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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↗
PubMed1988

Gas chromatographic analysis of shell membrane amino acids from hard-shelled, soft-shelled, and shell-less eggs.

The amino acid composition of shell membranes from hard-shelled (HS), soft-shelled (SS), and shell-less (SL) eggs produced by 62-wk-old hens was analyzed by gas chromatography using N-acetyl n-propyl ester derivatives. This technique succeeded in identifying tryptophane and ornithine as shell membrane components. There were no significant differences in the concentrations of any of the 17 amino acids analyzed among HS and SS eggs, HS and SL eggs, or SS and SL eggs. Stepwise discriminant analysis of the amino acid ratios correctly classified all of the amino acid chromatograms of shell membranes from HS/SL and SS/SL egg pairs, and 92.9% of the HS/SS and 90.0% of the HS/SS/SL amino acid chromatograms were classified correctly (F = 1.0). Higher F values reduced the percentage of correct classifications to 75.0%, 85.0%, and 67.5% (F = 2.0) for the HS/SL, SS/SL, and HS/SS/SL egg groups, respectively, and to 78.6% (F = 3.0) for the HS/SS egg group. Stepwise discriminant analysis also identified specific amino acid ratios that were most efficient at classifying the amino acid chromatograms according to shell type. This process identified three amino acid ratios for the HS/SS egg group (F = 3.0), two ratios for the HS/SL egg group, four ratios for the SS/SL egg group, and four ratios for the HS/SS/SL egg group (F = 2.0). Based on the number of times they appeared as efficient discriminating variables at higher F values, alanine, proline, and isoleucine seemed to be the most important amino acids for correctly classifying shell membranes by egg type.

Amino Acids↗
PubMed1981

The relationship of serum calcium to shell weight and other criteria in hens laying a low or high incidence of shell-less eggs.

Experiments were conducted to determine the relationship of serum calcium to shell weight and other criteria. Blood samples for calcium analysis were taken at oviposition in Experiments 1 and 2 from hens fed a 3.5% calcium diet. In Experiment 3, blood was taken at various intervals from hens laying a high or low incidence of shell-less eggs. These hens were fed a control diet or various calcium-deficient diets throughout a 45-day period. No relationship was found between serum calcium and shell weight, or egg weight. Hens laying a high incidence of shell-less eggs showed no decrease in serum calcium or egg production when fed a .58, .25, or .07% calcium diet. However, these criteria were reduced in hens laying a low incidence of shell-less eggs. It was concluded that the normal variation in serum calcium is not related to the hen's ability to produce eggshell. The mechanism of action responsible for cessation of lay when control hens were fed a calcium-deficient diet appeared not to function as it does in hens laying a high incidence of shell-less eggs.

Animals↗
PubMed1979

Water-vapor conductance of testudinian and crocodilian eggs (class reptilia).

Flexible-shelled eggs of snapping turtles (Chelydra serpentina) have conductances to water vapor that are 55 times higher than predicted for avian eggs of similar size, whereas rigid-shelled eggs of softshell turtles (Trionyx spiniferus) and American alligators (Alligator mississippiensis) have conductances that are only five times higher than expected for comparable eggs of birds. The differences between empirical and predicted values result from the much higher effective pore areas in reptilian eggshells than in those of birds. The relatively high porosities of these reptilian eggs presumably facilitate the transport of oxygen and carbon dioxide eggshells in later stages of incubation when air trapped inside nest chambers may become hypoxic and hypercapnic, yet seem not to lead to excessive transpiration of water vapor owing to the high humidities in nests where incubation occurs.

Alligators and Crocodiles↗
PubMed1999

A low frequency 1H-NMR external unit for the analysis of large foodstuff samples.

An inexpensive external unit that allows the use of a commercial high-resolution NMR spectrometer as a very low frequency instrument is described. The external unit is phase coherent, the pulse timing being given by the parent spectrometer. With the exception of the probe, the external unit does not contain any tuned elements. This permits easy change of frequency in the range 100 kHz-1 MHz. The external unit may be appropriately employed in food science where, in several cases, low frequency is desirable. An application to hen shell eggs at the frequency of 700 kHz is described.

Animals↗
PubMed1986

Ontogeny and oestradiol dependence of vitamin D-binding protein blood levels in chickens.

