• Korean Journal of Animal Reproduction
• /
• v.20 no.1
• /
• pp.71-76
• /
• 1996

This experiment was carried out to investigate the developmental ability of bovine embryos matured and fertilized in vitro to the gastrulation stage. The bovine oocytes were collected from 2∼5mm follicles, matured for 20∼24hrs in 5% CO2 incubator and then fertilized with frozen-thawed semen. On day 9 after IVF and after freezing and thawing the hatching abilities of expanding blastocysts were examined. Cleavage rate and production rate to expanding blastocysts were 59.7%(955/1604) and 20.7%(333/1604), respectively. Hatching rate of day-9 expanding blastocysts was 54%(40/74), that after freezing and thawing was 56%(79/141). Also, developmental ability of hatched blastocysts to the primitive streak stage was 26%(6/23).

• The Korean Journal of Ecology
• /
• v.6 no.1
• /
• pp.55-65
• /
• 1983

The authors reared the ash-gray leaf bug, Piesma maculata in the growth cabinet controlled as temperature groups of $15, 20, 25, 30, 40^{\circ}C$under condition of photoperiod 16L:8D, light intensity $510{\pm}240$ lus, relative humidity $65{\pm}3%$, and analyzed the effects of temperature on the development of the insect. The results are summarized as follow: There are highly significant differences the developmental periods for the temperature groups, and between the developmental periods for the developmental stages. The egg in the temperature of 15 and $40^{\circ}C$ was hatched, but the ecdysis was impossible. The thermal threshold was $12.34^{\circ}C$and the upper lethal temperature $40.39^{\circ}C$. The total developmental periods of egg to adulate in the temperature of 20, 25, 30 and $35^{\circ}C$are 40.52, 22.37, 15.91 and 13.00 days, respectively. That is, the developmental period was decreased, as the temperature was increased. In the developmental period for the developmental stages, the developmental period of egg stage was longer than that of 25, 30 and $35^{\circ}C$, and that of 25。C was longer than that of $35^{\circ}C$. But ther was not significant differences between the developmental periods for the other temperature group. The rate of hatch at$20^{\circ}C$is the greater value as 90%, and the rates of 25, 30 and $35^{\circ}C$ are 79, 79 and 67%, respectively. That is the rate of hatch was decreased, as the temperature was increased. The mortality in the temperature of $35^{\circ}C$ is the greatest value as 68%, and those of 30, 25 and $20^{\circ}C$are 59, 59 and 41%, respectively. That is, the mortality was increased, as the temperature was increased. There was not significantly differences between the developmental period of female and male.

• The Korean Journal of Malacology
• /
• v.19 no.2
• /
• pp.107-110
• /
• 2003

The effect of broodstock age on the spawning performance of cultured abalone, Haliotis discus hannai, was assessed for five age groups (3, 4, 5, 6, 7 years old). Spawning performance of the five age groups was assessed in terms of the percentage of spawning abalone, eggs per spawning female, fertilization rates, hatch rates and attachment rates per spawning. The percentage of spawning abalone increased along with broodstock age, reached maximum in female groups of 5- and 6-year age (60%), and in male group of 6-year age (100%), subsequently decreased in 7-year age group. The number of eggs produced per spawning also increased with broodstock age, and the maximum was found in 6-year age. Although the number of spawned eggs for the oldest abalone declined, it still spawned much more eggs than 3, 4, and 5 years old females. The fertilization and hatch rates were obviously larger for 4-6 years old group than the younger and older abalones. The maxima were found in 5-year age group (96.0% and 84.5%), and the minimum were appeared in 7-year age group (79.3% and 58.2%). The attachment rate increased with broodstock age, reached maximum in 6-year age group (33.6%), although the increment gradually declined. The attachment rate for 7-year age group rapidly decreased (16.6%). These results suggested that broodstock age affected the spawning performance of H. discus hannai, which peaked between 5 and 6 years old, and broodstock should be bred during this period for hatchery production.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2006.11a
• /
• pp.86-87
• /
• 2006

The hatchery sanitation has a significant impact on chick quality. This study was carried out to investigate the bacterial contamination in the broiler hatchery. The aerosol bacterial contamination was low except for the operating hatcher that the bacterial counts were measured almost over 300 counts/64cm$^{2}$. The bacterial contamination of the facilities and equipments had a similar tendency as compared with the aerosol bacterial contamination. More than six groups of the Salmonella species were isolated almost from the hatcher and the related facilities and equipments. Also, in this study, we compared the effects of four methods of 37% formalin adminstration in hatcher. At hatch, the aerosol bacterial counts in hatcher receiving 37% formalin as constant rate infusion method during hatching were significantly lower than in each hatcher receiving 37% formalin once at transfer and not receiving 37% formalin, respectively(p<0.05).

