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At least 343 records · Page 19Linked to original sources

PubMed2002

Eggshell conductance, embryonic growth, hatchability and embryonic mortality of broiler breeder eggs dipped into ascorbic acid solution.

1. Eggs from a broiler breeder flock between 25 and 29 weeks of age were dipped into solutions of various concentrations of ascorbic acid (AA) for up to 2 min, in order to evaluate its effects on eggshell conductance (EC), amniotic fluid pH, albumen height and pH, embryonic weight and hatchability. 2. Three experiments were conducted and the following treatments were used: control, non-dipped (CND); control, water-dipped (CWD); 10 g AA/l (AA1); 20 g AA/l (AA2) and 30 g AA/l (AA3). Measurements of EC before and after dipping were made in experiments 1 and 2 in eggs from hens at 25 and 27 weeks of age, respectively. Albumen height and pH were measured after dipping the eggs in experiment 2. In experiment 3, egg weight loss, embryonic weight and amniotic fluid pH at 14 d of age, hatchability percentage (HP), and embryonic mortality were measured in eggs from hens at 29 weeks of age. 3. AA treatment of eggs and dipping period of time (1, 1.5 and 2 min) increased EC of eggs from hens at 25 and 27 weeks of age. 4. AA3 treatment for 2 min reduced albumen height and increased albumen pH of eggs when compared with the CND treatment in eggs from hens at 27 weeks of age. 5. HP of AA1-treated eggs from hens at 29 weeks of age was higher than that of the CND treatment. AA2 and AA3 treatments of eggs reduced HP and increased the percentage of non-pips when compared with any of the other treatments. 6. AA2 and AA3 treatments of eggs increased egg weight loss when compared with the control treatments (CND and CWD). Dipping treatment did not influence amniotic fluid pH or embryo weight expressed as a percentage of initial egg weight. 7. It is concluded that dipping hatching eggs into AA solution increased EC of eggs. Dipping eggs into 10 g AA/l for a period of 2 min increased HP in eggs from hens at 29 weeks of age, although this was not associated with a significant increase in egg weight loss.

Albumins↗

PubMed2006

Comparison of eggshell hygiene in two housing systems: standard and furnished cages.

1. The hygienic properties of eggs produced in two designs of furnished cage were investigated and compared to two standard cage designs. 2. At 28, 37, 47 and 58 weeks of age, the proportion of dirty eggs was higher in one of the furnished cage designs while, in the other, it was similar to standard cages. 3. At 27, 33 and 60 weeks, the bacterial load on the eggshell (total aerobic bacteria and enterococci) was higher in furnished cage designs. A seasonal effect was observed with lower counts at 60 weeks (winter) than at 27 weeks (summer). 4. More dirty eggs and a higher bacterial load were observed in eggs laid outside the nests, which suggests egg hygiene in furnished cages could be similar to standard cages if the equipment in furnished cages was improved to enhance nest laying.

Aging↗

PubMed1987

Improving turkey poult quality by correcting incubator humidity to match eggshell conductance.

One of the most important factors determining hatchability of avian eggs is their proper water budget during incubation. We show here that water budget changes of turkey eggs effect not only hatchability but also poult quality. In addition to an increase in hatchability of 3.3%, poult quality was increased by 7.3%. This was achieved by sorting eggs into low (less than 18.5), medium (18.5 to 22.0) and high (greater than 22.0) eggshell mass-specific water vapour, conductance categories and incubating them in matching incubation humidities of 21.8, 26.6 and 31.4 Torr, corresponding to relative humidities of 45, 55 and 65% at 37.5 degrees C, respectively. A total diffusive water loss of 11.5% (range 10 to 14%) of the initial egg mass in 25 d of incubation yielded maximal hatchability and poult quality.

Animals↗

PubMed1998

Influence of dietary osteolathyrogens on the eggshell quality of laying hens.