The concentration of 25-hydroxyvitamin D3-binding protein (DBP) was measured, by immunodiffusion, in the blood of chickens from embryonic stages to sexual maturity. Low levels of DBP and 1,25-(OH)2D3 were detectable in the blood of chick embryos from the 12th and 17th day of incubation respectively and stayed at the same low levels until hatching. The blood concentration of DBP doubled between the 1st and 5th days of life, then increased slowly and reached the mean level of the adult male at 7-8 weeks of age. The concentration of DBP was independent of vitamin D status in growing chickens. A large increase was observed in DBP blood levels in hens just before sexual maturity. This change, and those observed in moulting hens, followed the variations in plasma concentrations of oestradiol more closely than those of progesterone or testosterone. Moreover, a large increase in plasma DBP levels was induced in immature chickens by oestradiol (0.5 mg/day), but not by testosterone or progesterone. Finally, the experimental suppression of egg shell formation and the associated decrease in 1,25-(OH)2D3 plasma levels had no effect on plasma DBP concentrations. However, 1,25-(OH)2D3 and DBP levels were higher in hens laying shell-less eggs than in immature pullets. The increases in DBP levels at hatching, in immature pullets treated with oestrogens, in hens laying uncalcified eggs and at the onset of egg production were associated with increases in 1,25-(OH)2D3, suggesting a relationship between the levels of DBP and 1,25-(OH)2D3 in the blood.

Animals↗
PubMed1981

Schistosoma mansoni: the effect of thiosinamine in vivo and in vitro.

It has been found that treatment of mice infected with Schistosoma mansoni with thiosinamine for five days had a significant effect on the formation of normal egg-shells within the ootype of female worms. The protein material, not organized into complete egg-shells, was nevertheless tanned and the surface of these amorphous masses was formed into microspines. Normal egg-shell formation was restored following drug withdrawal. The process of egg-shell formation consists of the integration of the physical moulding of egg-shell precursors derived from the vitelline cells, associated with the chemical process of protein tanning. It is suggested that thiosinamine treatment in vivo results in disruption of egg-shell formation by causing a breakdown in the moulding process and not by the inhibition of protein tanning involving the enzyme polyphenoloxidase. Treatment of worms with the drug under in vitro conditions resulted in a more enhanced effect of egg-shell formation.

Animals↗
PubMed1995

Experimental oral infection of specific pathogen-free laying hens and cocks with Salmonella enteritidis strains.

A total of 105 specific pathogen-free (SPF) laying hens and eight cocks were orally infected with strains of Salmonella enteritidis. The organs of these animals were examined bacteriologically for up to 6 weeks post infectionem (p.i.). One-half of the eggs laid on a single day were examined 1 day after laying, and the other half 28 days after laying. The siderophore, ferrioxamine E, was added to the pre-enrichment medium. A high correlation was found to exist between colonization of the caecum by salmonellas and the level of contamination of the egg shell. No correlation was found between the contamination of the egg shell and that of the egg content. The strains used for infection were not recovered from any yolk out of a total of 938 eggs. S. enteritidis was isolated from the albumen in four cases (0.4%). Storage of the eggs for 28 days after laying resulted in a decrease in the frequency of salmonella detection on the egg shell and in the egg content. The strains used for infection could be isolated from various sections of the sexual organs for up to 2 weeks p.i. S. enteritidis was most frequently found in the ovary and rarely in the oviduct, but never in the pre-ovulatory mature follicles. In the groups that included salmonella-infected cocks, the salmonella detection frequency did not increase either for the egg content or for the organs of the laying hens. It seems that primary vertical transmission of salmonellas occurs, in rare cases, as a result of an infection of the albumen but not of the yolk.

Animals↗
PubMed1996

Pasteurization of eggs in the shell.

A small percentage of all eggs may be contaminated with Salmonella enteritidis (SE). To eliminate this hazard from the food supply, procedures for pasteurizing eggs in the shell have been developed. At least four research groups are attempting to devise a process to achieve a pasteurized shell egg. Only one of the groups has reported procedures and results. Sound shell eggs were washed to remove surface contaminants. The clean eggs were then inoculated with high levels of SE cells. The inoculated eggs were then heated by one of several means to a yolk temperature of about 55 C and held at that temperature for varying periods of time. The number of surviving cells was determined. It is possible to obtain a 7 log cycle reduction of SE in inoculated eggs without a significant change in functional or visual quality of the eggs.

Animals↗
PubMed1984

Toxic shock-like syndrome in hens and its relationship to shell-less eggs.

