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PubMed1980

Source of carbon for the biosynthesis of eggshell carbonate in the hen. Comparison of six 14C labeled compounds as sources of carbon in eggshells, albumen, and yolk.

Laying hens received single-dose intravenous injections of one of six U-14C labeled metabolites (bicarbonate, acetate, D-glucose, glycine, L-leucine, and palmitate) at times coinciding with maximum shell formation. Eggs were collected and 14C activities in shell, yolk, and albumen were measured. Typical patterns of 14C incorporation were observed with each of the three egg fractions; in shells highest 14C activities were obtained on the first postinjection day (D+1 day), albumen on the D+2 day, while yolks increased gradually their activities from zero levels on the D+1 day, reaching a plateau at around the D+4 day. In the second experiment, the 14C entry into albumen was slower than in the first one, with bicarbonate effecting higher albumen activities in D+3 than in D+2 eggs. Levels of 14C entry into shells of eggs laid on the D+1 day by hens injected with bicarbonate, glucose, or acetate were similar; significantly lower levels were obtained with (listed in descending order) glycine, leucine, and palmitate. Highest activities in albumen were induced by the two amino acids, with leucine causing higher activities than glycine; progressively lower entries were obtained with glucose, acetate, bicarbonate, and palmitate. In yolks, highest activities were obtained with glucose, followed by leucine, acetate, glycine, palmitate, and bicarbonate. Unexpectedly high activities obtained in the albumen of the D+1 eggs, particularly with 14C supplied from glucose, indicate that 14C was transported during the shell formation stage into the egg. The physiological implications are discussed and a suggestion is made that the possibility of carbonate for shell formation being delivered to the site of this formation from the inside of the egg should not be overlooked.

Animals↗
PubMed1995

Saltationist and punctuated equilibrium models for the evolution of viviparity and placentation.

Vertebrate viviparity (live-bearing reproduction), placentation, and placentotrophy are widely assumed to have evolved as three successive, gradualistic transformations. From empirical data and predictive tests on lizards and snakes, this paper indicates that placentae and a degree of placentotrophy have evolved repeatedly as necessary correlates of viviparity, not as subsequent modifications. In addition, information derived from studies of anatomy, physiology, biogeography and systematics is used to evaluate new saltationist and punctuated equilibrium models for the evolution of viviparity. Phylogenetic reconstruction reveals that more than 100 squamate clades have made the transition to viviparity and placentation. However, various phenotypic intermediates postulated by the gradualistic model are either scarce or unrepresented among known forms, including those in which viviparity has evolved at specific and subspecific levels. Evolution in squamates seems to have produced a dichotomy between two evolutionarily stable patterns: (i) retention of weakly shelled or shell-free eggs to term (viviparity), with development of fully functional placentae; and (ii) deposition of shelled eggs at or near the limb bud stage of development (typical oviparity). Conflicting functional demands placed on eggshell morphology may constrain establishment of prolonged, oviparous egg-retention as a viable, historically stable pattern. Alternatively, the costs of prolonged egg-retention associated with decreased female mobility or decreased fecundity may exceed the benefits in oviparous forms.

Animals↗
PubMed1997

Genetic parameters for egg number, egg weight, and eggshell color in three Catalan poultry breeds.

Heritabilities for egg number, egg weight, and eggshell color (percentage light absorbance) at 39 wk of age, and the genetic correlations between them were estimated by restricted maximum likelihood in three Catalan poultry breeds: Penedesenca Negra (PN), Prat Lleonada (PL), and Empordanesa Roja (ER). Additive genetic differences between these breeds were also estimated. Data were from the IRTA Poultry Genetic Conservation Program and consisted of records from 1,309 PN, 1,466 PL, and 1,440 ER hens, which were obtained from 80 contemporary batches per breed hatched between 1987 and 1992. Estimates of heritability for egg number, egg weight, and eggshell color were, 0.20, 0.59, and 0.49 for PN, 0.31, 0.48, and 0.53 for PL; and 0.33, 0.50, and 0.27 for ER. Estimated genetic correlations between egg number and egg weight, egg number and shell color, and egg weight and shell color were, for PN, -0.22, -0.03, and 0.00; for PL, -0.21, -0.06, and 0.09; and -0.19, -0.29, and 0.30 for ER. Heritability for eggshell color and genetic correlation between eggshell color and other traits showed a different genetic pattern in ER breed. Significant additive genetic differences (P < 0.05) were found between ER and PN base populations for egg number (3.89), egg weight (0.91), and eggshell color (-3.50); and between ER and PL for egg number (6.69) and eggshell color (35.39). The PN and PL breeds differed significantly (P < 0.05) for eggshell color (38.22), which was darker in PN. These results could be taken as the expected genetic differences for these breeds.

