Position Of Egg Research Articles

Hatching success rate of sea turtle in the north coast of Pinrang Regency, South Sulawesi

Background: Turtles are endangered marine reptile species due to various factors, including hunting, habitat loss, and predation. Therefore, practical conservation efforts are essential to protect turtle populations. One effective conservation strategy is to transfer turtle eggs to safe semi-natural nests. Methods: This study was conducted in Turtle Village, Pinrang Regency. Leatherback and Green Turtle eggs were collected from natural nests along the coast and transferred to semi-natural nests. Observations were made to measure the hatching success rate of the eggs, and factors such as temperature, incubation period, predators, microorganism development, and changes in egg position were also recorded and analyzed. Finding: The results showed that the hatching success rate of eggs in semi-natural nests reached 80.23%. The highest hatching percentage was 86.36%, and the lowest was 68.33%. Factors that influenced hatching success included temperature and incubation period while hatching failure was caused by predators, microorganism development, and changes in egg position. Conclusion: This study shows that semi-natural nests in Turtle Village have a high hatching success rate with supportive environmental conditions and proper egg transmission. This indicates that conservation efforts through egg transfer to semi-natural nests can effectively increase turtle populations. Novelty/Originality: This study: It contributes to turtle conservation by demonstrating the effectiveness of semi-natural nests in increasing the hatching success rate of Leatherback and Green Turtle eggs. This approach can serve as a model for turtle conservation programs in other areas facing similar challenges.

Optimization of process parameters for specific pathogen-free chicken embryonic fibroblast cultivation for yellow fever vaccine production

The yellow fever (YF) vaccine is usually produced with egg-based methods, which has limitations, including potential adverse effects and low production yields. Alternatively, producing the vaccine using Vero cells or HEK 293 cells can overcome some of these issues, but these methods are significantly more expensive. In the current study, the YF vaccine candidate 17DD virus was produced in primary chicken embryo fibroblast (CEF) cells. The primary CEF cells isolation from eggs was optimized through a two-step process. In the first step, the important parameters that contribute to the development of the egg embryo, such as egg position, relative humidity (RH), and incubation time are optimized. In second step, primary CEF release parameters namely; trypsin volume and incubation temperature are optimized. Both steps were optimized using statistical methods. Further, the seeding cell density of isolated CEF was also optimized. It was observed that 5 x 104 cells/cm2 gave the highest virus titer of 3.89 million PFU/ml. The 17DD yields achieved in primary CEFs are much higher than egg-based production and it is an economically viable method.

Red-Wattled Lapwing (Vanellus indicus): A Traditional Rain Forecaster for Tribal Farmers of Southwestern Rajasthan

Abstract An intensive survey was carried out over the past 8 years in tribal-dominated areas of southwestern Rajasthan to document red-wattled lapwing (Vanellus indicus) behavior as a rain forecaster, relevant to farm planning and better crop production. The present study included tribal farmers, agriculture scientists, extension workers, ornithologists, and farm workers. The precision of their observations was compared with a contemporaneous study of 10–15 red-wattled lapwing nests across the 46-ha operational area of the Agricultural Research Sub-Station (ARSS) and Adaptive Trial Center (ATC), Sumerpur, Pali, Rajasthan (25.1526°N latitude, 73.0823°E longitude). Local knowledge was gathered through surveys and focus group discussions with the respondents to discuss lapwing behavior as a rain prediction indicator. Meteorological data were gathered from the ATC farm observatory. The findings revealed that the older tribal farmers have an assortment of knowledge about the behavior of red-wattled lapwing as rain prediction indicators such as nesting sites, egg position, egg arrangement, nesting material, numbers of eggs, and egg-laying patterns. These predictions have a direct correlation with modern meteorological observations. It was also noted that the elder tribal farmers planned their farms using lapwing indicators in order to increase crop production, whereas younger generations overlook the traditional rain prediction indicators and have significant knowledge about meteorological data-based weather forecasting. Both the elder and younger tribal farmers were equally interested in meteorological weather forecast announcements, but due to network connectivity challenges, residents in some remote places were unable to access modern meteorological information. Long-term accurate rain forecasting is needed for better agricultural planning and to secure crop production. Rain forecasting can be improved by blending modern meteorological information with traditional proven indications. Farmers who have considerable traditional knowledge along with modern technological updates are capable of using both sources of information in suitable and successful farm planning for better crop production. Significance Statement The purpose of this study is to examine red-wattled lapwing behavior as rain measurements and compare its reliability with modern rain forecasting methods. We also develop a theoretical framework for understanding traditional and modern rain forecasting methods for disaster management in remote and accessible areas, to assist resource management and to minimize costs of cultivation. Our results provide a guideline for blending both types of knowledge and for providing relevant information to remote tribal areas at appropriate times for better farm planning and crop production.

