High-quality Eggs Research Articles

키토산올리고당 기질-유기태 아연(Zn-OCHT) 섭이에 의한 산란계 계란 고품질 생산성 연구

키토산올리고당 기질-유기태 아연(Zn-OCHT) 섭이에 의한 산란계 계란 고품질 생산성 연구

The Effect of Storage Period and Temperature on Egg Quality in Commercial Eggs

Consumers demand fresh and high-quality eggs. Egg quality may be represented by shell color, shell weight, egg weight, shell thickness, shell density, albumen height, yolk color, albumen pH and viscosity. Various factors such as strain, age of hen, storage temperature, humidity, the presence of <TEX>$CO_2$</TEX> and storage time affect egg quality. Therefore, we investigated the effects of storage time and temperature on egg quality to define the freshness of Korean market eggs. A total of 1,800 eggs were used for this experiment and were separated into 45 treatments with 40 eggs in each. The treatments were consisted of 15 storage periods (2 d to 30 d) and 3 storage temperatures (<TEX>$2^{\circ}C$</TEX>, <TEX>$12^{\circ}C$</TEX>, <TEX>$25^{\circ}C$</TEX>). Each egg was weighed and broken, and the height of the thick albumen, Haugh units (HU), egg shell color and yolk color were measured by a QCM+system. We also observed the physiochemical properties of eggs such as yolk pH, albumen pH and albumen viscosity. The egg weight, shell weight, albumen height, HU and albumen viscosity significantly decreased with increasing storage time and temperature. However, the albumen and yolk pH significantly increased with increasing storage period and temperature. The interaction effects between the storage period and temperature were significant for shell weight, shell density, egg weight, albumen height, HU, yolk color, yolk pH, albumen pH and albumen viscosity. In the analysis of the correlation with egg quality, the storage temperature exhibited a higher correlation coefficient than the storage period. In conclusion, storage time and temperature are the major factors affecting egg quality, but the storage temperature is a more sensitive determinant of egg quality deterioration compared with the storage period.

Method for somatic cell nuclear transfer in zebrafish.

This chapter presents a detailed methodology for somatic cell nuclear transfer-cloning of zebrafish. We aim to place the reader in a virtual lab experience to assist acquisition of the technical skills required for reproducing the published protocol. All materials, including catalog numbers for reagents and techniques for their preparation, are provided. Our protocols describe laser inactivation of egg chromosomes, the transfer of a cell through the oocyte micropyle, and spontaneous activation of the reconstructed embryo. High-quality eggs are the key to cloning success, and Chinook salmon ovarian fluid is indispensable for keeping eggs arrested at the metaphase of meiosis II. This protocol continues to be refined by our laboratory. However, naive investigators should be able to apply it in its present form to generate cloned zebrafish.

FSH Regulates mRNA Translation in Mouse Oocytes and Promotes Developmental Competence.

A major challenge in assisted reproductive technology is to develop conditions for in vitro oocyte maturation yielding high-quality eggs. Efforts are underway to assess whether known hormonal and local factors play a role in oocyte developmental competence and to identify the molecular mechanism involved. Here we have tested the hypothesis that FSH improves oocyte developmental competence by regulating the translational program in the oocyte. Accumulation of oocyte proteins (targeting protein for the Xenopus kinesin xklp2 and IL-7) associated with improved oocyte quality is increased when cumulus-oocyte complexes are incubated with FSH. This increase is due to enhanced translation of the corresponding mRNAs, as indicated by microinjection of constructs in which the 3' untranslated region of the Tpx2 or Il7 transcripts is fused to the luciferase reporter. A transient activation of the phosphatidyl-inositol 3-phosphate/AKT cascade in the oocyte preceded the increase in translation. When the epidermal growth factor (EGF) receptor is down-regulated in follicular cells, the FSH-induced rate of maternal mRNA translation and AKT activation were lost, demonstrating that the effects of FSH are indirect and require EGF receptor signaling in the somatic compartment. Using Pten(fl/fl):Zp3cre oocytes in which the AKT is constitutively activated, translation of reporters was increased and was no longer sensitive to FSH stimulation. More importantly, the oocytes lacking the phosphate and tensin homolog gene showed increased developmental competence, even when cultured in the absence of FSH or growth factors. Thus, we demonstrate that FSH intersects with the follicular EGF network to activate the phosphatidyl-inositol 3-phosphate/AKT cascade in the oocyte to control translation and developmental competence. These findings provide a molecular rationale for the use of FSH to improve egg quality.

