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PubMed2001

Thermal inactivation kinetics of Salmonella spp. within intact eggs heated using humidity-controlled air.

The heat resistance of six strains of Salmonella (including Enteritidis, Heidelberg, and Typhimurium) in liquid whole egg and shell eggs was determined. Decimal reduction times (D-values) of each of the six strains were determined in liquid whole egg heated at 56.7 degrees C within glass capillary tubes immersed in a water bath. D-values ranged from 3.05 to 4.09 min, and significant differences were observed between the strains tested (alpha = 0.05). In addition, approximately 7 log10 CFU/g of a six-strain cocktail was inoculated into the geometric center of raw shell eggs and the eggs heated at 57.2 degrees C using convection currents of humidity-controlled air. D-values of the pooled salmonellae ranged from 5.49 to 6.12 min within the center of intact shell eggs. A heating period of 70 min or more resulted in no surviving salmonellae being detected (i.e., an 8.7-log reduction per egg).

Animals↗
PubMed1976

Effect of dieldrin and calcium on the performance of adult Japanese quail (Coturnix coturnix japonica).

Two experiments were conducted to determine the effects of dieldrin and calcium on reproductive performance of quail. At 25% egg production the quail received diets containing 0,10 or 25 p.p.m. of dieldrin for 6, 28-day periods in experiment 1 and 0, 5, or 25 p.p.m. of dieldrin for 4, 28-day periods in experiment 2. Pesticide treatments were employed with diets containing 0.5% and 3.0% calcium. The results show that egg shell thickness, cracked eggs, egg production, feed consumption, egg weights, fertility, hatchability and body weights were not affected by dieldrin treatments. However, egg shell thickness, cracked eggs, egg production and hatchability were adversely affected by the lower calcium level. Female body weights were consistently heavier for the low calcium diet. Mortality increased in the presence of 10 and especially 25 p.p.m. of dieldrin. Livability of chicks from hens receiving rations with 10 and 25 p.p.m. of dieldrin was significantly lower than those fed no dieldrin. In summary, dieldrin was without effect on egg shell quality or other reproductive factors but did exert a detrimental effect on adult mortality and livability of progeny.

Animals↗
PubMed1976

Effect of DDE, DDT and calcium on the performance of adult Japanese quail (Coturnix coturnix japonica).

Two experiments were conducted to determine the effects of DDE, DDT and calcium on performance of quail. The quail received diets containing 0 or 100 p.p.m. of DDE for eight 28-day periods in Exp. 1 and 0, 100 or 300 p.p.m. of DDE or 100 p.p.m of DDT for six periods in Exp. 2. Diets containing either 0.5 or 3% calcium were used with each pesticide level. No differences in egg shell thickness, cracked eggs, egg production, feed consumption, egg weights, female body weights, fertility or hatchability were obtained from DDE or DDT up to 100 p.p.m. Three hundred p.p.m. of DDE did result in a decrease in female body weights and in fertility on the low calcium diet. Egg shell thickness, cracked eggs, egg production and hatchability were affected by the lower calcium level. Male body weights were adversely affected from 100 p.p.m. or more of DDE. Mortality increased as the level of DDE increased for females, while no effect was observed with DDT. Males appeared more sensitive to 100 p.p.m. of DDE in Exp. 1 and 300 p.p.m of DDE and 100 p.p.m. of DDT in Exp. 2. Livability and growth of chicks from hens receiving rations containing DDE AND DDT were unaffected by maternal treatment. In summary, DDE and DDT were without effect on egg shell quality or most other reproductive factors, but DDE at 300 p.p.m. did exert a detrimental effect on adult body weights, fertility and mortality.

Animals↗
PubMed1986

Blood levels of ionized calcium, inorganic phosphorus, 1,25-dihydroxycholecalciferol and gonadal hormones in hens laying hard-shelled or shell-less eggs.