Numerical and experimental investigation of the effect of intact egg orientation and yolk positions on heat transfer and cold point location

AbstractThis paper explores the effects of egg orientation and yolk position during thermal processing using computational fluid dynamics simulation and experimentation. A carboxymethyl cellulose suspension was used to simulate the egg white, and a two‐dimensional model incorporated an air cell near the larger end. The simulation included four cases: two focused on vertical orientation with the yolk at the rear shell and the geometric center, and two on horizontal orientation with similar yolk positions. Repositioning the yolk in a horizontal orientation near the eggshell resulted in significant temperature variations. The findings show that a horizontal egg position, especially with the yolk near the eggshell, led to a significant 8%–16% reduction in heating times. This configuration also improved pasteurization efficiency, assessed by the F value, by about 13.8%. The study also revealed distinct flow patterns influenced by buoyancy forces, significantly related to temperature distribution inside the egg.

Egg Mercury Concentration and Egg Size Varies with Position in the Laying Sequence in two Songbird Species.

In birds, mercury embryotoxicity can occur through the transfer of mercury from the female to her eggs. Maternal transfer of mercury can vary by egg position in the laying sequence, with first-laid eggs often exhibiting greater mercury concentrations than subsequently laid eggs. We studied egg mercury concentration, mercury burden (total amount of mercury in the egg), and egg morphometrics by egg position in the laying sequence for two songbirds: tree swallows (Tachycineta bicolor) and house wrens (Troglodytes aedon). Egg mercury concentration in the second egg laid was 14% lower for tree swallows and 6% lower for house wrens in comparison with the first egg laid. These results indicate that in both species, after an initial relatively high transfer of mercury into the first egg laid, a smaller amount of mercury was transferred to the second egg laid. This lower mercury concentration persisted among all subsequently laid eggs (eggs three to eight) in tree swallows (all were 14%-16% lower than egg 1), but mercury concentrations in subsequently laid house wren eggs (eggs three to seven) returned to levels observed in the first egg laid (all were 1% lower to 3% greater than egg 1). Egg size increased with position in the laying sequence in both species; the predicted volume of egg 7 was 5% and 6% greater than that of egg 1 in tree swallows and house wrens, respectively. This change was caused by a significant increase in egg width, but not egg length, with position in the laying sequence. The percentage of decline in mercury concentration with position in the laying sequence was considerably lower in tree swallows and house wrens compared with other bird taxonomic groups, suggesting that there are key differences in the maternal transfer of mercury into songbird eggs compared with other birds. Finally, we performed simulations to evaluate how within-clutch variation in egg mercury concentrations affected estimates of mean mercury concentrations in each clutch and the overall sampled population, which has direct implications for sampling designs. Environ Toxicol Chem 2024;43:1844-1854. Published 2024. This article is a U.S. Government work and is in the public domain in the USA.

Lack of Genetic Variation in Low Heterozygosity and Clonal Animals Creates Lack of Physiological Variation

