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PubMed1979

The structure and formation of the egg-shell of Syphacia obvelata Rudolphi (Nematoda: Oxyurida).

The egg of Syphacia obvelata is a flattened elipsoid. The egg-shell consists of 5 layers: external uterine layer, internal uterine layer, vitelline layer, chitinous layer and lipid layer. An operculum is present at one pole of the egg. The opercular groove consists of a break in the uterine layers and the modification of the chitinous layer by the deposition of lipoprotein material. On the curved side of the egg the uterine layers are modified to form alternate ridges and depressions. Discrete spaces are present in the internal uterine layer between the ridges. These are open to the exterior via pores in the external uterine layer. The structure of the uterine layers is quite different on the flattened side of the egg. The morphology of the reproductive system and the formation of the egg-shell is described. It is suggested that the complex structure of the uterine layers of oxyurids forms by a self-assembly process.

Animals↗
PubMed1992

[Effect of the manganese content in laying hen feed with different Ca and mineral levels on the egg shell quality and bone mineralization of hens].

Four experiments with 270, 44, 432 and 66800 Leghorn hens were carried out to investigate the influence of various Mn additions to diets differed in mineral or Ca contents on egg shell quality. The addition of 300 mg Mn/kg diet improved significantly egg shell breaking strength by 4 N over one year. The supply of 50-500 mg Mn/kg diet for 10-24 weeks of the second half of laying year did not influence the egg shell quality. Addition of mineral mixture or Ca grit to layer rations with adequate or higher Mn levels did not influence egg shell strength. High mineral content in a low manganese diet increased number of cracks by 3%. Strength, weight and ash content of tibia were significantly reduced by feeding a low mineral level. Addition of 50-150 mg Mn per kg low mineral diet normalized partially tibia stability in young hens. It was concluded that supplied dietary Manganese influences calcification positively only in young hens. High levels of Ca did not influence the effects of Mn. 50 mg Mn per kg layers mixture have been considered as an essential supply.

Animal Feed↗
PubMed1999

Short-term effects of a chicken egg shell powder enriched dairy-based products on bone mineral density in persons with osteoporosis or osteopenia.

Based on the high calcium content, chicken egg shells are an interesting source of calcium. We studied the short-term effects on bone mineral density (BMD) of the lumbar spine and hip in 9 women and one man (mean age +/- SD, 63.9 +/- 8.1 years) with osteoporosis or osteopenia. Also the effects on pain and general well-being were monitored. Ten women (62.5 +/- 5.0 years) from a population study on BMD served as a control group. During a study period of 4-8 months, the intervention group consumed twice daily a dairy-based supplement which resulted in a daily intake of, among others, 3.0 g of egg shell powder, 400 IU of vitamin D3 and 400 mg of magnesium. BMD of the lumbar spine (anteroposterior (AP) and lateral (LA) position) and hip were measured by dual-energy X-ray absorptiometry. After the intervention period, BMDs of the lumbar spine, total proximal femur and trochanter were significantly (p < 0.05) increased with (median) 4.4%: (range) 1.7 to 10.4% (lumbar spine AP), 5.7%: -1.3 to 15.9% (lumbar spine LA), 2.2%: -1.9 to 9.4% (total proximal femur), 1.8%: -1.8 to 9.0% (trochanter). Within a period of 4 months, an important reduction in pain was reported and as a consequence an improvement in general well-being. In the control group, BMDs of the lumbar spine AP and of the femoral neck significantly decreased over a period of 8 months with -0.7% (-1.3 to 0.2%) and -0.9% (-2.4 to -0.1%) respectively. Six women of the intervention group continued to use the supplement on their own free will and without any check on compliance, up to 24 months. They consumed the supplement only once daily except for the last three months when they were asked to take the double dosage again. After 24 months BMDs did not differ from baseline. This study shows that egg shell powder is a source of bioavailable calcium. Furthermore, this pilot study indicates that the chicken egg shell powder enriched dairy-based supplement increases BMD of subjects with a low bone mass in the short term and as a consequence delays bone demineralisation for a longer period. (Tab. 3, Fig. 1, Ref. 23.)

