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PubMed1992

Inheritance of tinted eggshell colors in white-shell stocks.

The present study was conducted to study the genetics of tinted eggshell colors in two breeds of chickens laying white-shell eggs. Reciprocal crosses were made between an inbred White Leghorn line (ES) and an inbred Ancona line (ANC). The F1 birds were intercrossed and F1 females were backcrossed to each of the original lines. Eggshell color from each resultant group was measured using a Minolta chromometer, and a value (e) representing the color intensity adjusted by hue and saturation was used as the measurement criterion. Age, hatch group, and crosses each contributed significantly to the variation seen in eggshell color. Distribution comparisons indicated that two major autosomal loci affected the trait in these lines: one gene having incomplete dominance controls the amount of pigment deposition; the second completely inhibits pigment deposition when homozygous recessive. A test of goodness of fit supported this hypothesis. Genetic components were estimated by linear models. Epistasis, dominance, and additive effects contributed significantly to this trait. No sex-linked effects were noted.

Analysis of Variance↗
PubMed1984

Experimental studies on brucellosis in chickens.

The present study was carried out on 30 one-day old and 50 six-months old chicks in two separate experiments. Exposure of one-day old chickens to Br. abortus showed no apparent clinical signs, although the microorganism was recovered from 2 out of 10 infected cases. 40% of chicks which were exposed to Br. melitensis showed signs of illness 48-72 hours post infection with fatal termination within 12-36 hours after onset of symptoms. The microorganism was isolated from 6 out of 10 infected chicks. Adult chicks, when exposed to Brucella infection showed no clinical signs except a slight decrease in egg-yield among hens infected intraperitoneally with Br. melitensis, although brucella organisms were recovered from droppings, egg-shell, egg-yolk and white, and from internal organs of some chicks. Bacteriological evaluation of diagnostic procedures showed that Rose Bengal and Brucellosis card tests were efficient for the diagnosis of brucellosis in chickens. The brucellin test proved its efficacy when applied in the wattle, better than in wing-folds with a peak of reaction within 48 to 72 hours post inoculation. Brucella organisms isolated from experimentally infected chicks were identical to the original strains used. In droppings of chicks Br. melitensis survived for 48 days at room temperature (12-22 degrees C). Beside the economical losses resulting from infection by Br. melitensis of one-day old chicks, the results obtained assure the significance of infected chicks, their eggs and droppings in disseminating brucellosis for man and animals.

Allergens↗
PubMed1983

The relationship of dietary levels of phosphorus to the production of soft-shelled and shell-less eggs.

The relationship among available levels of dietary phosphorus (.2, .3, and .4%) and the production of soft-shelled (SS) and shell-less (SL) eggs was investigated in 864 White Leghorns of a commercial strain. An 11-month performance profile included hen-day production of hard-shelled (HS), SS, and SL eggs, feed consumption, livability, egg weight, and specific gravity. Percent HS egg production and feed consumption were significantly lower and egg specific gravity was significantly higher among hens consuming the .2% available phosphorus diet when compared to hens consuming the .3 or .4% available phosphorus diets. The level of available phosphorus in this study did not affect significantly hen livability or the production of SS or SL eggs. Five hours (HS egg in uterus) or 15 hr (SL egg in uterus) prior to expected oviposition time, 1 ml of a 200 mM phosphate solution was injected into the brachial vein (i.v.) or the uterus (i.u.) of hens observed to lay consistently HS eggs. Injections i.v. did not alter expected oviposition time when either a HS or SL egg was in the uterus, but i.u. injections induced premature oviposition when a SL egg was in utero. The concentrations of inorganic phosphorus and total calcium in the plasma and uterine fluid of hens that laid a high or low incidence of SS + SL eggs were determined 5 hr after the egg entered the uterus. Uterine fluid inorganic phosphorus and total calcium and plasma inorganic phosphorus levels of the high and low incidence groups were not significantly different. However, plasma total calcium was significantly higher among high incidence SS + SL layers when compared to low incidence SS + SL layers at this time during the ovulatory cycle.

Animals↗
PubMed1982

Disorders of cholecalciferol metabolism in old egg-laying hens.