Data variability frequently complicates reproducibility and interpretation of experimental results. Such variability arises from numerous sources such as differences in procedures or not accounting for key biological factors (e.g. sex, biological rhythms, prandial state). Making the situation more problematic, variation in physiological performance is often viewed as highly labile, easily and rapidly influenced by environmental stressors, development, etc., making it diffcult to pin down a source for variation. Undeniably, however, unknown (or ignored) genetic variation among and within strains/lines can also be a significant source of data variability in published physiological measurements, though surprisingly this has not been extensively investigated as a specific source of physiological variation. We hypothesized that variation in physiological performance is correlated with the intrinsic degree of genetic variability of the subject animal. To test this hypothesis, we employed two animal models: 1) Inbred lines ( e.g., NHGRI-1) derived from wild type strains of the zebrafish ( Danio rerio), with an estimated 15% of the genetic heterozygosity of wild type AB zebrafish, and 2) the parthenogenetically reproducing marbled crayfish ( Procambarus virginalis), all specimens of which are genetically identical clones. For these two animal models, we measured both physiological variables (e.g. heart rate, stroke volume, cardiac output, oxygen consumption) and morphological variables (e.g. yolk-chorion ratio, body mass, embryo mass, total length, condition factor, specific growth rate) during development. We subjected the two animal models to environmental stress in the form of both temperature and hypoxia to stimulate physiological responses that could be compared and contrasted among populations. From these data we then calculated the resultant coeffcients of variation for measured variables for wild type and low/zero heterozygosity populations and/or species. In zebrafish, both the wildtype AB and NHRGI-1 lines showed similar developmental trajectories characterized by similar mean values for physiological and morphological variables. Additionally, similar mean values for physiological and morphological variables were recorded in the face of temperature and hypoxia challenge. Yet, importantly, the coeffcient of variation for each measured variable was significantly lower in NHGRI-1 than AB larvae for >90% of the assessed endpoints. In the clonal crayfish, genetically identical early stage marbled crayfish reared in different temperatures or oxygen levels show major acclimation responses, but generally showed less morphological and physiological variation about the mean than sexually-reproducing species crayfish with inherently much greater genetic variation, as evident from comparisons of calculated coeffcients of variation. A key question regarding the clonal crayfish is how can there be any morphological or physiological variation between individuals? We suggest that variability that persists may arise from microenvironmental differences during rearing (e.g. egg position during incubation on the mother’s pleon) and/or stochastic differences in gene expression (e.g. due to random epimutations) in this clonal species. In conclusion, genetic diversity clearly contributes to physiological variability. For future experiments, low heterozygosity lines and/or clonal species may be useful for decreasing inter-individual variation, thus aiding interpretation of results and enhancing reproducibility. In any event, scientific documentation of physiological studies should include as much information on (genetic) background of the experimental animals as possible. NSF IOS-2103499. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Spotlight on Eupeodes americanus: Oviposition and fertility under HPS- and full spectrum LED-extended photoperiod in northern greenhouses

In northern temperate regions, high-pressure sodium vapor (HPS) or light-emitting diode (LED) lights for supplemental lighting in winter greenhouses are used to extend the photoperiod and increase plant production. These different greenhouse light treatments influence crop pests and their natural enemies. In this study, different greenhouse light treatments were evaluated for their effect on the green peach aphid, Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae) and its predator the American hoverfly, Eupeodes americanus (Wiedemann, 1830) (Diptera: Syrphidae). In particular, the development of M. persicae and the oviposition and egg hatchability of E. americanus were studied under three light treatments in winter greenhouse: 1) short photoperiod of natural sunlight, and extended photoperiod using either 2) full spectrum LED or 3) HPS lights. The results showed that both extended photoperiod treatments significantly increased M. persicae population growth by 103–130 %, after 12 days compared to short photoperiod of sunlight. Compared to the winter short photoperiod of sunlight, extending the photoperiod did not affect the oviposition of female hoverflies in terms of fecundity, fertility, and niche use (i.e., position of eggs on the plant). Nevertheless, extended photoperiod significantly increased the egg hatchability of E. americanus by 9 % (HPS) and 16 % (LED) compared to short photoperiod of sunlight. This treatment had the highest proportion of unhatched eggs (13 %). Finally, LED lights decreased the proportion of unhatched eggs by 71 % compared to HPS lights. This study, therefore, confirms the potential of the American hoverfly as a biological control agent in winter greenhouses, both with or without artificial light.

