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At least 235 records · Page 13Linked to original sources

PubMed1990

Effect of cimetidine on eggshell quality and plasma 25-hydroxycholecalciferol in laying hens.

Experiments were conducted to investigate the effect of feeding cimetidine (CIMET), ranging from 0 to 750 mg/kg, on vitamin D3 metabolism and eggshell calcification in laying hens fed two levels of vitamin D3 (500 and 2,000 ICU/kg). Final BW and feed intake were not significantly affected by either CIMET or vitamin D3 level. Feeding 500 and 750 mg of CIMET significantly decreased total egg production in hens fed either level of vitamin D3, but no differences were observed at lower CIMET levels. Tibia ash decreased significantly in hens fed 150 to 750 mg of CIMET, regardless of the vitamin D3 level. Plasma Ca and inorganic P concentrations were decreased in hens fed high CIMET levels (500 and 750 mg/kg) at Week 2, but no differences were observed at Week 4. Feeding CIMET (500 and 750 mg/kg) significantly decreased plasma 25-hydroxycholecalciferol (25-OHD3) levels at Week 2 in hens fed both vitamin D3 diets but not at Week 4. Eggshell breaking force, shell thickness, and percentage shell weight were decreased significantly by CIMET in all experiments; however, in one experiment, shell quality recovered by Week 8. These results suggest that the CIMET-induced reduction in bone mineralization, eggshell quality, and plasma 25-OHD3 levels could be due to interference of CIMET with vitamin D3 metabolism in vitamin D3-replete laying hens. Shell quality decreased in CIMET-treated hens fed the higher vitamin D diet even though 250-HD3 plasma levels were three times higher than in hens fed the lower vitamin D diet, suggesting that CIMET affected shell quality through some mechanism other than inhibition of 250-HD3 synthesis.

Animal Feed↗

PubMed1990

Influence of vitamin D3, 1 alpha-hydroxyvitamin D3, and 1,25-dihydroxyvitamin D3 on eggshell quality, tibia strength, and various production parameters in commercial laying hens.

Four hundred 53-wk-old Hyline W36 laying hens were randomly allocated to 10 treatments. The effects of feeding two vitamin D3 metabolites, 1 alpha-hydroxyvitamin D3 [1 alpha-(OH) D3] and 1,25-dihydroxyvitamin D3 [1,25-(OH)2 D3], each at five dietary levels (0, .75, 1.50, 3.00, and 4.50 micrograms/kg of feed) were determined on eggshell quality and tibia strength in commercial laying hens (Experiment 1). In Experiment 2, 1,440 Hyline W36 65-wk-old laying hens were used to determine the effects of four levels of vitamin D3 (0, 500, 1,000, and 1,500 ICU vitamin D3/kg) and three levels of dietary 1,25-(OH)2 D3 (0, .5, and 1.0 microgram/kg of feed) on eggshell quality, tibia strength, and egg production. In Experiment 1, neither 1,25-(OH)2 D3 nor 1 alpha-(OH) D3 affected eggshell quality or production criteria. Tibia weight was increased by adding either 1,25-(OH)2 D3 or 1 alpha-(OH) D3. In Experiment 2, 1,25-(OH)2 D3 increased percentage of shell, shell weight, and egg breaking strength when 0 ICU D3/kg was fed but had no effect at higher levels of vitamin D3. Egg production, feed consumption, and egg weight were also increased with supplemental 1,25-(OH)2 D3 when 0 ICU D3/kg was fed. Tibia weight and tibia breaking strength were also increased by adding 1,25-(OH)2 D3 to the diet. The commercial laying hen metabolizes sufficient 1,25-(OH)2 D3 from dietary vitamin D3 to maintain shell quality but not enough to maintain tibia strength.

Animals↗

PubMed1991

Effects of selection for growth and selection diet on eggshell quality and embryonic development in Japanese quail.

Decreased hatchability in Japanese quail following selection for growth and relative improvements in hatchability following selection during goitrogen treatment were investigated. An unselected quail line (Line C) and lines selected for high 4-wk body weight while being fed diets containing either 20% CP and .2% thiouracil (TU) (Line T), or 28% CP and no TU (Lines P and H-CD) were used. Egg weight loss between 0 and 4, and 0 and 14 days of incubation, hatchability, and developmental stage of embryonic mortalities were determined in Experiment 1. Length of the incubation period, and percentages of body water and dry body weight were determined for 10- and 14-day embryos and 18-day-old chicks in Experiment 2. Eggshell quality was determined in Experiment 3. Hatchability was lower in selected than in unselected quail due to increased early and late embryonic mortality. Egg weight loss during incubation was greater in Line P than in Line C eggs. Weight loss, measured across lines, was lower in eggs that hatched than in those in which embryos died early. Percentage body water was higher in Line C than in Lines P and T at 14 and 18 days of incubation; however, percentage body water in Line T was lower than Line P at 14 days. Percentage of dry body weight was greater in Lines P and T than in Line C at 14 and 18 days. Eggshell thickness was greater in Line H-CD when compared with Line C. Increases in eggshell permeability occurring during selection for growth were associated with increased embryonic mortality and decreased hatchability.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Inheritance of tinted eggshell colors in white-shell stocks.

