Opaque Eggs Research Articles

Eggshell translucency in late-phase laying hens and its effect on egg quality and physiological indicators.

Eggshell translucency severely affects external egg quality, and variations in the eggshell or eggshell membrane are considered the structural basis of the trait. Research has shown that 1.85% additional mixed fatty acids in the diet would greatly decrease the occurrence of eggshell translucency. Only a few studies have examined the phenotypic regularity of eggshell translucency with the increasing age of hens. Therefore, two strains, 1139 Rhode Island Red-White (RIR-White) and 836 Dwarf Layer-White (DWL-White), were used, and from each strain, 30 hens each that consecutively laid translucent or opaque eggs at 67 wks of age were selected. Subsequently, eggshell translucency, internal quality and external quality of eggs, and total cholesterol, albumin, calcium binding protein and other physiological indicators related to lipid, lipoprotein, and calcium metabolisms at the 75th, 79th, and 83rd wks of age in the late phase of the laying cycle were determined. Results: (1) In terms of flocks, for both strains, the translucency scores of the translucent groups were significantly higher than those of the opaque groups (P < 0.05); in terms of individuals, 81.1% RIR-White and 82.8% DWL-White hens consecutively laid eggs of the same or similar translucency, indicating the stability of the trait with increasing hen age; (2) In RIR-White, the eggshell strength of the translucent group at 75 weeks was significantly higher than that of the opaque group (P < 0.05); in DWL-White, the eggshell membrane thickness of the translucent group at the 75th and 83rd weeks was significantly lower than that of the opaque group (P < 0.05); (3) Compared to the opaque groups, the translucent groups had lower total cholesterol content in both RIR-White and DWL-White, lower albumin content in DWL-White at the 79th weeks (P < 0.05), and higher calcium-binding protein (CALB1) in RIR-White at the 83rd weeks (P < 0.05). In summary, this study illustrates the stability of eggshell translucency in late-phase laying hens and provides a reference of physiological indicators for exploring the formation of translucent eggs.

A new candling procedure for thick and opaque eggs and its application to avian conservation management.

The ability to monitor developing avian embryos and their associated vascular system via candling enables the application of important reproductive management techniques. Egg candling facilitates the confirmation of egg viability throughout the incubation process and identification of a precise position on a vein for the safe extraction of blood. Blood samples may then be analysed to retrieve vital health and genetic information to assist in conservation management. However, the thick or opaque egg shell characteristics of some avian species prevents the observation of egg contents using traditional candling methods, thus limiting management options. This paper tests a novel method of preparing thick-shelled or opaque eggs so that traditional egg candling and blood extraction methods may be applied. Eggs from captive emu (Dromaius novaehollandiae, Latham 1790) and southern cassowary (Casuarius casuarius johnsonii, Linnaeus 1758) were obtained, and partial fenestration was performed on two areas of shell either before incubation or at ⅓ of incubation. Hatchability and weight loss were examined as a measure of effect of the fenestration process on the developing embryo. Clear observation of vascular development was successful in 97% of viable fenestrated eggs, without affecting hatchability or weight loss. Blood samples were taken from developing embryos and DNA was successfully extracted for proof of concept of this new technique. The ability to observe vascular development and monitor the developing embryo in thick and opaque eggs will significantly improve both in situ and ex situ population management options such as in ovo sexing in species of concern.

Вплив біотехнологічних процедур трансгенозу на виживаність ембріонів свійської качки

Вплив біотехнологічних процедур трансгенозу на виживаність ембріонів свійської качки

Fecundity of diploid and triploid Carassius gibelio (Bloch, 1782) females

Fecundity of diploid and triploid Carassius gibelio (Bloch, 1782) females

Combination effects of NaOH and NaCl on the rheology and gel characteristics of hen egg white proteins

The effects of NaOH and NaCl on the rheology and gel properties of hen egg white were investigated. As the concentration of NaOH increased, egg white gel exhibited lower opacity and particle turbidity with coincidental increase in zeta potential, while the addition of NaCl resulted in the formation of opaque egg white gel and increase of surface hydrophobicity, particle turbidity and zeta potential. Rheological tests showed that alkali treatment will affect the unfolding state of egg white proteins during the heat stage while NaCl addition can inhibit the unfolding of egg white proteins. The results of correlation analysis indicated that random coil and α-helix were in good correlation with gel textural properties. Therefore, the rheology and gel properties of alkali/salt-induced egg white dispersions were closely related to the changes in surface hydrophobicity, molecule surface charge, and protein secondary structure.