Adipokines expression in reproductive tract, egg white and embryonic annexes in hen

In mammals, molecules mainly secreted by white adipose tissue named adipokines are also synthetized locally in the reproductive tract and are able to influence reproductive functions. In avian species, previous studies indicated that the adipokine chemerin is highly abundant in the albumen, compared to the yolk and this was associated to high chemerin expression in the magnum. In addition, the authors observed that chemerin and its receptors are expressed by allantoic and amniotic membranes and chemerin is present in fluids during the embryo development. Here, we studied other adipokines, including adiponectin, visfatin, apelin, and adipolin in egg white and their known receptors in the active (egg-laying hen) and regressed (hen not laying) oviduct and embryonic annexes during embryo development. By using Western blot, RT-qPCR analysis and immunohistochemistry, we demonstrated the expression of different adipokines in the egg albumen (visfatin) and the reproductive tract (adiponectin, visfatin, apelin, adipolin, and their cognate receptors) according the position of egg in the oviduct. We showed that the expression of adipokines and adipokines receptors was strongly reduced in the regressed oviducts (arrested laying hen). Results indicated that visfatin and adiponectin appeared at ED11 to 14 and increased until ED18 in amniotic fluid whereas it was found from ED7 and was unchanged during embryo development in allantoic fluid. Taken together, adipokines and their receptors are expressed in the egg white, the reproductive tract and the embryonic annexes. Data obtained suggest important functions of theses metabolic hormones during the chicken embryo development. Thus, adipokines could be potential biomarkers to improve the embryo development.

An optimized wavelet neural networks using cuckoo search algorithm for function approximation and chaotic time series prediction

Although the practicability of using wavelet neural networks (WNNs) in nonlinear function approximation has been addressed extensively, selecting the optimal number of hidden nodes and their appropriate initial locations remains a great challenge for WNNs’ initialization. The cuckoo search algorithm (CSA) is used in this study for optimizing WNNs. The position of the cuckoo eggs represents the translation of the wavelet hidden nodes, which are optimized based on the egg-laying and breeding strategy of cuckoos. The solutions from the CSA are assigned as initial translation vectors for the WNNs and subsequently evaluated on a few benchmarking functions and real-world applications. Performance assessment demonstrates its superior approximation capability than the existing methods used for WNNs initialization.

Influence of egg storage time, position and turning on egg weight loss, embryonic mortality and hatching traits in chukar partridge (Alectoris chukar)

The aim of the study was to evaluate the effect of storage length (7, 14, 21 and 28 days), turning frequency (0, 1 and 24 times per day) and egg position (pointed end up, blunt end up and horizontal) on egg weight loss during storage and incubation; hatchling chick weight, incubation length and hatchability results in 56-week-old chukar partridges (Alectoris chukar). A total of 1800 daily collected eggs was assigned to 36 subgroups (4 × 3 × 3 experimental design) consisting of 50 eggs for each subgroup. Progressive decrease in egg weights and increase in egg weight loss during storage was observed with the lengthening of storage period (p < .001). Prominent effects were observed in total egg weight loss rate and incubation length when the eggs were stored more than 21 days (p < .001). The highest hatchling chick weights were observed in horizontal eggs stored for 7 days (p < .001). Most indices of hatching results showed detrimental effects when turning wasn’t applied and the eggs were stored with the position of blunt end up. General recommendations from the hatching results showed that chukar eggs can be stored up to 21 days of storage length irrespective of turning and egg position. If the chukar eggs are to be stored more than 21 days, turning should be implemented and the eggs should be placed with the position of pointed end up for optimum hatching results. HIGHLIGHTS Due to their chicks’ valuability, partridge eggs are aimed to be incubated. In addition, scientific studies of egg hatching assessment under different conditions during storage period are lacking. For these reasons, the study was carried out to determine optimum conditions of storage in chukar eggs. The present results revealed that storing the chukar eggs with the position of pointed end up till 21st days improves the quality of the eggs. If the storage length is to exceed 21 days, the eggs should be turned at least once a day and placed with the position of pointed end up.

Quality assessment of chukar partridge (A. chukar) eggs during different conditions (time, turning and position) of storage.