Absorptiometry, Photon↗
PubMed1987

Penetration of ovicidal fungus Verticillium chlamydosporium through the Ascaris lumbricoides egg-shells.

The course of penetration of the ovicidal fungus Verticillium chlamydosporium Goddard through the Ascaris lumbricoides egg-shells was studied in electron miorographs. The contact area between the egg and the fungus is smooth at the stage of the contact of the ovicidal fungus with the egg surface, as well as at the stage of adhesion. No special attaching organs are formed which indicates that no mechanical penetration of the fungal hypha through the egg-shells is involved. Traces of enzymatical activity of the fungus penetrating upright through the egg-shells can be observed during the penetration stage proper. At the consumption stage, the branching of the ovicidal fungus becomes more dense and some hyphae grow through the egg envelopes parallelly under the egg surface. The fungus grows through all parts of the infected egg, even through its contents.

Animals↗
PubMed1989

Physiological changes associated with the production of defective egg-shells by hens receiving sodium chloride in the drinking water.

1. Supplementing the drinking water of laying hens with 600 or 2000 mg sodium chloride/l induced large increases in egg-shell defects without corresponding changes in egg production, egg weight or food and water intakes. A supplement of 2000 mg NaCl/l resulted in a high incidence of shell-less eggs. 2. The increased incidence of egg-shell damage in hens receiving the NaCl was associated with a decrease in egg-shell quality measured objectively. These responses persisted even after the NaCl was removed from the drinking water. 3. The NaCl treatment had little effect on blood acid-base balance and electrolytes, but significant reductions were observed in the carbon dioxide tension, and bicarbonate and calcium concentrations in the fluid surrounding the egg in the shell gland. 4. The poor shell quality appeared to be associated with a reduced supply of bicarbonate, rather than with an effect on Ca, in the lumen of the shell gland, although a reduced residence time of eggs in the shell gland may also have contributed to the problem.

Animals↗
PubMed1987

Chitin in egg shells of Onchocerca gibsoni and Onchocerca volvulus.

Chemical analysis of adult females of Onchocerca gibsoni gave estimated chitin contents of 200-500 micrograms (g dry weight)-1. Egg shells from both O. gibsoni and Onchocerca volvulus stained with Calcofluor white and with fluorescent wheat germ agglutinin as shown by fluorescent light microscopy, and bound gold-labelled wheat germ agglutinin as shown by electron microscopy, under conditions specific for chitin. The egg shells appeared as single electron dense layers from 50 to 85 nm in thickness. Purified chitinase digested these egg shells, leaving coiled microfilariae unattacked. We conclude that chitin is a major component of the egg shells.

Animals↗
PubMed1998

Trace elements in egg contents and egg shells of slider turtles (Trachemys scripta) from the Savannah River Site.

In this paper we examine the levels of trace elements in the egg contents and egg shells of slider turtles (Trachemys scripta) from the Savannah River Site, near Aiken, South Carolina. Trace elements have seldom been examined in the tissues or eggs of reptiles, although some turtles and large snakes occupy a high trophic level. Lead, mercury, cadmium, selenium, chromium, and manganese levels were examined in one egg and its egg shell collected from each of 16 females that laid in late May and June 1996. We were interested in determining background levels, whether certain metals were sequestered in the egg shells, and whether levels were higher in contents or shells. Concentrations were higher in egg contents than in shells for lead, mercury, and selenium, while chromium was higher in the shell. There were no differences for cadmium and manganese. Compared to eggs from other reptiles, levels in slider turtles were generally similar for cadmium and selenium, lower for chromium and lead, and higher for manganese.

Animals↗
PubMed1989

Egg shell quality responses of pullets given saline drinking water at different ages.

