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[Inter-laboratory evaluation studies of notified ELISA methods for allergic substances (egg)].

Inter-laboratory evaluation studies were conducted for the notified ELISA methods for allergic substances (Egg). Standard extracts of egg spiked in extracts of sausage, sauce, cookie, bread and cereal at a level of 5-20 ng/mL as the sample solution were analyzed in replicate in 10 laboratories. Coefficients of variation (CVs) of all three ELISA methods using an Egg Protein ovalbumin ELISA Kit (ovalbumin kit), an Egg Protein ovomucoid ELISA Kit (ovomucoid kit) and a FASTKIT Egg ELISA kit (Egg ELISA kit) were mostly less than 10%. Mean recoveries of the standard extract of egg were over 40% in the three ELISA methods. Repeatability relative standard deviations of egg standard solution in five food extracts were in the ranges of 18.7-25.5%, 18.6-41.8%, 21.3-43.3% for the ovalbumin kit, the ovomucoid kit and the Egg ELISA kit, respectively. Reproducibility relative standard deviations of egg standard solution in five food extracts were 16.8-35.1%, 19.6-35.8%, 24.7-51.1% for the ovalbumin kit, the ovomucoid kit and the Egg ELISA kit, respectively. The detection limits of all the ELISA methods were 4-5 ng/mL in sample solutions. These results suggested that the notified ELISA methods are reliable and reproducible for the inspection of egg protein levels in extracts of sausage, sauce, cookie, bread and cereal.

Allergens↗

Phosphorus phase feeding and uterine and isthmus mucosal enzymes and minerals in relation to soft-shelled and shell-less egg production.

The relationships among phosphorus phase feeding, egg shell quality, and the activities and concentrations of several enzymes and minerals in the uterine and isthmus mucosae of hens at the time of oviposition were investigated. During the first 8 months of production (Phase 1), layer diets contained .3, .5, or .7% available phosphorus. Between 9 and 12 months of production (Phase 2), dietary available phosphorus was either increased or decreased by .2% phosphorus, or was left unchanged. No significant differences due to Phase 1 diets were demonstrated for hard-shelled (HS), soft-shelled (SS), or shell-less (SL) egg production, livability, egg weight, or specific gravity. Phase 2 diets had no significant effect on SS or SL egg production, livability, or egg specific gravity; however, decreasing dietary phosphorus reduced egg weight. Levels as high as .9% had no effect on specific gravity or HS egg production, while .1% dietary phosphorus was detrimental to HS egg production and feed consumption. No significant differences due to dietary available phosphorus or egg type (SS vs. HS) were demonstrated for uterine or isthmus mucosal enzyme activities or mineral contents, with one exception. Higher inorganic phosphorus concentrations were found in the uterus of HS egg layers when compared to levels in the uterus of SS egg layers and the isthmus of HS and SS egg layers. Acid phosphatase and carbonic anhydrase activities, and total calcium levels were significantly higher in the isthmus than the uterus, while alkaline phosphatase and pyrophosphatase activities, and inorganic phosphorus levels were significantly higher in the uterus than the isthmus.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗

Relationship of parents' age, hatching egg weight, and shell quality to day-old chick weight as influenced by oviposition time.

This study was conducted with 840 eggs from commercial breeder hens to determine relationship of parents' age, egg weight, and to oviposition time and shell quality and day-old chick weight. Results indicate that eggs laid in the afternoon were significantly smaller with significantly better shell quality than those laid in the morning (64.1 vs. 64.5 g and specific gravity of 1.077 vs. 1.074, respectively). Also, chicks from afternoon eggs tended to weigh significantly less than those from morning eggs. However, the egg weight: chick weight ratio was not significantly affected by oviposition time; it was the same for morning and afternoon eggs (70.7 vs. 70.1%). The linear relationships between egg weight, age, and chick weight or between egg weight and chick weight were strong (R2 = .78 to .91), but the associations between specific gravity and chick weight were weaker (R2 = .28 to .24). It was possible to use both parents' age and egg weight or egg weight alone to predict chick weight for chicks hatched from morning and afternoon eggs.

Aging↗

Relationship of time of feeding and strain to egg shell quality and hatchability in broiler breeders.