Foreign materials were inserted into the hens' uteri and anti-inflammatory and immune suppressant drugs were used to determine possible causes of shell-less eggs. The presence of foreign shell-membranes and tampons in the uteri (shell glands) of hens caused a toxic shock-like syndrome ( TSLS ). Primary clinical signs were high fever, vomiting, diarrhea, and death. The presence of other materials, including inflated rubber balloons, had no adverse affect on the hens. Calcium carbonate deposits occurred on the surface of the balloons but not on other material inserted into the uteri. Injection of anti-inflammatory or immunosuppressive drugs did not increase shell weight in hens laying shell-less eggs. The hens' reproductive system was found to be sensitive in varying degrees to different types of foreign materials; thus, the avian female might serve as an animal model for studying toxic shock syndrome.

Animals↗
PubMedDate not supplied

Avian adenoviruses: effect on egg production, shell quality, and feed consumption.

Four avian adenovirus isolants (Indiana C, DPI-2, IBH-2, and B-3)were examined for pathogenicity in laying birds. None affected shell quality, and only one (IBH-2) had even a minimal effect on egg production (faster decline). Of three isolants tested (Indiana C, DPI-2, and IBH-2), only IBH-2 caused feed intake to be reduced. No other clinical signs were observed during these experiments. Egg transmission, virus excretion, and antibody production were found to mimic patterns reported for serotype-1 avian adenoviruses.

Adenoviridae Infections↗
PubMed2001

Characterisation of some Ornithobacterium rhinotracheale strains and examination of their transmission via eggs.

The biochemical characteristics and antibiotic susceptibility of 12 Ornithobacterium rhinotracheale strains isolated from chickens and turkeys suffering from respiratory clinical signs and the survival of some isolates on egg-shell and within chicken eggs during hatching were examined. All O. rhinotracheale strains showed typical biochemical characteristics. Among the 16 drugs examined, penicillin G, ampicillin (MICs ranging from < or = 0.06 microgram/ml to 1 microgram/ml), ceftazidim (with MICs from < or = 0.06 microgram/ml to 0.12 microgram/ml), erythromycin, tylosin, tilmicosin (with some exceptions MICs ranged from < or = 0.06 microgram/ml to 1 microgram/ml) and tiamulin (MICs varied from < or = 0.06 microgram/ml to 2 micrograms/ml) were the most effective. Lincomycin, oxytetracycline and enrofloxacin also gave good inhibitions, but with most strains in a higher concentration (MICs ranged in most cases from 2 micrograms/ml to 8 micrograms/ml). The other antibiotics inhibited the growth of O. rhinotracheale only in very high concentrations (colistin) or not at all (apramycin, spectinomycin, polymyxin B). At 37 degrees C, O. rhinotracheale did not survive on egg-shell for more than 24 hours, while upon inoculation into embryonated chicken eggs it killed embryos by the ninth day, and from the 14th day post-inoculation no O. rhinotracheale could be cultured from the eggs at all. These results suggest that O. rhinotracheale is not transmitted via eggs during hatching.

Animals↗
PubMed1980

Prevalence of salmonellae on eggs from poultry farms in New York State.

The purpose of this study was to determine the prevalence of salmonellae on egg shells. One hundred eggs from each of 14 Central New York poultry farms were tested for salmonella contamination of the shell. The egg magma was examined in those eggs that were positive on shell culture. Only .21% or three of the egg shells yielded salmonellae, all three of which were identified as S. typhimurium. No salmonellae were found in the magma of these eggs. Feed samples from 12 farms were also negative for salmonellae. From this study it would appear that the incidence of salmonellae on eggs from Central New York poultry farms is very low.

Animals↗
PubMed1997

Toxocara canis (Nematoda:Ascaridae): the fine structure of the oviduct, oviduct-uterine junction and uterus.

The fine structure of the oviduct, oviduct-uterine junction and uterus of the nematode Toxocara canis (Werner, 1782) is described. Columnar-type epithelioid cells with numerous microvilli at the apical membrane border the oviduct lumen. Many electron dense secretory products are present in these cells. The cells lining the oviduct-uterine junction have no microvilli. They are coated with an electron-dense layer and contain numerous membrane-bound dense material containing bodies. Externally, the cells are surrounded by a basal lamina and muscle cells. The epithelial cells lining the greater part of the paired uteri appear to be rather flat. The oocytes inside the oviduct are covered with a dense thick plasma membrane and contain lipid droplets, dense granules and glycogen. The morphology of the oocytes before the fertilization inside the oviduct-uterine junction resembles that of the oocyte in the oviduct. After the fertilization the egg shell formation takes place. The egg shell of T.canis is composed of four layers: uterine, vitelline, middle chitinous and inner layer. The differences between the fine structure of the egg shell of T. canis and other related nematodes are discussed.