The present study was conducted with the aim of investigating the effect of storage length, turning frequency and egg position on internal quality traits of chukar eggs obtained from 56-week-old chukar partridges under the same nutrition and management conditions. A total of 720 eggs were collected and assigned to 36 subgroups according to storage length (7, 14, 21, and 28 d), turning frequency (0, 1, and 24 per day) and egg position (pointed end up, blunt end up and horizontal). As a result of the study, almost all the internal quality traits of chukar eggs were negatively affected by lengthening of storage period especially 21 days and longer (p < 0.001). Internal egg quality traits weren’t statistically affected by turning frequency except yolk index (p < 0.01). An improvement was observed in Haugh unit, albumen index and heigh of eggs stored with pointed end up (p < 0.001). Some significant interactions occurred among all internal egg quality traits which were mostly dependent on the eggs stored horizontally, extended storage time more than 21 days and egg turning during storage. The results and interactions showed that internal quality traits would be preserved well for the eggs stored less than 21 days with the position of pointed end up independent of turning. If the storage period was to exceed 21 days, the eggs should be positioned horizontally and turning should be applied to preserve the quality of chukar eggs.

Vegan Egg: A Future-Proof Food Ingredient?

Vegan eggs are designed with the aim to provide a healthier and more sustainable alternative to regular eggs. The major drivers of this industry are the increasing prevalence of egg allergies, awareness towards environmental sustainability, and the shift to vegan diets. This study intends to discuss, for the first time, the vegan egg market, including their formulation, nutritional aspects, and some applications (i.e., mayonnaise and bakery products). Recreating the complete functionality of eggs using plant-based ingredients is very challenging due to the complexity of eggs. Current, but scarce, research in this field is focused on making mixtures of plant-based ingredients to fit specific food formulations. Nutritionally, providing vegan eggs with similar or higher nutritional value to that of eggs can be of relevance to attract health-conscious consumers. Claims such as clean labels, natural, vegan, animal-free, gluten-free, and/or cholesterol-free can further boost the position of vegan eggs in the market in the coming year. At present, this market is still in its infancy stages, and clear regulations of labeling, safety, and risk assessment are deemed mandatory to organize the sector, and protect consumers.

Free Convection of Ag/H2O Nanofluid in Square Cavity with Different Position and Orientation of Egg Shaped Cylinder

A numerical simulation was conducted to study the free convection of Ag/H2O nanofluid between a square cavity with cold walls and an egg shaped cylinder with a hot wall. Utilizing the egg equation, dimensionless governing equations were solved using the Galerkin Finite Element Method (GFEM). In this work, several parameters were studied, i.e. Rayleigh number (103 ≤ Ra ≤ 106), volume fraction (0 ≤ φ ≤ 0.05), position (-0.2 ≤ Y ≤ 0.2), and orientation angle (-90° ≤ γ ≤ 90°). The numerical results are presented as streamline contours, isotherm contours, and local and average Nusselt numbers. Moreover, the results were used to analyze the fluids’ structure, temperature distribution, and heat transfer rate. The numerical results confirmed that the stream intensity value increased with an increase of the Rayleigh number as well as the movement of the cylinder towards the bottom wall for all values of the orientation angle. Variation of the vertical position of the cylinder inside the cavity had a noticeable effect on , which increased by 50% at γ = -90°, and by 58% at γ = -45°. However, at Y = -0.2, increased by 58% at γ = -45° and decreased by 7% at γ = -90°. The highest heat transfer rate was obtained at high Rayleigh number (Ra = 106), volume fraction (φ = 0.05), negative position (Y = -0.2), and the highest positive orientation angle (γ = 90°).

Research Note: The effects of chick pipping location on broiler live performance

The objective of this study was to determine the effects of chick pipping location on live broiler performance. A total of 1,350 hatching eggs were collected from a commercial flock of Ross 308 at 38 wk of age. Eggs were incubated with either their large end up (LEU) or small end up (SEU). After transfer on d 19, the air cell area of each fertile egg was marked with a marker pen on the egg surface with a candling light and monitored every 6 h during the hatching period to accurately determine the location of the pip hole. Chicks were classified into 3 groups: 1) egg position LEU and pipped through the air cell (LAC); 2) egg position SEU and pipped through the air cell (SAC); and 3) egg position SEU and pipped through the small end of the egg, not through the air cell (SSE). Individual BW was recorded at placement and at 7, 21, and 35 d of age. Feed consumption was also determined at 7, 21, and 35 d of age. The feed conversion ratio (FCR) was calculated on a pen basis for the same time periods. Mortality was recorded twice a day, and percent mortality was calculated throughout the study. The European production efficiency index (EPEI) was also calculated.All chicks that hatched from LEU eggs emerged from the egg at the region of the air cell; however, only 10.3% of chicks from the SEU position hatched through air cells. Pipping location greatly affected the hatch time. Chicks pipped through the air cell location hatched earlier than the chicks pipped without using air cell (P < 0.001). The initial BW at placement was higher in the LAC and SAC groups than in the SSE group (P < 0.001). This BW difference was still evident in the subsequent growing period, and the chicks that pipped the SSE exhibited a lower (P = 0.059) BW at 35 d. Additionally, the SSE group had a poorer FCR and numerically higher mortality than the other two groups at 35 d. Overall, the EPEI values in the LAC and SAC groups were higher than that in the SSE group at 35 d (P < 0.001). We concluded that broiler performance was negatively affected when the chicks pipped and hatched without using air cells.