Traits of eggshells and shell membranes of translucent eggs

Translucent eggshells negatively affect the appearance of eggs and decrease their economic value. Translocation and accumulation of water from the contents to the shells of eggs are frequent occurrences. Causes of translucent eggshell formation have been investigated, but the primary reason is uncertain. In previous studies, scientists have found that the thickness of the eggshell membrane was significantly different between translucent and opaque eggs. However, there are some conflicts among studies. We performed 2 experiments with 3 breeding flocks of chickens to target the reasons for egg translucence. In experiment 1, eggs of 1,024 Brown-Egg Dwarf Layers (DWL) were used. Approximately 1,600 eggs were collected over 2 consecutive days. They were stored for 3 days, and then 120 translucent and 120 opaque eggs were selected for measurement of egg quality traits and weight loss over several weeks. In experiment 2, we used DWL and White Leghorn pure line (WLL) for assessment of eggshell ultrastructure and membrane traits. We chose 120 translucent and 120 opaque eggs from 3,500 DWL eggs and 125 translucent and 125 opaque eggs from 5,028 WLL eggs. The results are as follows: (1) translucent eggs had greater eggshell strength and lower ultimate failure stress of shell membrane than opaque eggs in both DWL and WLL groups, (2) translucent eggs had thicker shells and thinner shell membranes than opaque eggs in DWL, (3) no significant differences were found in either gas pore or bubble pore traits between translucent and opaque eggs in either line, and (4) no significant differences were detected in internal egg quality or weight loss between translucent and opaque eggs in either line. In summary, the present study suggests that variations in both eggshells and shell membrane structures are implicated in the formation of translucent eggs.

Sperm And Egg Quality In Catla And Rui Between Spawning Seasons In Bangladesh

Sperm and egg quality of catla Catla catla and rui Labeo rohita were investigated in Brahmaputra and Sarker Hatchery, Mymensingh, Bangladesh over two spawning seasons as early (March to May) and peak (June to August ). In both hatcheries, catla and rui produced nearly 90% motile sperms as well as higher sperm concentration (catla: Brahmaputra hatchery. 2533.33 ± 119.65 million mL-1 and Sarker hatchery, 2658.89 ± 76.55 million mL-1; rui: Brahmaputra hatchery, 2856.67 ± 67.57 million mL-1 and Sarker hatchery, 2811.67 ± 51.90 million mL'1), seminal pH (catla: Brahmaputra hatchery, 7.41 ± 0.06 and Sarker hatchery, 7.41 ± 0.06; rui: Brahmaputra hatchery, 7.39 ± 0.05 and Sarker hatchery, 7.35 ± 0.05) and fertilizability in catla were 88% and In rui 92% in both hatcheries in the peak season. The occurrence of opaque eggs in catla and rui was 12% and 8% in both hatcheries in the peak season, respectively. The present study points to the fact that the quality of fish sperm and egg depends on seasons&#x0D; Asiat. Soc. Bangladesh, Sci. 40(2): 231-241, December 2014

Características sensoriais de ovos armazenados em diferentes embalagens sob temperatura ambiente

