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PubMed2003

Sperm supply and egg fertilization in the ostrich (Struthio camelus).

We used egg break-out and spermatozoa trapped in the perivitelline layer of eggs to test the hypothesis that sperm supply and egg fertilization rate are high in the ostrich. Egg fertilization status was determined at break-out by the appearance of the germinal disc (GD) and then the perivitelline layer overlying the GD region was collected to count sperm (SpermOPVL) under fluorescence following staining with 4',6'-diamidino-2-phenyindole (DAPI). The study was carried out on commercial ostrich farms over two laying seasons. In the first year, 229 eggs from nine randomly chosen ostrich pens comprising pairs, trios (two females, one male) and larger groups were collected for 1 week of every month of laying. Eggs contained 253 +/- 18 SpermOPVL/mm2 of the GD (mean +/- SEM; range 0-1330). Egg fertilization rate averaged 89.4 +/- 3.4% and varied from 78.6 to 98.2% between pens. Month had no effect on sperm supply or egg fertilization status. Eggs from paired birds (sex ratio 1 : 1) had less sperm in the GD than the eggs from pens with a higher sex ratio. In the second year, 150 eggs from seven pens, each containing only one male and either one, two or three females, were studied for 2 weeks at the beginning (winter), middle (spring) and end (summer) of laying. Eggs contained 364 +/- 45 SpermOPVL/mm2 of the GD (range 0-2880). Season had no effect on sperm supply or egg fertilization. The number of SpermOPVL varied between pens, assumed to be due to variation between individual males. The number of SpermOPVL increased as the sex ratio increased only when very high-ranking males were excluded from the analysis. Egg fertilization rate was 94.4 +/- 3.1% but varied from 64.0 to 100% between pens. Egg fertilization was not affected by season or sex ratio. Low fertilization rates were observed in two pens and appeared related to the lack of synchrony between timing of laying and sperm production in the first, and lack of mating in the second pen. We conclude that ostrich flocks generally have high rates of egg fertilization and any infertility is associated with lack of sperm supply.

Animals↗
PubMed2004

Effects of storage time on hatchability of artificially incubated Greater Rhea (Rhea americana) eggs.

(1) A study was conducted to determine the effects of the length of the storage period on the hatchability of artificially incubated Greater Rhea eggs. Hatchability was evaluated in eggs gathered daily from a captive population and in eggs collected less frequently from a semi-captive population. (2) Eggs form both sites were either immediately incubated after being collected or were stored for 1 to 9 d prior to incubation. (3) The maximum number of days for which an egg could be stored without depressing hatchability (with respect to non-stored eggs) was longer in the eggs collected daily. (4) Eggs collected daily and stored for 4d or more showed total hatchability (28%) and fertile hatchability (43%) which was approximately 30% lower than non-stored eggs or eggs stored for 3 d or less. In the semi-captive population, the total and fertile hatchability of non-stored eggs and of eggs stored for one day were 40% greater than of eggs stored for 2 to 9 d (20 and 34%, respectively). (5) The period for which Greater Rhea eggs could be stored without depressing hatchability varied depending on the frequency of egg collection: non-daily egg collection reduces the possible period of storage.

Animals↗
PubMed1983

Periodic hyperpolarizing responses in hamster and mouse eggs fertilized with mouse sperm.

