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PubMed2000

Changes in egg composition of American kestrels exposed to dietary polychlorinated biphenyls.

Changes in the quality of eggs of birds exposed to polychlorinated biphenyls (PCBs) have been described, but have never been directly attributed to PCBs. Polychlorinated biphenyl residues in eggs have been associated with reduced reproductive success and embryonic deformities in wild birds. Egg size and composition, specifically the amount of albumen, yolk, and water in an egg, also influence the growth and viability of embryos and hatchlings, and consequently the reproductive success of birds. To deter mine whether PCB exposure of adult birds affected the size and composition of their eggs, 25 pairs of captive American kestrels (Falco sparverius) were fed a mixture of PCB-spiked (1248:1254:1260) food to give an approximate exposure of 7 mg/kg body weight/d, beginning 1 mo prior to pairing, and continuing throughout the courtship, egg-laying, and incubation periods. This dietary level in the adult female kestrels resulted in mean total PCB residues in the eggs of 34.1 microg/g wet weight (geometric mean), which is environmentally relevant. PCB residues in eggs increased with the time of female exposure to the contaminated diet and laying date. Variation in egg size within PCB clutches was significantly greater than within control clutches, although absolute egg mass and volume did not differ markedly by treatment. Only infertile eggs and only one egg per clutch were used for egg composition analysis. Yolks in the PCB-contaminated eggs were heavier, with less wet and dry albumen relative to control eggs. Water content and eggshell thickness were not significantly affected by PCB exposure. These results suggest that eggs from the PCB treatment have relatively more lipid and less protein available for embryonic development. Changes in egg composition were not associated with egg size, lay date, ambient temperature, humidity, or precipitation, which are factors known to affect these variables in bird eggs. The PCB-induced changes in egg composition described here provide insight into possible mechanisms contributing to reduced reproductive performance in wild birds exposed to PCBs.

Administration, Oral↗
PubMed1976

Calcium and phosphorus requirements of the laying hen.

Three experiments were conducted; the first studied the influence of pre-laying dietary calcium levels on subsequent hen performance, while in the second and third the influence of various levels of dietary calcium and phosphorus on performance, egg shell quality and calcium and phosphorus retention were investigated. Pre-dietary calcium levels (0.5 and 1.5%) resulted in a significant strain X diet interaction for weight gain up to commencement of lay but did not influence production, feed intake, egg size or sheel quality. Dietary calcium levels varying from 2.5 to 4.0% did not significantly alter the avove parameters during a 140 day laying test. Compared to a non-pelleted control diet, steam pelleting resulted in a significant enhancement in phosphorus availability is judged by higher levels of performance. Percent calcium retention varied with the level of dietary calcium and there was an indication that level of dietary phosphorus influenced calcium retention. Lower levels of dietary phosphorus resulted in egg shells with slightly lower deformation values. Regardless of dietary phosphorus, retention values were quite low. Changing the level of dietary calcium and phosphorus had little or no effect on the retention of phosphorus thus suggesting a relatively constant and low requirement for this nutrient.

Animal Feed↗
PubMed1999

A Mexican restaurant-associated outbreak of Salmonella Enteritidis type 34 infections traced to a contaminated egg farm.

In May 1996, the Georgia Division of Public Health was notified about a cluster of persons with Salmonella Enteritidis (SE) infections in Waycross, Georgia. A matched pair case-control study to determine risk factors for illness found a statistically significant association of SE infection with a history of having eaten at Restaurant A during the 5 days before onset of illness (relative risk = 13 [95% confidence interval (CI) = 3-62, P < 0.01]). In a second case-control study, to determine specific food exposures, consumption of a deep-fried Mexican dish (chile relleno) (4 of 21 cases vs. 0 of 26 controls, odds ratio undefined, 95% CI > 1.46, P = 0.034) was found to be significantly associated with SE infection. An environmental investigation found evidence of suboptimal food storage and cooking temperatures at Restaurant A; cross contamination of foods may have contributed to the low attributable risk identified for chile rellenos. Five of 37 Restaurant A food and environment specimens yielded SE strains. All five positive specimens were from chiles rellenos. Of the seven outbreak-associated strains (six patient isolates and one food isolate from Restaurant A) for which phage typing was conducted, all were phage type 34. A FDA traceback investigation through Restaurant A's single-egg supplier identified the potential source as three interrelated farms in South Carolina. Environmental culture from one of these farms yielded SE phage type 34. As a result of this outbreak, FDA helped institute a statewide egg quality-assurance programme in South Carolina to minimize SE contamination of eggs.