This study evaluated the sensory charac-teristics of white-shelled eggs, sanitized or not, stored under different packaging conditions at room temperature. There were used 200 eggs, distributed in a completely randomized design in a 3x2x4+1 factorial arrangement, three packaging conditions (PVC film, partial vacuum, partial vacuum with oxygen gas absorber), storage period (7, 14, 21 and 28 days), sanitized or not, and control (fresh eggs), with four repetitions of two eggs, and ten judges. The eggs were visually and olfactorily evaluated in different periods of storage, by Quantitative Descriptive Analysis (QDA) by means of unstructured scales of 9 cm. Partial vacuum condition showed that the eggs were rejected by the external and internal appearance and external odor, especially if not sanitized. In this condition were observed sour smells and opaque egg yolks. In vacuum with O2 sachets absorbers were noted sour smells, especially if sanitized. It can be concluded that eggs packed in PVC film, sanitized or not, showed the best acceptances in all attributes.

Life history features of the nonindigenous three-spined stickleback (Gasterosteus aculeatus Linnaeus, 1758) in the Gomishan wetland (southeast Caspian Sea, Iran)

The Caspian Sea forms the southern limit of the distribution range of the three-spined stickleback (Gasterosteus aculeatus), but little is known about its life history in this area. A total of 362 specimens were collected from the Gomishan wetland (southeast Caspian Sea, Iran) to describe the stickleback's life history characteristics. Samples were taken monthly between February and July of 2008. The maximum ages of the population observed were 2+ years for males and 3+ years for females. The length-weight relationship (LWR) was estimated as W = 0.0042TL^{3.711} for immature specimens, W = 0.0095TL^{3.1328} for males, and W = 0.0057TL^{3.4678} for females. The sex ratio was 1:2.63, in favor of females. Reproduction of the three-spined stickleback in the wetland occurred around March-June, with the highest average value of 2.82 for males and of 17.12 for females in April. Two kinds of eggs were found in the ovary: small white opaque eggs with a mean diameter of 0.549, and large yolk-filled eggs with a mean diameter of 1.317. The number of small eggs ranged from 311 to 4709, and of large eggs from 128 to 885. The mean absolute fecundity was 1241.69 eggs, while the mean relative fecundity was 535.24 eggs/g of body weight.

Population Collapses in a Forecasted Outbreak ofLambdina fiscellaria(Lepidoptera: Geometridae) Caused by Spring Egg Parasitism byTelenomusspp. (Hymenoptera: Scelionidae)

A major outbreak of the hemlock looper, Lambdina fiscellaria (Guenee), predicted for 1997 on the Gaspe Peninsula in Quebec, collapsed due to egg parasitism by Telenomus spp. Only 3,857 ha of balsam–spruce forest were defoliated from the forecasted 130,000-ha outbreak area. This represents only 3% of the anticipated outbreak area. We present data that indicate highly efficient natural control by Telenomus spp. The L. fiscellaria population also collapsed due to egg parasitism by Telenomus spp. on Anticosti Island in the same year. In the past, L. fiscellaria egg parasitism has usually been estimated from egg samples collected in the fall or early spring surveys and was based mostly on the eggs’ black coloration. However, our observations indicate that entirely black and opaque eggs result from parasitism by Trichogramma spp., those attacked by Telenomus spp. varying from translucent to dark brown but always showing a single dark spot on the chorion. Moreover, our data on seasonal egg parasitism showed important and rapid increases in parasitism by Telenomus spp. in late spring. Therefore, similar unexplained L. fiscellaria outbreak collapses that occurred in the past might have also been caused by egg parasitism by Telenomus spp. There are several species in the Telenomus complex attacking L. fiscellaria and the most abundant one might be a “keystone species” in the population dynamics of this defoliator. The spring activity of Telenomus spp. may lead to errors when forecasting L. fiscellaria populations based only on fall egg surveys.