The relationship of feeding time to egg production, egg weight, egg shell quality, fertility, and hatchability was examined in two trials. Slow and fast-feathering strain Hubbard females were used in Trial 1 and slow-feathering strain Arbor Acres females were used in Trial 2. Feeding times of 0800 or 1300 h throughout the laying periods were compared. Slow feathering females in Trial 1 exhibited significantly increased egg weight and significantly decreased percentage shell when compared with fast-feathering females. Feeding at 1300 h increased significantly egg specific gravity, egg shell weight, and percentage shell in Trials 1 and 2. Significant interactions of feeding time and strain occurred in Trial 1 with respect to fertility and hatch of all eggs set. Feeding at 1300 h increased fertility and hatch of all eggs set in fast-feathering hens but the opposite occurred in slow-feathering hens in Trials 1 and 2. Within slow-feathering hens, hatch of fertile eggs was decreased by 1.7% (Trial 1) and 1.5% (Trial 2). The results show that afternoon feeding that provides calcium intake near the time of egg shell calcification decreased significantly hatchability in eggs from two slow-feathering strains of females but not in eggs from a fast-feathering strain. These results suggest that altering time of feed intake can decrease hatchability.

Animals↗

Schistosoma japonicum in the pig: a new technique for estimation of intestinal tissue egg counts.

This study introduced a new method for estimating intestinal tissue Schistosoma japonicum egg counts, based on scraping of the mucosal layer of different sections of the intestines. Twenty-eight Danish Landrace/Yorkshire/Duroc crossbred pigs were divided into 3 groups of 15, 5 and 8 pigs, respectively. Pigs were fed either a high- or low- protein diet and were infected by an intra-muscular or per-oral route of infection with doses of either 1,000, 1,500 or 3,000 S. japonicum cercariae. The pigs were killed 9-11 weeks post infection. For all 28 pigs the intestines were divided into 3 sections: cecum, colon and rectum and the entire mucosa was scraped off the serosa of each section and homogenized. Subsequently, samples corresponding to 5 g homogenised mucosal tissue were digested and egg counts were determined and correlated to liver egg counts. In order to compare the relative distribution of eggs in the mucosa and the serosa, small intestinal wall subsamples formerly taken from each section from a subgroup of 5 pigs were homogenized and egg counts determined for both the mucosa and serosa. The number of eggs were significantly higher in the mucosa than in the serosa. Egg counts estimated from digestion of mucosa subsamples either over or underestimated egg counts based on scrapings of the entire mucosa when compared, reflecting the very patchy distribution of S. japonicum eggs in the intestinal wall. Correlating liver egg counts with the number of eggs based on scrapings from the entire mucosa from cecum, colon and rectum, respectively, significant correlations were found for 2 out of 3 groups of pigs. The present study revealed that estimating intestinal tissue egg counts based on scrapings of the entire mucosa is a reliable and convenient approach, nicely supporting the liver tissue digestion approach. In addition, a reduction of the processing time of intestinal tissue in general was achieved due to the very simple scraping technique.

Animals↗

Recovery of Salmonella from shell eggs.

A preenrichment procedure and a direct selective enrichment procedure were compared for recovery of Salmonella artificially inoculated into liquid whole egg, egg yolk, and egg albumen. For liquid whole egg and egg yolk, the 2 procedures were comparable. With egg albumen, however, preenrichment in lactose broth gave significantly higher recoveries than did direct selective enrichment in either selenite cystine or tetrathlonate broths. The lactose preenrichment procedure was used to determine the survival of S. enteritidis in egg yolk and egg albumen over a period of 7 days. As shown by most probably number determinations, counts of S. enteritidis inoculated into egg albumen decreased by 3 log units, whereas those in egg yolk did not change significantly. It is recommended, therefore, that only the egg yolk be examined for this pathogen. In a comparison of 5 different preenrichment media (lactose broth, brain heart infusion broth, trypticase soy broth, buffered peptone water, and nutrient broth), lactose broth was somewhat less productive than the other 4 media for the recovery of Salmonella from egg yolks. Trypticase soy broth gave the highest recovery.

Culture Media↗

Eggshell morphology of the small eggs of human trematodes in Thailand.