The production of shell-less eggs was induced in hens to measure the effects of the high demands made by shell formation on the blood minerals and hormones whose concentrations change during egg formation. In control hens laying hard-shelled eggs, the concentration of ionized calcium in plasma decreased at the onset of shell formation, but no change was found in hens laying shell-less eggs. Total calcium concentrations in plasma decreased slightly throughout the ovulation cycle in both groups. Concentrations of inorganic phosphorus in the plasma were increased in the control group during the period of shell formation and decreased when calcification was suppressed. Finally, the concentrations of 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) in plasma were significantly increased 16 and 20 h following an ovulation compared with 4 h after ovulation, or compared with the concentrations observed in hens laying shell-less eggs. The variations in the plasma concentrations of ionized calcium, inorganic phosphorus and 1,25-(OH)2D3 associated with egg formation were therefore absent in hens laying shell-less eggs demonstrating their direct link with shell calcification. On the other hand, suppression of shell production had no influence on the changes in the plasma concentrations of progesterone, oestradiol and testosterone which are associated with the normal ovulatory cycle. It is concluded that the increases in intestinal and uterine calcium transport and in 1,25-(OH)2D3 production which occur at the onset of egg production in hens are mainly controlled by factors involved in maintaining calcium homeostasis rather than by gonadal hormones.

Animals↗
PubMed2002

Incubation of rigid-shelled turtle eggs: do hydric conditions matter?

Rigid-shelled eggs of the broad-shelled river turtle Chelodina expansa were incubated at 28 degrees C in wet (-100 kPa), intermediate (-350 kPa) and dry (-750 kPa) conditions. Incubation period was influenced by clutch of origin, but was independent of incubation water potential. Rates of water gained from the environment and pre-pipping egg mass were influenced by incubation water potential -- eggs incubating at higher (less negative) water potentials absorbing more water from their environment. Hatchlings from wet conditions had greater mass but a smaller amount of residual yolk than hatchlings from dry conditions and it is suggested that the amount of yolk converted to tissue is influenced by the amount of water absorbed by the egg during incubation. Water content of yolk-free hatchlings from the -100-kPa treatment was greater than those from the -350-kPa and -750-kPa treatments, but the water content of residual yolks was similar across all hydric conditions.

Absorption↗
PubMed1976

Parathyroid hormone and eggshell calcification in Japanese quail.

The effect of parathyroid hormone (PTH) on egg-shell calcification has been investigated in egg-laying Japanese quail. Lilly parathyroid extract (PTE) when injected into quail within 2-6 h of oviposition caused a significantly increased deposition of a chronic 45Ca label into the sequential egg-shell compared with the previous egg in the clutch, indicating increased mobilization of bone Ca and its subsequent incorporation into the egg-shell. At the same time egg-shell weight/unit area and egg-shell Ca/unit area were significantly decreased. Parathyroid extract injected 12-16 after oviposition had none of these effects. Purified PTH also caused a significant decrease in egg-shell weight/unit area if injected within 2-6 h of oviposition. This result indicated an action of PTH either directly or indirectly on the avian oviduct limiting egg-shell calcification. The loss of responses in the 12-16 h treated birds may reflect high endogenous PTH levels with subsequent saturation of target organ receptors.

Animals↗
PubMed1975

Dietary calcium levels in pre-lay and lay diets in Leghorn pullets.

Four experiments over a period of four years with 1350 first-year pullets were designed to determine the influence of the calcium and phosphorus levels in the pre-lay diets on the growing birds and on their subsequent performance. Several dietary calcium levels in the lay period were studied, as well as the interaction between the pre-lay and lay diets. During the growing phase the pullets fed 3.0% calcium and 0.4% phosphorus had significantly (P less than 0.05) lower body weight at 20 weeks of age than thep ulletsin the other pre-lay treatments. Feed consumption and feed efficiency were also adversely affected by this treatment, and sexual maturity was significantly (P less than 0.05) delayed. Early lay mortality from this treatment was evident. On the basis of egg production, egg weight, shell deformation and percent poorly shelled eggs (PSE) at point-of-lay, the pre-lay diets did not influence lay performance nor was there an interaction between any combination of pullet and lay diets. As the calcium levels of the lay diets increased, egg production, feed consumption and shell rigidity increased. The 1.5% calcium level did not maintain bone mineralization as compared to the 3.0 and 4.5% calcium levels. It was noted that shell quality on the basis of PSE and deformation does not begin to deteriorate immediately after the onset of production. In fact there is a short period of time where the egg shells improve and then there is a gradual decline in shell rigidity. The layers fed the lay diet containing 1.5% calcium produced eggs weighing an average of 57.4 g. This was significantly (P less than 0.05) lower than the eggs of the 2.3, 3.0 or 4.5% calcium fed groups which produced eggs weighing 59.1, 58.6 and 59.4 g. respectively.