Protein identification of vitellogenin in river catfish (&lt;i&gt;Hemibagrus nemurus&lt;/i&gt;)

Mass production of fish broodstock with high quality eggs requires the knowledge on the chemical composition and physiochemical properties of vitellogenin (Vtg) during ovulation. Vtg is an egg yolk precursor phospholipoglycoprotein, and has been analysed to evaluate the reproductive conditions and determine the spawning period in captive and wild fish. In this study, Vtg was induced in male H. nemurus through three intramuscular injections of 17- estradiol (E2). The Vtg was purified from the serum using gel filtration chromatography and thepurified protein was reduced via SDS-PAGE. One major polypeptide corresponding to 130 kDa was observed. Vtg identification was done using peptide mass fingerprint (PMF) from the trypsin digestion of male H. nemurus Vtg induced with E2. The sequence homology of H. nemurus AYLAGAAADVLEVGVR matched the Vtg of other fish species when analysedusing MALDI-TOF. Vtg was confirmed by MASCOT at 95% significant level. The potential protein that controls the reproductive process and oocyte development isolated from this study was discussed to understand the structure and function of Vtg.

Assessment of welfare and egg production of laying hens moravia ssl in small-scale breeding

The purpose of this study was to investigate the welfare of laying hens Moravia SSL housed in small-scale hen house with free range, behavior, egg production and selected physical indicators of eggs and chemical indicators of egg mass. The laying hens were kept in a hen house on deep litter. Breeding facility of hen house was within the meaning of recommendation for applying the principles of welfare, i.e. the space and breeding facility within the meaning of enriched breeding environment. Stocking density of the laying hens corresponded with recommendations for unrestricted movement and implementing natural activities. The hen house was equipped with the perch, nest, feeder and drinker. The commercial feed mixture was used for feeding, which is intended for laying hens. The kitchen remains were added to feed mixture, as are wet bread, the non-edible remains of foodstuffs. A feed mixture was served to laying hens 825 g per day. The laying hens had free access to drinking water, grazing, ground pecking, ground scratching and dust-bathing and in the free range. We focused investigation of on the egg laying intensity, selected parameters of physical egg quality and chemical egg contents. Time to relax of laying hens was adjusted according to the summer and winter breeding seasons. The main activities of free-range hens are grazing, ground pecking, ground scratching and dust-bathing. The main activities of free-range hens are grazing, ground pecking, ground scratching and dust-bathing. These activities were investigated in laying hens too in dependent of year period, more in the summer. Housing of the hens was equipped with the perch. The laying hens regularly used a perch. A beginning of occupation the perch was at the time of time growing dark, at the end of the light day. A nesting material was selected regular, monthly exchange. It was meadow hay of excellent quality for the collection of high quality and safe eggs from nests in the hen house. The laying hens had unlimited access to feed and water. The commercial feed mixture was available ad libitum and fresh kitchen remnants were added in a small amount, provided that they fed in the short term, so that not subject to harmful degradation process. The management of our experiment was scheduled at age of laying hens 30 to 90 weeks. The egg laying intensity was observed 50% in a moment of the experimental 1st week (age of laying hens 30 weeks). High egg laying intensity of laying hens was at their age between 39 to 63 weeks. At the end of the experiment, at age of laying hens 90 weeks was decreased egg laying intensity at 26.19%, which represents almost half of egg laying intensity recorded at the beginning of the experiment. An indicator of egg production in the our experiment was studied under defined conditions for small-scale breeding, i.e. in alternative production system with free range, under defined conditions of nutrition and timing of investigation more than one year, from the end of October to the end of December of the following year. The results of our experiment can be related to the season, months of the year. The laying hens laid the eggs by individual weeks 33-90 weeks of age about average weight from 57.5 to 75.0 g. The fat content of an egg mass was 11.3 g.100-1 and protein 12.39.g.100-1. The table eggs from conditions of small-scale breeding are an important source of foodstuffs for the population, especially in rural areas. It must be given to this source of table eggs for human nutrition the highest quality and health safety too.