Light and scanning electron micrographs of Opisthorchis viverrini, Haplorchis taichui, H. pumilio, A Phaneropsolus bonnei, and Prosthodendrium molenkampi eggs were studied. Under light microscopy. O. viverrini eggs had rough eggshells and prominent shoulders. H. taichui, H. pumilio were similar in shape and had smooth eggshells and prominent shoulders. H. pumilio eggs were bigger than H. taichui eggs. P. bonnei and P. molenkampi eggs had smooth eggshells and indistinct shoulders. P. bonnei eggs were thinner and bigger than P. molenkampi eggs. Some deformed eggs of O. viverrini and Haplorchis sp. were found and they had no embryos and indistinct opercula. Under scanning electron microscopy, O. viverrini eggs looked like musk-melon skin; they had prominent shoulders and long knobs. H. taichui eggs had curly, thread-like ridges and prominent shoulders and knobs. H. pumilio eggs had streched ridges, like Chinese bitter mormodica, and prominent shoulders. P. bonnei and P. molenkampi eggs had smooth eggshells and small shoulders and knobs.

Animals↗

Shell conductance, daily water loss, and water content of Andean gull and Puna ibis eggs.

Characteristics of Andean gull (Larus serranus) and Puna ibis (Plegadis ridgwayi) eggs laid at 4,400 m in the Peruvian Andes were studied to determine how the conflicting requirements of maximizing O2 availability to the embryo while minimizing excessive losses of water vapor and CO2 have been met by avian populations breeding at high altitudes. Egg masses, linear dimensions, and surface areas of these montane eggs were similar to those of Heermann's gull (Larus heermanni) and glossy ibises (Plegadis falcinellus), but conductance to water vapor (GH2O, standardized to 760 torr) of Andean gull and Puna ibis eggs averaged 74.5% and 68.4%, respectively, of lowland values. The difference in GH2O of Andean gull eggs was caused primarily by a reduction in the number of pores per egg; both an increased shell thickness and a smaller number of pores reduced GH2O of Puna ibis eggs. Since the reduction of GH2O of montane eggs did not fully compensate for the change in barometric pressure (59% of sea level) and the increase in gaseous diffusion coefficients at 4,400 m, the "effective" conductance of the eggs at that altitude was greater than at sea level. Therefore, the eggs lost substantially more water during incubation than did lowland eggs. The modifications in eggshell characteristics of montane eggs may have resulted from selection to increase O2 availability to the embryo.

Altitude↗

Organochlorine and metal residues in eggs of waterfowl nesting on islands in Lake Michigan off Door County, Wisconsin, 1977-78.

One egg from each of 114 red-breasted merganser (Mergus serrator) nests in 1977 and 92 nests in 1978 was collected and later analyzed for organochlorines, polybrominated biphenyls (PBBs), polychlorinated styrenes (PCSs), and metals. One egg was also collected from each of the dabbling duck nests located. Twenty-nine of these eggs were analyzed for organochlorines and metals in 1977; 10 eggs were analyzed in 1978. All merganser eggs contained DDE, polychlorinated biphenyls (PCBs), and dieldrin; all but one egg collected in 1978 contained DDT. DDE and PCB levels had declined since 1975 to a geometric mean of 7.4 ppm DDE and 20 ppm PCBs in 1977 and 7.6 ppm DDE and 19 ppm PCBs in 1978. Dieldrin residues in eggs had not declined from 1975 levels; the geometric mean was 0.78 ppm in 1977 and 0.76 ppm in 1978. Other organochlorines were present at low levels. Mercury residues averaged greater than 0.50 ppm in merganser eggs and had not declined since 1975. Other metals were present at low levels. Dabbling ducks generally had much lower organochlorine and Hg residues than mergansers; DDE and PCBs were the only organochlorines present in the majority of eggs. Geometric means of PCBs and DDT in dabbling duck eggs did not exceed 2.0 ppm and 1.0 ppm, respectively. PBBs and PCSs were detected only in a few merganser eggs, at low levels. Eggshell thickness for red-breasted merganser eggs averaged 0.359 mm in 1977 and 0.355 mm in 1978, which is only 2%-3% below pre-1946 thicknesses. Mallard (Anas platyrhynchos) eggshell thicknesses averaged 0.331 mm in 1977 and 0.377 mm in 1978.