1. Laying hens were fed osteolathyrogens, either semicarbazide hydrochloride at 0.3 or 0.4 g/kg or beta-aminopropionitrile fumarate at 0.5 or 0.6 g/kg diet to examine their effects on eggshell quality. 2. Shell quality characteristics considered for evaluation were shell surface area, shell thickness, shell weight, percentage shell, shape index and the specific gravity of eggs. Measurement of shell quality traits revealed that the hens fed osteolathyrogens laid eggs with significantly lower specific gravities and proportion of shell by weight. These differences were not explained by differences in shell thickness or weight or the shape index of eggs. 3. It was concluded that osteolathyrogens cause hens to lay eggs with poor shell quality and such eggs are weak and fragile.

Aminopropionitrile↗

PubMed1999

Transmission electron microscopy of the vertical crystal layer and cuticle of the eggshell of the domestic fowl.

1. Eggshell pieces (1 cm2) were decalcified using a solution of EDTA (200 g/litre, pH 6.9 to 7.0) in paraformaldehyde (2 g/litre) and glutaraldehyde (0.5 g/litre) in phosphate buffer. 2. They were prepared for transmission electron microscopy (TEM). 3. TEM identified a vertically aligned matrix associated with the vertical crystal layer (VCL). It is hypothesised that the vertical orientation of calcite crystals in the VCL is closely linked to this vertical matrix. 4. TEM also revealed the presence of a 2-layered cuticle, the inner layer containing vesicles which were absent in the outer. 5. Cuticular vesicles contain hydroxyapatite and are thought to play a role in the termination of shell formation. The current paper presents data relating to microbial apatitic systems that strengthen this hypothesis.

Animals↗

PubMed2005

Phylogenetics of eggshell morphogenesis in Antheraea (lepidoptera: saturniidae): unique origin and repeated reduction of the aeropyle crown.

Integrated phylogenetic and developmental analyses should enhance our understanding of morphological evolution and thereby improve systematists' ability to utilize morphological characters, but case studies are few. The eggshell (chorion) of Lepidoptera (Insecta) has proven especially tractable experimentally for such analyses because its morphogenesis proceeds by extracellular assembly of proteins. This study focuses on a morphological novelty, the aeropyle crown, that arises at the end of choriogenesis in the wild silkmoth genus Antheraea. Aeropyle crowns are cylindrical projections, ending in prominent prongs, that surround the openings of breathing tubes (aeropyle channels) traversing the chorion. They occur over the entire egg surface in some species, are localized to a circumferential band in many others, and in some are missing entirely, thus exhibiting variation typical of discrete characters analyzed in morphological phylogenetics. Seeking an integrated developmental-phylogenetic view, we first survey aeropyle crown variation broadly across Antheraea and related genera. We then map these observations onto a robust phylogeny, based on three nuclear genes, to test the adequacy of character codings for aeropyle crown variation and to estimate the frequency and direction of change in those characters. Thirdly, we draw on previous studies of choriogenesis, supplemented by new data on gene expression, to hypothesize developmental-genetic bases for the inferred chorion character transformations. Aeropyle crowns are inferred to arise just once, in the ancestor of Antheraea, but to undergo four or more subsequent reductions without regain, a pattern consistent with Dollo's Law. Spatial distribution shows an analogous trend, though less clear-cut, toward reduction of coverage by aeropyle crowns. These trends suggest either that there is little or no natural selection on the details of the aeropyle crown structure or that evolution toward functional optima is ongoing, although no direct evidence exists for either. Genetic, biochemical, and microscopy studies point to at least two developmental changes underlying the origin of the aeropyle crown, namely, reinitiation of deposition of chorionic lamellae after the end of normal choriogenesis (i.e., heterochrony), and sharply increased production of underlying "filler" proteins that push the nascent final lamellae upward to form the crown (i.e., heteroposy). Identification of a unique putative cis-regulatory element shared by unrelated genes involved in aeropyle crown formation suggests a possible simple mechanism for repeated evolutionary reduction and spatial restriction of aeropyle crowns.

Animals↗

PubMed1999

The amino acid sequence of ovocleidin 17, a major protein of the avian eggshell calcified layer.