The present study was conducted to study the genetics of tinted eggshell colors in two breeds of chickens laying white-shell eggs. Reciprocal crosses were made between an inbred White Leghorn line (ES) and an inbred Ancona line (ANC). The F1 birds were intercrossed and F1 females were backcrossed to each of the original lines. Eggshell color from each resultant group was measured using a Minolta chromometer, and a value (e) representing the color intensity adjusted by hue and saturation was used as the measurement criterion. Age, hatch group, and crosses each contributed significantly to the variation seen in eggshell color. Distribution comparisons indicated that two major autosomal loci affected the trait in these lines: one gene having incomplete dominance controls the amount of pigment deposition; the second completely inhibits pigment deposition when homozygous recessive. A test of goodness of fit supported this hypothesis. Genetic components were estimated by linear models. Epistasis, dominance, and additive effects contributed significantly to this trait. No sex-linked effects were noted.

Analysis of Variance↗

PubMed2001

Use of luminescent Campylobacter jejuni ATCC 33291 to assess eggshell colonization and penetration in fresh and retail eggs.

A luminescent phenotype in Campylobacter jejuni ATCC 33291, generated by a transcriptional fusion between the C. jejuni flaA sigma28 promoter and the luxCDABE genes of Xenorhabdus luminescens on plasmid pRYluxCDABE, was used to examine colonization and penetration of fresh and retail eggs. C. jejuni colonized both fresh and retail eggs at 37, 40, and 42 degrees under microaerophilic conditions. Fresh eggs were more heavily colonized than retail eggs. Under aerobic conditions, fresh eggs were colonized at similar levels for all three temperatures. C. jejuni was found to penetrate the eggshell in 2 of 48 (4.2%) fresh eggs assessed. Although the lux+ phenotype did not provide an effective means of predicting penetration sites, it was effective at visualizing eggshell colonization. Also, it effectively demonstrated the organism's opportunistic nature, as eggshell surfaces with flaws and slight cracks were extensively colonized and easily detected by a photon counting charge-coupled device camera. Using scanning electron microscopy, C. jejuni ATCC 33291 was visualized on both the exterior and interior surfaces of the egg membranes indicating penetration of these barriers.

Animals↗

PubMed1991

Collection and separation of Aedes taeniorhynchus eggshells from mangrove soil.

Two methods to separate eggshells of Aedes taeniorhynchus from mangrove soil were compared. Selective sieving, using nested sieves with 0.185 and 0.170-mm screen openings, and water flotation both removed over 99% of the soil. However, water flotation recovered a significantly greater percentage of eggshells (62% vs. 34%). There was no significant difference in the recovery rate of viable eggs and new and old eggshells using water flotation.

Aedes↗

PubMedDate not supplied

F strain Mycoplasma gallisepticum vaccination of post-production-peak commercial Leghorns and its effect on egg and eggshell quality.

Forty-five-week-old commercial leghorns negative for antibodies to Mycoplasma gallisepticum (MG) and M. synoviae were vaccinated with high-passage F strain MG (FMG). Hens were confined in modified Horsfall-Bauer isolation units through 60 weeks of age. Egg production (% hen day) and parameters of egg and eggshell quality were monitored, including egg weight, eggshell strength, Haugh unit score, pimpling, and blood/meat spot incidence. Egg production was significantly lower (P less than 0.05) for FMG vaccinates than controls (down 5.76% and 5.80% in Trials 1 and 2, respectively). However, vaccinates and controls did not differ significantly in eggshell strength, shell thickness, pimpling, or blood/meat spot incidence. Haugh unit scores were significantly (P less than 0.05) greater for FMG vaccinates. At necropsy, all reproductive tracts appeared grossly normal. These studies suggest that high-passage FMG vaccination of post-production-peak hens does not adversely affect oviduct function.

Animals↗

PubMed1983

Supplemented eggshell restores calcium transport in chorioallantoic membrane of cultured shell-less chick embryos.