Animals↗

Use of a polyurethane carrier for assessing the survival of helminth eggs in liquid biological sludges.

Soft expanded polyurethane (plastic foam) was used as an egg carrier. A carrier of helminth eggs and a method for their isolation were tested. They proved applicable to evaluation of the survival of helminth eggs in liquid biological substrates (sludges, liquid excrements). The inside of the carrier was inoculated with 1,000 +/- 50 Ascaris suum eggs. After 21 days of incubation in an aerated medium at room temperature, 660.7 (66.1%) eggs were isolated on the average (n = 10, Tab. I). The carriers incubated in the medium at 4 degrees C yielded 716.2 eggs (71.6%) on the average (Tab. II). The intactness of the carriers in helminth eggs was proved during 21 days of incubation in aerated medium when the detected mean percentage of embryonated eggs was 80.5% (Fab. I). From the carriers kept at 4 degrees C for 21 days and subsequently incubated 76.6% of embryonated eggs were recovered on the average (Tab. II). Control showed 80.95% of embryonated eggs on the average, which is a statistically insignificant difference (P < 0.05). With the use of the carrier more than a 13-fold increase in the viable eggs was recorded, compared with a 5% yield obtained at a direct inoculation into liquid substrates. This method is rewarding for its optimization of experimental results and for reducing the number of eggs used in the experiments.

Animals↗

Management and environmental risk factors for Salmonella enteritidis contamination of eggs.

OBJECTIVE: To analyze data for 60 poultry flocks voluntarily enrolled in the Pennsylvania Salmonella enteritidis Pilot Project and determine management and environmental risk factors associated with production of S enteritidis-contaminated eggs. SAMPLE POPULATION: 60 flocks for which at least 1 environmental sample (manure or egg-handling equipment) was positive for S enteritidis. PROCEDURE: Samples of manure, egg-handling equipment, and mice were submitted for bacterial culture of S enteritidis. When S enteritidis was isolated from environmental samples, 1,000 eggs were collected from the flock every 2 weeks for 8 weeks and submitted for bacterial culture. RESULTS: 18 flocks were found to have produced contaminated eggs. Estimated overall prevalence of contaminated eggs was 2.64/10,000 eggs produced, but flock-specific prevalence ranged from 0 to 62.5/10,000 eggs. Flocks with high levels of manure contamination were 10 times as likely to produce contaminated eggs as were flocks with low levels. However, 5 flocks with low levels of manure contamination produced contaminated eggs. CONCLUSIONS: Evaluation of the level of manure contamination could be used to help identify flocks at risk of producing S enteritidis-contaminated eggs. CLINICAL RELEVANCE: Flocks with high levels of S enteritidis-contaminated manure appeared to pose the greatest public health threat, and on-farm programs to reduce the prevalence of egg contamination should be developed for farms with high levels of manure contamination. Efforts to reduce the overall number of on-farm pathogens should decrease the incidence of foodborne disease in humans.

Animal Husbandry↗

Salmonellosis in Trinidad: evidence for transovarian transmission of Salmonella in farm eggs.

The aim of this study was to determine whether the contents of farm eggs in Trinidad are contaminated with Salmonella and if transovarian transmission occurs. 750 fresh eggs from 10 farms supplying 75% of the country's eggs were cultured for Salmonella. Salmonella was found on the egg shells' surfaces from all farms, and in the egg contents from three farms. Isolates were obtained from the cultures of the contents and shells of nine (1.2%) and 35 (4.66%) eggs, respectively (p < 0.005). Serotypes found in the contents were S. enteritidis (0.8%; deduced to be contaminated by transovarian transmission) and S. typhimurium (0.4%); those isolated from the shells (contaminated by faecal transmission) were S. typhimurium (3.06%), S. enteritidis (0.67%), S. ohio (0.27%), S. cerro (0.27%), S. infantis (0.27%) and S. heidelberg (0.13%). This study provides the first evidence for Salmonella and, more importantly, S. enteritidis, in eggs in Trinidad. This is of major public health significance because S. enteritidis infected eggs appear normal and the organism is difficult to detect and control. The consumption of these eggs may increase the risk of Salmonella infection. Food safety practices, particularly the thorough cooking (> or = 70 degrees C) of all egg dishes and the refrigeration (< 10 degrees C) of shell eggs and egg dishes, are recommended.

