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PubMed2005

The effect of soybean soapstock on the quality parameters and fatty acid composition of the hen egg yolk.

The effects of increasing proportions of soybean soapstock (SSS) in laying hen diets on egg quality parameters and on the fatty acid (FA) composition of the yolk were studied. One hundred sixty Babcock B-300 x laying hens, 20 wk of age, were allotted to 5 dietary treatments comprising a control diet (D5) with soybean oil at 100% or SSS in proportions of 25% (D1), 50% (D2), 75% (D3), and 100% (D4) replacing the oil source in commercial-type diets throughout the 15-wk laying period. Egg quality parameters were recorded weekly. Four pooled yolks for each treatment were collected at 0, 9, and 15 wk, and their FA profiles were determined. Egg weight, shell thickness, shape index, and Haugh unit were not influenced by dietary treatment. The concentrations of saturated FA (SFA) in yolks were generally kept at a constant level, regardless of the percentage of SSS in the hen diets. Total monounsaturated FA (MUFA) content did not vary over the course of the experiment, except for C14:1. After 15 wk of feeding, the total polyunsaturated FA (PUFA) n-3 increased in yolks of all diets. Among the long-chain PUFA, the percentage of C20:4 (arachidonic acid) was less affected. Inclusion of 100% SSS allowed production of eggs with similar PUFA/SFA and n-6/n-3 ratios when compared with eggs from hens fed D5. As SSS represents one-third of the oil cost, its inclusion in layer diets could represent an important economic benefit.

Animals↗
PubMed1992

Sodium-dependent short-circuit current across the yolk sac membrane during embryonic development in normal and shell-less cultured chicks.

The transepithelial electrical characteristics of the isolated yolk sac membrane of normal in ovo or shell-less cultured chick embryos were investigated. In normal chicks the potential difference (blood side positive relative to yolk side) and short-circuit current of the membrane increased during development. Ouabain (10(-4) M) on the blood side (basolateral side, serosal side) significantly decreased potential difference and short-circuit current but was without effect on the yolk side (brush border side, mucosal side). Substitution of choline for Na+ in the bathing solutions abolished the potential difference and the short-circuit current; when Na+ replaced choline this effect was reversed. Amiloride added to both sides of the yolk sac membrane had no effect on potential difference or short-circuit current. Injection of aldosterone (50 micrograms) and T3 (10 microM) into yolk did not induce amiloride sensitivity. The short-circuit current was not altered by addition of either glucose or alanine to the bath. The short-circuit current of the yolk sac membrane of shell-less cultured embryos was significantly lower than that of normal controls. Addition of Ca2+ to the serosal bathing medium did not reverse the foregoing condition, but decreased the short-circuit current. It is concluded that the yolk sac short-circuit current is Na+ dependent and increases with developmental age in the chick embryo.

Animals↗
PubMed2004

Identification of the major proteins of the organic matrix of emu (Dromaius novaehollandiae) and rhea (Rhea americana) eggshell calcified layer.

1. The eggshell is a composite consisting of 95% calcite and an organic matrix. 2. While many proteins of the chicken eggshell matrix have already been identified, little is known about the matrix of other birds. 3. Isolation of the emu and rhea eggshell matrix and analysis of its major constituents showed that the predominant components were C-type lectin-like proteins related to those of ostrich, chicken and goose. 4. Serum albumin, vitelline membrane outer layer protein I (VMO-I) and the turpentine-induced acute phase serum protein 18-B were identified as minor components of the emu shell matrix. Both eggshell matrices also contained a novel proline- and alanine-rich protein. 5. Like ostrich, and unlike chicken and goose, both emu and rhea eggshell matrix contained two different C-type lectin-like proteins as major components, indicating that the occurrence of two proteins of this family may be widespread among ratites.

Amino Acid Sequence↗
PubMed1994

Calcium homeostasis in in ovo and ex ovo turkey embryos.

Calcium homeostasis of in ovo (normal) and ex ovo (shell-less) turkey embryos was investigated at 15, 18, and 21 days of incubation. Hypocalcemia and an elevation in circulating 1,25(OH)2D3 in ex ovo embryos were observed by 15 days. Calcium and phosphorus concentrations in femora and tibiae in ex ovo embryos were significantly lower compared to their normal counterparts. These results suggest that shell calcium mobilization is required prior to 15 days of incubation for maintaining serum calcium and supporting bone mineralization. Furthermore, the elevation of 1,25(OH)2D3 is indicative of a functional calcium homeostatic mechanism responding to the absence of the primary calcium source (eggshell) during the second half of turkey embryonic development.