It was previously reported (Tuan, 1980a) that the development-specific expression of calcium transport and related functions in the chick embryonic chorioallantoic membrane (CAM) requires the continuous presence of the eggshell, the calcium source of the embryo. To further understand the mechanism of action of the eggshell on the CAM functions, this study reports the effects of eggshell supplementation on chick embryos maintained in shell-less cultures. The cultured embryos were able to accumulate and utilize the exogenous shell calcium, applied directly onto the CAM, for skeletal formation. In the region of the CAM directly adhering to the added shell, calcium transport activity, calcium-binding protein (CaBP) activity, and vitamin K-dependent gamma-glutamyl carboxylase activity were significantly restored. These results strongly suggest that the proximity of shell calcium may regulate expression of calcium transport and related functions in the chick embryonic CAM.

Allantois↗

PubMed1997

Ultrastructure of the calcareous layer eggshell of the turtle Emys orbicularis (L.). Preliminary study.

The calcareous layer of Emys orbicularis eggshell was examined by scanning electron microscopy. The layer is composed of well distinguished shell units which consist of needle-like crystallites radiating outwards from the cores. The linear structures of the cores on the inner surface appear to be similar to those in the eggshell of Mauremys caspica. On the inner surface of shell units of eggs with dead embryos there are flat, conical depressions. This surface in specimens from unfertilized eggs is almost flat. It may suggest that a developing embryo derives calcium from the eggshell.

Animals↗

PubMed2025

Oocyte surface proteins EGG-1 and EGG-2 are required for eggshell integrity in Caenorhabditis elegans.

Metazoan eggs are surrounded by a specialized coat of extracellular matrix that mediates sperm-egg interactions. This coat is rapidly remodeled after fertilization to form a barrier that prevents polyspermy, protects against environmental insults, and provides structural support to the developing embryo. In C. elegans several oocyte surface proteins have been identified that mediate these events. However, whether two of these proteins, EGG-1 and EGG-2, are required for fertilization or downstream events has been unclear. Here, we address this question using more recent advances in genome editing tools through the creation of egg-1 egg-2 deletions of the endogenous loci. We found that egg-1 egg-2 oocytes are fertilization competent and form rudimentary eggshells. While the integrity of the egg-1 egg-2 eggshells are compromised and often rupture within the uterus, surprisingly, some embryos are capable of undergoing several rounds of cell division. Overall, our findings demonstrate that EGG-1 and EGG-2 are not required for fertilization but are involved in post-fertilization processes.

Caenorhabditis elegans↗

PubMed1975

Eggshell aspiration in infants.

Two infants inhaled eggshell fragments. The first aspirated a small fragment into the upper part of the trachea and resuscitation attempts resulted in descent of the foreign body to the right lower lobe bronchus. Two attempts at bronchoscopy were unsuccessful and spontaneous disintegration occurred. The second infant aspirated an eggshell fragment to the entrance of the larynx where it was removed by laryngoscopy. Laryngeal or tracheal foreign body in infants under 1 year of age are rare, and the diagnosis and removal are difficult.

Animals↗

PubMedDate not supplied

Dinosaur eggshell study using scanning electron microscopy.

Visualization and analysis of structural features in fossil dinosaur eggs by scanning electron microscopy augment information from traditional petrographic light microscopy. Comparison of characteristics in fossil and modern eggshells allows inferences to be made regarding dinosaur reproductive biology, physiology, and evolutionary relationships. Assessment of diagenetic alteration of primary eggshell calcite structure that occurs during fossilization provides important information necessary for taxonomic identification and paleoenvironmental interpretations.

Animals↗

PubMed1995

Onchocerca volvulus: identification and characterization of an immunogenic eggshell protein (Oveg1).

A major antigen recognized by human sera in Onchocerca volvulus infections is a parasite eggshell protein. The cDNA clone for this antigen was isolated from a lambda gt11 O. volvulus cDNA library using antisera from patients with high microfilarial counts. Sequence analysis of the cDNA clone predicts a polyglutamine repeat near the 5' end of the cDNA, and a motif of four arginines near the 3' end, reminiscent of that found in many regulatory proteins. The cDNA was subcloned into a yeast expression vector and reagent quantities of recombinant antigen produced in Saccharomyces cerevisiae. Antisera produced to the recombinant purified protein localized the antigen to the eggshell of developing microfilariae within the adult female uterus. No other sites of Oveg1 expression were noted in adult worms, but labeling was seen in internal membrane structures of L3 larvae. Sera from infected chimps recognized Oveg1 only after infections became patent. Sera from infected humans showed reactivity to Oveg1 that varied from 39 to 95%, depending upon the geographic location.

Amino Acid Sequence↗

PubMed1995

Purification and immunochemistry of a soluble matrix protein of the chicken eggshell (ovocleidin 17).