Animal Husbandry↗
PubMed2003

Differential investment and costs during avian incubation determined by individual quality: an experimental study of the common eider (Somateria mollissima).

Individuals of different quality may have different investment strategies, shaping responses to experimental manipulations, thereby rendering the detection of such patterns difficult. However, previous clutch-size manipulation studies have infrequently incorporated individual differences in quality. To examine costs of incubation and reproductive investment in relation to changes in clutch size, we enlarged and reduced natural clutch sizes of four and five eggs by one egg early in the incubation period in female common eiders (Somateria mollissima), a sea duck with an anorectic incubation period. Females that had produced four eggs (lower quality) responded to clutch reductions by deserting the nest more frequently but did not increase incubation effort in response to clutch enlargement, at the cost of reduced hatch success of eggs. Among birds with an original clutch size of five (higher quality), reducing and enlarging clutch size reduced and increased relative body mass loss respectively without affecting hatch success. In common eiders many females abandon their own ducklings to the care of other females. Enlarging five-egg clutches led to increased brood care rate despite the higher effort spent incubating these clutches, indicating that the higher fitness value of a large brood is increasing adult brood investment. This study shows that the ability to respond to clutch-size manipulations depends on original clutch size, reflecting differences in female quality. Females of low quality were reluctant to increase investment at the cost of lower hatch success, whereas females of higher quality apparently have a larger capacity both to increase incubation effort and brood care investment.

Animals↗
PubMed1983

Ahemeral light cycles and protein levels for older laying hens.

Variations in light:dark ratios and timing schedules of 26- and 28-hr ahemeral cycles were examined for their effects on shell quality and egg weight. In two experiments utilizing 2578 White Leghorn Laying hens, 16-week long ahemeral treatments were instituted abruptly late in the pullet laying season and again following a forced-molt production cycle. Ahemeral light-dark cycles of 28-hr length resulted in significantly heavier shell and egg weights as compared to 26-hr ahemeral cycles or the control 24-hr cycle. Ahemeral 26-hr cycles did not significantly increase egg weight compared to the 24-hr controls but did increase shell weight. Varying total light in 28-hr cycles from 20 to 10 hr with the light given in either one continuous period or interrupted by two intermediate dark periods and as either 18 or 16 hr of continuous light in the 26-hr cycles did not result in significant differences in shell or egg weight compared to the other treatments of the same cycle length. Rate of lay was lower for the hens given only 10 hr of interrupted light in a 28-hr cycle but was not otherwise affected by light treatment. Dietary protein levels of 15% (as compared to 17%) and 14% (as compared to 16 and 18%) consistently reduced egg weights (P less than .10 or less than .05) and tended to improve shell quality. These experiments further demonstrated the effectiveness of 26- and 28-hr ahemeral light-dark cycles in increasing shell weight as a method of extending the economic laying period of either older pullets or force-molted hens without a sacrifice in the number of eggs produced.

Age Factors↗
PubMed1992

Sunflower meal as a major vegetable protein source in layers' ration.