Teknologi Domestikasi dan Pematangan Gonad Ikan Pawas (Osteochilus hasselti CV) dari Perairan Sungai Kampar Riau

A study on domestication and triggering gonadal maturation technique ofOsteochilus hasselti CV were conducted from March to May 2015. The study aimed to obtaina high quality brooder with good gonado somatic index and high quality eggs and sperm, inthat the fishes were treated with defference diets. Fish samples were kept in 1 x 1 x 1 mcages, with density of 20, 30 and 40 fishes/cage respectively. Fishes were fed on three typesof food namely dried Tubifex, shrimp pellet (without vitamin E addition) and shrimp pelletthat is enriched with vitamin E. The fishes was fed 10 % of total fish body weight/day. Itrevealed domestication can be conducted by keeping them in the cages that natural habitat.During the first week, fishes were not fed and in the following weeks they were provided withthe treated fed. The best result obtained in the fishes that are 20 fishes/cage and are feed withshrimp pellet that is enriched with vitamin E. During the research period (80 days), 20 fisheswere sampled in the 4th gonadal maturity level, their maturity indices was 14,7 %, fecundity360 eggs, egg diameter 0,936 mm and semen volume produced 0,575 ml.

무기태 철 대체제로서 키토산올리고당 기질-유기태 철(Fe-OCHT) 섭이에 따른 산란계 계란 고품질 생산성 연구

무기태 철 대체제로서 키토산올리고당 기질-유기태 철(Fe-OCHT) 섭이에 따른 산란계 계란 고품질 생산성 연구

Thermal and maternal environments shape the value of early hatching in a natural population of a strongly cannibalistic freshwater fish.

Hatching early in the season is often assumed to elevate fitness, particularly in cannibalistic fish in which size-dependent predation mortality is a major selective force. While the importance of the thermal environment for the growth of fish is undisputed, the relevance of maternal effects for offspring growth in the wild is largely unknown. Otoliths of 366 age-0 pike (Esox lucius L.) were sampled in a natural lake over three seasons. All offspring were assigned to more than 330 potential mothers using 16 informative microsatellites. We found temperature and past maternal environment (as represented by juvenile growth rate), but not female total length, to jointly contribute to explain within- and among-season size variation in juvenile pike. While there was no statistical evidence for maternal effects on offspring growth rate, fast female juvenile growth positively correlated with the offspring length in early summer. One mechanism could be related to fast-growing females spawning somewhat earlier in the season. However, the more likely mechanism emerging in our study was that fast-growing females could have been in better condition prior to spawning, in turn possibly producing higher numbers of high-quality eggs. Our study is among the few to reveal carry-over effects related to past maternal environments on offspring performance in a naturally reproducing fish stock. At the same time, our study underscores recent arguments that size-dependent maternal effects may not be expressed in the wild and that early hatching does not generally produce size advantages in light of stochastically varying temperature conditions.

Profiling of the embryonic Atlantic halibut (Hippoglossus hippoglossus L.) transcriptome reveals maternal transcripts as potential markers of embryo quality.