It has been reported that the rate of cracked or soft-shelled eggs markedly increases in old laying hens. We investigated the effect of age on cholecalciferol metabolism in different age groups of laying hens. The egg production rate in hens more than 500 days old was maintained within a range of about 70% of that in young hens (230-320 days old), whereas the rate of cracked or soft-shelled eggs increased markedly with age. When kidney homogenates from the different age groups were incubated with [3H]-25-hydroxyvitamin D-3, renal 25-hydroxyvitamin D-3-1 alpha-hydroxylase activity was found to decrease markedly with age. When birds were given intravenously either [3H]-25-hydroxyvitamin D-3 or [3H]-1 alpha,25-dihydroxyvitamin D-3, the accumulation of [3H]-1 alpha,25-dihydroxyvitamin D-3 in plasma and target tissue also decreased with age. Forced molting performed in old hens restored eggshell quality. The treatment also restored, though partially, the in vivo accumulation of [3H]-l alpha,25-dihydroxyvitamin D-3 in the target tissues. These results suggest that the increased rate of cracked or soft-shelled eggs seen in older birds is associated with disorders of vitamin D-3 metabolism.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed2003

Comparison of homogenization methods for recovering Salmonella Enteritidis from eggs.

For Salmonella Enteritidis (SE) detection, shell eggs have been homogenized with stomachers, with electric blenders, and by hand massaging. However, to date, there have been no published reports addressing whether the method of homogenization affects the recovery of SE from raw eggs. Three inoculum levels (10, 126, and 256 SE cells per pool of 10 eggs) were used to conduct three experiments. The 10-egg pools were homogenized by one of four homogenization methods--mechanical stomaching, electric blending, hand massaging, and hand stirring-for 30 s. The homogenized eggs were then incubated at 37 degrees C, and SE colonies were enumerated after 24 and 48 h of incubation. After 24 h of incubation, no SE was recovered from egg samples from stomached or electrically blended pools inoculated with <10 cells, while levels of 106 CFU/ml were found for samples from whipped or hand-massaged pools inoculated with <10 cells. Similarly, after 24 h of incubation, the numbers of SE cells recovered from hand-massaged or hand-stirred egg pools inoculated with 126 cells were significantly larger than the numbers recovered from stomached or electrically blended egg pools inoculated with 126 cells. The number of SE cells recovered from samples homogenized with a blender was still significantly smaller than the numbers recovered from samples homogenized by the other three methods when the inoculum level was increased to 256 CFU per pool. However, the SE count for all samples approached 9 log10 CFU/ml after 48 h of incubation. It is concluded that the detection of small SE populations in shell egg samples could be improved with the use hand massaging and hand stirring for homogenization.

Animals↗
PubMed2000

Vitellocytes and vitellogenesis in cestodes in relation to embryonic development, egg production and life cycle.

Vitellocytes have two important functions in cestode embryogenesis: (1) formation of hard egg-shell (e.g. Pseudophyllidea) or a delicate capsule (e.g. Cyclophyllidea), and (2) supplying nutritive reserves for the developing embryos. During evolution any of these two functions can be reduced or intensified in different taxa depending on the type of their embryonic development, degree of ovoviviparity and life cycles. Within the Cestoda, there are three monozoic taxa with only one set of genital organs: Amphilinidea, Gyrocotylidea and Caryophyllidea. In these monozoic taxa and some polyzoic groups with well developed vitellaria (e.g. Pseudophyllidea, Trypanorhyncha) a single oocyte [=germocyte] and a large number of vitellocytes (up to 30) are enclosed within a thick, hardened egg-shell, forming a type of eggs typical for the basic pattern of Neodermata. Only one type of egg-shell enclosures, the so-called 'heterogeneous shell-globule vesicle' is common for the above mentioned cestode taxa. Each membrane-bounded vesicle of mature vitellocytes contains numerous electron-dense shell globules embedded in a translucent matrix. In free-living Neoophora and Monogenea there are two types of vesicles with dense granules; the second is considered to be proteinaceous reserve material. Within the Cestoda, the numbers of vitellocytes per germocyte are reduced in those taxa forming eggs of the 'Cyclophyllidean-type' (e.g. Cyclophyllidea, Tetraphyllidea, Pseudophyllidea). This is particularly evident in Cyclophyllidea; for example, in vitellocytes of Hymenolepis diminuta (Hymenolepididae) there are numerous vitelline granules of homogeneously electron-dense material; in Catenotaenia pusilla (Catenotaeniidae) there are three large, homogenous vitelline vesicles, while in Inermicapsifer madagascariensis (Anoplocephalidae) there is only one large vitelline vesicle, containing homogeneously electron-dense material, which occupies most of the vitelline cell volume. In this respect the Tetraphyllidea and Proteocephalidea, in forming eggs that lack a hard egg-shell, hold an intermediate position. A comparison of interrelationships which exist among types of vitellocytes, vitellogenesis, types of embryonic development, ovoviviparity and life cycles indicates parallelisms and analogies in adaptation to the parasitic way of life in different groups of cestodes. Knowledge on cestode vitellogenesis may also have an important applied aspect. Vitellocytes, due to their high metabolic rate, represent a very sensitive target for analysing effect of anthelminthic drugs upon the egg formation (ovicidal effects); rapid degeneration of vitellocytes is usually accompanied by a cessation of egg production.