The amino acid sequence of ovocleidin 17, a major protein of the chicken eggshell calcified layer, contains 142 amino acids including 2 phosphorylated serines. Data base searches show that ovocleidin belongs to a heterogeneous group of proteins consisting of a single C-type lectin domain (CTL). The most similar sequences with an average of 30% identical amino acids were those of pancreatic stone protein (lithostathine) and lectins and anticoagulant proteins from snake venom.

Amino Acid Sequence↗

PubMed1999

Development and in vitro evaluation of buccoadhesive tablets using a new model substrate for bioadhesion measures: the eggshell membrane.

For oral delivery of antimicrobial and anti-inflammatory drug, mucoadhesive tablets based on gelatin/hydroxypropylcellulose (HPC), gelatin/hydroxypropylmethyl-cellulose (HPMC), and gelatin/sodium carboxymethylcellulose (NaCMC) at different ratios were prepared by direct compression of the mixed powders. Metronidazole and benzydamine were used as model drugs. The in vitro bioadhesive properties, evaluated by a commercial tensile tester, were significantly affected by the model substrate employed, that is, a polypropylene (PP) membrane or a biological membrane (eggshell membrane). The use of the biological substrate seemed to supply more reliable data. All studied formulations showed an erosion-diffusion mechanism of release, anomalous or non-Fickian release, in agreement with the behavior of the swellable systems.

Administration, Oral↗

PubMed1972

Specific protein synthesis in cellular differentiation. Production of eggshell proteins by silkmoth follicular cells.

Silkmoth follicles, arranged in a precise developmental sequence within the ovariole, yield pure and uniform populations of follicular epithelial cells highly differentiated for synthesis of the proteinaceous eggshell (chorion). These cells can be maintained and labeled efficiently in organ culture; their in vitro (and cell free) protein synthetic activity reflects their activity in vivo. During differentiation the cells undergo dramatic changes in protein synthesis. For 2 days the cells are devoted almost exclusively to production of distinctive chorion proteins of low molecular weight and of unusual amino acid composition. Each protein has its own characteristic developmental kinetics of synthesis. Each is synthesized as a separate polypeptide, apparently on monocistronic messenger RNA (mRNA), and thus reflects the expression of a distinct gene. The rapid changes in this tissue do not result from corresponding changes in translational efficiency. Thus, the peptide chain elongation rate is comparable for chorion and for proteins synthesized at earlier developmental stages (1.3-1.9 amino acids/sec); moreover, the spacing of ribosomes on chorion mRNA (30-37 codons per ribosome) is similar to that encountered in other eukaryotic systems.

Animals↗

PubMed1978

Secretory kinetics in the follicular cells of silkmoths during eggshell formation.

Procedures for quantitative autoradiography were used for studying the process of secretion of eggshell (chorion) proteins in the follicular epithelium of silkmoths. The method was based on photometric measurements of the reflectance of vertically illuminated autoradiographic silver grains. Results were analyzed and plotted by computer. Secretory kinetics were also determined by analysis of labeled proteins in physically separated epithelium and chorion. Rapid accumulation of radioactivity into "clumps" visualized by light microscope autoradiography and evidence from preliminary electron microscope autoradiography indicate that, within 2 min from the time of synthesis, labeled chorion proteins move to Golgi regions scattered throughout the cytoplasm. The proteins begin to accumulate in the apical area 10-20 min later and to be discharged from the cell. The time for half-secretion is 20-25 min, and discharge is essentially complete 30-50 min after labeling. At the developmental stages examined, the kinetics of secretion appear to be similar for all proteins. Within the chorion the proteins rapidly assume a characteristic distribution, which varies for different developmental stages. Two relatively slow steps have been identified in secretion, associated with residence in Golgi regions and in the cell apex, respectively. By contrast, translocation of proteins across the cell and deposition of discharged proteins in the chorion are rapid steps.

Animals↗

PubMed1998

Sodium chloride concentration in drinking water and eggshell quality.