Animals↗
PubMed1980

The eggshell of Drosophila melanogaster. I. Fine structure of the layers and regions of the wild-type eggshell.

The fine structure of the several layers and regional specializations in the Drosophila melanogaster eggshell has been studied by a combination of shell isolation procedures and ultrastructural techniques (conventional TEM, whole-mount TEM, SEM, HVEM, freeze-fracture electron microscopy utilizing rotary replication, shadow casting, optical diffraction and stereo imaging). The main shell consists of 5 layers: the vitelline membrane (300 nm thick), the wax layer, the innermost chorionic layer (40-50 nm), the endochorion (500-700 nm), and the exochorion (300-500 nm). The vitelline membrane consists of irregularly organized particles. The wax layer appears to contain multilayered hydrophobic plates which split tangenitally upon freeze fracturing. The innermost chorionic layer is composed of a crystalling lattice. The endochorion is made of a thin (40 nm) fenestrated floor composed of 40-nm fibres and an outer solid (200 nm) roof covered with a network of 40-nm strands. Intermittently spaced pillar connect these 2 parts. Similarities in the substructure of the floor, pillars and roof suggest that they may be composed of similar or identical structural elements. The specialized regions of the shell are the 2 respiratory appendages, the operculum area and the posterior pole. The appendages exhibit 2 sharply distinct surfaces, a dorsal side with isolated 1.5-micrometer plaques and a ventral side with strands of 40-50 nm connected in a network with openings of 70-80 nm. The operculum area, which includes the micropoyle and the collar, is distinguished by 3 unique types of cell imprints. The posterior pole contains 2 distinctive populations of cell imprints: the central area has very thin intercellular ridges and a thin, perforated, endochorionic roof, while the peripheral area contains mixed, thick and thin, intercellular ridges and serves as a transition zone to the main shell pattern. The pillars in the central area of the posterior pole have a distinct arrangement, forming one peripheral circle within each cell imprint. An analysis utilizing structural and developmental criteria indicates that as many as ten different populations of follicular epithelial cells may be involved in the construction of the various regions of the Drosophila eggshell.

Animals↗
PubMed1997

Eggshells are shaped by a precise spatio-temporal arrangement of sequentially deposited macromolecules.

The avian eggshell is a composite bioceramic which is formed by a controlled interaction of an organic and an inorganic phase. The organic phase contains, among other constituents, type X collagen and proteoglycans, mainly keratan and dermatan sulfate. Understanding the principles governing the synthesis and temporo-spatial distribution of such macromolecules, and their influence on the organization of the crystalline phase, is an essential aspect of establishing the biological basis of the quality of eggshell, both as an embryonic chamber and as a natural food package. In the present study, we have examined the process of eggshell formation by immunohistochemistry, scanning electron microscopy and energy dispersive X-ray microanalysis. Precise sites and timing of secretion were established for the deposition of particular macromolecules. Type X collagen is detected at the very first moment of shell membrane formation. The appearance of keratan sulfate coincides with the appearance of mammillae, while dermatan sulfate is deposited later, coincident with shell matrix deposition. We propose that keratan sulfate, due to its precise localization, temporal appearance and calcium-binding affinity, relates to the maintenance of calcium reserve bodies, the primary source of calcium for the embryo. On the other hand, dermatan sulfate may control crystal growth, resulting in a preferential orientation of calcite crystals within the palisade layer.

Animals↗
PubMed1982

The initiation of pulmonary respiration in a bird embryo: blood and air cell gas tensions.