1. The zona-free hamster egg allows multiple entries of heterologous as well as homologous sperm. The hamster egg inseminated with mouse sperm (M x H egg) showed recurring, transient hyperpolarizing responses (h.r.s) with the peak of -70 to -80 mV. They were superimposed on a hyperpolarizing shift of the resting potential (h.s.) which gradually reached -60 mV in 50 min after insemination.2. Unlike the hamster sperm, the cessation of flagellar motion of the first mouse sperm (;1-stop') failed to induce the first h.r. but produced only a small hyperpolarizing ;step' of 3-7 mV. Similar steps occurred for each of additional sperm with a one-to-one correspondence, 4-50 sec ahead of the cessation of sperm motion.3. In M x H eggs, the h.r. first appeared about 15 min after the ;1-stop'. The intervals of the h.r.s thereafter were in the range between 2-10 min, in contrast to 30-45 sec in hamster eggs inseminated with hamster sperm (H x H eggs).4. The h.r.s in M x H eggs were abolished by intracellular injection of EGTA, suggesting that they were caused by periodic increase in the intracellular Ca(2+) concentration ([Ca(2+)](i)) as in H x H eggs.5. The gradual h.s. in M x H eggs was considered to be due mainly to an increase in Ca-independent K permeability, since the resting potential beyond -60 mV at 50-70 min after insemination was changed by only 3-5 mV on the removal of Cl ions and on EGTA injection.6. Histological observations revealed that the resumption of the second meiosis, the indication of egg activation, is delayed in M x H eggs by about 15 min, compared with that in H x H eggs. There was a good correlation between the delay of activation and that of the occurrence of the first h.r.7. In M x H eggs, the probability of egg activation within 70 min was dependent on the number of sperm penetrations: 90% for more than ten sperm while 20-30% for less than five sperm. Eggs in which sperm penetration was not followed by activation showed no h.r.s.8. The mouse egg inseminated with mouse sperm showed small h.r.s (3-4 mV) superimposed on the h.s. from -35 to -55 mV in 50 min after insemination. Both h.r.s and h.s. were associated with an increase in the membrane conductance. The h.s. was considered to be due mainly to a Ca-independent increase in K permeability.9. Iontophoretic injection of Ca(2+) into the unfertilized mouse egg could not increase the K conductance with injection currents up to 4 nA. However, the h.r.s were suggested to be resulted from a periodic increase in [Ca(2+)](i), since they were abolished by injection of EGTA.

Animals↗
PubMed1976

Differentiation and positioning of nuclei in eggs of the cecidomyid Heteropeza pygmaea.

During the first three cleavage divisions of the egg nuclei a precise sequence of spindle orientation and elongation parallel to the longitudinal axis of the egg is apparently involved in positioning one nucleus among the polar granules at the posterior pole of the egg. The size of this nucleus, and the position at which the egg cleaves when pole cell formation occurs, appear to constitute part of the mechanism which ensures that only one nucleus is included in the first pole cell. Blastoderm formation occurs without a well-defined migration of nuclei to the egg surface. Nuclei are so large in relation to the size of the egg that uniform spacing and distribution of nuclei ensures that a large proportion are situated near the egg surface. Those nuclei which are near the egg surface divide synchronously to form a layer of blastoderm nuclei, while membranous cleavage furrows invaginate from the egg surface between them. Nuclei in the central region of the egg chamber condense to form yolk nuclei before blastoderm nuclei have been separated from the rest of the egg by the completion of the cleavage membranes. Polar granules provide the only evidence of fine-structural differences in different regions of the egg chamber cytoplasm. They are found near the posterior pole of the egg from an early stage of oogenesis. They undergo a specific sequence of structural changes and increase in size as the egg grows. No microtubular or microfibrillar arrays have been found in the egg chamber which might form a cytoskeletal basis for spindle orientation or for the spatial differences which develop during differentiation of the uncleaved egg cytoplasm.

Animals↗
PubMed2006

Mortality factors of eggs of Leptocorisa chinensis (Hemiptera: Alydidae) in rice fields.

To clarify factors causing mortality of Leptocorisa chinensis Dallas (Hemiptera: Alydidae) eggs in rice fields, sentinel egg masses were exposed for seven days in two rice, Oryza sativa L. (Poaceae), fields. An insecticide was sprayed to remove natural enemies in one-half of each field before exposing egg masses to predation. An egg mass containing 14 eggs was glued to a plastic label, and 21 egg masses each were placed in the sprayed and unsprayed control plots. During exposure, the number of hatched and missing eggs was observed daily. Egg predators were sampled in the fields before and after insecticide application. After the egg masses were retrieved from the fields, mortality factors of the unhatched eggs were assessed in the laboratory. The mean number of hatched and missing eggs was not significantly different between the sprayed and control plots in field A. In field B, however, the numbers were significantly different. The percentage of missing eggs in damaged egg masses ranged from 80 to 100%. In the laboratory, we observed that feeding marks caused by the grasshopper Conocephalus chinensis (Redtenbacher) were similar to those on the eggs exposed in the rice fields. The density of C. chinensis was low in control plots of field A. In contrast, the density was high in those of field B. These observations suggest that the density of egg predators, e.g., C. chinensis, is a mortality factor of L. chinensis eggs in rice fields.