Animals↗
PubMed1996

Risk assessment of use of cracked eggs in Canada.

In 1992, Agriculture and Agri-Food Canada (AAFC) amended its Egg Regulations to restrict movement of Canada C eggs (cracks) to federally registered processed egg stations for pasteurization. This was questioned by egg producers and some provinces on economic grounds. It was also in conflict with long-standing practices of marketing eggs in some provinces to retail stores, bakeries, restaurants and institutions or at the farm gate. In order to determine how much of a risk these eggs were to human health, AAFC requested that the Health Protection Branch (HPB) of Health Canada (HC) conduct a risk assessment. On the basis of outbreak data, the main hazard in these eggs was identified as Salmonella. Salmonellae may occasionally be present on shell eggs even after washing, and any Salmonella reaching the membranes can be transferred to an egg mixture through breaking, and will rapidly grow under improper storage conditions. A Relative Risk analysis showed that cracked eggs are 3 to 93 times more likely than uncracked shell eggs to cause outbreaks. A probability of illness of 1 in 3800 was derived from the 40 million cracked eggs produced in Canada and not pasteurized and the probable 10,500 illnesses arising from these. This was for the general population, but this would be greater for those who consume many shell eggs or would do so in an unsafe manner, or are more likely to be infected (5% of consumers who eat raw or lightly cooked eggs daily, rural communities with more opportunities for obtaining cracked eggs, and those who are immunocompromised and in institutions). Even though it is not possible to precisely determine the risk of salmonellosis through cracked eggs, this assessment indicated that there was enough of a concern that a management strategy was needed. Eight options for managing the risk were considered and ranked for acceptability by both HC and AAFC. Ideally, all cracked eggs should be broken and pasteurized, but this is impractical in certain regions of the country, and other options, such as sales to food processors operating under Good Manufacturing Practices (GMP), and at the farm gate in marked cartons and under controlled conditions, were considered to be acceptable, whereas sales to institutions and bakeries were not. This is the first fromal food-related microbiological risk assessment that HC has completed. Although this is a Canadian problem, any country producing eggs has to recognise that despite any regulations controlling the use of cracked eggs, economics will dictate that some of these will be consumed as whole eggs or egg products, and a management plan is desirable to limit hazardous practices associated with these eggs.

Canada↗
PubMed2001

Egg marketing in national supermarkets: specialty eggs--part 2.

Large eggs promoted as having one or more features beyond conventional white or brown shell eggs (specialty eggs) were evaluated for quality and price in a national retail study. Subtypes of specialty eggs included: nutritionally altered eggs, organic eggs, fertile eggs, eggs from welfare-managed hens, or hens fed all-vegetable diets. Extension Poultry Specialists in California (CA), Connecticut, Illinois, North Carolina, Pennsylvania and Texas conducted a survey of egg quality and price and compared 246 dozen specialty eggs with 390 dozen conventional white shell eggs during the summer of 1996. Age of the eggs based on carton dating indicated specialty eggs were older (16.5 d) than white eggs (11.7 d). Average egg weights for specialty compared to white were 60.2 and 59.6 g, respectively. Interior egg quality evaluations including albumen height, Haugh units (HU), and percentage HU <55, indicated white eggs were superior (5.0 mm, 67.5, and 10.6%, respectively) compared to specialty eggs (4.7 mm, 63.8, and 16.3%). Although the percentage of cracked eggs was similar between specialty and white eggs (5.4 and 5.7%), the percentage of leakers was threefold higher for the specialty eggs (1.0 vs. 0.3%). Egg price was substantially higher for the specialty eggs, averaging $2.18/dozen with a range from 0.88 to $4.38, compared to white eggs, averaging $1.23/dozen and ranging from 0.39 to $2.35.