Animal Feed↗
PubMed1994

Relationship between shell porosity, shell thickness, egg weight loss, and embryonic development in Japanese quail eggs.

Japanese quail eggs that hatched (H) or pipped (PIP) exhibited less weight loss through 15 d of incubation than did eggs that died late (LD), whereas eggs containing early dead (ED) embryos exhibited the greatest weight loss. The pore concentration at the large end of each egg was greatest in H eggs when compared with all other types. The pore concentration at the equator was greatest in H eggs and least in the eggs of the ED embryos. All other egg types lay statistically between these two types with regard to equator porosity. The small end pore concentration was similar in H, INF, and LD eggs and in the LD, PIP, and ED eggs. The least number was exhibited by the ED eggs and most by the H eggs. The thinnest shells at the small end were exhibited by H eggs, whereas thicker small end shells were exhibited by ED, LD, and PIP egg types. No differences were observed at the large end or equator. The data suggest that ED eggs exhibit excessive weight loss even though shell porosity was lower and shell thickness was similar to other egg types. This suggests that some functional component of the egg such as the shell membrane or albumen may contribute to this excessive weight loss. A similar statement can be made for LD eggs, which experienced greater weight loss through 15 d than did PIP or H eggs.

Animals↗
PubMed2001

Egg marketing in national supermarkets: products, packaging, and prices--part 3.

As part of a national retail egg quality study, the variety of shell eggs and egg products offered for sale, type of packaging, and price relationships were compared in five major metropolitan regions. A total of 81 stores in 28 cities were sampled in California (CA), Illinois (IL), North Carolina (NC), Texas (TX), and New England (NE). Data were recorded for the variety of brands, sizes, white or brown shell eggs, specialty eggs, liquid or frozen eggs, carton sizes, package labeling and coding, and price relationships of shell eggs, liquid, and frozen egg products displayed for sale. The total variety of shell eggs displayed per store was the greatest for CA and NE stores. Stores in CA and TX offered more (P < 0.05) variety of white shell eggs than did stores in the other states, whereas stores in NE displayed the greatest variety (P < 0.05) of brown shell eggs. The average number of liquid and frozen egg products was highest (P < 0.05) for NC stores. Packaging type, USDA labeling, and carton coding differed somewhat among states. The price per one dozen cartons of all white shell egg sizes was highest (P < 0.05) in CA stores, and the average liquid plus frozen egg product prices were higher in CA and NE stores compared to the other states. However, the ratio of liquid and frozen product prices to all large shell egg prices was among the lowest for CA and NC stores. These data indicate that product selection, packaging, and consumer prices for shell eggs and egg products varied considerably across five separate regions of the country.

Animals↗
PubMed2005

The ultrastructure of the gravid uterus of Brugia pahangi, another rich source of antigen of the filarial parasite.

The gravid uterus with zygotes and microfilariae in utero of Brugia pahangi, a rich source of antigen as revealed by a recent immunofluorescent technique, were studied ultrastructurally. The epithelial cells of uterus show ultrastructural features of synthetically active cells. Their secretions may provide nutrients for the egg in utero. On the basal side, the uterine epithelial cells may also secrete substances to form the basal lamina of the uterus which is rather thick and irregularly fused with the basal lamina lining the body wall where the pseudocoelomic cavity is obliterated. For the most part, the uterine basal lamina contains uniform granular material of moderate electron density. There are also elongated visceral muscle cells embeded in it, and which surround the uterus, with adjacent cells overlapping. The gravid uterus contains several stages of developing microfilariae within its lumen, the cleaving zygotes are also present at another level. The morula of zygotes are composed of several closely packed cells surrounded loosely by their own egg shell membranes. The egg shell becomes more convoluted as development proceeds. The egg shell surrounding the developing microfilariae in utero is secreted by the uterine epithelium. This structure later becomes the sheath of circulating microfilariae, and is highly antigenic as indicated by intense labeling with fluorescent antibodies.

Animals↗
PubMed1991

Plasma, follicular, and uterine levels of prostaglandins in chickens laying soft-shelled and shell-less eggs.