Aging↗
PubMed1981

SEM observations of the membranous structure of eggs from Taenia solium.

The shell of Taenia eggs are easily ruptured and lost if the eggs are prepared according to routine methods for SEM observation. As a result, only the vitelline layer is normally seen. When the uterus is fractured while frozen, the eggs located in the lateral uterine branches are exposed and do contain intact shells. In the fully developed eggs of T. solium, six layers surround the oncosphore. Starting from the outermost structure, they are the egg shell, the vitelline layer, the outer embryonic membrane, the middle embryophoric block layer, the inner basal membrane and the oncosphoral membrane, Numerous lacunae and capillaries from a fine tubular system in he embryophore. The functional significance of these structures is discussed. In addition two structures, which can be used to distinguish eggs of T. solium from those of T. saginatus are presented.

Animals↗
PubMed1988

Regional differences in diffusive conductance/perfusion ratio in the shell of the hen's egg.

Are both gas exchange and gas tensions uniform in different regions of the developing hen's egg? To answer this question we measured the O2 uptake and CO2 production of the whole egg, and at the same time the O2 and CO2 tensions of the air cell. The gas exchange ratio (R) of the whole egg differed from R calculated from air cell PO2 and PCO2 values, in agreement with the findings of Visschedijk [Br. Poultry Sci. 9:173-184 (1968)], who measured gas exchange separately over both the air cell region and the remainder of the egg. We constructed a diffusive shell conductance/perfusion (G/Q) line on the O2-CO2 diagram from a blood nomogram for the chick embryo in late development [Olszowka et al., Fed. Proc. 46:512 (1987)], and used this to analyze our results. The G/Q ratio for the area of shell over the air cell differs from that for the remainder of the egg. Our analysis permits us to calculate, for each area, the regional shell conductance, blood flow, and O2 and CO2 tensions in the gas spaces between the shell and the chorioallantoic capillaries.

Animals↗
PubMed1980

Behavior of enterococci in egg processing operations.

Since enterococci were detected in dried and frozen egg products (whole egg and egg yolk), the origin of the enterococci and their behavior in the different stages of egg processing were surveyed. The bacterial survey of unwashed and washed eggs, gathered from several parts of Japan, showed the presence of an average of 60 enterococci per egg on the shell surface of unwashed eggs. Smaller numbers of enterococci were detected on the shell surface of washed eggs. Most of the detected enterococci were Streptococcus faecalis and S. faecalis var. liquefaciens. The contents of two eggs were contaminated with enterococci when 120 washed eggs were examined. Enterococci were destroyed to some extent by the disinfectants used for washing the shell eggs, but they seemed to have greater resistance than Escherichia coli and Pseudomonas fluorescens used for comparison. In whole egg and egg yolk, enterococci grew rapidly at 25 C, slowly at 10 C, and very slowly at 2.5 C. The frozen storage of both whole egg and egg yolk at -20 C for 3 months only slightly decreased the number of enterococci. They were decreased only slightly by normal pasteurization but were destroyed in the desugaring process by the glucose oxidase method. Enterococci numbers were only slightly decreased by spray-drying whole egg and yolk. Considering these characteristics of enterococci, it appears to be difficult to produce enterococci-free egg products in a normal production line.

Animals↗
PubMed1979

Effects of organochlorine residues on eggshell thickness, reproduction, and population status of brown pelicans (Pelecanus occidentalis) in South Carolina and Florida, 1969--76.

Shells of brown pelican (Pelecanus occidentalis) eggs collected in South Carolina from 1969 through 1975 and in Florida during 1969, 1970, and 1974 were significantly thinner (P greater than 0.05) than eggshells collected before 1947. Thickness of South Carolina eggshells increased in 1975, and mean thickness of eggshells collected in Florida during 1974 was greater than that of eggshells collected during 1969 and 1970, primarily in Gulf Coast colonies. Residues of 13 organochlorines were found in eggs and tissues of pelicans found dead during 1974 and 1975, although residues in brains of these specimens were not high enough to cause death. Residues of organochlorines, except PCBs, declined through 1975. PCBs increased in eggs from Atlantic Coast colonies. Reproductive success and population status of brown pelicans in South Carolina have improved markedly since authors began their studies in 1969. Good reproductive success was reported in 3 of 5 years from 1973 through 1977.