Animals↗
PubMed1981

Osteoclast cell-surface specializations and nuclear kinetics during egg-laying in Japanese quail.

Medullary bone deposits serve as a reservoir of labile calcium for egg-shell calcification in birds. Quantitative transmission-electron-microscope methods and light-microscope autoradiographic cell-population-kinetic analyses were used to determine changes in cell-surface specializations and population dynamics of medullary bone osteoclasts during egg-laying in Japanese quail. Prior to egg-shell formation, from 0 to about 8 hours after the previous oviposition, very few osteoclast profiles had ruffled borders. The appearance of ruffled borders coincided with the beginning of egg-shell calcification, about 9-10 hours after the previous oviposition. During egg-shell calcification, about 10-21 hours after the previous oviposition, most osteoclast profiles had ruffled borders. Ruffled borders disappeared at the completion of egg-shell calcification and commencement of egg-shell pigmentation. Thus, functional activities of medullary bone osteoclasts appear to be closely synchronized with egg-shell calcification during egg-laying. From 1 to 48 hours after a single injection of 3H-thymidine (3H-TdR), very few labeled osteoclast nuclei were seen during egg-laying. Following multiple injections of 3H-TdR, the percentage of labeled nuclei reached a peak at about 170 hours after the first injection. At this peak-labeling time, relatively few of the osteoclast profiles that had labeled nuclei had two or more; although the average number of nuclei per osteoclast profile was about 3.6. These kinetic data suggest that the medullary bone osteoclast population has a prolonged rate of turnover compared to rapid changes in cell activities associated with each 24-hour egg-laying cycle; and collectively they would suggest that rapid changes in osteoclast functions occur independently of changes in cell-population dynamics.

Animals↗
PubMed2006

Investigations of the vertical transmission of Erysipelothrix rhusiopathiae in laying hens.

Erysipelas was diagnosed in a layer breeder flock in Sweden in 2002. Although vertical transmission of Erysipelothrix rhusiopathiae has not been previously described in chickens, the potential of erysipelas infection to adversely affect hatching eggs was of concern. To clarify the possible impact of erysipelas on hatching eggs and their progeny, an experiment was done using 200 hatching eggs collected from the infected flock. The eggs were incubated for 21 days, and the egg shells, infertile eggs, dead-in-shell embryos, and a sample of day-old hatched chicks and blood samples from 5-day-old chicks were cultured for E. rhusiopathiae. In addition, after 28 days of grow-out, the male chickens were euthanatized and cultured for the bacterium, and the remaining female chickens were placed as a backyard flock and observed over a 4-mo period. Bacteriological test results of the above-mentioned samples were negative for E. rhusiopathiae. Mortality rates were not excessive, and no clinical symptoms of erysipelas were observed during the period of observation. The result of the investigation suggests that in layer breeder chickens, E. rhusiopathiae is not vertically or egg transmitted and that the disease outbreak in the parent stock had no adverse impact on the quality of hatching eggs in terms of increased embryo mortality.

Animals↗
PubMed1991

Uterine calcium-binding protein activity of nonlaying hens and hens laying hard-shelled or shell-less eggs.

Uterine calcium-binding protein (CaBP) activity was compared at oviposition and 14 h postoviposition in nonlaying (NL) hens and hens laying a high incidence of shell-less (SL) or hard-shelled (HS) eggs fed a commercial laying diet. Epithelial cells were removed from uteri of NL, SL, and HS hens and homogenized in Tris buffer, pH 7.4. Proteins in homogenate were fractionated by the addition of ammonium sulfate and centrifugation, separated by Sephadex chromatography, and measured by ultraviolet spectrophotometry at A280. Calcium-binding protein activity was determined using a 45Ca-chelex binding assay. Two peaks of CaBP activity were detected and designated CaBP-a (28,000 Da) and CaBP-b (16,000 Da). Uterine CaBP-b may differ from CaBP-a only in Ca content. The activities of CaBP (a and b) were higher (P less than or equal to .05) in HS and SL hens than in NL hens at 0 h. There was no significant difference (0 h) between CaBP activity (a versus b) of either HS or SL hens. There was also no difference (0 h) of CaBP-a or CaBP-b activity when SL and HS hens were compared. Uterine CaBP-a activity was lower (P less than or equal to .05) in SL hens than HS hens at 14 h. Under normal dietary conditions, the level of CaBP activity at 14 h may be associated with SL egg production.

Animals↗