Animals↗

Egg allergy, influenza vaccine, and immunoglobulin E antibody.

In a study of 70 patients with asthma, rhinitis, and eczema, those giving a definite history of allergic reactions to egg more frequently showed positive skin tests to egg extracts (p = less than 0.003), the wheal diameters of which were significantly larger (p = less than 0.01) than in patients with only a possible or no such history. Patients with a definite history of egg allergy had significantly higher levels of specific IgE antibody against egg yolk, egg white, and allantoic fluid than patients in the other two groups (p = less than 0.005). Seven patients, all of whom had given a definite history of allergy to egg, were found to have positive skin prick tests to influenza vaccine, at the concentration used in medical practice. Two of these patients had previously been given influenza vaccine and both had developed adverse reactions. Of the 22 patients giving a definite history of allergy to egg, the 7 (35 per cent) with positive skin tests to influenza vaccine had significantly larger skin tests and higher levels of specific IgE antibody to the egg extracts than the group as a whole (p = less than 0.001). Allergic reactions to influenza vaccine are likely to occur in patients who have a definite history of allergy to egg and large skin prick test reactions or high levels of specific IgE antibody to egg extracts. Those at risk can best be identified by skin prick testing with egg extracts and undiluted influenza vaccine.

Adolescent↗

Strain comparison of turkey egg components.

Two experiments were conducted to quantify the composition of turkey hatching eggs in relation to strain of bird and age of breeder. In one experiment, 20 Nicholas and British United Turkeys of America (BUTA) eggs produced at 3, 12, and 24 wk of production were examined for physical and chemical components. Eggs from Nicholas hens were always some 4 g heavier (P < .05) due essentially to a larger albumen content. Although absolute components increased over time (P < .05), there were few changes in proportional composition (P > .05). Eggs from BUTA turkeys initially contained more yolk protein (P < .05). At 12 and 24 wk of production, eggs from Nicholas hens changed most rapidly and at these ages contained more yolk protein than the BUTA strain eggs (P < .05). At the end of the production cycle, BUTA eggs contained less lipid and protein in the yolk (P < .05). For both strains there was an increase in stearic acid content of yolk lipid with increased breeder age. In a second experiment, comparable studies were conducted on eggs obtained from male and female line BUTA breeding stock. Although male line eggs were heavier (87 vs 78 g), the smaller female line eggs exhibited proportionally more yolk (P < .05), as absolute yolk weight was similar for both strains (22.4 vs 22.5 g). It was concluded that only minor differences exist in components of eggs from different turkey strains.

Age Factors↗

Molecular aspects of sperm-egg fusion.

Fertilization, as one of the few well-studied physiological cell fusion systems, provides a glimpse of hierarchies of control that may exist in other membrane fusions as well. Sperm become fusogenic only after undergoing exocytosis from an apical vesicle; this acrosome reaction, induced by an egg surface component, confers upon the sperm the capacity to bind to and fuse with an egg. The acrosome reaction requires Ca2+ and Na+ and is mediated by a complex series of ionic alterations in sperm, including plasma membrane potential depolarization, Ca2+ influx, and increased intracellular pH. These changes take their toll of the sperm, which dies soon thereafter if it does not fertilize an egg. Sperm-egg fusion itself is rapid, with a negligible requirement for extracellular Ca2+, and is inhibited by depolarization of the egg plasma membrane potential. Gamete membrane fusion is followed by dramatic changes in egg physiology, including those that inhibit subsequent sperm-egg fusions. These blocks to polyspermy include a partial decrease in egg surface receptivity caused by egg membrane depolarization immediately after gamete fusion, followed by a complete inhibition of sperm entry due to a massive exocytosis from vesicles beneath the egg plasma membrane, with a concomitant change in the egg plasma membrane and cell coat. The sperm that has successfully fused with an egg contributes not only its genome, but cytoplasmic components as well. Some cytoplasmic constituents from the sperm, including several proteins, persist without degradation throughout early development; several remain localized in a single region. Whether these cytoplasmic components transferred from the sperm play a role in subsequent morphogenesis of the embryo is not clear.

