Modified pressure imaging for egg crack detection and resulting egg quality.

Cracks in the shell surface compromise the primary barrier for external microbial contamination of the egg. Microcracks are very small cracks in the shell surface that are difficult to detect by human graders. New technology has been developed that uses modified pressure and imaging to detect microcracks in eggs. Research has shown the system to have an accuracy of 99.6% in detecting both cracked and intact eggs. A study was undertaken to determine if quality differences existed between modified pressure imaged and control eggs during extended cold storage. Three replicates were conducted with eggs stored at 4 degrees C for 5 wk with weekly quality testing. The physical quality factors monitored were Haugh units, albumen height, egg weight, shell strength, vitelline membrane strength and elasticity, and whole egg total solids. All measurements were conducted on individual eggs (12/treatments per replicate) each week with the exception of whole egg solids, which were determined from 3 pools (4 eggs each)/treatment per replicate each week. Percentage of whole egg total solids was the only significant difference (P < 0.05) between treatments (23.65% modified pressure imaged and 23.47% control). There was a significant difference (P < 0.05) for egg weight between replicates (60.82, 58.02, and 60.58 g for replicates 1, 2, and 3, respectively). Therefore, imaging eggs in the modified pressure system for microcrack detection did not alter egg quality during extended cold storage. Utilizing the modified pressure crack detection technology would result in fewer cracked eggs reaching the consumer, consequently enhancing food safety without affecting product quality.

Comparative study on histological structures of the vitelline membrane of hen and duck egg observed by cryo-scanning electron microscopy.

The histological structures of the vitelline membranes (VM) of hen and duck eggs were observed by cryo-scanning electron microscopy (cryo-SEM), and the chemical characteristics were also compared. The outer layer surface (OLS) of duck egg VM showed networks constructed by fibrils and sheets (0.1-5.2 microm in width), and that of hen egg presented networks formed only by sheets (2-6 microm in width). Thicker fibrils (0.5-1.5 microm in width) with different arrangement were observed on the inner layer surface (ILS) of duck egg VM as compared to those (0.3-0.7 microm in width) of hen egg VM. Upon separation, the outer surface of the outer layer (OSOL) and the inner surface of the inner layer (ISIL) of hen and duck egg VMs were quite similar to fresh VM except that the OSOL of duck egg VM showed networks constructed only by sheets. Thin fibrils interlaced above a bumpy or flat structure were observed at the exposed surface of the outer layer (ESOL) of hen and duck egg VMs. The exposed surfaces of inner layers (ESIL) of hen and duck egg VMs showed similar structures of fibrils, which joined, branched, and ran in straight lines for long distances up to 30 microm; however, the widths of the fibrils shown in ESOL and ESIL of duck egg VM were 0.1 and 0.7-1.4 microm, respectively, and were greater than those (<0.1 and 0.5-0.8 microm) of hen egg VM. The continuous membranes of both hen and duck egg VMs were still attached to the outer layers when separated. The content of protein, the major component of VM, was higher in duck egg VM (88.6%) than in hen egg VM (81.6%). Four and six major SDS-soluble protein patterns with distinct localization were observed in hen and duck egg VMs, respectively. Overall, the different histological structures of hen and duck egg VMs were suggested to be majorly attributable to the diverse protein components.

The study of vitelline gland of Haploporus lateralis (Digenea: Trematoda).

The study of vitelline glands of digenean Haploporus lateralis, indicates that the glands consist of vitelocytes in various stages of maturation. The cytoplasmic process of nurse cells which surrounded the vitelline lobes, intrude between vitelocytes and surround them. Immature vitelline cells are undifferentiated, they possess small amount of cytoplasm and large nucleus. The synthesis of shell globules begin in the maturing vitelline cells. Increasing numbers of vitellocytes reach develop of mature vitelline cells. The cytoplasm of mature vitelline cells is filled with shell globules. Mature vitelline cells usually found in the center of vitelline lobe. They release into the vitelline duct and vitelline reservoir. The vitelline reservoir and duct are lined with a syncytial epithelium. Basement membrane is present between nurse cells and vitelline cells.

Possible involvement of a sperm-associated body in the process of fertilization in quail.

The present paper describes a novel structure, termed the sperm-associated body, which is found both in the lumen at the oviductal infundibulum and in the vitelline membrane of the ovum in the quail Coturnix japonica. The fully developed sperm-associated body, which is about 100 microm long, consisted of two parts; a core of concentric-circular appearance and a cortex of needle-like projections. The outer surface of the body was coated with CaCO3. The body was always accompanied by spermatozoa. About 70 sperm-associated bodies were observed in a single ovum. Electron-microscopically, small numbers of holes were detected in the vitelline membranes of a fertile ovum, and the sperm-associated bodies were always present in these holes. Frequently observed in the vitelline membranes was a disk speculated to be a portion of the inner layer of the membrane partially affected by spermatozoa. However, neither sperm-associated bodies nor spermatozoa were observed there. It was suggested that the sperm-associated bodies assist fertile spermatozoa in binding the inner layer of the vitelline membrane and penetrating it.