Animal Feed↗
PubMed2000

Producing and marketing a specialty egg.

Eggland's Best, Inc. markets premium quality shell eggs under the Eggland's Best (EB) brand name. The company, started in 1988, is comprised of a franchise network of established egg producers and covers most of the United States. Eggland's Best provides its franchisees with marketing and technical support. The franchisees produce, process, and distribute EB eggs according to the strict program established and monitored by EB. Production follows the all-natural vegetarian feed program in accordance with the company's US patent entitled "Eggs Compatible with a Cholesterol Reducing Diet and Method of Producing the Same." The EB program excludes animal fat and other animal byproducts. Eggland's Best eggs have seven times the generic level of vitamin E, nearly three times more omega-3 fatty acids and iodine, and 25% less saturated fat than regular generic eggs. Eggland's Best has one of the finest shell egg quality assurance programs anywhere. Eggland's Best franchisees submit weekly egg samples that are analyzed for shell quality, interior quality, vitamin E, iodine, cholesterol and fatty acids. Samples of feed and the EB-patented feed supplement are also analyzed. Approximately 28,000 total laboratory tests are conducted annually. Nationwide product and display retail evaluations are contracted through an outside audit company (40 to 50 cities evaluated four times per year). All EB eggs are USDA graded according to EB's strict quality standards. Producers must follow a food safety quality assurance program (United Egg Producers Association 5-Star or equivalent state or company program). Each egg is stamped "EB" as assurance of meeting EB's highest standards of flavor, quality, and nutrition. Eggland's Best has enjoyed record sales growth for the past 3 yr.

Animals↗
PubMed1995

Human bilharzial ureters: I. Fine structure of eggs deposited in the submucosa and muscularis.

The internal fine structure of the partially calcified Schistosoma haematobium eggs in the lower ureteral segments of Saudi patients with chronic urinary schistosomiasis is described. The egg shell is penetrated by cribriform pores and consists of the three previously described layers: outer microspinous, middle intermediately dense, and inner dense layers. The space between the egg shell and the developing embryo is partitioned by three layers. An outer acellular Reynolds' layer of unknown origin and function consists of a fibrillar material mixed with a finely granular matrix extending to the egg-shell pores via racimose channels. The middle von Lichtenberg's envelope consists of a single layer of flattened epithelial cells containing several mitochondria in other previously described Schistosoma eggs suggesting an active, and perhaps selective, transport in or out of the egg shell. The inner fluid filled cavity, or Lehman's lacuna, between the von Lichtenberg's envelope and the embryo contains numerous lipoid bodies suggesting a relation to vitelline cells. - Four systems (out of eight previously described for the free, mature Schistosoma miracidium) have been recognized for the first time in the developing miracidium within S. haematobium eggs and include: 1) ciliated epidermal plates representing the epithelial system, 2) an outer circular and an inner longitudinal muscle layers forming the musculatures, 3) lateral penetration glands, and 4) ciliated flame cells representing the excretory system.

Adult↗
PubMed1995

Human bilharzial ureters: I. Fine structure of eggs deposited in the submucosa and muscularis.