An experiment was conducted with Starcross layers to evaluate the replacement value of sunflower meal (SFM) for cotton seed meal (CSM) and sesame meal (SM). The birds (aged 24 weeks) were given 4 isonitrogenous and isocaloric rations containing 0, 5, 10 and 15% dehulled sunflower meal. The substitution of SFM for CSM and SM did not generally affect the egg production, feed consumption, feed conversion nor did it have any effect on the quality of eggs as measured by Haugh Units (HU) and yolk index. Egg shell thickness, however, improved by increasing dietary levels of SFM. The feed costs per hen were generally lower for the SFM group since SFM was cheaper than CSM and SM.

Animal Feed↗
PubMed1980

[Action of Bacitrafen Premix on layers and broilers].

Observations were made concerning the effect of Bacitraphen-Premix, consumed by poultry with their food. It was proved that similarly to other nutritive antibiotics, the preparation agreed well with them. It was also proved that it does not show toxicity--LD0 and LD50 were higher than the maximal does applied. Bacitraphen-Premix had a positive effect on the egg-laying abilities of layers, as well as on the fecundity ability and incubation qualities of eggs. It showed a definite antistress effect due to which it can be successfully used as a prophylactic means in poultry-raising in case of stress reactions.

Animal Feed↗
PubMed1993

The analysis of egg wash water for the rapid assessment of microbiological quality.

A total of 101 egg wash water samples from five different egg grading stations in eastern Ontario were analyzed for a variety of physical and chemical variables in an attempt to find a correlation with total bacterial counts. Temperature, pH, total chlorine, and percentage transmission at 600 nm (%T) were found to be significant variables, and a multiple regression equation was derived that accounted for 65% of the total variation. The equation was used to classify wash water samples as acceptable (< or = 10(5) cfu/mL) or unacceptable and correctly classified 77.2% of the samples. Classification of a second (validation) data set from 58 wash water samples was correctly predicted in 72% of the cases. The predictive value of the equation was especially good for those wash water samples obtained from stations that had used a chlorinated alkaline detergent, 90.4 and 100% for the modeling and validation data, respectively. Maintenance of wash water at recommended levels for temperature and pH (i.e., > or = 40 C and pH > or = 10) was insufficient to ensure bacterial numbers would be < or = 10(5) cfu/mL. Under normal operating conditions a minimum total available chlorine concentration of .45 mg/L should be maintained in wash water to ensure that bacterial numbers are kept at an acceptable level. Monitoring of temperature, pH, total chlorine, and %T will assist in maintaining wash water quality and minimize the number of samples returned to laboratories for microbiological analysis.

Animals↗
PubMed2003

Ovarian reserve, female age and the chance for successful pregnancy.

Both quantitative and qualitative factors regarding egg production are strong influences on IVF outcome. Markers of ovarian reserve such as basal FSH, clomiphene citrate challenge test (CCCT), and antral follicle counts are good predictors of the quantity of eggs which can be induced to grow. However, the quality of those eggs seems better predicted by the age of the women. In women past age 40, current success rates are low overall, even in those who good ovarian reserve who make many eggs; at this age, quantity does not make up for quality. By contrast, young women with limited ovarian reserve can have good success rates despite their limited cohort of eggs, because the eggs themselves are of high potential; here quality matters more than quantity. The ramifications of these observations include the following: diminished ovarian reserve should not be used as an exclusionary criterion in young women, because overall they still have satisfactory pregnancy rates, though their risk of cancellation is increased. In women past age 40, normal ovarian reserve testing is not reassuring because even reduced egg quality is likely to limit the opportunity for successful pregnancy no matter how many eggs are available.

Age Factors↗
PubMed1979

Effect of diurnal or nocturnal heat stress on egg formation.

1. Mature laying hens were subjected to ambient temperatures sufficient to maintain body temperature of 43 degrees C for periods of 6 to 7 h during the day (eight periods) or the night (five periods). This did not reduce total daily food consumption. 2. The effect of heat stress during the day was mostly on egg-shell quality, being adverse and significant. During the night heat stress caused a significant decrease in egg production, its effect during the day was less marked in this respect. 3. Heat stress thus seems mostly to affect the early stages of shell formation, while its effect on egg production seems to depend on the time at which it occurs in relation to ovulation. 4. These results suggest that egg production is directly affected by heat stress; prolonged heat stress probably also acts indirectly, by suppression of food intake.