The protein components of biomineralized structures (matrix proteins) are believed to modulate crystal nucleation and growth, and thereby influence the shape and strength of the final structure. The chicken eggshell contains a complex array of distinct matrix proteins. The most abundant of these was purified to homogeneity by a combination of anionic exchange and hydroxyapatite chromatographies. Antibodies to this protein were raised in rabbit, and utilized for Western blotting and immunohistochemistry. These studies indicated that the 17 kDa antigen (ovocleidin 17, OC-17) is found in the shell gland mucosa, and that only the tubular gland cells were positive. Immunohistochemistry with decalcified shell indicated that OC-17 is uniformly distributed throughout the shell matrix, but concentrated in the mammillary bodies. Our results indicate that this protein is secreted during shell formation and becomes incorporated into this structure. It may therefore play a role in the crystallization process and influence the properties of the resulting eggshell.

Amino Acid Sequence↗

PubMed1993

Evolution of the dec-1 eggshell locus in Drosophila. II. Intraspecific DNA sequence analysis reveals length mutations in a repetitive region in D. melanogaster.

The dec-1 eggshell gene in Drosophila melanogaster encodes follicle cell proteins required for proper eggshell assembly. As shown by Southern and Northern analyses the dec-1 gene occurs in four alleles (Fc1-4) among wild-type strains. Its second exon has a distinct feature in the form of 12 repeats with 78-91 nucleotides; the first five show nearly 100% homology. DNA sequence comparison of the repeated region of the alleles revealed that the length polymorphisms are caused by changes in the numbers of the first five repeats. The results suggest that the alleles have been generated by unequal intragenic crossing-over and/or slippage during DNA replication and that the allelic length variants have arisen independently. The possibility that the most common allele, FC1, has a selective advantage over the other alleles is discussed.

Alleles↗

PubMed1978

Some observations on the calcium ion binding to the eggshell matrix.

The calcified matrix of the hen eggshell has been demineralized with the EDTA. Aliquots of this material are soluble in water and have been characterized by column chromatography and by chemical analyses. Of particular interest is the high hexosamine and uronic acid content, which confirms the protein-polysaccharide nature of this water-soluble material. The calcium ion binding to the eggshell matrix has been studied by the equilibrium dialysis technique at different pH values, with both free and blocked carboxylic groups. The material with the free carboxylic side chain groups binds more calcium ions with increasing pH value. When the carboxylic groups have been previously blocked with a water-soluble carbodiimide, the calcium ion binding rapidly decreases. The residual capacity to bind calcium ions in the material with the carboxylic functions modified is probably due to the sulfate ions. In agreement with previous observations on other calcified substrates, the calcium ion binding seems to depend on the presence of ionized carboxylic functions of the matrix.

Amino Acids↗

PubMed2004

Ultrastructure of eggshell of Chrysomya nigripes Aubertin (Diptera: Calliphoridae).

We examined the eggshell structure of the blowfly, Chrysomya nigripes Aubertin, a species of forensic importance, using scanning electron microscopy. A relatively wide plastron region was located dorsally. It extended almost the entire length of the egg and bifurcated slightly, close to the micropyle, which is a deep cavity surrounded by an elevated, fine, wavy rim. The chorionic sculpture had an hexagonal pattern, with a smooth and elevated boundary. The ruptured eggshell showed the outermost exochorion, membranous outer endochorion and pillar layer, which also had an hexagonal pattern on a perforated mesh pillar layer. This study provides a greater database on the egg of this forensically significant blowfly.

Animals↗

PubMed1990

Multiple proteins are produced from the dec-1 eggshell gene in Drosophila by alternative RNA splicing and proteolytic cleavage events.

The defective chorion-1 gene (dec-1) in Drosophila encodes follicle cell proteins necessary for proper eggshell assembly. A distinctive feature of the gene is the production of multiple products by both alternative RNA splicing and proteolytic processing events. DNA and protein sequencing studies have revealed several dec-1 protein products. The predominant translation product, fc106, has a vitelline membrane-like N-terminal domain followed by a glutamine, methionine-rich central region, largely in the form of 26 amino acid repeats. During late stage 10 the N-terminal portion of fc106 is cleaved, yielding s80, a major eggshell protein. Conceptual translation of the DNA sequence as well as molecular analyses of several dec-1 mutants suggest that the less abundant alternatively spliced RNAs encode primary translation products with different carboxy terminal ends. These results are discussed with respect to previous genetic analyses of dec-1 mutants as well as with respect to potential protein-protein interactions which may underlie stabilization of this complex extracellular structure.

Amino Acid Sequence↗