• International Journal of Industrial Entomology and Biomaterials
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• 제33권2호
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• pp.92-95
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• 2016

The black soldier fly is economically important because its prepupae are used as feed for many animals, including fish and swine. In Korea, black-soldier-fly farms have attempted to increase annual breeding and mass egg production for use in animal feed, as well as the decomposition of organic waste. Such efforts require an understanding of optimal mating and oviposition techniques. Specifically, adult densities and cage size may both improve the efficiency of mass egg production. Our study used four sizes of nylon cages ($1.0{\times}1.0{\times}2.5m$, $1.5{\times}1.5{\times}2.5m$, $2.0{\times}2.0{\times}2.5m$, $2.5{\times}2.5{\times}2.5m$) and three density treatments (4 kg, 8 kg, and 10 kg of pupae) to investigate optimal habitat size and adult density. We found that cage size (independent of density) did not significantly influence female fecundity (number of egg clutches and egg weight), whereas higher densities increased egg number and weight regardless of cage size. Thus, we recommend manipulating adult density to enhance productivity in commercial black-soldier-fly farming. However, we also propose further detailed research to develop methods that account for seasonal changes and environmental conditions, as climatic variables (temperature, sunlight) likely influence female fecundity as well.

• 한국수산과학회지
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• 제36권6호
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• pp.625-631
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• 2003

The aim of the present study was to investigate the ecological relationship between female body size (=shell length) and fecundity in a Korean population of protandric hermaphrodite, Crepidula onyx Sowerby, using 6 reproductive variables (the number of capsules per brood, capsule size, the number of embryos per capsule, total number of embryos per brood, egg size, and larval size). The investigation was based on 32 females, 107 egg capsules, 263 eggs, and 250 veliger larvae sampled in January 2000, from Yangpo, the southeastern coast of Korea. All foregoing reproductive variables, except larval size, were significantly correlated with the female body size (p<0.001$\~0.01$). There was a significant increase both in the number of capsules per brood and the number of embryos per capsule with female body size (p<0.001). Consequently, the fecundity of the female C. onyx increased with female body size to over 14.65 mm (the minimum size of egg brooding in the present study). This investigation, therefore, provides additional evidence that female fecundity of protandric hermaphrodites is positively correlated with female body size.

• 한국발생생물학회지:발생과생식
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• 제17권1호
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• pp.25-35
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• 2013

We investigated the effects of shell height on reproductive potential of the female Rapana venosa in three regions of different salinities (the coastal zone of the Gwangyang Bay (S-1); the upper reaches (S-3); lower reaches (S-2) of the Seomjin River). The number of egg capsules, egg capsule height, and fecundity associated with reproductive potential of larger female rapa whelks were higher than those of smaller individuals in all three regions. Correlation analyses showed that there is a significant positive correlation between egg capsule and female shell height. Mean of shell heights, egg capsule heights, the number of egg capsules in an egg mass, and fecundity in an egg capsule produced from female individuals inhabiting S-1 region were markedly higher than those inhabiting S-2 and S-3 regions. In particular, the fecundity of the rapa whelk increased with the salinity and shell height. Although large rapa whelks produced a large number of egg capsules at S-1 region, those at S-3 habitat laid less egg capsules with smaller size. If these rapa whelks were put into S-2 region, the number of egg capsules produced by a female at S-2 region was slightly larger than those produced by a female at S-3 region. This provides a clear evidence that the number of the egg capsules can be controlled by the salinity. In the coastal zone of the Gwangyang Bay and the upper reaches of Seomjin River, the fecundity of this species was estimated to be approximately 182,000-1,302,000 eggs/ind./yr.

• 한국식품과학회지
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• 제20권2호
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• pp.225-230
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• 1988

난황의 사용량을 각각 2%, 3.5%, 5%, 6.5%, 8%, 9.5%로 변화시켜 시험 제조한 마요네즈에 대하여 동결법 및 진동 원심법에 의해 유화 안정성을 비교하였고, 점도 및 입경을 측정하였다. 난황 함량이 많을수록 기름 입자의 크기가 작고, 점도가 높았으며, 유화 안정성이 좋았다. 동결에 대한 안정성은 난황 6.5% 이하에서 급격히 떨어졌으며. 진동에 대한 안정성은 난황 2%, 3.5%의 경우 매우 나빴으나, 난황 5% 이상의 경우에는 비교적 안정하였다. 마요네즈의 점도는 $-10^{\circ}C$ 보존의 초기 24시간에서 급격히 감소하였고 그 이후에는 서서히 감소하였다. $-10^{\circ}C$ 보존 중의 입경은 난황 6.5% 이하의 경우 계속 커지는 경향을 보였으나 난황 8%, 9.5%의 경우에는 분리에 이르기 전까지 비교적 변화가 적었다. 마요네즈의 유화 안정성을 높이기 위해서는 제조의 기본 배합에 있어서 유화제인 난황을 6.5% 이상 사용하는 것 이 적절 하다고 판단되 었다.

• 수산해양교육연구
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• 제26권6호
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• pp.1402-1411
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• 2014

This study about morphological observation of pre- or post ovulated eggs obtained from artificially maturated female eels. Female eels were divided with two groups as wild eels from nature and feminized eels from farm. Artificial maturation had been conducted with the established methods in this laboratory, and then maturate eggs sampled at fixed 3 times and these were observed with stereomicroscope. Rate of increased body weight (RIW) were measured with 2 times. Egg diameters and development of oil droplets are determined for standardization of egg maturation degree, and the transparency of egg cytoplasm and the homogeneous degrees of egg size were referred to determine of egg quality. Rate of increased body weight (RIW) were good in range about 10 % at final salmon pituitary extracts (SPE) injection time and in range about 20 % at $17{\alpha}$, $20{\beta}$-dihydroxy-4-pregnen-3-one (DHP) injection time. Good matured egg for fertilization had $900-1000{\mu}m$ diameter, and they had about 50 oil droplets in size about $100{\mu}m$ diameter. There were not predominant differences at egg size and oil droplet development between wild female and feminized eels.

