• Ocean and Polar Research
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• v.38 no.4
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• pp.303-314
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• 2016

We tested the combined effects of increased partial pressure of $CO_2$ ($pCO_2$) and temperature on the reproduction and survival of the copepod Calanus sinicus from Asan Bay, the Yellow Sea under laboratory conditions to understand the impact of acidification on copepods. Egg production rate, survival rate, and fecal pellet production of C. sinicus were not affected by 1305 ppm $pCO_2$ or with combined treatments of temperature and $pCO_2$, including $8^{\circ}C$ and 289 ppm $pCO_2$ (ambient), $8^{\circ}C$ and 753 ppm $pCO_2$ (high $pCO_2$), $12^{\circ}C$ and 289 ppm $pCO_2$ (high temperature), and $12^{\circ}C$ and 753 ppm $pCO_2$ (greenhouse), for 5 or 10 d of exposure. However, egg hatching success of C. sinicus decreased significantly in the greenhouse treatment compared with the ambient or the high $pCO_2$ treatments. These results suggest that a combined treatment ($pCO_2$ and temperature) affected egg viability more than a single treatment($pCO_2$).

• Korean Journal of Ichthyology
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• v.23 no.2
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• pp.150-157
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• 2011

In this study we described reproduction study of Korean endemic species, Acheilognathus koreensis and three other acheilognathinae species A. signifer, Rhodeus pseudosericeus, and R. uyekii. Morphology of egg shape and larvae just hatched is unique by the species respectively. There is no interrelation factor between size of female and number of spawned eggs per one time. Minium water temperature for spawning of A. koreensis was observed in $13.0^{\circ}C$ having low hatching rate with 43.5 percent. The egg of A. koreensis began to hatch approximately 79 hours after insemination. As higher as water temperature until $22.0^{\circ}C$ hatching elapsed time for developing eggs of A. koreensis and three species in this study was shortened. A. koreensis was grew up to be a adult enough which can be join to new production for three hundred days after hatching with 52.4 mm in total length. This reproduction study will be applied to preservation of Korean endemic fresh water fishes basically.

• Korean Journal of Poultry Science
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• v.31 no.4
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• pp.299-306
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• 2004

The objective of this study was to investigate the influence of egg storage, broiler breeder age, and the change of egg weight during incubation on growth rate of chicks and 43-day-old dressing percentage. The trials involved hatching eggs obtained from 27-wk-old hens and stored for 6 d for the Young-EXP group, from 28-wk-old hens and stored for 0 d for the Young-CON group, from 51-wk-old hens and stored for 6 d for the Old-EXP group, and from 52-wk-old hens and stored for 0 d for the Old-CON group, The hens were two commercial broiler breeder flocks of the same strain (Cobb) but of different egg producing stages(early and middle stages of egg production). The chicks were grown on floor pens for 6 wks, The differences of setting egg weights between Old-CON and Old-EXP groups were 1 g, but those between Young-CON and Young-EXP groups were 2.9 g(P<0,05). The loss of egg weight during 18 d incubation did not greatly differ among four groups, but the loss of egg weight during 21 d incubation was significantly (P<0.05) more in the middle stage of egg production groups than in the early stage of egg production groups. The mean birth weights of the middle stage of egg production groups were significantly(P<0,05) heavier by 8,7 g than those of the early stage of egg production groups; however, the differences of 6-wk-old body weight were not significant between egg producing stages. The differences of body weights in both egg producing stages were not significantly influenced by egg storage period in overall wks of ages. Egg storage and hen age did not greatly influence to the 43 d dressing percentages, either, The correlations of the setting egg weight with 18 d egg weight during incubation, growth rate of chicks, or 43 d dressing percentage were not significant.