The gaseous stimuli for pipping and the initiation of pulmonary respiration were examined in th Wedge-tailed Shearwater (Puffinus pacificus) by measuring blood gas tensions in the chorioallantoic vein and air cell gas tensions (Pao2 and Paco2) prior to and during the pipping process. External pipping (shell fracture) was the first observed pipping event and preceded internal pipping (penetration of air cell and initiation of pulmonary ventilation). This sequence of cracking the eggshell prior to the initiation of pulmonary respiration resulted in higher Pao2 and lower Paco2 values than the pre-pip air cell gas tensions. Pip-cracks in the shell allow greater diffusion than could normally be obtained across the intact eggshell. This also favors the establishment of large partial pressure gradients of O2 and CO2 across the chorioallantois, thereby improving gas exchange across the inner resistance barrier. The gaseous stimuli for pipping may be attenuated and thus favor the 5-6 day pip-to-hatch interval in this species.

Allantois↗
PubMed1984

Bone parameters of thick and thin eggshell lines of chickens.

Comparative measurements of bone parameters were made on chickens from thick and thin eggshell lines that were maintained on a normal diet containing 3.5% calcium, injected i.v. with 45CaCl2 and sacrificed 30 min later. There were no significant differences between shell lines for the following measurements on the left femur: specific gravity, ash wt, total calcium, percent calcium and 45Ca content. There was deposition of 45Ca in the femur of all hens--even those in the process of eggshell formation. Skeletal metabolism was not a limiting factor in determining whether a hen produced a thick or thin eggshell.

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↗
PubMed1984

External incubation alters the composition of squamate eggshells.

Eggshells of the skink, Eumeces fasciatus, and of the rough green snake, Opheodrys vernalis, contain 28-40% of total shell mass as calcium at oviposition. After incubation, both calcium concentration and content were reduced 17-41%. Protein accounted for 33-65% of shell mass in Eumeces and Opheodrys eggshells at oviposition. Reductions in protein concentration and content from 22-86% following incubation were observed. Comparing amino acid compositions of eggshells collected following oviposition with those collected from the same clutch after hatching reveals similarities among all eggshells except those of Eumeces from Michigan which lack desmosine and isodesmosine. Concentrations of desmosines in eggshells from Missouri and Michigan Eumeces appeared to decrease following incubation by 49.7% and 12.2%, respectively. Although neither the mechanisms involved in apparent losses of calcium and protein, nor the fate of the mobilized materials are known, possible pathways for mobilization of eggshell constituents are outlined and their pertinence to the physiology of squamate eggs and the evolution of viviparity in reptiles is suggested.

Amino Acids↗
PubMed1975

Improved hatch rate in helium-oxygen by reducing shell diffusion area.

For eggs incubating in a He atmosphere (79% He/21% O2), covering approximately 50% of the shell with melted paraffin improves hatch rate to control values (from 20% to 74%) and decreases egg weight loss to control values (from 17% to 9%). In air (79% N2/21% O2) the same paraffin treatment depresses hatch rate. The role of the inert gases in incubation appears to be an indirect one related to their modification of the rate of gaseous flux across the shell with the adverse effects of He due to excessively rapid diffusion.

Air↗
PubMed2004

Antinematodal effect of antimicrobial peptide, PMAP-23, isolated from porcine myeloid against Caenorhabditis elegans.

The antinematodal activity and mechanism of a 23-mer antimicrobial peptide, PMAP-23, derived from pig myeloid was investigated. PMAP-23 displayed a strong antinematodal activity against the eggs and worms of Caenorhabditis elegans. To investigate the antinematodal mechanism of PMAP-23, fluorescence activated flow cytometry and confocal laser scanning microscopy were performed. C. elegans treated with PMAP-23 showed higher fluorescence intensity by propidium iodide (PI) staining than normal cells. Confocal microscopy showed that the peptide was localized in the egg's shell and cell membrane. The action of the peptide against C. elegans membranes was examined by testing the membrane disrupting activity using liposome (PC/PS; 3:1, w/w). The result suggests that PMAP-23 may exert its antinematodal activity by disrupting the structure of the cell membrane via pore formation or via direct interaction with the lipid bilayers.

Animals↗
PubMed1989

A simple method for shell-less cultivation of chick embryos.

The chorio-allantoic membrane of explanted chick embryos can be used for the study of vascular development and of the vascular response to drugs and to tissue implants or tissue extracts. Three different types of vials for shell-less cultivation of chick embryos were compared in terms of short-term survival. Plastic cups with rounded bottoms were superior to Petri dishes and polyethylene film bags, in that they combined a high survival rate of the embryos with a possibility of using a large number of embryos in each experiment. With the use of plastic cups this method is simple, reliable and inexpensive.