Animals↗
PubMed1992

Research note: variability in preincubation embryonic development in domestic fowl. 2. Effects of duration of egg storage period.

Embryos of eggs from Single Comb White Leghorn hens were analyzed to determine whether duration of egg storage significantly affects embryonic development prior to incubation. Eggs were gathered over a period of 5 days from 25-wk-old hens that were naturally inseminated and housed in floor pens. Within 1 h of oviposition the eggs were collected and assigned randomly to one of five storage treatment groups of 0, 4, 7, 14, or 21 days. Fresh egg weight was recorded and the eggs were placed on plastic egg flats and stored at 14 C. Weight of each egg was measured after storage to determine amount of weight lost during storage. A total of 500 embryos were examined after storage. Viable embryos were staged for development using a modified Eyal-Giladi and Kochav classification. The incidence of embryonic mortality was noted. Duration of storage (P = .5815) collection date (P = .5815), and fresh egg weight (P = .3789) did not affect embryonic development significantly. A significant linear relationship was observed between duration of the storage period and loss of egg weight (P = .0001). Embryonic mortality was significantly related to loss of egg weight (P = .0001). Mortality was highest in eggs that were stored for a longer period of time. The data from the current study indicate that storing fertile eggs below physiological zero inhibits embryonic development. One of the reasons for the increased incidence of embryonic mortality in eggs that were stored for longer periods may be related to the increased egg weight loss in these eggs.

Animals↗
PubMed1999

Effect of dietary conjugated linoleic acid on the quality characteristics of chicken eggs during refrigerated storage.

Twenty-four, 79-wk-old White Leghorn hens were assigned randomly to three diets containing 0, 2.5, or 5.0% conjugated linoleic acid (CLA). The diets were fed for 4 wk to determine the effect of dietary CLA on quality characteristics of eggs. Eggs were collected daily and stored at 4 C for 1, 7, 21, or 49 d. At the designated times, the eggs were processed to evaluate water content, fatty acid composition, color, proportions and pH of yolk and albumen. Firmness of yolk after the eggs were hard-cooked was also determined. The proportions of myristic, palmitic, stearic, CLA (9-cis, 11-trans CLA and 10-trans, 12-cis CLA isomers), and unidentified fatty acids in egg yolk lipids were increased as dietary CLA increased, but those of palmitoleic, oleic, linoleic, linolenic, arachidonic, and docosahexaenoic acid were decreased. Duration of refrigeration increased the proportion of egg yolk but decreased the contents of albumen and yolk lipids after 21 d or longer of storage. Egg yolk pH increased as refrigeration time increased, regardless of dietary treatment, but the increase was greater in the eggs produced by hens fed the CLA diets. Albumen pH increased significantly after 7 d of storage but remained unchanged until 21 d and then decreased by 49 d. Dietary CLA had no effect on the pH of albumen until 49 d of storage. After 49 d storage, egg albumen pH from hens fed CLA diets was lower than that of albumen from hens fed the control diet. Yolk color was not influenced by the dietary CLA and storage, but the egg yolk surface from hens fed CLA diets sometimes had relatively dark color with light spots. Dietary CLA and storage of CLA eggs increased the firmness of hard-cooked egg yolk. The texture of yolks from hard-cooked CLA eggs was rubbery and elastic, and the yolks were more difficult to break using an Instron. It was speculated that the quality changes of CLA eggs were related to the increase of yolk water content, the movement of ions between yolk and albumen through yolk membrane, and the changes of egg yolk pH during storage.

Animal Feed↗
PubMed2004

Determination of cooling rates and carbon dioxide uptake in commercially processed shell eggs using cryogenic carbon dioxide gas.