BackgroundCommercial Atlantic halibut (Hippoglossus hippoglossus) farming is restricted by variable oocyte quality, slow growth, and early maturation of male fish. Maternally transferred components regulate early developmental processes; therefore, they have an effect on the future viability of the embryo. Using a newly developed Agilent 10 k custom-made oligonucleotide array, we profiled components of the transcriptome involved in immune defence as well as germline and muscle development during early developmental stages: 8-cell embryos (8CS), germ ring stage (GR), 10-somite stage (10SS), and hatched embryos (HT). In addition, we identified differentially expressed transcripts in low (≤9 ± 3% hatching) and high (≥86 ± 3°% hatching) quality eggs at 8CS to identify potential maternal markers for embryo quality.ResultsOut of 2066 differentially expressed transcripts, 160 were identified as maternal transcripts being specifically expressed at 8CS only. Twenty transcripts were differentially expressed in 8-cell embryos between low and high quality egg groups. Several immune-related transcripts were identified as promising molecular markers of hatching success including interferon regulatory factor 7 and mhc class 2A chain. Differential expression was positively validated with quantitative real-time PCR.ConclusionsWe have demonstrated maternal transfer of innate and adaptive immune system transcripts into Atlantic halibut embryos and their relation with future embryo developmental potential. We identified several transcripts as potential molecular markers of embryo quality. The developed microarray represents a useful resource for improving the commercial production of Atlantic halibut.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-829) contains supplementary material, which is available to authorized users.

Variation in embryonic mortality and maternal transcript expression among Atlantic cod (Gadus morhua) broodstock: A functional genomics study

Early life stage mortality is an important issue for Atlantic cod aquaculture, yet the impact of the cod maternal (egg) transcriptome on egg quality and mortality during embryonic development is poorly understood. In the present work, we studied embryonic mortality and maternal transcript expression using eggs from 15 females. Total mortality at 7days post-fertilization (7 dpf, segmentation stage) was used as an indice of egg quality. A 20,000 probe (20K) microarray experiment compared the 7hours post-fertilization (7 hpf, ~2-cell stage) egg transcriptome of the two lowest quality females (>90% mortality at 7 dpf) to that of the highest quality female (~16% mortality at 7 dpf). Forty-three microarray probes were consistently differentially expressed in both low versus high quality egg comparisons (25 higher expressed in low quality eggs, and 18 higher expressed in high quality eggs). The microarray experiment also identified many immune-relevant genes [e.g. interferon (IFN) pathway genes ifngr1 and ifrd1)] that were highly expressed in eggs of all 3 females regardless of quality. Twelve of the 43 candidate egg quality-associated genes, and ifngr1, ifrd1 and irf7, were included in a qPCR study with 7 hpf eggs from all 15 females. Then, the genes that were confirmed by qPCR to be greater than 2-fold differentially expressed between 7 hpf eggs from the lowest and highest quality females (dcbld1, ddc, and acy3 more highly expressed in the 2 lowest quality females; kpna7 and hacd1 more highly expressed in the highest quality female), and the 3 IFN pathway genes, were included in a second qPCR study with unfertilized eggs. While some maternal transcripts included in these qPCR studies were associated with extremes in egg quality, there was little correlation between egg quality and gene expression when all females were considered. Both dcbld1 and ddc showed greater than 100-fold differences in transcript expression between females and were potentially influenced by family. The Atlantic cod ddc (dopa decarboxylase) complete cDNA was characterized, and has a 1461bp open reading frame encoding a 486 amino acid protein that contains all eight residues of the conserved pyridoxal 5’-phosphate binding site including the catalytic lysine. This study provides valuable new information and resources related to the Atlantic cod egg transcriptome. Some of these microarray-identified, qPCR-confirmed, Atlantic cod egg transcripts (e.g. ddc, kpna7) play important roles during embryonic development of other vertebrate species, and may have similar functions in Atlantic cod.