Two experiments with White Leghorn hens (36 and 49 wk old, respectively) were conducted to examine the effects of varying NaCl concentrations provided through drinking water upon eggshell quality. Experiments were of 6 and 5 wk duration, respectively. Seven replicate pens of five individually caged hens received each water treatment. Treatments were the same in both studies and consisted of low-Na (9 ppm) tap water supplemented with 0, 200, 400, 600, or 800 ppm NaCl. Solutions were prepared weekly. All eggs produced were examined visually for shell defects, and egg weight and specific gravity were determined. In the second experiment, eggs from 2 consecutive d were also broken out each week for Haugh Unit determinations. In both studies, hen-day egg production, daily feed and water intake, egg weight, and body weight change over the experimental period were not influenced by any level of waterborne NaCl. Haugh Units were also not affected in Experiment 2. In contrast to other literature reports, visually determined shell defects and egg specific gravity were not adversely affected by NaCl supplementation of layer drinking water.

Animals↗

PubMed1999

Effects of microbial phytase supplementation on egg production, eggshell quality, and mineral retention of laying hens fed different levels of phosphorus.

A 20-wk feeding trial (21 to 40 wk of age) was conducted to evaluate the effects of phytase supplementation on egg production, egg quality, nutrient retention, and P excretion of laying hens fed diets containing different levels of P. Nine hundred and sixty ISA Brown hens were randomly allocated to completely randomized block arrangement of four diets: corn-soybean diet (1.4% tricalcium phosphate, TCP) without (T1, control) and with phytase (T2); 0.7% TCP (T3) or 0% TCP (T4) diet with phytase. Dietary microbial phytase was added at a level of 500 U/kg. Both hen-day and hen-housed egg production of T2 were significantly (P < 0.05) higher than other treatments, which were not different among themselves. Egg weights were also significantly (P < 0.05) different among treatments ,with T2 being the highest. Feed consumption of T2 was significantly (P < 0.05) higher than other treatments but feed conversion ratio was not significantly different from others. Specific gravity and shell thickness of the eggs were highest in the control (T1) but eggshell strength and broken egg to total egg ratio were not different among treatments. Haugh units were not different among treatments. Retention of Ca, P, Mg, Fe, and Zn were greater (P < 0.05) in phytase-supplemented groups. There were significant (P < 0.05) differences in excretion of ash, P, and Zn. The excretion of these components were highest in the control, whereas P excretion was significantly lower in the T3 and T4 groups. In conclusion, supplementation of the microbial phytase to normal corn-soybean diet improved egg production and can reduce TCP level in the diet without affecting egg production and egg quality. Significant reduction of P excretion can be also achieved.

6-Phytase↗

PubMed2000

New insight in eggshell formation.

The matrix proteins that participate in crystalization fulfill important functions during the formation of the calcified tissues and contribute to the biomechanical properties of the mature product. We suggest that osteopontin (OPN) is part of an array of macromolecules synthesized and secreted by the cells adjacent to the mineralization front that self-assemble outside the cell and direct crystal formation. The OPN meets the theoretical requirements for involvement in the mineralization process. The phosphorylated residues of acidic phosphoprotein have been shown to exist in the protein as reactive monoesters that are available for interaction with other ions, among them crystal constituents such as calcium ions. In addition, sulfation of OPN was also found to be associated with mineralization of other tissues. In contrast to the calbindin gene, whose expression is dependent on the calcium flux, the regulation of OPN synthesis is at least in part dependent on the mechanical strain imposed by the resident egg. These results demonstrate the complexity of the regulation of the matrix genes governing eggshell formation.

Animals↗

PubMed2002

Comparison of eggshell surface microbial populations for in-line and off-line commercial egg processing facilities.

The objective of this project was to evaluate the aerobic plate counts (APC) of eggshells at in-line and off-line egg processing facilities at selected sites, throughout the processing procedure. Samples were collected from four sites in the processing plant and five time periods during the daily processing shift. Site 1 was from the conveyor system before the eggs passed through the washing system. Site 2 was after detergent wash but before sanitizer application. Site 3 was immediately after sanitizer treatment. Site 4 was immediately before packaging. Samples were collected from the sites at five equally spaced intervals beginning 15 min after the processing shift began and ending 15 min before the processing shift ended. At each sampling time, eggs were aseptically collected from each site and placed into sterile plastic bags containing 50 mL of PBS that was serially diluted immediately. The dilutions were plated on APC agar within 8 h of collection and were incubated at 37 C for 48 h. APC counts of in-line and off-line eggs were compared within time periods across sites. As the processing shift progressed, off-line APC counts were significantly higher than in-line counts at Site 1. At Site 2, off-line APC counts were significantly higher than in-line counts for Periods 2 through 5. At Site 3, off-line APC counts were significantly higher than in-line counts for Periods 2 through 5. Site 4 off-line counts were significantly higher than in-line counts at all time periods.