The ability to rapidly cool shell eggs to 7 degrees C is important in the prevention of Salmonella Enteritidis (SE) growth. In addition, quality may also be maintained longer from rapid cooling of shell eggs. A commercial cryogenic CO2 egg cooling unit was designed and installed in a commercial egg processing facility. This unit was installed on a packer head to rapidly cool eggs individually prior to packaging. The objective of this study was to determine cooling rates and CO2 gas changes that result from rapidly cooling eggs using this commercial cryogenic egg cooling system and subsequent storage for 15 wk. Results indicated that cryogenic CO2 cooling quickly cooled shell eggs in approximately 45 min, whereas traditional cooling required from 19 to 116 h. CO2 uptake into the albumen was greater in cryogenically cooled eggs (2.11 mg/g) than in traditionally cooled eggs (1.81 mg/g) immediately after processing. No differences were observed in albumen CO2 content after 2 wk of storage; at 10 wk statistically greater CO2 content remained in the cryogenically cooled eggs (1.75 mg/g) compared with the traditionally cooled eggs (1.60 mg/g). These results suggest that a large amount of CO2 enters the egg during the cryogenic cooling process but is quickly lost during storage. Beyond 10 wk of storage, the albumen CO2 content in cryogenically cooled eggs was higher than in the traditionally cooled eggs suggesting chemical changes may have occurred in the albumen.

Animals↗
PubMed2004

Effects of dietary conjugated linoleic acid on the productivity of laying hens and egg quality during refrigerated storage.

Five hundred and four 40-wk-old Brown Dwarf hens (1.51 +/- 0.08 kg BW) were fed corn-soybean meal diets containing 0, 1, 2, 3, 4, 5, or 6% conjugated linoleic acid (CLA) for 56 d to measure the effects of dietary CLA on laying hen productivity and egg quality during refrigerated storage. Four hens were placed in 1 cage, and 3 cages were grouped as 1 replicate resulting in 6 replicates per treatment. After feeding the experimental diets for 11 d, eggs were collected to determine the fatty acid composition of egg yolks. From d 12 to 18, eggs from hens fed diets containing 0, 2, 4, and 6% CLA diets were stored at 4 degrees C for up to 28 d. At designated times (1, 14, or 28 d), eggs were taken, broken, and shelled to evaluate water content, pH, and ion concentration. Firmness of hard-cooked egg yolk was also determined. With increased dietary CLA, feed intake, BW gain, rate of egg production, egg weight, and feed efficiency all decreased linearly (P < 0.01). The weight of the yolk, albumen, and shell decreased linearly (P < 0.01) with increasing dietary CLA. Concentration of CLA in the yolk lipids increased quadratically (P < 0.01), with increasing dietary CLA. Concurrent increases (P < 0.01) in the concentration of myristic, palmitic, and stearic acids and decreases (P < 0.01) in oleic, linoleic, linolenic, and archidonic acids in egg yolk lipids were observed. Days of storage and CLA (P < 0.01) increased yolk firmness. Egg yolk water content and pH increased with storage and CLA content (P < 0.01). Corresponding decreases were observed in albumen pH. Regardless of dietary treatment, the concentrations of Na, K, and Mg in egg yolks increased with longer storage time. At 28 d of storage, there was a linear (P < 0.01) increase in Na, K, and Mg content in egg yolks as dietary CLA increased. In contrast to the egg yolk, the concentrations of Na, K, and Mg in egg albumen decreased with storage time. On d 28, there was a linear decrease (P < 0.01) in the Na content of albumen with increasing CLA. This study suggests that the greater firmness of CLA-fed eggs might be related to the change of pH, water content, and ion concentrations during refrigerated storage.

Albumins↗
PubMed2002

The origin of lactation as a water source for parchment-shelled eggs.

Available evidence indicates that mammary gland secretions first evolved in synapsids that laid parchment-shelled eggs. Unlike the rigid-shelled eggs of birds and some other sauropsids, parchment-shelled eggs lose water very rapidly when exposed to ambient air of lower vapor pressure, whether due to differences in relative humidity or to differences in temperature. This precludes endothermic incubation of parchment-shelled eggs in an open nest. Synapsids may have avoided egg desiccation by incubating eggs in a pouch, but this would limit maternal activity. Parchment-shelled eggs are able to take up liquid water across the eggshell. I propose that mammary secretion originally evolved as a means of supplying water to eggs, and as such was essential to the evolution of endothermy among the egg-laying cynodonts that were ancestral to mammals. It is possible that synapsid eggs, like parchment-shelled squamate eggs, were also capable of uptake of some nutrients, such as sodium and ionic calcium. Living monotremes still produce parchment-shelled eggs. The porous eggshell and bilaminar yolk sac membrane of these eggs permit substantial uptake of uterine secretions during the intrauterine period, and might also facilitate uptake of mammary secretions during egg incubation. In its simplest form, mammary secretion may be an ancient trait of egg-laying synapsids, having had an important role long before milk became obligatory for suckling young.