Some Features in Gel Drying Process and Dehydrated Substances

Left in a dry. atmosphere for a while, gels become glasslike dehydrated substances. We investigated the dehydration process of some gels by adopting simultaneous time-resolved measuring method of weight and other properties. The feature during the dehydration process was different depending on the properties of the network and solvent in gel. Besides, in the DTA measurements of the dehydrated egg white gel, we observed an endothermic peak of which the intensity and peak position increased with elevating heating rate, similar to the glass transition in the non-crystalline polymers. §1. Change in some properties during the gel dehydration process Opaque egg white gel converts into a transparent glasslike substance by dehy­ dration. 1 ) During the dehydration process of the heat-treated egg white gel, the log weight decreased in proportion to the measurement time, and the slope altered at a certain time (t~)- 1 ) The decrease process with a steep slope before t~ is due to the loss of free water, while that after t~ with a gentle slope results from the loss of bound water. 1 ) We carried out time-resolved simultaneous weight-and-volume measurements during the dehydration process of the heat-treated egg white gel (HTEWG) and the pressure-treated egg white gel (PTEWG). 2 ) With the similar feature in the weight decrease in both of HTEWG and PTEWG, the different preparation treatment was found to have an effect on the behavior of volume during the dehydration process: the volume of HTEWG decreased in the same way as the weight did, while that of PTEWG kept almost constant (Figs. 1 and 2). The difference in the volume change between HTEWG and PTEWG can result from the network polymer chain strength (caused by the different denaturation de­ grees of the polymer chain which comes from the difference of treatment 3 )) compared with the free-water capillary force in the gel.

Predation on Larval and Embryonic Amphibians by Acid-Tolerant Caddisfly Larvae (Ptilostomis postica)

We examined effects of predation by larvae of the caddisfly Ptilostomis postica on survival of embryonic and larval wood frogs (Rana sylvatica) and spotted and Jefferson salamanders (Ambystoma maculatum and A. jeffersonianum). Studies of predation were conducted both in the laboratory and natural ponds. We also estimated the tolerance to low pH of P. postica in laboratory trials. There were significant effects of predation by P. postica on overall hatching success of A. maculatum in one laboratory experiment; there was no difference between embryos from opaque versus clear egg mass morphs. Ptilostomis postica preyed on larvae of R. sylvatica and A. jeffersonianum in the laboratory and showed no preference in choice of prey

Free calcium wave upon activation in Xenopus eggs

Eggs of Xenopus laevis were preloaded with aequorin and the spatial and temporal pattern of free calcium release in the egg cortex on artificial activation was determined by the aequorin luminescence emitted from the thin cortical layer of naturally opaque eggs. The aequorin luminescence was detected with a photonic microscope system consisting of a light microscope and a two-dimensional photon-counting system with an image processor. A free calcium increase was initiated around the point of prick activation. The state of increased Ca 2+ propagated in the cortical cytoplasm of the egg as a wave with a velocity of about 8 μm/sec at 22°C. This wave reached the antipode by 5 to 6 min of prick activation. The spatial pattern of the Ca 2+ wave was similar to that of changes in brightness of the egg surface on activation, termed the “activation wave” by K. Hara and P. Tydeman (1979, Wilhelm Roux's Arch. Dev. Biol., 186, 91–94). To examine the temporal correlation between the Ca 2+ wave and the activation wave, images of aequorin luminescence and those of the egg cortex taken by incident light illumination were recorded alternately in the same egg. The zone of free calcium increase corresponded to the light (relaxation) zone of the activation wave, where exocytosis of cortical granules and elongation of microvilli were taking place.

A New Bleaching Technique with Possible General Use in Entomology1

Studies of aedine mosquito eggs have been hampered by the opaque egg shell and the resultant inability to observe the enclosed embryo. In efforts to overcome this obstacle various investigators have used chlorine-containing solutions (Mortenson 1950; Beckel 1953; Craig 1955; Christophers I960) or dilute aqua regia (DeCoursey and Webster 1952) to decolorize or remove the dark chorion. While these methods have been valuable for embryological and morphological studies, the drastic chemical treatment is frequently lethal (Christophers, p. 158) or has obvious deleterious effects on the embryos (personal observations) which render them unsuitable for physiological studies. Due to our need to observe normal aedine mosquito embryos before and during hatching, a search for a more satisfactory bleaching technique was initiated.