• International Journal of Industrial Entomology and Biomaterials
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• v.11 no.2
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• pp.107-111
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• 2005

Impact of microsporidian infection and season on reproductive potential of Bombyx mori L. was investigated in the laboratory. Microsporidian infection significantly (P<0.01) reduced fecundity and hatching and increased sterility and mortality of eggs. Among the microsporidia, Nosema sp. 2 infected silkworm produced eggs with least fecundity and hatching percent as well as highest dead and sterile eggs followed by Nosema sp. 1 and N. bombycis. Microsporidia, in general, significantly reduced fecundity and hatching percent of eggs and increased number of dead and sterile eggs in all the three seasons except N. bombycis in July - August (S3) and Nosema sp. 2 in January February (S1). Since, seed production is the anchor sheet of mulberry sericulture, coefficient of egg lying is considered as an important aspect and the industry quite often facing shortage of disease free layings. The present study indicates that B. mori is more susceptible to microsporidia during S2 followed by S3 and S1 and Nosema sp2. is most virulent followed by Nosema spl. and N. bombycis.

• Korean Journal of Poultry Science
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• v.46 no.2
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• pp.77-86
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• 2019

This study was conducted to compare the heat stress response and production performance of chicks hatched in winter and summer. Among the 2,090 Korean native chickens examined, 1,156 hatched in winter and 934 hatched in summer. The amount of telomeric DNA, the expression of heat shock protein (HSP) genes, survival rate, egg production, and body weight were analyzed to evaluate the stress response and production performance of chickens. The results showed that the expression of HSP-70, $HSP-90{\alpha}$, and $HSP-90{\beta}$ genes in the winter-hatched chickens were significantly higher than those in the summer-hatched chickens during the growing and laying period (P<0.05). There was no significant difference in the amount of telomeric DNA between summer- and winter-hatched chickens. The survival rate was significantly higher in the summer-hatched chickens than in the winter-hatched chickens at the laying period (P<0.01). The hen-day egg production and egg weight in the summer-hatched chickens were also significantly higher than those in the winter-hatched chickens (P<0.05). In contrast, age of sexual maturity of winter-hatched chickens was significantly earlier than that of summer-hatched chickens (P<0.01). The body weights from birth to 24 weeks were significantly lighter in the summer-hatched chickens than in the winter-hatched chickens, however, it was reversed after 28 weeks (P<0.05). In conclusion, the chicks hatched in the summer are more resistant to heat stress, with better productivity than the chicks hatched in the winter. These results suggest that the chicks grown at high temperatures have greater adaptability to the thermal environment.

• Journal of fish pathology
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• v.11 no.2
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• pp.113-117
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• 1998

The influence of temperature on the rate of egg production and embryonic development of Microcotyle sebastis was investigated to determine the precise time of a second treatment. The survival time of the adults of M. sebastis was inversely proportional to temperature. The number of laid eggs per each replicate during the first 24 h was $39.3{\pm}4.0$ at $10^{\circ}C$, $62.7{\pm}14.2$ at $15^{\circ}C$, $101.0{\pm}5.6$ at $20^{\circ}C$ and $89.0{\pm}11.0$ at $25^{\circ}C$. The time required for egg hatching of M. sebastis was $31.30{\pm}4.88$, $17.52{\pm}3.24$, $11.59{\pm}3.02$ and $10.76{\pm}3.10$ days at 10, 15, 20 and $25^{\circ}C$, respectively. The regression models of the time required for the beginning and 50% point of hatching according to the different temperatures were as follows; Beginning of hatch: D=58.2000-$4.2067{\times}Temp+0.0867{\times}(Temp)^2$ ($P\leq0.01$), 50% of hatch: D=91.3833-$7.5767{\times}Temp+0.1767{\times}(Temp)^2$ ($P\leq0.01$).

• Journal of Aquaculture
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• v.12 no.1
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• pp.39-45
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• 1999

In order to obtain the basic biological data for artificial seedling production of sea cucumber, Stichopus japonicus, the influence of water temperature and air dry for spawning induction, egg development and larvae rearing was investigated during the period from April, 1995 through September, 1995. Spawning induction rate by the water temperature was 6.0~17.5% and air dry was responsed 1.4~4.0%. Number of eggs spawned of Stichopus japonicus were $50~500\times10^4$ individuals, the fertilization and hatching rate were ranged 84.0~96.0%, 71.4~84.6% respectively. The fertilized egg of Stichopus japonicus appeared mean diameter of $154{\mu}m$. At a constant water temperature of $23^{circ)C$, it become 4 tell stage from fertilization after 2 hours 10 minutes, hatching larvae after 14 hours half, auricularia larvae after 3 days, doliolaria larvare after 11 days and pentactula larvae after 15 days ready for settlement. The suitable food in the larvae reared for 17 days after fertilization were shown the best growth and survival in the larvae food of Chaetoceros calcitrans. Optimum density for larvae rearing were maintained of the larval density lower than 2 individuals/ml.