• Preventive Nutrition and Food Science
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• 제3권3호
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• pp.292-294
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• 1998

Surimi sol and gel were prepared by mixing egg albumin, starch, oil and carrageenan, which are used as representative ingredients in the surimi composite, at different ratio. Structural properties in surimi composite were investigated by examining the phase changes and dispersion pattern (average particle size, size range and the averge number of particle) of the particulate ingredients in sol and gel with an image analyzer. A staining technique of the specimen containing egg albumin in surimi gel was developed by adjusting pH of a toluidine staining solution. Image analysis revealed that size and density of ingredient particles were function of the level and dispersion of ingredients except of starch-incorporated surimi gel which showed maximum particle size at 6%.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1998년도 추계학술대회 및 발표대회 강연 및 발표논문 초록집
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• pp.10-10
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• 1998

The growth process of solid grains in a liquid matrix is usually explained in tem1S of Ostwald ripening. The variation of growth (dissolution) rate as a function of grain size during Ostwald ripening predicted that the dissolution rate becomes very large as grain size decreases but the growth rate of a large grain is rather limited. Therefore. a rather uniform size distribution of grain size is maintained once after the quasi-equilibrium state is reached. Quite frequently, however, the exaggerated grain growth (EGG) is observed to occur: only a limited number of grains grow exceptionally. From the observation that the EGG occurs only for the faceted grains with apparently straight solid-liquid interfaces, the EGG is suggested to be the consequence of growth process controlled by 2-dimensional nucleation. In this study, the result by computer calculation on the grain growth process controlled by various mechanisms will be given.

• 한국생태학회:학술대회논문집
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• 한국생태학회 2002년도 VIII 세계생태학대회
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• pp.107-111
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• 2002

During the breeding season of 1998, breeding ecology of the Great Reed-Warbler (Acrocephalus arundinaceus orientalis) was studied at Yangsoo-ri and Yongdam-ri of the Yangpyung-gun, Kyunggi province, Korea. Egg-weight (CV: 6.25) was more variable than either length or breadth, and breadth was the least variable of the measures. Significant variations In overall egg-weight occurred between clutches, and that more of the total variation in egg-weight and shape are due to inter-clutch variation as to intra-clutch variation when the data were pooled. The last egg tends to be larger than the remaining eggs in the clutch of the Great Reed-Warbler, suggest- ing the Great Reed-Warbler may adopt the brood-survival strategy. When method 3 was used, the most common incubation period is 12 days. In the Great Reed-Warbler, the length of the incubation period was related to clutch-size when method 1 (r=0.485, p<0.05) and method 2 (r=0.621, p<0.01) were employed, but not related to egg weight. The average number of days of hatching asynchrony was 2.5, raging 0.5∼2.5. Asynchronous hatching was related to the clutch size (r=0.66, p<0.01). Hatching sequence was closely related to the laying sequence (r=0.93, p<0.001), suggesting Great Reed-Warblers incubate their eggs before clutch completion. The effect of egg weight on hatching asynchrony was found in Great Reed-Warblers (t-test, p<0.01).

• Applied Microscopy
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• 제52권
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• pp.6.1-6.5
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• 2022

We examined the morphology of the fertilized egg and the fine structure of fertilized egg envelopes of Poropanchax normani belonging to the family Poeciliidae, also known as Norman's lampeye using light and electron microscopes. The fertilized eggs with narrow perivitelline space were found to be spherical and demersal, additionally containing small oil droplets in the vitelline membrane. Further, a bundle of adhesive filaments was observed to be present on one side of the fertilized egg. These filaments possessed remarkably high elasticity and were approximately 1-3mm in length. The size of the fertilized egg was determined to be about 1.49 ± 0.07mm (n=30). The outer surface appeared smooth, and adhesive filaments originating at different location of the surface of the envelope were found to be distributed around the egg envelope and were joined together to form a single long bundle in scanning electron microscopic observation. A peak-like structure formed of several straight wrinkles was observed around the micropyle. However, the complete structure of the micropyle could not be studied due to the depth at which it was located. Additionally, the total thickness of the egg envelope was ascertained to be approximately12.5-14.5㎛. The egg envelope consisted of two distinct layers, an outer electron dense layer and an inner lamellar layer, further consisting of 10 sublayers of varying thicknesses. Collectively, it was observed that the morphological characteristics of the fertilized egg, fine structures surrounding the micropyle, outer surface, adhesive structure consisting adhesive filaments, and sections of fertilized egg envelope displayed species specificity.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1995년도 제16회 생물과학 심포지움 강연록
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• pp.68-73
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• 1995

Most female Great Tits lay one egg each day until the clutch is complete. However, some exceptions are found. “Pause day/s” most frequently occur after the 1st egg is laid. In general, egg-size increase with laying sequence, but there is year-to-year variation. The relationship between egg size and laying sequence is found more significantly in relatively larger clutches than in smaller ones. Great Tits tend to advance the hatching of their chicks by starting to incubate earlier in relation to clutch completion as the breeding season progresses. hatching asynchrony affects chick´s growth rate, but when the effect of laying date on hatching asynchrony is controlled, the effect of hatching asynchrony on growth rate is not found. These findings support the ´hurry-up´ hypothesis.