The internal fine structure of the partially calcified Schistosoma haematobium eggs in the lower ureteral segments of Saudi patients with chronic urinary schistosomiasis is described. The egg shell is penetrated by cribriform pores and consists of the three previously described layers: outer microspinous, middle intermediately dense, and inner dense layers. The space between the egg shell and the developing embryo is partitioned by three layers. An outer acellular Reynolds' layer of unknown origin and function consists of a fribrillar material mixed with a finely granular matrix extending to the egg-shell pores via racemose channels. The middle von Lichtenberg's envelope consists of a single layer of flattened epithelial cells containing several mitochondria as in other previously described Schistosoma eggs suggesting an active, and perhaps selective, transport in or out of the egg shell. The inner fluid filled cavity, or Lehman's lacuna, between the von Lichtenberg's envelope and the embryo contains numerous lipoid bodies suggesting a relation to vitelline cells. Four systems (out of eight previously described for the free, mature Schistosoma miracidium) have been recognized for the first time in the developing miracidium within S. haematobium eggs and include: (1) ciliated epidermal plates representing the epithelial system, (2) an outer circular and an inner longitudinal muscle layer forming the musculatures, (3) lateral penetration glands, and (4) ciliated flame cells representing the excretory system.

Adult↗
PubMed1976

Reproductive tissue activity in hypothyroid or heat stressed hens.

The ability of the reproductive tract of the White Leghorn hen under heat stress or methimazole thyroid blockage to assimilate 32P was examined. Both treatments increase the uptake of 32P by the shell gland and egg shell but only heal stress increases 32P uptake by the ovaries and reduces shell thickness. The greater shell thinness under the heat stress is related to an increased deposition of phosphate in the shell. Gilbert (1967) has reported an increased serum calcium, due to calcification inhibitions by phosphate, leading to an increased gonadotropin secretion. Thyroid blockage appears to stimulate TSH and gonadotropin LH secretion but in the absence of phosphate inhibition of calcification shell thickness is not affected. It is also speculated that hypothyroidism does not stimulate FSH secretion and therefore ovarian tissues is not activated by this condition.

Animals↗
PubMed2004

Genetic mapping of quantitative trait loci affecting body weight, egg character and egg production in F2 intercross chickens.

Phenotypic measurements of chicken egg character and production traits are restricted to mature females only. Marker assisted selection of immature chickens using quantitative trait loci (QTL) has the potential to accelerate the genetic improvement of these traits in the chicken population. The QTL for 12 traits (i.e. body weight (BW), six for egg character, three for egg shell colour and two for egg production) of chickens were identified. An F2 population comprising 265 female chickens obtained by crossing White Leghorn and Rhode Island Red breeds and genotyped for 123 microsatellite markers was used for detecting QTL. Ninety-six markers were mapped on 25 autosomal linkage groups, and 13 markers were mapped on one Z chromosomal linkage group. Eight previous unmapped markers were assigned to their respective chromosomes in this study. Significant QTL were detected for BW on chromosomes 4 and 27, egg weight on chromosome 4, the short length of egg on chromosome 4, and redness of egg shell colour (using the L*a*b* colour system) on chromosome 11. A significant QTL on the Z chromosome was linked with age at first egg. Significant QTL could account for 6-19% of the phenotypic variance in the F2 population.

Analysis of Variance↗
PubMed2005

Metal accumulation in eggs of the red-eared slider (Trachemys scripta elegans) in the Lower Illinois River.

The Illinois River is a highly utilized navigable waterway in the US Midwest, and has historically been contaminated with metal toxicants from various industrial and municipal pollution sources. Little information on metal contamination is available in the Lower Illinois River, and in particular, in the habitat of the red-eared slider (Trachemys scripta elegans) at the southern end of the river near Grafton, IL. This study was conducted to determine current levels of metal contamination in water, sediment, soil, and plants in the habitat, as well as to reveal temporal and spatial variations of metal accumulation in eggs of the red-eared slider. Aluminum, Cd, Cr, Cu, Mn, Ni, Pb, V, Sn, and Zn were analyzed by inductively-coupled plasma spectroscopy. High concentrations of metals were observed in lake sediment, compared with the concentrations in water, soil, and plant tissues. Sediment Ni concentrations (mg kg(-1)) varied from 66 to 95 and Sn from 1100 to 1600. Five detectable metals in egg content were Zn (24.2 +/- 13), Al (2.2 +/- 1.2), Sn (1.8 +/- 1.1), Mn (1.1 +/- 0.6), and Cu (0.9 +/- 0.5); nine detectable metals in egg shell were Zn (6.8 +/- 3.9), Sn (3.7 +/- 3.1), Cu (1.9 +/- 1.3), Cr (1.6 +/- 1.5), V (1.6 +/- 1.4), Pb (1.3 +/- 0.7), Ni (1.3 +/- 0.9), Mn (1.0 +/- 0.8), and Cd (0.16 +/- 0.11). Zinc accumulation in egg content was significantly correlated with Zn in egg shell (r = 0.445, P < 0.002, n = 42). While significant spatial variation was observed in egg shell, metal accumulation in eggs (content and shell) collected from the same ground of turtles consecutively for 4 years did not show a significant temporal change.