• Journal of Animal Science and Technology
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• v.51 no.4
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• pp.295-306
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• 2009

This experiment was conducted to investigate the effects of dietary calcium (Ca) and vitamin $D_3$ metabolite on eggshell quality and hatching egg production in aged egg-type breeder hens. A total of five hundred and forty 60-week-old Hy-Line Brown breeder hens were randomly allocated to nine treatments in a $3\times3$ factorial design to determine the effects of dietary Ca levels (3.3, 3.9, and 4.5%), combined with three levels of 25-hydroxycholecalciferol [25-$(OH)D_3$ 0, 75, and $150{\mu}g/kg$], on eggshell quality and egg production for 10 weeks. There were significant Ca and 25-$(OH)D_3$ effects (P<0.01) on egg production rate. There was a linear (P<0.01) increase in eggshell strength and thickness with increasing dietary Ca and 25-$(OH)D_3$ levels. Dietary 25-$(OH)D_3$ had a significant effect (P<0.05) on hatchability of egg although fertility was not influenced by dietarylevels of Ca and 25-$(OH)D_3$. Dietary Ca levels affected Ca content in tibia (P<0.05). These results indicated that relatively high levels of dietary Ca in combination with 25-$(OH)D_3$ had a beneficial effect on improving eggshell quality and reproductive performance in aged egg-type breeder hens.

• International Journal of Industrial Entomology and Biomaterials
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• v.18 no.1
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• pp.1-7
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• 2009

Quality of seed in the mulberry silkworm, Bombyx mori (L.) is determined by many important factors, wherein unfertilized eggs play an important role. Unfertilization of eggs are caused by several reasons such as, abnormality in the sexual organs of the male and female, abnormal development of the micropylar end of the egg, unfavorable environmental conditions during spinning, cocoon preservation, imperfect handling of moths, mating, ovipostion, cold storing of pupae / moths and indiscriminate use of male moths etc. Though the presence of unfertilized eggs would in no way affect the fertilized ones and their quality directly, the frequency of their occurrence underrates the quality and brings down the hatching percentage. Lower the occurrence of unfertilized eggs, higher is the rating of seed quality. Of the various intrinsic and extrinsic factors and events involved in egg deposition of an adult silk moth, mating is an instinct and a biological obligation for the ultimate perpetuation of the species and a must to provide stimulus for oogenesis and bring about biochemical changes in the spermatophore of the silkworm in order to ensure the presence of sufficient number of normal sperms and testicular fluid in the female reproductive organ, activating ovulation and accelerating oviposition behavior and egg deposition. An attempt has been made in this article to briefly elucidate the characteristics of unfertilized eggs, causes of their occurrence and its impact as well as the significance in silkworm seed production.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1662-1668
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• 2005

This review has been done to examine sex-linked dwarf gene in broiler production in hot-humid climates. Introduction of sex-linked dwarf gene especially in hot harsh tropical environments brings a great advantage for broiler production. The heavy broiler parent suffers due to the stress of these adverse climates. Sex-linked dwarf genes reduce body weight, egg weight, but are superior for adaptability under harsh tropical environments, with a lower requirement for housing and feed, better survivability and reproductive fitness giving fewer defective eggs, more hatching eggs, better fertility, hatchability, feed conversion efficiency and resistance to disease. Overall the cost of chick production from dwarf hens is lower than from their normal siblings. Market weights of broilers from sexlinked dwarf dams is almost similar to those of broilers from normal dams with normal sires. But the net benefit of broiler production from sex-linked dwarf dams is found to be greater than that of broilers from normal dams. This will be the most important to the rural communities in Bangladesh and in other countries where the similar environment and socio-economic conditions exist. Therefore, sexlinked dwarf hens might be used in broiler breeding plan as well as broiler production in the tropics.