Not all eggs produced by chickens are laid at the expected time of oviposition. Some eggs are laid prematurely, which result in inadequate shells. These uncollectible eggs are referred to as soft-shelled (partial calcification) or shell-less (no calcification) eggs. Of all soft-shelled or shell-less eggs that were laid in the present study, 57% were expelled prematurely. To determine whether prostaglandins were correlated with the expulsion of soft-shelled or shell-less eggs, prostaglandin F2alpha (PGF2alpha), 13,14-dihydro-15 keto prostaglandin F2alpha (PGFM), and 13-14-dihydro-15 keto prostaglandin E2 (PGEM) were measured in the peripheral plasma and follicular and uterine tissues of hens laying soft-shelled eggs and shell-less eggs. Controls were represented by hens laying hard-shelled eggs (normal calcification). Plasma concentrations of PGFM increased (P less than .01) upon the premature oviposition of soft-shelled eggs but not shell-less eggs. The source of the peripheral PGFM may have been the preovulatory follicle, because PGF2alpha levels were higher (P less than .07) in the soft-shelled or shell-less egg layers when compared with the controls. Plasma and tissue levels of PGEM did not differ between hens laying soft-shelled or shell-less eggs versus hard-shelled eggs. These results suggest that PGF2alpha and PGFM are involved in the premature oviposition of some chicken eggs.

Animals↗
PubMed1985

Variability of shell conductance and gas exchange of chicken eggs.

In 395 fertilized chicken eggs (strain Warren) obtained from a commercial hatchery the following coefficients of variation (SD/mean) were found: egg shell conductance for water vapor, GH2O, 22%; freshly laid egg weight, W, 8%; the specific conductance, gH2O (= GH2O/W), 22%. In 20 eggs selected for widely varying gH2O (range 57%-195% of the mean, 0.246 mg/(day X torr X g), the specific O2 uptake and the CO2 output, measured on days 16-19 of incubation, showed a maximum at medium gH2O values, decreasing at both lower and higher gH2O. The variations of gH2O in the selected eggs were shown to cause a variation of water loss up to hatching from 9 to 26% (average 15%), and a variation of the O2 tension from 84 to 123 torr, and of the CO2 tension from 18 to 54 torr, in the perichorioallantoic air space on days 16-19 of incubation. Mechanisms responsible for the observed changes in the metabolic rate and for the physiological adjustments to varied egg shell conductance are discussed.

Animals↗
PubMed1993

A study of carbohydrate metabolism in the eggs (oncospheres) of the tapeworm, Hymenolepis diminuta, with special reference to glucose.

When incubated in vitro for 24 h, intact eggs, chemically shelled eggs (obtained by treating intact eggs with NaOCl), activated larvae (eggs in which the outer shell and inner envelope were removed), and oncospheres (activated larvae treated with papain to remove the embryophore) absorb and metabolize radioactive glucose. Intact eggs, which are covered by the impermeable shell, absorb only small amounts of exogenous radioactive glucose, while chemically shelled eggs, activated larvae, and oncospheres absorb much larger amounts. Only very small amounts of the exogenous glucose are incorporated into the ethanol-precipitable carbohydrate fraction (which would include glycogen) by any of the preparations of eggs/larvae. However, the glucose is incorporated into higher molecular weight end-products that are liberated into the incubation medium. There is a temporal shift in the ability of activated larvae and oncospheres to metabolize exogenous glucose. Activated larvae and oncospheres absorb but do not metabolize glucose during the first 8 h post-activation. Between 8 and 16 h post-activation, however, virtually all of the absorbed glucose is metabolized into higher molecular weight end-products that are liberated into the incubation media. This temporal shift suggests that activation of oncospheres and cysticercoid morphogenesis are accompanied by distinct changes in carbohydrate metabolism.

Animals↗
PubMed2003

Electron miscroscopy and histochemical studies on four Egyptian helminthes eggs of medical importance.