Animals↗
PubMed2003

Production performance, serum/yolk cholesterol and immune competence of white leghorn layers as influenced by dietary supplementation with probiotic.

An experiment was conducted to measure the influence of a dietary probiotic on the production performance, the concentrations of cholesterol in the serum and yolk and immune competence in White Leghorn layers from 25 to 72 weeks of age. One hundred and twenty commercial White Leghorn layers, aged 24 weeks, with an average of 62% hen-day egg production, were equally and randomly distributed into three groups, with eight replicates of 5 birds in each. The birds were reared in individual laying cages. They were placed on one of three dietary treatments: basal, or basal with probiotic supplementation at a rate of 100 or 200 mg/kg feed. The addition of probiotic significantly increased the egg production, shell weight, shell thickness and serum calcium, and reduced the concentrations of cholesterol in the serum and yolk. However, no differences in these traits was observed between the groups receiving 100 or 200 mg probiotic. Feed conversion, egg weight, serum phosphorus and serum alkaline phosphatase activity were not influenced by supplementation with probiotic. Antibody production in response to the inoculation of sheep red blood cells and the cutaneous basophilic hypersensitivity (CBH) responses to inoculation with phytohaemagglutinin did not differ significantly among the dietary groups at either 24 or 40 weeks of age. The antibody titre was significantly higher in the groups supplemented with probiotic at 64 weeks of age. The addition of 100 mg/kg of probiotic in the diet significantly increased the CBH response at 64 weeks of age.

Alkaline Phosphatase↗
PubMed1987

The effect of age on egg production in the domestic hen.

The effect of age on egg production was investigated in the domestic fowl. The rate of egg production was reduced with increasing age and the incidence of thin-shelled and cracked eggs was markedly increased. Older hens which remained in lay produced fewer but larger eggs than the younger birds. The ovaries of these two groups of hens were of similar appearance but the largest preovulatory follicle and the oviduct were significantly heavier in the older birds. No differences in the circulating levels of progesterone or estradiol were apparent between the young and old birds but the activity of the renal 25-hydroxycholecalciferol 1 alpha-hydroxylase was found to be significantly reduced with age. Circulating levels of total and ionized calcium were very similar in the young and old laying birds, plasma ionized calcium levels being markedly depressed during egg shell calcification in both groups. The decreased rate of ovulation in the older birds and the increase with age in the size of the follicles ovulated is thought to be associated with a reduced rate of recruitment of follicles for rapid growth followed by a prolonged period of follicular growth and development. The poor calcification of egg shell in old birds would appear to be due to some dysfunction of the shell gland, possibly associated with reduced synthesis of 1,25-dihydroxycholecalciferol by the kidney. The maintenance of plasma ionized calcium concentrations does not appear to be of primary importance in this respect.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed2006

Bacterial shell contamination in the egg collection chains of different housing systems for laying hens.

The bacterial eggshell contamination of eating eggs in different commercial housing systems; two conventional cages, one organic aviary system and one barn production, were compared. The total counts of aerobic bacteria and the total counts of Gram-negative bacteria on the shell were used to detect key points where contamination occurred and to study the progress of contamination in the egg collection and transportation chains. The key points in the chain were those where eggs accumulated on a short conveyor belt, initial shell contamination in the alternative housing systems and extra nest-boxes placed on the ground. The high bacterial load of floor eggs (>6.3 log CFU total aerobic flora/eggshell) explains why they cannot be used for eating. On average higher initial shell contamination with total counts of aerobic bacteria was found for eggs from the alternative housing systems compared to the conventional systems; respectively 5.46 compared to 5.08 log CFU/eggshell. However, initial contamination with total counts of Gram-negative bacteria on the shells was less in the alternative systems: 3.31 compared to 3.85 log CFU/shell. Initial bacterial shell contamination tended to correlate positively with the concentration of bacteria in the air of the poultry houses. Storing shell eggs, whether temporarily refrigerated or not, for 9 d or more, resulted in a decrease in bacterial eggshell contamination for both bacterial variables.