Animals↗

PubMed2003

A comparison between cholecalciferol and 25-OH-cholecalciferol on performance and eggshell quality of hens fed different levels of calcium and phosphorus.

Two experiments were conducted to determine whether the presence of 25-OH-cholecalciferol (25-OH-D3) as compared to vitamin D3 produces any beneficial effect on shell quality of laying hens. Experiment 1 consisted of a 4 x 2 factorial arrangement of the treatments with four determined Ca levels (3.34, 4.3, 4.73, and 4.94%) and two sources of vitamin D (vitamin D3 and 25-OH-D3, which were used at 69 microg/kg diet or 2,760 IU/kg diet). Experiment 2 consisted of a 3 x 2 x 2 factorial arrangement of the treatments with three determined levels of nonphytate P (NPP) (0.11, 0.21, and 0.41%), two levels of phytase (0 and 300 U/kg diet), and two sources of vitamin D (vitamin D3 and 25-OH-D3, which were used at 69 microg/kg diet, the equivalent of 2,760 IU/kg diet). Substitution of vitamin D3 with 25-OH-D3 in neither of the experiments produced any beneficial effect on shell quality. A Ca level of 3.34%, which provided the birds with 3.63 g Ca/hen per d, was adequate for performance and eggshell quality. The NPP level of 0.11% was not sufficient to support performance. However, a NPP level of 0.21% was adequate and resulted in performance that was comparable to that of birds fed the 0.41% NPP diet. The presence of phytase did not have an effect on performance but reduced several indices of the shell quality. In conclusion, under the conditions of the current experiments, the use of 25-OH-D3 did not provide any advantage for shell quality or production performance.

6-Phytase↗

PubMed2005

Enzymatic and microbiological inhibitory activity in eggshell membranes as influenced by layer strains and age and storage variables.

Eggshell membranes (ESM) have been shown to exhibit antibacterial activity. The purpose of this study was to evaluate the enzymatic and biological [decimal reduction times (D-values)] activities of ESM as a function of bird breed, age, and ESM stabilization treatments. Younger White Leghorn (WL) hens produced ESM with 28% higher lysozyme activity than Rhode Island Red (RIR) layers. In contrast, older WL layers produced ESM with 17% less lysozyme activity than ESM from RIR layers. Similarly, beta-N-acetylglucosaminidase (beta-NAGase) ESM activities differed by hen age within breeds with younger hens yielding 14 to 16% more enzyme activity. D54 degrees C-values of Salmonella Typhimurium cells preexposed to WL ESM did not differ as a function of bird age (33, 50, and 81 wk). The ESM Lysozyme and beta-NAGase activities varied somewhat over a 6-mo storage study after treatment with 1 of 5 stabilization methods [i.e., storage at 4 degrees C, -20 degrees C, or ambient air storage after freeze drying, air drying (23 degrees C), or forced-air drying (50 degrees C)]. Both air and forced-air drying yielded significant reductions in beta-NAGase and lysozyme ESM activity (ca 12 to 30%) after the initial 24 h and then remained fairly stable during the extended storage. Freeze-dried samples retained the most enzymatic activity (95%) throughout the 6-mo trial, whereas refrigerated ESM lost 20 and 18% of the beta-NAGase and lysozyme activities, respectively. Frozen ESM lost 22% of the beta-NAGase activity, whereas lysozyme was nearly unaffected after 6 mo. The ESM biological activities against S. Typhimurium were not adversely impacted by layer breed or age. No significant loss in biological activity of ESM was detected 24 h after processing or after 6 mo of storage for refrigerated, frozen, and freeze-dried membranes, whereas significant reductions were observed for air- and heat-dried ESM. These findings demonstrate that ESM enzyme and biological activities are relatively constant across layer breeds and over extended storage. Based on these and other findings, ESM may have potential commercial value as a processing adjuvant in food and pharmaceutical product applications.