Animals↗
PubMed1997

Analysis of P[gal4] insertion lines of Drosophila melanogaster as a route to identifying genes important in the follicle cells during oogenesis.

We report the analysis of a number of lines of Drosophila melanogaster containing insertions of the yeast gal4 gene. By crossing a UAS-lacZ fusion gene as a reporter into these lines, we analysed the expression patterns of beta-galactosidase during oogenesis. Since there is no expression of GAL4 in the germ-line in these experiments, this is an ideal system for the analysis of expression patterns in sub-sets of follicle cells. These lines provide ideal markers for sets of follicle cells, e.g. anterior or posterior polar cells for studying genetic interactions in oogenesis; however, they can also be used in the same way as conventional enhancer traps to clone nearby genes with similar expression patterns. The advantages of this dual gal4/UAS system over conventional enhancer trapping includes the possibility of GAL4-directed misexpression and antisense expression studies to establish the function of the genes we identified during follicle cell determination and differentiation. These studies could lead to the isolation of homologous genes crucial in mammalian oogenesis. Understanding how the somatic cells and germ cells interact to promote growth and maturation of the mammalian follicle and oocyte could well be crucial for improving the fertility of eggs used for in-vitro fertilization programmes, and could provide methods for assessing the quality of eggs.

Animals↗
PubMed1994

Relationship of plasma calcium and phosphorus to the shell quality of laying hens receiving saline drinking water.

1. From 36 to 43 weeks of age 210 White Leghorn laying hens were used to study the relationship of plasma calcium and phosphorus concentrations to egg-shell quality when saline drinking water was given. 2. Seven experimental treatments in which different amounts of sodium chloride were supplied by the food and/or the drinking water were compared. 3. Increasing salt intake through the drinking water or the food reduced shell thickness and shell calcium, and increased the numbers of damaged eggs. Sodium chloride given in the drinking water was more effective in reducing shell quality and increasing plasma calcium and phosphorus than sodium chloride given in the food.

Animals↗
PubMed1982

Performance of laying hens subjected to intermittent lighting initiated at 24 weeks of age.

Leghorn pullets of a commercial strain were subjected to a conventional light program of constant photoperiod or an intermittent programming involving, during the house of conventional "lights-on", 45 min light (L): 15 min dark (D) from 24 to 27 weeks of age; 30 min L:30 min D from 28 to 35 weeks; and 14 min L:45 min D from 36 weeks to the duration of the trial. Each light treatment was tested with 12 replicate groups of 14 individually caged birds housed in adjacent rooms, with all birds fed a standard 15% crude protein, 2750 kcal ME/kg diet. Intermittent lighting resulted in a significant (P less than .05) reduction in feed intake and a consistent but nonsignificant (P less than .05) reduction in egg production. Egg size, egg shell quality, and albumen quality, as assessed by Haugh units, were not affected by light treatment. Due to the effect on egg production, it is concluded that intermittent lighting programs should not be initiated close to time of peak egg production.

Animals↗
PubMed1994

n-3 fatty acid enriched table eggs: a survey of consumer acceptability.

Table eggs enriched with n-3 fatty acids may provide an alternative to fish as a source of these proposed healthful fatty acids. Successful marketing of this product may be influenced, however, by consumer perceptions of the egg as an unhealthful food. Therefore, the objectives of the current study were to assess consumer perceptions of table egg health quality and to determine the potential consumer acceptability of an n-3 fatty acid-enriched table egg. A survey was conducted in five major Texas cities; over 500 consumers completed the survey. Data were analyzed using the chi-square procedure. The majority of consumers surveyed considered eggs healthful and reported purchasing eggs at least once monthly and consuming an average of three whole eggs per week, as compared with an average reported fish consumption of only one serving per week. Sixty-five percent of the consumers reported willingness to purchase an n-3 fatty acid-enriched table egg and of these, 71% were willing to pay an additional $.50 per dozen. These data indicate that n-3 fatty acid-enriched table eggs represent a viable means of incorporating n-3 fatty acids into the diet of health-conscious consumers.