Air Microbiology↗
PubMed2003

Outbreak of Salmonella Potsdam associated with salad dressing at a restaurant.

Between 27 January and 7 February 2002, 12 cases of Salmonella Potsdam infection were notified to NSW Health of which nine were residents of the Hunter Health Area. Interviews with two cases notified by two local doctors initiated the investigation and revealed exposure to foods from the same restaurant (restaurant A). All New South Wales S. Potsdam cases, those accompanying cases to restaurant A and people from restaurant A booking lists were interviewed. Of the 34 people interviewed, 17 met the case definition. The epidemiological investigation did not detect a food source of S. Potsdam infection, however, shell egg-based Caesar salad dressing and mayonnaise, and a swab of a cap from a mayonnaise bottle collected at restaurant A tested positive for S. Potsdam. Environmental and laying hen feed samples from the egg supplier to restaurant A and meat meal, (the major component of laying hen feed) tested positive for various Salmonella serotypes. The investigation identified problems of inadequate cleaning, time-temperature abuse, and ignorance of the hazardous nature of raw shell eggs at the restaurant level, poor sanitation and a lack of hygiene inspections at the egg production level, and problems with cleaning, storage and lack of bacterial monitoring of final product at the animal rendering plant. Investigation of 12 notified cases of Salmonella resulted in public health interventions, which likely prevented further cases of foodborne disease due to Salmonella and other pathogens in the Hunter Health Area and elsewhere in New South Wales.

Disease Outbreaks↗
PubMed2003

Long-term effects of feeding flaxseed on performance and egg fatty acid composition of brown and white hens.

Two hundred fifty-six 18-wk-old Shaver White and ISA-Brown pullets were fed commercial diets containing either 0 or 10% flaxseed in order to study the long-term effects of feeding flaxseed on hen performance and egg production parameters. Performance was monitored over 10 consecutive 28-d periods. Flaxseed was introduced gradually at 28 wk of age and was maintained until hens were 53 wk of age, when flaxseed was gradually eliminated from the diet. Feed intake was less (P < 0.05) for hens fed flaxseed compared to those consuming the control diet. Flax-fed hens were also lighter (P < 0.05) compared to the control birds. Egg production, egg weight, shell weight, albumen height, and shell thickness were not significantly (P > 0.05) different for hens consuming 0 and 10% flaxseed; however, yolk weight was reduced (P < 0.05) in hens fed flaxseed. Both strains of birds fed flaxseed deposited significantly more n-3 fatty acids into their eggs. Sampling of livers at the end of the trial showed that hens fed flaxseed had a higher (P < 0.05) incidence of liver hemorrhages.

Aging↗
PubMed1993

Vitamin profiles of eggs as indicators of nutritional status in the laying hen: riboflavin study.

Two experiments determined the effect of dietary riboflavin supplementation on egg yolk and albumen riboflavin concentrations, egg production, egg weight, shell thickness, hen weight, hatchability, incidence of clubbed down, and incidence of hemorrhagic embryos. In the first experiment, hens were fed rations containing 1.55, 2.20, 4.40, and 8.80 mg of riboflavin/kg of diet for 27 wk. Significant (P < .05) depressions in both yolk and albumen riboflavin concentrations were noted at the two lower riboflavin levels after 1 wk. Egg production, egg weight, hatchability, and hen weight were all significantly depressed by the two lower riboflavin levels later in the experiment when compared with the two higher levels. Results indicate that egg riboflavin concentrations are related to important production parameters that may be used to predict future dietary riboflavin inadequacies. In the second experiment, hens were fed either an unsupplemented diet or a riboflavin-adequate diet. Measurements of egg albumen riboflavin content, egg production, hatchability, and embryo abnormalities were made twice each week. Results showed depressed albumen riboflavin concentrations and hatchability and increased incidence of hemorrhagic embryos and clubbed down without changes in egg production during the 4- to 7-day period following feeding of the unsupplemented diet. These results show that low albumen riboflavin content immediately affect hatchability and embryonic development. The estimated minimum critical albumen riboflavin concentrations needed to support maximum reproductive function are between 1.9 and 2.9 micrograms of riboflavin/g of egg albumen. These critical values might be used to evaluate riboflavin status of laying and breeding flocks.

Animal Feed↗