Characterization and application of an avian in vitro spermatozoa-egg interaction assay using the inner perivitelline layer from laid chicken eggs.

The inner perivitelline layer, separated from laid chicken eggs, was investigated as readily available material for studying the spermatozoa-egg interaction in vitro. This layer was found to have a similar response to hydrolysis by spermatozoa as the inner perivitelline layer from ovulated and follicular ova, in terms of the numbers of points of hydrolysis made by spermatozoa during a 5 min incubation at 40 degrees C. Initiation of hydrolysis of the inner perivitelline layer was found to occur within 2.5 min, after which the size, but not the number of holes, increased with time. The frequency of the points of hydrolysis per unit area of the inner perivitelline layer was positively correlated with the concentration of spermatozoa in the incubation medium. The perivitelline hydrolysis assay was able to detect more damaged spermatozoa in samples that had been either stored at 5 degrees C or cryopreserved in liquid N2 than did other tests of sperm quality, which are known to overestimate the fertilizing ability of stored avian semen.

A comparative study of sperm-egg interactions in birds.

A comparative study was made of the number of spermatozoa trapped on the outer perivitelline layer and the number of spermatozoa penetrating the inner perivitelline layer of the eggs of 27 species of bird. The total number of spermatozoa (trapped spermatozoa plus holes made by spermatozoa) varied between 29 and 164,000 per egg among species and was significantly and positively correlated with size of the ovum. In most species, holes formed a 'halo' around the germinal disc area and the density of holes was much greater in this region than elsewhere, especially in passerine birds. In some species, a high proportion of holes occurred at some distance from the germinal disc. This seems to be an artefact due to the fact that some spermatozoa trapped in the outer perivitelline layer undergo proteolytic activity between fertilization and oviposition and create additional holes in the inner perivitelline layer both at and away from the germinal disc. Across all species and within most individual species, the number of trapped spermatozoa was positively correlated with the number of holes in the inner perivitelline layer. Decreases in the total number of spermatozoa on successive eggs of a clutch provided an index of the rate at which spermatozoa were used from the sperm storage tubules.

Growth of the chick area vasculosa in ovo and in shell-less culture.

The rates of growth and cell proliferation of the chick area vasculosa (Days 2-5 of incubation) were examined in windowed eggs and in shell-less culture preparations. For embryos of developmental Stages 15 to 23, the area vasculosa in shell-less cultures was significantly smaller than in corresponding eggs; however there was no significant difference in the radial growth between these groups. The cultivation of embryos in shell-less culture did not affect the normal macroscopic or histological appearance of the membrane, or the rate of proliferation of its constituent cells, as assessed by tritiated thymidine incorporation. These results indicate that the area vasculosa in shell-less culture provides a suitable assay of factors which regulate angiogenesis.

The development of primordial and definitive amniotic cavities in early Rhesus monkey and human embryos.

Re-examination of early rhesus monkey and human embryos in the collection of the Carnegie Institution of Washington suggests that the mechanism of amniogenesis in both is basically similar to that of the hedgehog and vespertilionid bats. A primordial amniotic cavity develops by cavitation within the embryonic mass of 10-day rhesus monkey, and 7-day human, blastocysts. This primordial cavity has no relationship initially with the overlying trophoblast, contrary to earlier reports. Subsequently, there is a thinning and peripheral spreading of the epiblastic roof of the primordial cavity, resulting in partial opening of the roof and formation of a slightly cupped embryonic disc. The resulting space is not homologous with the primordial amniotic cavity; instead, it is a transitory tropho-epiblastic cavity. The definitive amniotic epithelium forms by the upfolding and mitotic proliferation of the margins of the epiblastic disc; this process is completed in 11-day rhesus, and 9-day human, blastocysts. Amniogenesis by cavitation is associated with the persistence of polar trophoblast following implantation, and it is suggested that this cavitation process may be essential for providing a free epithelial surface for the morphogenetic movement of epiblastic cells during subsequent formation of the primitive streak.

Morphological studies on the fetal membranes of the normal singleton foal at term.

Of 211 consecutive thoroughbred foalings, 145 satisfied a set of criteria for normal parturition and foal viability. The fetal membranes from these and from 10 pony foalings have been systematically examined morphologically and quantitatively and the findings compared to those of other authors. Five sites on the allantochorion were consistently devoid of villi. Expulsion usually occurred with the non-villous side outermost. In 24 per cent of allantochorions the non-pregant horn was of equal length or longer than the pregnant horn. These placentae tended to be shed with the villous side outermost. All membranes contained a hippomane in the allantoic cavity. Remnants of the yolk sac placenta and extra-embryonic coelom were always present. Large vestigeal yolk sacs have previously been confused with anomalous twins. In most cases the endometrial cup sites were site recognisable, usually arranged around the umbilical cord attachment. This attachment was found on the dorsal aspect of the uterine cavity either at the junction of the horns or within the pregnant hor; rarely, it was in the non-pregnant horn. A degree of twistng of the umbilical cord is normal. In 6.2 per cent of cords small urachal dilatations were noted, resulting from flight stenosis of the urachal luman at the site of a twist. Ninety-five per cent of cords measured between 36 and 83 cm.