Accumulation of docosapolyenoic fatty acids in developing oocytes of the winged pearl oyster Pteria sterna

Ensuring supplies of pearl oyster spat for commercial grafting operations in Mexico is an ongoing problem. This has refocused research toward improving hatchery propagation protocols. Since gender plays an important role in the physiology of bivalves, we studied the use of fatty acids in the gonad and digestive gland of male and female winged pearl oyster (Pteria sterna) over its natural breeding season. Sampling included two peaks of ripening (February and April 2009), a pre-reproductive period (November 2008), and a post-reproductive period (June 2009). We found a significant increase in storage of docosapolyenoic fatty acids during development and ripe stages only in the female gonad, which indicates that these fatty acids could be a limiting factor for successful development of high quality eggs. The content of total monounsaturated fatty acids in male gonads, especially the fatty acid 16:1 n7, was significantly higher than in female gonads at the development and ripe stages. We also found differences between males and females in the use of some fatty acids in the digestive gland, especially at the spawned stage. Our results have future application in developing protocols for rearing of this pearl oyster in hatcheries. Incorporating dietary supplements containing docosapolyenoic fatty acids into diets of pearl oyster broodstock could be a practical way to improve their performance, which is crucial for enhancing the viability of larvae and spat.

Selective Disruption of Aurora C Kinase Reveals Distinct Functions from Aurora B Kinase during Meiosis in Mouse Oocytes

Aurora B kinase (AURKB) is the catalytic subunit of the chromosomal passenger complex (CPC), an essential regulator of chromosome segregation. In mitosis, the CPC is required to regulate kinetochore microtubule (K-MT) attachments, the spindle assembly checkpoint, and cytokinesis. Germ cells express an AURKB homolog, AURKC, which can also function in the CPC. Separation of AURKB and AURKC function during meiosis in oocytes by conventional approaches has not been successful. Therefore, the meiotic function of AURKC is still not fully understood. Here, we describe an ATP-binding-pocket-AURKC mutant, that when expressed in mouse oocytes specifically perturbs AURKC-CPC and not AURKB-CPC function. Using this mutant we show for the first time that AURKC has functions that do not overlap with AURKB. These functions include regulating localized CPC activity and regulating chromosome alignment and K-MT attachments at metaphase of meiosis I (Met I). We find that AURKC-CPC is not the sole CPC complex that regulates the spindle assembly checkpoint in meiosis, and as a result most AURKC-perturbed oocytes arrest at Met I. A small subset of oocytes do proceed through cytokinesis normally, suggesting that AURKC-CPC is not the sole CPC complex during telophase I. But, the resulting eggs are aneuploid, indicating that AURKC is a critical regulator of meiotic chromosome segregation in female gametes. Taken together, these data suggest that mammalian oocytes contain AURKC to efficiently execute meiosis I and ensure high-quality eggs necessary for sexual reproduction.

Reproduction of hatchery-produced meagre Argyrosomus regius in captivity II. Hormonal induction of spawning and monitoring of spawning kinetics, egg production and egg quality

The present study aimed at the development of an effective and efficient hormonal spawning induction method for meagre Argyrosomus regius, using controlled-release delivery systems loaded with gonadotropin-releasing hormone agonist (GnRHa). Three sets of spawning induction experiments were undertaken in the course of three years. In experiment 1, group spawnings were performed at different times during the reproductive period, in order to determine the most appropriate time for hormonal induction of spawning. Experiment 2 described in more detail the spawning kinetics of individual females induced to spawn at different times during the season, in order to obtain important information on spawning kinetics, batch fecundity and total fecundity in response to the hormonal treatment. In experiment 3, two similar broodstocks were used to obtain further production characteristics and monitor variations in egg/larval quality over the spawning period. The effective GnRHa doses used were 55–84μgGnRHakg−1 body weight in males and 46–92μgGnRHakg−1 in females. In general, successful spawning induction was achieved between early May and early June. Implantation with GnRHa induced spawning 2–3d after treatment and produced an average (±SD) of 12±5 spawns per broodstock or female over 3weeks, most of them over consecutive days. Batch fecundity was extremely variable (mean of 6631 to 104,409eggskg−1), with the largest batches occurring 3–4d after treatment, and very low fecundity after 1week from GnRHa treatment. As a result, the first 4 spawns of all spawning induction experiments constituted a mean of 75±13% of the total relative fecundity. Overall mean total relative fecundity was variable at 380,780±167,577eggskg−1. Evaluation of the ovaries after the cessation of spawning, demonstrated that the females still contained large numbers of oocytes in full vitellogenesis, and it is hypothesized that these fish could spawn further in response to a second GnRHa implantation. Fertilization success was very high in all spawning induction experiments, with the overall mean being 89±5%. Similarly, the produced eggs were of very high quality, based on the survival of the eggs during embryogenesis (>95%), hatching success (>99%) and larval survival 5d after egg collection (>87%), resulting in an overall larva survival of 73% of the total number of eggs spawned. These studies demonstrate that the GnRHa implants are an effective and efficient method for the induction of spawning in meagre, leading to the production of eggs of high fecundity and quality.