Allantois↗
PubMed1976

Three dimensional structure of the endochorion in wild type Drosophila melanogaster.

The endochorion of the Drosophila melanogaster eggshell has been isolated and its structure examined by transmission and scanning electron microscopy. In the main shell the thin inner endochorion (floor) shows small pits or pores and characteristic fenestrae crossed by irregular strands; vertical columns surrounded by air spaces separate this layer from the thick outer endochorion (roof) which is covered by a regular, external reticulum of thin fibers. The endochorion of the respiratory horns has sharply divided dorsal and ventral surfaces, with characteristic structures somewhat reminiscent of the floor and the external reticulum of the roof, respectively.

Animals↗
PubMed1975

Studies on the isthmus region of the somestic fowl.

The isthmus extends from the aglandular zone, which delimits it from the magnum, to the tubular shell gland, which to the naked eye is marked by a distinct colour change from off-white to brown. 2. The surface epithelium comprises three cell types, ciliated, non-ciliated and mitochondrial, of which only the non-ciliated cells contribute towards the carbohydrate moiety of the shell membranes. 3. The gland cells are distinctive, containing granules of variable electron density, variations also occurring within individual granules. 4. Although two types of gland cell have been observed, they may merely represent different phases of development. 5. In the type 1 cell, the rough endoplasmic reticulum and Golgi complex are typical of the normal protein secreting cell; in the type 2 cell the RER is sparse, dilated and filled with intracisternal granules while the Golgi complex is likewise distended.

Animals↗
PubMed2004

Western immunoblotting in avian shell gland sample immunoblotting methods.

Avian shell gland tissue was subjected to Western blot analysis using anti-human estrogen receptor-alpha antibody H222. Initial attempts to obtain consistent, high-quality blots were unsuccessful because, as it turned out, excessive lipid in tissue preparations interfered with protein separation. Incremental additions of acetone eventually proved to be the critical step in solubilizing lipids and allowing consistent separation of bands on gels. A detailed description of the methodology is presented.

Animals↗
PubMed1989

Effect of dietary phosphorus levels on performance of turkey breeder hens.

One hundred 30-wk-old medium weight white Orlopp turkey breeder hens were equally divided into four treatment groups according to the level of available P in the diet (.15, .30, .50, and .70%, respectively). The P provided in the basal diet (.15% available, .35% total) was from cereal grains and soybean meal. No supplemental phosphate was added. During the 20-wk experiment, there were no differences in number of days required to come into lay and in subsequent egg production. Specific gravity, egg weight, number of shell pores, and body weight were similar under all treatments. The P levels of birds fed the four diets were 4.82, 4.93, 4.93, and 4.94 mg/100 mL, respectively, in serum and in femur were 15.8, 16.1, 16.8, and 16.4%, respectively. The P levels were slightly lower in birds fed the diet without added P. Excreta P levels (1.93, 2.49, 2.81, and 3.10%, respectively, in birds fed the four diets) were significantly (P less than .05) higher with each successive increase in dietary P. Hens fed diets containing .50 or .70% available P retained (46.9 and 54.8%, respectively) significantly more P than those fed diets containing .15 or .30% available P (28.1 and 33.8%, respectively). Fertility (76, 93, 90, and 89%, respectively) was significantly lower (P less than .05) from feeding the diet without added P. Hatchability rates of fertile eggs were similar for all treatments.

Animals↗
PubMed1980

Growth and differentiation of chicken embryos in simplified shell-less cultures under ordinary conditions of incubation.

The growth and differentiation of chicken embryos maintained in evaporating dishes as shell-less cultures were compared to that of control embryos in ovo under the same conditions of incubation. The development of cultured embryos appears to be indistinguishable from that of embryos in ovo up to 10 days of total incubation. Thereafter, the growth of shell-less embryos is significantly retarded as evidenced by morphological criteria of the Hamburger-Hamilton stages of development, body weight, tibia length, and total protein content. Cultured embryos are smaller in size than controls, but show normal morphological features including a fully-differentiated skeleton. Skeletal defects and other anomalies were not detected in any of the specimens studied. Limitations as to the use of the simplified method of culture are evaluated and discussed.

Animals↗