Animals↗
PubMed1983

Toxicity of a vitamin D steroid to laying hens.

Two experiments were conducted with 56-week-old or 104-week-old Leghorn hens to determine if feeding vitamin D steroids in excess of requirement levels caused any marked affects on eggshell quality. In the first experiment caged hens had reduced feed consumption, egg shell quality, and egg production as early as 6 weeks after initially consuming a basal diet supplemented with 6.8 micrograms 1 alpha-hydroxycholecalciferol (1 alpha-OH-D3)/kg. The second experiment confirmed the previous results and showed that extensive weight loss occurred with continued feeding of 10 or 15 micrograms 1 alpha-OH-D3/kg diet. No adverse affects were observed in either experiment when the level of 1 alpha-OH-D3 supplementation was 5.0 micrograms/kg diet or less. No toxic effects were observed when the hormone precursor 25-OH-D3 was supplemented to diets at 6 or 12 micrograms/kg. It is suggested that the pathological effects observed are related to the potent calcium homeostatic properties of 1 alpha-OH-D3 that at elevated levels may cause aberrations in circulating calcium.

Animals↗
PubMed1984

Plasma phosphorus at 0, 6, and 21 hours postoviposition in hens laying in the morning or afternoon.

Two experiments were conducted using White Leghorn hens. Blood samples were collected immediately following oviposition (0 hr) or 6 or 21 hr postoviposition from hens laying in the morning or afternoon. Plasma phosphorus was determined at each time period. In Experiment 1, plasma phosphorus at oviposition was essentially the same for hens laying in the morning or afternoon (3.95 and 4.10 mg/dl, respectively). At 6 hr postoviposition plasma phosphorus was lower than that observed at 0 hr (3.22 and 3.15 mg/dl, respectively). When comparing plasma phosphorus levels at 21 hr postoviposition of hens laying in the morning or afternoon a higher (P less than or equal to .05) phosphorus level was observed for hens that laid in the morning (5.90 vs. 4.91, respectively). In Experiment 2, plasma phosphorus levels at 0 and 6 hr postoviposition were 3.32 vs. 3.18 and 2.81 vs. 2.74 mg/dl for hens laying in the morning and afternoon, respectively. At 21 hr postoviposition, phosphorus values of 5.30 vs. 3.65 mg/dl were reported for hens laying in the morning and afternoon, respectively. Data also indicated that on the day a hen does not lay an egg, plasma phosphorus does not rise. An hypothesis is offered to explain the difference in egg shell quality between eggs laid in the morning or afternoon.

Animals↗
PubMed1978

Differential response of calcium transport systems in laying hens to exogenous and endogenous changes in vitamin D status.

Changes in intestinal calcium absorption, calcium deposition into egg shell, and intestinal, renal and uterine calcium-binding protein (CaBP) in laying hens were related to changes in 25 hydroxycholecalciferol-1-hydroxylase activity (1-hydroxylase), or to the supplementation of 1alpha-hydroxycholecalciferol (1alpha-OH-CC). The onset of egg production resulted in an increased kidney 1-hydroxylase activity and intestinal and uterine CaBP. Renal concentrations of CaBP remained unchanged. Intestinal calcium and phosphorus absorption, during the period of egg shell formation, and duodenal calcium-binding protein (CaBP), were higher in 1alpha-OH-CC-fed than in cholecalciferol-fed hens. Renal or uterine CaBP and calcium deposition into the egg shell did not fluctuate with the vitamin D source or concentration. 1alpha-OH-CC injection into non-laying Nicarbazinfed hens resulted in an increase in intestinal but not renal or uterine CaBP concentrations. It is suggested that (a) CaBP in various organs responded independently to the same stimuli; and (b) calcium deposition into egg shell and uterine CaBP level are not related to kidney 1-hydroxylase activity or concentration of 1,25 dihydroxycholecalciferol.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