Minimal ovarian stimulation in conjunction with array comparative genomic hybridization provides a new approach to improve pregnancy rates for patients with advanced maternal age

Minimal ovarian stimulation (Mini-IVF) has several advantages include less medication and producing fewer but higher quality eggs. Several studies demonstrate that aneuploidies are very common in embryos from patient with advanced maternal age (AMA) which usually result in poor IVF outcome. This study was conducted to determine if Mini-IVF and array comparative genomic hybridization (aCGH) can improves the pregnancy rates for patient with AMA.

A FEASIBILITY STUDY AND COST PERFORMANCE FOR INDUSTRIAL AND COMMERCIAL PRODUCTION OF TRICHOGRAMMA SSP. IN EGYPT

Biological control of phytophagous insects by mass release of egg parasitoids has become more practical in recent years. Trichogrammatides and other egg parasitoids are generally part of the local ecosystem and often contribute to control certain lepidopterous pests in the absence of disruptive pesticides. The wide use of Trichogrammatides is mostly due to the easy mass production technique of these parasitoids on numerous hosts which are mainly the lepidopterous insect-pests of stored products, such as Sitotroga cerealella (Olivier), Ephestia kuehniella Zeller and Corcyra cephalonica (Stainton). Eggs of the Mediterranean flour moth, E. kuehniella Zell. are widely utilized as substitution host or prey for rearing different parasitoids and predators. The economical production of great amounts of high quality eggs of E. kuehniella is therefore one of the basic requirements of many rearing systems. Consequently, quality control of E. kuehniella is a part of the complete control system in mass production. The main finding indicated that, the cost of production per 1000 parasitoid (one card) is 0.5 LE. Moreover, the capital recovery period after one year estimated 95% .

Eggshell Spottiness Reflects Maternally Transferred Antibodies in Blue Tits

Blue-green and brown-spotted eggshells in birds have been proposed as sexual signals of female physiological condition and egg quality, reflecting maternal investment in the egg. Testing this hypothesis requires linking eggshell coloration to egg content, which is lacking for brown protoporphyrin-based pigmentation. As protoporphyrins can induce oxidative stress, and a large amount in eggshells should indicate either high female and egg quality if it reflects the female's high oxidative tolerance, or conversely poor quality if it reflects female physiological stress. Different studies supported either predictions but are difficult to compare given the methodological differences in eggshell-spottiness measurements. Using the blue tit Cyanistes caeruleus as a model species, we aimed at disentangling both predictions in testing if brown-spotted eggshell could reflect the quality of maternal investment in antibodies and carotenoids in the egg, and at improving between-study comparisons in correlating several common measurements of eggshell coloration (spectral and digital measures, spotted surface, pigmentation indices). We found that these color variables were weakly correlated highlighting the need for comparable quantitative measurements between studies and for multivariate regressions incorporating several eggshell-color characteristics. When evaluating the potential signaling function of brown-spotted eggshells, we thus searched for the brown eggshell-color variables that best predicted the maternal transfer of antibodies and carotenoids to egg yolks. We also tested the effects of several parental traits and breeding parameters potentially affecting this transfer. While eggshell coloration did not relate to yolk carotenoids, the eggs with larger and less evenly-distributed spots had higher antibody concentrations, suggesting that both the quantity and distribution of brown pigments reflected the transfer of maternal immune compounds in egg yolks. As yolk antibody concentrations were also positively related to key proxies of maternal quality (egg volume, number, yellow feather brightness, tarsus length), eggshells with larger spots concentrated at their broad pole may indicate higher-quality eggs.

