerobic plate counts by ultraviolet irradiation.

The effects of 254 nm ultraviolet light (UV) radiation on aerobic plate count (APC) of egg shells were investigated. In the first experiment, eggs were exposed to UV treatment (7.35 mW/cm2) for 0, 15, 30, and 60 s. Three eggs from each treatment were aseptically collected and placed into sterile plastic bags containing 50 mL of sterile phosphate-buffered solution. Serial dilutions of the phosphate-buffered solution were plated on aerobic plate count agar and incubated at 37 C for 48 h. Exposure of eggshells to 30 and 60 s UV significantly reduced aerobic plate counts compared to untreated eggs. Exposure to 60 s of UV resulted in a 2 to 3 log10 cfu/egg APC reduction and reduced counts below detectable levels. In the second experiment, UV lights were placed in a chamber equipped with a commercial-style egg conveyor. A UV treatment of 7.5 mW/cm2 and time intervals of 0, 12, 36, and 48 s were used. Three eggs were placed consecutively on the conveyor and passed through the chamber. The center egg was selected for APC evaluation. Sample size, dilution, plating, and incubation procedures were used as described for the first experiment. A significant 1 to 2 log10 reduction in colony-forming units per egg between the eggs treated 48 s to the untreated eggs was detected. The results of these studies show that UV light treatment at high intensities and low time intervals has the potential to reduce aerobic plate counts of eggshells.

Animals↗