Adult↗
PubMed2007

Deglycosylation of ovalbumin prohibits formation of a heat-stable conformer.

To study the influence of the carbohydrate-moiety of ovalbumin on the formation of the heat-stable conformer S-ovalbumin, ovalbumin is deglycosylated with PNGase-F under native conditions. Although the enzymatic deglycosylation procedure resulted in a complete loss of the ability to bind to Concavalin A column-material, only in about 50% the proteins lost their complete carbohydrate moiety, as demonstrated by mass spectrometry and size exclusion chromatography. Thermal stability and conformational changes were determined using circular dichroism and differential scanning calorimetry and demonstrated at ambient temperature no conformational changes due to the deglycosylation. Also the denaturation temperature of the processed proteins remained the same (77.4 +/- 0.4 degrees C). After heat treatment of the processed protein at 55 degrees C and pH 9.9 for 72 h, the condition that converts native ovalbumin into the heat-stable conformer (S-ovalbumin), only the material with the intact carbohydrate moiety forms this heat-stable conformer. The material that effectively lost its carbohydrate moiety appeared fully denatured and aggregated due to these processing conditions. These results indicate that the PNGase-F treatment of ovalbumin prohibits the formation and stabilization of the heat-stable conformer S-ovalbumin. Since S-ovalbumin in egg protein samples is known to affect functional properties, this work illustrates a potential route to control the quality of egg protein ingredients.

Animals↗
PubMed1989

Physiological changes associated with the production of defective egg-shells by hens receiving sodium chloride in the drinking water.

1. Supplementing the drinking water of laying hens with 600 or 2000 mg sodium chloride/l induced large increases in egg-shell defects without corresponding changes in egg production, egg weight or food and water intakes. A supplement of 2000 mg NaCl/l resulted in a high incidence of shell-less eggs. 2. The increased incidence of egg-shell damage in hens receiving the NaCl was associated with a decrease in egg-shell quality measured objectively. These responses persisted even after the NaCl was removed from the drinking water. 3. The NaCl treatment had little effect on blood acid-base balance and electrolytes, but significant reductions were observed in the carbon dioxide tension, and bicarbonate and calcium concentrations in the fluid surrounding the egg in the shell gland. 4. The poor shell quality appeared to be associated with a reduced supply of bicarbonate, rather than with an effect on Ca, in the lumen of the shell gland, although a reduced residence time of eggs in the shell gland may also have contributed to the problem.

Animals↗
PubMed2000

Assessment of fresh and stored duck spermatozoa quality via in vitro sperm-egg interaction assay.

An in vitro sperm-egg interaction assay was used to measue the quality of duck spermatozoa in fresh and stored semen. The inner perivitelline layer (IPVL), which had been separated from laid duck eggs, was incubated with spermatozoa in vitro. The number of points of sperm hydrolysis in the IPVL in vitro was logarithmically correlated with the fertility of the eggs laid by inseminated females, for both fresh semen (r = 0.85, P < 0.001) and stored semen at 5 degrees C for 24 h (r = 0.84, P < 0.001). After semen storage, the ability of spermatozoa to hydrolyze the IPVL decreased by 67.4% compared with the values for fresh semen, whereas egg fertility and sperm motility decreased by 47.8% and 15.2%, respectively. These results suggest that the in vitro sperm-egg interaction assay accurately reflects the fertilizing ability of fresh and stored duck spermatozoa and detects spermatozoal damage due to semen storage more sensitively than motility or fertility tests.

Animals↗