Erratum to: Egg collection from hatchery-reared broodstock of spotted halibut Verasper variegatus treated with LHRH analog

The objective of this study is to establish a method for acquiring large quantities of high-quality eggs for artificial fertilization from hatchery-reared broodstock of spotted halibut Verasper variegatus. We estimated the optimum conditions for implantation of luteinizing hormone-releasing hormone analog (LHRHa) cholesterol pellet (LHRHa-CP) to induce ovulation from two experiments which focused on the dose and the timing combined with monitoring of oocyte development by ovarian cannulation. From the results of cannulation, vitellogenesis of hatchery-reared broodstock was suggested to occur normally, although final oocyte maturation was not initiated in the first clutch of oocytes. In late December, oocytes in the most advanced clutch still underwent vitellogenesis, having diameter of about 0.82 mm. LHRHa-CP implantation during this period had no remarkable effects, except for administration at high dose (100 μg/kg). In contrast, in mid January, when oocyte diameter reached about 0.95 mm, ovulation occurred in most individuals, even at low dose (20 μg/kg). In mid February atretic oocytes became remarkable and LHRHa-CP implantation showed much lower performance in terms of egg quality. The diameter of growing oocytes converged to about 0.95 mm, which was that of fully grown postvitellogenic oocytes. Thus, oocyte diameter is suggested to be an effective indicator to estimate the timing of LHRHa-CP implantation.

The Relationship between the Developmental Stage of Oocytes in Various Seasons and the Quality of the Egg Obtained by Artificial Maturation in the Feminized Japanese Eel Anguilla japonica

Feminized 2-year-old eels were reared in freshwater at 26℃ until October, then the water temperature was gradually decreased to 16℃ to December, and gradually increased to 26℃ from February to April. They received weekly injections of salmon pituitary extract (body weight, 15 or 30 mg/kg) to induce sexual maturation in September, December, or April. The quality of the eggs obtained in each season was evaluated by the resulting fertilization, hatching, and 8-day sur- vival rates. High quality eggs were obtained via high-dose injections in most experimental groups. In the high-dose injection groups, eels were induced to the final maturation phase in all seasons; however, egg quality obtained in April was extremely low in contrast to that obtained in September and December. Histological observation of oocytes just before the process of artificial maturation was commenced indicated that the developmental stages of oocytes varied by season: oil droplet in September, early vitellogenic in December, and regressive from vitellogenesis in April. The extremely low egg quality in April is probably due to the fact that the oocytes had already entered the regressive stage. These results indicated that better quality of eel eggs can be obtained by starting the process of artificial maturation between September and December.

동물복지형 달걀에 대한 광고매체의 효율성 분석: Ranked Logit Model을 중심으로

The object of this study is to establish proper consumer-oriented advertisement strategies of animal welfare egg. Data were collected by consumer survey on November 4th, 2011 at Hanaromart in Chunchon area. SAS 9.1 and Excel 2007 were used as statistical package and ranked logit model was used to analyze the data. From the results of the study the following advertisement strategies were suggested for animal welfare egg considering the effects of advertisement media. First, internet based media were most preferred. For effectively using the internet based media the message should be succinctly and clearly transferred to consumers. Therefore if phrases and pictures emphasizing the difference between animal welfare egg and general egg were used, then positive effects could be attained from consumers in a short period. Second, advertisement media should be used differently based upon the consumers' income level. In the case of consumers under three million won income level the advertisement in the purchasing site was most effective regarding the advertisement effects. Therefore if the advertisement showing the breeding surroundings between animal welfare egg and general egg was used, positive effects could be attained. For consumers over three million won income level the homepage of egg producers was most effective in advertisement. So if more accurate information were distributed to consumers visiting the homepage and high quality egg were sold via the homepage, positive effects could be attained.