Animals↗
PubMed2000

Ectotherms, Temperature, and Trade-offs: Size and Number of Eggs in a Carabid Beetle.

We studied the allocation of total egg mass to size and number in the carabid beetle Notiophilus biguttatus F. at several temperature and day length regimes. Eggs increase in number and decrease in size with increasing (constant) temperature. Day length interacts with temperature: at short day the effect of temperature on size and number of eggs is weaker than at long day. In diurnally fluctuating temperature regimes, egg size is affected disproportionately by the high temperature period. All treatments, however, are similar in affecting number and size of eggs in an opposite direction. Consequently, egg size is explained to a high degree by egg production rate. The relationship between size and number of eggs among treatments is furthermore characterized by a decrease in egg size with an increase in total egg mass production. Within treatments, rate of egg production and egg size are negatively correlated among females in the low-temperature groups but not in the high-temperature groups; the correlations among females are also characterized by a decrease in egg size, with an increase in total egg mass production. Hence, possible trade-offs between size and number of eggs are masked by phenotypic variation in reproductive effort. The observations enable us to propose a simple conceptual model that explains the within-treatment correlation by the same causal factor as the negative relationship among treatment means.

Carabidae↗
PubMed2002

Nutritional effect of including egg yolk in the weaning diet of breast-fed and formula-fed infants: a randomized controlled trial.

BACKGROUND: Egg yolks can be a source of docosahexaenoic acid (DHA) and iron but are often associated with adverse consequences on plasma cholesterol. OBJECTIVE: Our goal was to investigate the effect of consumption of 4 egg yolks/wk on infant DHA status and hemoglobin, ferritin, and plasma cholesterol concentrations. Secondary outcomes included plasma iron, transferrin, and transferrin saturation. DESIGN: This was a randomized controlled trial comparing no dietary intervention, consumption of 4 regular egg yolks/wk, and consumption of 4 n-3 fatty acid-enriched egg yolks/wk in breast-fed and formula-fed infants from 6 to 12 mo of age. Erythrocyte DHA concentrations, cholesterol, and iron status were assessed at 6 and 12 mo of age. RESULTS: Of the 82 breast-fed infants recruited, 23 of 28 (no intervention), 23 of 27 (regular eggs), and 24 of 27 (n-3 eggs) completed the trial. Of the 79 formula-fed infants enrolled, 23 of 27 (no intervention), 24 of 26 (regular eggs), and 20 of 26 (n-3 eggs) completed the trial. Erythrocyte DHA concentrations were 30-40% higher after the n-3 egg intervention than after treatment with regular eggs or no eggs in both breast-fed and formula-fed infants. Egg treatment had no significant effect on plasma cholesterol, hemoglobin, ferritin, and transferrin but did result in improvements in plasma iron and transferrin saturation compared with no egg treatment. CONCLUSIONS: n-3 Fatty acid-enriched eggs may provide a means of increasing dietary DHA during the second 6 mo of life. Egg yolks may also be a useful source of iron during the weaning period and can be safely included in the weaning diet with no perturbations in plasma cholesterol.

Aging↗
PubMed1978

Hydrolysis of sugar nucleotides in chicken egg white in response to embryonic development.