By SEM the Fasciola gigantica egg is ovoid with a small knob like operculum, while the egg of Heterophyes heterophytes is broad oval with the operculum more tapering. The egg shell of fertilized Ascaris lumbricoides has interconnected ridges and peak-like projections, while the egg of Enterobius vermicularis is flattened with a thicker margin at the curved side. By TEM, Fasciola egg shell consists of fine reticulum fibrils of three layers. The outer lipoprotein of perivitelline membrane beneath which 2 membranes separated by inclusions, middle of protein globules and inner lipoprotein layer with minute electron-dense granules of melanin or polymer origin, in some parts of the shell giving the egg its brown coloration. The Heterophyes egg shell is more or less similar to that of Fasciola but lacking the minute electron-dense granules. The egg shell of Ascaris has outer ulterine layer with three consecutive layers, basal lipoprotein layer and the inner lipid or ascaroside layer which is the most resistant layer. The Enterobius egg shell consists of five layers, external uterine, internal uterine, vitelline, chitinous and lipid layer. Histochemically, Fasciola egg shell consists of nine amino-acids, and that of Heterophyes consists of ten amino acids. In Ascaris, the lipid layer characteristically consists 25% protein and 75% lipid. The histochemical examination of Enterobius as a detailed example, showed different degrees of reactions with mercuric bromophenol blue, diazotization coupling, Sakaguchi reaction, Sudan black and Mallory's triple stain. Temperature showed marked effect on eggs survival. Eggs of Fasciola and Heterophyes withstand more low temperatures but those of Ascaris and Enterobius withstand more high ones. There are marked correlations between the egg shell constitution, histochemical compositions on one hand and water permeability and egg dryness on the other hand. The results were photographed and discussed.

Animals↗
PubMed1978

[The shell of the quail's egg: ultrastructural and crystallographic study (author's transl)].

The egg-shell of Japanese quail was studied by several techniques. Semithin sections (1 micron thick) of non-decalcified shell were observed by normal and polarized light microscopy. Thin sections of non-decalcified shell, examined by transmission electron microscopy, permitted us to observe the forms and dimensions of crystals of calcite within different layers of the shell: mammilary layer, layer of cones, palissade layer and surface crystal layer. There appears to be two distinct zones in the layer of cones as well as in the superficial crystal layer. Electron microdiffraction revealed the orientation of calcite crystals in the columns. Some crystal defects (twins?) were described and the possibility of their artefactual formation during ultramicrotomy is discussed. Localization of Ca, Mg, P and S were made by X-ray microanalysis of semithin sections. This technique shows that shell membranes, and chiefly the true cuticle, are also mineralized but, in these layers, minerals are not crystallized. Otherwise the distribution of Mg is not uniform throughout the shell thickness; it is less concentrated in the external zone of the layer of cones. These results together with observation of developing shells by scanning electron microscopy allowed us to propose a scheme for shell organization of the quail egg. This organization was related with decalcification which occurs during hatching.

Animals↗
PubMed1975

Egg production, shell thickness, and other physiological parameters of laying hens affected by T-2 toxin.

T-2 toxin has been reported to cause severe oral lesions and neural disturbances in young broiler chickens. T-2 toxin, when added at a level of 20 mug per g of feed, caused oral lesions but no abnormal neural disturbances in young broiler chickens. T-2 toxin, when added at a level of 20 mug per g of feed, caused oral lesions but no abnormal neural symptoms in laying hens. T-2 toxin had no effect on either hemoglobin, hematocrit values, erythrocyte count, plasma glucose, prothrombin times, or the sizes of the liver, spleen, pancreas, and heart. Lipid content of the liver was not altered. Feed consumption, however, was reduced, as were the total plasma protein and lipid concentrations and the total leukocyte count. Most important economically was the lowered egg production and a thinner egg shell. The timing and severity of the symptoms suggest that T-2 toxin causes primary oral lesions that reduce feed consumption with a consequent reduction in serum proteins and lipids, which culminate in decreased egg production. The leucopenia and thinner egg shell may be independent systemic effects of T-2 toxin in laying hens.

Animals↗
PubMed1995

Effect of estrogen on egg production, shell quality and calcium metabolism in molted hens.

Force-molted White Leghorn laying hens were implanted with 0.25, 0.5, 1 and 3 Compudose 200 pellets (24 mg 17 beta estradiol/pellet). Plasma estradiol increased with increasing E2 dosages in a linear manner and decreased over time in a quadratic manner (P < 0.01). E2 treatment had a nonlinear effect on total plasma calcium. Oviduct weight, shell thickness and egg weight were not significantly affected by exogenous estradiol whereas tibial bone ash percentage was increased at only one dose (P < 0.05:0.5 pellet group). Physiological supplementation with estradiol does not improve shell quality.

Animals↗