A method of monitoring and locating eggs laid by breeding geese based on photoelectric sensing technology

On the current breeding goose farm, the detection of individual egg laying mainly depends on some judgement experiences of farm workers. At present, there have been some egg laying detection systems developed with images and weighing sensors, which only signal the eggs being laid, but no egg position being achieved. Meanwhile, the detection rate of the system is not high due to environment limitations like dim light of the goose barn. Therefore, to solve these problems mentioned above, an intelligent detection and positioning system is proposed by integrating technologies of the Radio Frequency (RF) and photoelectric sensors, together with the geometric calculation principle. In this research, individual egg laying information of breeding geese in a non-cage state was examined to improve the level of automatic detection and positioning in the field of breeder egg production. The results showed that an accurate detection and positioning of an egg in a nest filled with the artificial turf could be achieved under some conditions: the height of sensor is 3.5 cm from the bottom plate of the egg laying nest, the spacing of the photoresistor module is 5 cm, and the external light intensity is less than 110 LUX. It also shown that the error of the goose egg position recognition is 0.443 cm with a suitable level of straw in the nest. Therefore, the monitoring system and positioning method that was developed in this research could provide a reference for the analysis of individual egg laying behavior, and could result in an improvement in the automatic egg collection for the breeding geese production.

Demonstration of a Multiple Drift Net for Aquatic Organisms

Abstract The distribution of drifting semi-buoyant fish eggs within a river is useful for understanding the ecology of pelagic-broadcast spawning fish. The vertical position of semi-buoyant eggs in the water column is an important parameter describing transport processes for these species. We designed a multiple drift net (five rectangular nets attached to a frame) to vertically divide the water column into stacked horizontal layers to sample drifting semi-buoyant particles. We deployed the multiple drift net gear beside Moore egg collectors in a wadeable channel to sample the vertical distribution of semi-buoyant polyacrylamide gel beads as surrogates for fish eggs in the water column. The vertical distribution of beads was predominantly found in the deeper nets of the multiple drift net gear while the surface nets and Moore egg collectors had fewer beads which is similar to the results in other studies of pelagic-broadcast spawning fish. The multiple drift net gear is a tool that demonstrates the capability to sample the water column under variable flow conditions (depth, velocity and turbulence) for field data on the vertical distribution of drifting eggs (or surrogates). These empirical data can quantify drift patterns of eggs for modeling transport and retention in pelagic-broadcast spawning species.

An Integrated Unit for Hatching and Rearing Quail

This study was conducted to compare between the new integrated quail rearing unit with egg hatching sub-unit, and common egg incubator with traditional rearing system for (black Japanese quail and white jumbo quail) at two eggs hatching positions (vertical position with small end up and down). An integrated unit provided with upper egg incubator and furnished rearing battery cage located lower of it. The chicks were reared for 40 days of age in traditional litter floor and in furnished battery cage. The evaluation include the percentage of hatchability, chick weight, growth performance and mortality number of quail. The result indicated that the new incubation unit was able to maintain a high hatching percentage of 78.53 % for eggs of white jumbo quail with vertical egg position with small end down in average of hatching period 17 days. Chicks were growing in normal weight at 6.99 and 8.19 gram and did not suffer from any disability for black Japanese and white jumbo quail eggs, respectively and with vertical position with small end up. At different time intervals the growth performance of quail didn't show significant difference among the treatment viz. common commercial egg incubator and new incubation sub-unit. The mortality number at the first days increases for quails hatched in common commercial egg incubator. The same capacity attached egg incubator saved about 81.25 % of the total cost compared to the common commercial egg incubator, so it is recommended to use the integrated unit for incubating and rearing quail