The egg white of newly laid chicken egg was found to contain about 45 mumol of UDP-N-acetylgalactosamine 4-sulfate, 34 mumole of GDP-mannose, 6 mumol of UDP-N-acetylhexosamine, and 1 mumol of UDP-N-acetylgalactosamine 4,6-bissulfate per liter. There was no significant difference between infertile and fertile eggs in the initial levels of the sugar nucleotides. During incubation for 4 days, the nucleotide levels in infertile eggs showed little change while those in fertile eggs fell continuously until the complete disappearance of the nucleotides on the fourth day. Initial removal of the blastoderm from fertile eggs resulted in cessation of the reduction in nucleotide levels in the 2- to 4-day period after the operation. The decrease of UDP-N-acetylgalactosamine 4-sulfate was followed by an increase of 1-phospho-N-acetylgalactosamine 4-sulfate then N-acetylgalactosamine 4-sulfate in the egg white. When UDP-N-acetylgalactosamine 4-[35S]sulfate or GDP-[14C]mannose was injected into the egg white of a fertile egg, the main feature of the metabolism of the labeled compounds was the successive hydrolysis of their pyrophosphate and phosphate bonds, with the formation of sugar 1-phosphate and sugar. A significant activity of nucleotide pyrophosphatase was detected in the egg white in newly laid eggs (0-day egg). However, no such activity could be detected in egg-white specimens from 1-, 2-, and 3-day eggs. The results suggest that although the decrease of sugar nucleotides in the first day could be ascribed to the hydrolytic action of the enzyme originally present in the egg white, the decrease in the subsequent 3 days results from a more complex process in which the hydrolysis of the sugar nucleotides is related to the development of the embryo.

Acetylgalactosamine↗
PubMed2006

Monitoring of eggshell breakage and eggshell strength in different production chains of consumption eggs.

We first tried to monitor the critical points for eggshell breakage in different logistic chains. Second, we examined whether there was a difference in eggshell strength among eggs produced in different housing systems. Finally, we developed a model to investigate the relation between eggshell strength and the likelihood of an egg cracking during handling and grading. Four logistic chains with different housing systems (battery cages, furnished cages, aviary, and free-range), all housing Bovans Goldline chickens in their mid-lay (45 wk), were compared. In every chain, a randomized set of 1,500 eggs was sampled, and the strength was defined. At every critical point in every logistic chain, the eggs were reexamined for breakage. The classic and furnished cage systems showed the highest percentage of breakage directly at point of lay (6.73 and 10.72%), whereas the other systems showed lower breakage (1.94% in the aviary and 1.99% in the free-range system). Further, in the logistic chain, grading and packing of the eggs generated the second highest percentage of breakage (from 1.50 to 2.65%). Breakage due to transportation ranged from 0.16 to 2.65%. There was a significant difference among the eggshell strength (shell stiffness and damping ratio) of eggs from chickens in different housing systems, showing eggs from chickens in the aviary system to be stronger than cage eggs (classic and furnished) and free-range eggs to be weaker than the other eggs. A significant correlation was found between eggshell strength and the likelihood of breakage in the production chains. In conclusion, it was first shown that, besides the laying, packing of the eggs is a critical point in the logistic chain of consumption eggs; second, the strength of the eggs in the different housing systems differed, and, finally, the eggshell stiffness and damping ratio of consumption eggs are an acceptable measure for rapid eggshell quality assessment and could provide a good predictive value for eggshell breakage in all types of table egg production chains.

Animal Husbandry↗
PubMed1995

Salmonella enteritidis colonization of the reproductive tract and forming and freshly laid eggs of chickens.

Salmonella enteritidis colonizes the tissues of the chicken ovary and oviduct, presumably contaminating eggs and thereby contributing to human outbreaks of salmonellosis. In this study, commercial adult laying hens were given an oral inoculation of 10(8) S. enteritidis organisms. Tissues from various organs, the intestines, and the reproductive tract, including freshly laid eggs, were collected daily for up to 40 days postinoculation (p.i.). Within 2 days p.i. S. enteritidis was detected by culture in pools of the spleen, liver, heart, and gallbladder tissues, in intestinal tissues of all infected birds, and in various sections of the ovary and oviduct. Detection of organisms by immunohistochemical staining was rare for most tissues in spite of their culture-positive status, suggesting a low level of tissue colonization. However, S. enteritidis could be detected by immunohistochemical staining in oviduct tissues associated with four forming eggs, indicating the possibility of a heavier colonization in the egg during its development. In two subsequent experiments, forming eggs taken from the oviduct with their associated tissue, were found to be culture positive for S. enteritidis at a rate of 27.1 and 31.4%, while freshly laid eggs in these experiments were culture positive at the rate of 0 and 0.6%. These observations suggest that while forming eggs are significantly colonized in the reproductive tract, factors within the eggs may control the pathogen before the eggs are laid. The data show that prior to egg deposition, forming eggs are subject to descending infections from colonized ovarian tissue, ascending infections from colonized vaginal and cloacal tissues, and lateral infections from colonized upper oviduct tissues. The data are consistent with an ascending infection of freshly laid eggs from the cloaca, as the incidence of positive eggs in experiments 1 and 3 coincided with heavily contaminated cloacal tissues (50.7 and 80%, respectively), while no positive eggs were detected in experiment 2 when cloacal colonization was low (8.3%). The data do not support the possibility of egg invasion by bacterial translocation from the peritoneal cavity.