1. Saline drinking water given to pullets before sexual maturity had no effect on their subsequent egg shell quality. 2. Hens receiving saline drinking water from or after laying their first egg produced significantly more egg shell defects than hens receiving town water. 3. The production of eggs with defective shells occurred more rapidly when saline drinking water was given to 40-week-old hens than to hens during the first few weeks of lay. 4. The high incidence of egg shell defects resulting from the use of saline drinking water was reduced to control levels when hens in early lay were given town water for 5 weeks. This response was not observed with 40-week-old hens.

Age Factors↗
PubMed1996

Soluble egg shell membrane protein as a regulating material for collagen matrix reconstruction.

Soluble egg shell membrane protein (SEP) was prepared from egg shell membrane by the combined treatment of performic acid oxidation (4 or 25 degrees C for 24 h) and pepsin digestion (25 degrees C for 24-72 h) before dialyzing against water and lyophilizing. The yield of SEP was about 16-39%. SEP had high contents of acidic amino acids (320-340 residues/1000 residues) containing cysteic acid (101-108 residues) converted from cystine, a small amount of saccharides, a main molecular weight of 12,000-22,000 and pI 4.2-4.8. SEP accelerated the reconstruction of collagen matrix with ordered molecular rearrangement and reduced redissolution of the collagen matrix under several solvent conditions. SEP elevated the denaturation temperature of the matrix.

Amino Acids↗
PubMed1988

Relationship of time of feeding and strain to egg shell quality and hatchability in broiler breeders.

The relationship of feeding time to egg production, egg weight, egg shell quality, fertility, and hatchability was examined in two trials. Slow and fast-feathering strain Hubbard females were used in Trial 1 and slow-feathering strain Arbor Acres females were used in Trial 2. Feeding times of 0800 or 1300 h throughout the laying periods were compared. Slow feathering females in Trial 1 exhibited significantly increased egg weight and significantly decreased percentage shell when compared with fast-feathering females. Feeding at 1300 h increased significantly egg specific gravity, egg shell weight, and percentage shell in Trials 1 and 2. Significant interactions of feeding time and strain occurred in Trial 1 with respect to fertility and hatch of all eggs set. Feeding at 1300 h increased fertility and hatch of all eggs set in fast-feathering hens but the opposite occurred in slow-feathering hens in Trials 1 and 2. Within slow-feathering hens, hatch of fertile eggs was decreased by 1.7% (Trial 1) and 1.5% (Trial 2). The results show that afternoon feeding that provides calcium intake near the time of egg shell calcification decreased significantly hatchability in eggs from two slow-feathering strains of females but not in eggs from a fast-feathering strain. These results suggest that altering time of feed intake can decrease hatchability.

Animals↗
PubMed2001

Egg shell ultrastructure of the fish nematode Huffmanela huffmani (Trichosomoididae).

The egg shell of Huffmanela huffmani Moravec, 1987 forms three main layers: an outer vitelline layer, a middle chitinous layer, and an inner lipid layer. The vitelline layer, forming the superficial projections of the egg shell, comprises two parts: an outer electron-dense, and an inner electron-lucid part. The chitinous layer is differentiated into three parts: an outer homogenous electron-dense part, a lamellated part, and an inner electron-dense net-like part. The lipid layer comprises an outer net-like electron-lucid part, and an inner homogenous electron-lucid part. The polar plugs are formed by electron-lucid material with fine electron-dense fibrils.

Air Sacs↗
PubMed1997

Egg shells of mallophagans and anoplurans (Insecta: Phthiraptera): morphogenesis of specialized regions and the relation to F-actin cytoskeleton of follicular cells.

The egg shells of investigated phthirapterans consist of three basic elements: an anterior operculum, a main egg shell and a posterior hydropyle. In some species these elements show further regional specializations: bristles and projections that facilitate attachment to feathers of the host, micropyles and aeropylar openings. All of the egg shell specializations are formed by distinct subpopulations of follicular cells. Staining with rhodamine-conjugated phalloidin has revealed that these subpopulations significantly differ in the distribution of microfilaments (F-actin). In this respect four morphological categories of the follicular cells have been distinguished: (1) cells devoid of processes and microvilli, with basal arrays of microfilaments, responsible for the secretion of a flat chorion; (2) cells devoid of processes and microvilli, separated by intercellular spaces, with basal arrays of microfilaments, responsible for the secretion of attachment structures; (3) cells equipped with actin-containing processes, responsible for the formation of micropyles or aeropyles, and (4) cells equipped with bundles of microvilli, responsible for the formation of hydropyles.