Acetylglucosaminidase↗

PubMed2005

Effect of eggshell temperature during incubation on embryo development, hatchability, and posthatch development.

An experiment was conducted to study the effects of different eggshell temperature (EST) profiles during incubation on embryo mortality, hatchability, and embryo development. Furthermore, chicks from different EST profiles were reared under low and high housing temperatures to investigate subsequent posthatch growth and rectal temperature. Two batches of eggs were used in this experiment. Hatching eggs were subjected to 36.7 or 37.8 degrees C EST during the first week, to 37.8 degrees C EST during the second week, and to 37.8 or 38.9 degrees C EST during the third week of incubation. Posthatch housing temperature decreased from 35 degrees C at d 1 to 30 degrees C at d 7 (high) or decreased from 30 degrees C at d 1 to 25 degrees C at d 7 (low). The difference between machine temperature and EST (DT) was used to illustrate the effect of EST on heat production during incubation. DT differed per batch, and was smallest when eggs were incubated at 36.7 degrees C instead of 37.8 degrees C during wk 1. High EST during wk 3 of incubation (38.9 degrees C instead of 37.8 degrees C) reduced DT only in batch 2. Embryo development was most retarded in eggs incubated at 36.7 degrees C EST compared with at 37.8 degrees C during the first week of incubation. However, highest hatchability and embryo development were always found when EST was maintained at 37.8 degrees C constantly throughout incubation. Chicks that hatched from eggs incubated at low EST during wk 1 of incubation had lower rectal temperature after hatching, especially under low housing temperatures, and this effect lasted until 7 d posthatch in batch 1. The highest rectal temperatures were always found in chicks incubated at 37.8 degrees C EST constantly throughout incubation. Eggs and chicks from different batches require different environmental conditions for optimal embryo development, hatchability, and posthatch growth. Rearing temperature and incubation conditions affect the ability of young chicks to maintain their rectal temperature during the first week posthatch.

Animals↗

PubMed2006

The effects of suboptimal eggshell temperature during incubation on broiler chick quality, live performance, and further processing yield.

Different incubation conditions can cause eggshell temperature (EST) to deviate from optimum. Two experiments were performed to determine the effect of low EST at the start of incubation and high EST at the end of incubation on hatchability, chick quality, 6-wk live performance, and breast meat yield of broiler chickens. In each experiment, 1,800 eggs from a single flock were divided and set into 2 setters. From 0 to 10 d of incubation, one setter was set to attain an EST of 36.6 degrees C (considered low), whereas the other was set to 37.8 degrees C (the control temperature). Using an infrared thermometer, EST was measured daily on a sample of eggs to ensure treatment intentions. On d 11 of incubation, the temperature of the low EST setter was increased to 37.8 degrees C in synchrony with the other setter until transfer. On d 18 of incubation, eggs from both setters were combined into 2 equal groups and transferred to hatchers. The EST in one hatcher was set to 37.8 degrees C (control) and in the other to 39.5 degrees C (considered high) until 21 d of incubation. Hatched males were placed in battery cages (Experiment 1) or floor pens (Experiment 2) and reared on common feeds to 1 or 6 wk of age, respectively. Low EST in the first 10 d of incubation reduced hatchability, increased BW and chick yield, and reduced 1-wk gain compared with the control EST. Throughout rearing, BW was reduced for low EST chicks compared with control EST chicks; consequently, carcass, fillet, and tender weights were also reduced. High EST in the hatcher increased hatchability, and reduced BW, chick yield, and 1-wk gain compared with control EST in the hatcher. By 3 wk of age, there was no difference in BW between chicks in high EST and control EST treatments. Subsequent carcass and processing yields were also similar. Incubation at the control EST of 37.8 degrees C, particularly from 0 to 10 d, resulted in the best performance overall.

Animals↗