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↗
PubMed2001

Optimization of iron supplementation for enhanced detection of Salmonella Enteritidis in eggs.

Mixed raw egg contents were inoculated with approximately 10 CFU of Salmonella Enteritidis and supplemented with 0 to 7 mg of FeSO4 per g of egg contents. Egg contents were then incubated at 37 degrees C, and Salmonella Enteritidis colonies were enumerated for up to 106 h. Iron supplementation significantly enhanced the growth of Salmonella Enteritidis. Within the first 24 h of incubation, the optimum iron level for Salmonella Enteritidis growth in egg contents was between 0.2 and 2 mg of FeSO4 per g of egg contents. After 24 h of incubation at 37 degrees C. Salmonella Enteritidis counts in eggs supplemented with 0.5 mg of FeSO4 per g of egg contents consistently reached approximately 1 x 10(9) CFU/ml, whereas Salmonella Enteritidis counts in eggs without iron supplementation varied from less than 5 CFU/ml to 8.4 x 10(6) CFU/ml. A 3 by 3 factorial design was used to study the effect of type of preenrichment and level of iron supplementation on the growth of Salmonella Enteritidis in egg contents. No significant differences in Salmonella Enteritidis counts between preenrichment and nonpreenrichment treatments were observed when egg contents were supplemented with 0.5 mg of FeSO4 per g of egg contents. It was concluded that preenrichment was not necessary for isolation of Salmonella Enteritidis from eggs. The effect of iron supplementation on the sensitivity of detection by the direct plating method was investigated. The direct plating method detected a significantly higher percentage of Salmonella Enteritidis in raw egg contents supplemented with 0.5 mg of FeSO4 per g of egg contents (90%) than in raw egg contents without iron supplementation (63.3%).

Animals↗
PubMed1975

The Schistosoma japonicum egg granuloma.

Although Schistosoma japonicum egg granulomas are generally considered to be similar to those of S. mansoni (which are largely immunologic reactions of the delayed hypersensitivity type) there are suggestions that the histopathology and perhaps the etiology of the lesions are different. In mice with light S. japonicum infections, at 5 weeks after infection (2 weeks after egg production began), the livers contained 36,000 eggs each, but there was no reaction to the eggs, nor any evidence of hepatosplenic disease. By 6 weeks, large abscesses replete with cosinophils occurred around some of the eggs, and there was periportal inflammation consisting predominantly of plasma cells. From this time on, major lesions occurred mainly around large aggregates of eggs, and there was hepatosplenomegaly and portal hypertension. Living S. japonicum eggs injected into the pulmonary microvasculature of mice did not evoke significant granulomatous reactions on either primary or secondary exposure. Even when the eggs were injected into the lungs of infected animals, which had large granulomas around egg aggregates in the liver, little or no inflammatory reaction was seen around the eggs distributed singly throughout the pulmonary vessels. When the priming dose of eggs or soluble egg antigens was injected subcutaneously with or without complete Freund's adjuvant, significant granuloma formation occurred around eggs subsequently injected into the lungs. On the basis, therefore, of differences in the parasite factor (eggs) and host factors (histopathology and responses to routes of injection) it is suggested that the immunologic factors responsible for granuloma formation around S. mansoni and S. japonicum eggs may differ significantly.

Animals↗