Actual time determination of egg freshness: A centroid rate based approach

• The centroid rate changed synchronously with egg freshness during storage. • The egg yolk position continually changed with redistribution and diffusion of water. • The centroid position of eggs directionally moved towards the blunt end. • A rapid, actual-time approach to nondestructively determine egg freshness was reported. Developing rapid and nondestructive technologies to evaluate egg quality is meaningful for both industrial and consumer application. In this work, a novel determination technology based on centroid rate was explored. Egg samples were stored at 25 °C and 50–60 % relative humidity. With increasing of storage time, the water states of eggs changed with an increase in immobilized water and a decrease in free water. The egg yolk continuously moved to the air chamber with redistribution and diffusion of water, causing the centroid position of eggs directionally to move towards the blunt end. Accordingly, the correlation between the centroid rate and Haugh unit (HU) value has been established, and the coefficient of determination (R 2 ) in the predictive model reached 0.961. This suggested that the approach possessed a high accuracy and had a potential to be applied in evaluating egg quality in actual time during storage.

The effect of spatial position and age within an egg-clutch on embryonic development and key metabolic enzymes in two clownfish species, Amphiprion ocellaris and Amphiprion frenatus.

Since the size of newly hatched larval fish is directly related to egg size, small differences in initial egg size can be critical to survival and further development of offspring. Underlying processes causing size variation in fish offspring are still not entirely understood. In this study we investigated whether the spatial position of an individual egg within a clutch affects size variation in two benthic spawning coral reef fishes, the clownfishes Amphiprion ocellaris and A. frenatus. To evaluate the effects of within-clutch position on embryonic development, egg growth metrics and protein content were analysed on day 2, 5 and 8 after deposition (adp). Additionally the activities of the key metabolic enzymes citrate synthase (CS) and lactate dehydrogenase (LDH) were investigated to evaluate the physiological status of the embryos. Central eggs of A. frenatus were significantly longer and heavier than peripheral eggs only on day 2 and 5 adp (2.07 mg, 2.59 mm vs. 1.84 mg, 2.49 mm). No significant differences were observed in A. ocellaris between eggs originating from a central or peripheral (5 mm from edge) position (1.33 mg, 2.26 mm vs. 1.15 mg, 2,18 mm). Diameter of the eyes did not differ between the two fish species nor between different positions, for any age group. The protein content of eggs (7.5% of wet weight) was independent of age, position and species. Enzymatic activity increased from 2 adp until peak activity was observed for both enzymes on day 8 adp, independent from position. The range of CS- and LDH-activity was 0.3–13.0 and 0.2–71.7 U g-1 wet weight, respectively. Significant differences in enzymatic activity were observed between age groups in both species, which in connection with significantly larger eggs of A. frenatus at day 2 and 5 adp could hint at a better O2 supply of central eggs. Potential implications for captive breeding are given.

PENGARUH FREKUENSI PEMUTARAN DAN POSISI TELUR PADA KEBERHASILAN PENETASAN TELUR AYAM KAMPUNG (Gallus gallus Domesticus)

EFFECT OF TURNING FREQUENCY AND EGG POSITION ON HATCHABILITY OF CHICKEN EGGS (Gallus gallus Domesticus). This study aimed to determine effect of turning frequency and egg position on the hatching ability of chicken eggs. Study was conducted using 162 eggs of local hens inserted into hatching machine withcapacity of 300 eggs and implemented for 24 days. The experimental design of the completely factorial randomized design was applied consisting of 9 treatments and 3 replications. The two treatment factors were turning frequency consisted of 2 times a day, 3 times a day, 4 times a day, and egg position of 300, 600, and 900. The results of the analysis show that the effect of the turning frequency did not show a significant effect (P&gt;0.05) on hatchability. However, egg position had a significant effect (P&lt;0.5) on hatchability. There was no interaction between turning frequency and egg position againt hatchability and mortality. The conclusion of this research was the turning frequency of 2 times a day with egg slope position of 300 produced high hatchability and low level of mortality. Keywords : Egg turning frequency and position, hatchability, local hen.