Actins↗
PubMed1980

Egg-shell permeability and hatching of Ascaris suum.

When eggs of Ascaris suum were transferred from glass-distilled water into 0.1--0.4 M NaCl solutions, the water content of the unhatched juveniles fell with increasing concentration of solute. The effect was reversible. The egg-shell was thus permeable to water. The osmotic pressure of the egg fluid was osmotically equivalent to between 0.1 and 0.2 M trehalose. In hatching experiments in Fairbairn's medium containing 0.1 or 0.2 M trehalose, only 5 and 3% respectively of the eggs hatched; 83% of the eggs hatched in the absence of trehalose. The evidence suggests that loss of solutes from the egg fluid permits an increase in the water content of the unhatched juveniles and that this may be responsible for ending their quiescence.

Animals↗
PubMed1981

Pimpling of egg shells and hatchability in several strains of turkeys.

Eggs from several strains of turkeys (two randombred control populations of different origin and differing greatly in body weight and several sublines of these control strains selected for various traits) were scored for the amount of egg shell pimpling over a 12-week hatching period. The frequency of pimpled eggs averaged 15.6% in the medium-bodied strains and 21.2% in the large-bodied strains. The two randombred control strains, based on hen averages, did not differ significantly from each other, nor was there any significant difference among medium-bodied strains for pimpling scores. A large-bodied subline selected for decreased broodiness had a higher pimpling score than its corresponding randombred control. There were no other significant differences among the large-bodied strains. These data suggest that there is either little genetic variation in egg pimpling or little association between egg pimpling and traits for which selection was practiced (egg production, 16-week body weight, blood level of corticosterone after cold stress, clutch length, fertility, or plasma level of estrogens during the laying period). Pimpling increased with length of the hatching period. There was a small but significant correlation coefficient (-.11) between pimpling score and hatch of fertile-eggs. There was no significant association between pimpling score and percent 7-day incubation weight loss.

Aging↗
PubMed1999

Efficacy of disinfection of shell eggs externally contaminated with Salmonella enteritidis. Implications for egg testing.

Experimental contamination of the surface of shell eggs by dipping in a culture of Salmonella enteritidis resulted in the presence of Salmonella enteritidis in/on the shells as well as shell membranes but not in the egg content. Disinfection with Lugol's solution, chlorhexidine, ethanol, quarternary ammonium solutions or flaming after dipping in ethanol failed to achieve complete decontamination of the shell and membranes with resulting false positives when eggs were broken for culturing of the content. Dipping eggs for three seconds in boiling water resulted in complete destruction of Salmonella enteritidis in shells and membranes but sometimes caused the eggs to crack. A method of aseptically opening eggs without risk of contaminating the content from the shell or membrane was developed. Salmonella enteritidis deposited in/on the shell and membranes did not multiply during storage of the eggs at 20 degrees C for four weeks, the counts seemed to decrease. No Salmonella enteritidis was detected in the contents of any contaminated eggs.

Animals↗
PubMed1991

Role of magnesium in egg shell formation in the domestic hen.

1. The effects of feeding diets containing various amounts of magnesium on plasma concentration of calcium and magnesium in the domestic hen were investigated. 2. Plasma concentrations of calcium and magnesium decreased during shell formation in all birds. 3. Plasma magnesium content and egg shell thickness were severely reduced in birds given diets containing either 207 or 132 mg Mg++/kg. 4. Using electron microscopy, a precise correlation was observed between the normal distributions of magnesium and organic material across the egg shell of the domestic hen.

Animals↗