Acrosome↗

Ultrastructural observations on rabbit, hamster and mouse eggs following electrical stimulation in vitro.

The fine structural changes were studied in the plasma membrane, cortical granules (CGs) and meiotic spindle of rabbit, hamster and mouse eggs in response to electrical stimulation. Eggs were collected 16 to 18 hours after HCG injection, and freed from the cumulus oophorus. They were stimulated in vitro by delivering a single monophasic square wave pulse of 150 V for 1 msec. Stimulated and unstimulated eggs were fixed for fine structural observations 1, 30 and 60 minutes after stimulation. Within one minute of stimulation the microvilli of rabbit eggs were long, branching and had bulbous ends. Umbonate protrusions were also present on their surface. By 30 minutes after stimulation the rabbit eggs lacked microvilli and the perivitelline space with detached vesicles. Degenerating changes were readily noticeable in the microvilli of hamster eggs by 60 minutes. Changes were not noted in the microvilli of stimulated mouse eggs. There were markedly fewer CGs in the hamster and mouse, but not rabbit, eggs by 30 minutes after stimulation, and nearly all of them disappeared in the mouse and hamster eggs by 60 minutes. The density of the CGs in the rabbit was not altered. The meiotic spindle of hamster eggs dissipated within one minute of stimulation, however, the microtubules reappeared by 60 minutes after stimulation. Rotation of the meiotic spindle occurred in the mouse and hamster eggs by 30 minutes after stimulation. In some of the mouse eggs the spindle migrated to the center and the chromosomes were in telophase.

Animals↗

Sperm interaction with the zona-free hamster egg.

The interaction of sperm with the zona-free hamster egg was studied. Hamster sperm were capacitated in Tyrodes media, containing 50% heat-inactivated serum and used to inseminate zona-free eggs in BWW containing 10% serum. Capacitated sperm began fusing with eggs within the first hour of insemination and by 3 h penetration had ceased as indicated by the absence of further changes in the mean number of sperm incorporated per egg. Penetration by capacitated hamster sperm was linearly related to the log of the motile sperm concentration at concentrations above 10(4) cells/ml. The viability of sperm and eggs in culture was limited in these studies to approximately 3-5 h. The existence of a block to unlimited sperm penetration of the zona-free egg was sought in reinsemination experiments. A relatively low sperm concentration was used to initiate egg responses, followed, at timed intervals, by reinsemination with a high challenge concentration of sperm. Subsequent polyspermy levels reflected the presence or absence of the egg's block to polyspermy response. In order to circumvent the problems arising from the rapid aging of hamster sperm in culture, mouse sperm were employed, a convenience afforded by the lack of species specificity in this egg. Reinseminated eggs incorporated additional sperm during the challenge; therefore, the hamster egg is not capable of preventing unlimited sperm penetration. The implications of these findings to the use of the zona-free hamster egg test in fertility evaluation is discussed.

Animals↗

Mutual mate choice in sticklebacks: attractive males choose big females, which lay big eggs.

Brighter red three-spined stickleback, Gasterosteus aculeatus, males have been shown to be preferred by females in the laboratory but in the field, these males did not receive more eggs. Instead, they had heavier eggs in their brood. We investigated the hypothesis that sexual selection for red coloration in male sticklebacks acts through mate choice by preferred males, who can afford to be choosy, for high-quality females which lay heavier eggs. We assume here that heavier eggs provide a direct fitness advantage. In simultaneous choice tests males were presented with two females differing in size. The number of zigzags directed to and the time spent orienting to each female were measured. After the test the females laid eggs, which we counted and weighed. Bigger (i.e. longer and heavier) females laid significantly more and heavier eggs than smaller females. For all 23 males pooled together, the preferred female was the bigger of the two in 17 cases, laid more eggs in 18 cases, but laid heavier eggs in only 13 cases. When bright and dull males were analysed separately, we found that bright but not dull males spent more time oriented to the bigger female, and to the female that laid more eggs. Females preferred by bright males tended to lay heavier eggs than nonpreferred females, although this result was not quite significant. We conclude that in nature this preference for bigger females results in brighter males receiving on average heavier eggs. Assuming higher survival of bigger offspring, we propose that this can explain how brightness can be sexually selected in spite of brighter males not receiving more eggs. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