• Journal of Microbiology and Biotechnology
• /
• v.24 no.11
• /
• pp.1510-1515
• /
• 2014

Lysobacter capsici YS1215 isolated from soil previously showed nematicidal potential for biological control of the root-knot nematode. In this study, lactic acid, a nematicidal compound, was isolated from culture filtrate of YS1215, and its ovicidal activity was investigated. Purification and identification of lactic acid were performed by a series of column chromatographies and identified by $^1H$ and $^{13}C$ NMR spectra and GC-MS analysis. Our results showed that bacterial culture filtrate containing lactic acid significantly inhibited egg hatching. The lowest egg hatch rate (5.9%) was found at a high concentration ($25 {\mu}l/ml$) of lactic acid at 5 days after incubation, followed by 20 (15.2%), 15 (23.7%), 10 (29.8%), and $5(36.4%){\mu}l/ml$, while egg hatching in the control (sterile distilled water) was 44.5%. This is the first report of lactic acid as an ovicidal compound, and it may be considered as an alternative of chemical pesticide against root-knot nematodes.

• Journal of Aquaculture
• /
• v.13 no.1
• /
• pp.69-78
• /
• 2000

Bioactivity growth and survival rte of yolk sac larvae in cultured black seabream (Acanthopogrus schlegeli) red seabream (Pagrus major) and olive flounder (Paralichthys olivaceus) to 5 different concentration (0, 25, 50, 75 and 100%) of water soluble fraction (WSF) of Kuwait crude oil were studied. The 75% and 100% of WSF concentration influenced negatively on the length growth of larvae in each species so the growth rates of total length in the concentration of WSF were significantly lower than those of control. The high concentration (50%, 75%, and 100%) of WSF influenced negatively not only on the swimming frequency and speed but also on the morphological abnormality of larvae. Red seabream larvae showed the highest rate of abnormality by WSF among the tested fishes. The fish larvae exposed during pre-and post-hatch (egg and larval stages) and during post-hatch (larval stage only) to the WSF were significantly influenced on their survival rate. The larvae of red seabream were more sensitive to WSF than those of black seabream and olive flounder. The survival rates of larvae exposed to higher concentration (50%, 75%, and 100%) of WSF were significantly lower than those of the control but those of the 25% group were not.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.6
• /
• pp.881-887
• /
• 2011

Feathers are one of the integument appendages that form the outer covering, or plumage, on birds. The goslings hatch with a downy coat of feathers formed in embryonic development. They moult the natal plumage into juvenile feathers between 3-5 weeks of age and than moult that juvenile plumage into adult plumage between 8-11 weeks of age. Feather weight of an adult goose makes up about 6.2% of its total body weight. Heritability of the feather production ability is relatively low ($h^2$ = 0.35). Within species or genotype, the quantity and composition of the plumage are affected by genetics (age, body weight or body surface area, feathering rate, sex) and environmental factors (nutrition and production system, weather, microclimate). After slaughter some 90-220 g marketable feathers can be obtained per goose. The yield of feathers and down from each hand-harvesting amounts to between 80 to 120 g per goose, depending upon the frequency and degree of completeness of the harvesting.

• Structural Engineering and Mechanics
• /
• v.3 no.4
• /
• pp.341-358
• /
• 1995

The results of a series of ten W-shaped test specimens subjected to monotonic, quasi-static cyclic loading and fatigue type of loading in the form of constant amplitude tests are presented. The objectives were to assess and compare the rotation capacity and energy absorption of monotonically and cyclically loaded beams, and for the latter specimens to document the deterioration in the form of low cycle fatigue due to local buckling. In addition, strength and energy dissipation deterioration and damage models have been developed for the steel beam section under consideration. Finally, a generalized model which uses plate slenderness values and lateral slenderness is proposed for predicting rate in strength deterioration per reversal and cumulated damage after a given number of reversals.

• Development and Reproduction
• /
• v.16 no.2
• /
• pp.107-112
• /
• 2012

Early growth, the rate of yolk sac absorption, and nucleus size in liver parenchymal cells were correlated with the nutritional status of first feeding larval haddock, Melanogrammus aeglefinus. Larvae that successfully began exogenous feeding maintained high growth rates, delayed yolk sac resorption, and had larger hepatocyte nuclear sizes than starved larvae. At 10 days post hatch (DPH) the cumulative mortality in the starved larval haddock group was 100%. The area of the hepatocyte nuclei in starved larvae gradually decreased, reaching its lowest value by 9 DPH. Our results support the current practice of providing the first food supply at 3 DPH. Hepatocyte nuclear size can be used to assess larval haddock nutrition status, and may be a good criterion for assessing the success of transition from endogenous to exogenous feeding.

• Journal of Embryo Transfer
• /
• v.23 no.1
• /
• pp.1-4
• /
• 2008

This study was performed to investigate the effect of laser-assisted hole in the zona pellucida (ZP) of frozen-thawed ICR mouse embryos on the process of hatching that is critical for expanded blastocysts to implant into endometrium, Vitrification medium, composed of ethylene glycol and sucrose supplemented with 7.5% (w/v) PVP, was used to freeze $2{\sim}4$ cell stage embryos recovered from oviducts of superovulated and mated female mice before storing them in $LN_2$. Right after thawing them, a laser beam was shot to make a hole in ZP followed by culturing in KSOM for $96{\sim}120\;hr$ and examining development to blastocyst and hatching every 12 hr. Laser-treated embryos showed significantly higher hatching rate compared to control (92.9% vs. 22.1%, p<0.05). From around Day 4, blastocysts developed from laser-treated embryos started hatching while the blastocysts of control group failed to hatch showing a lot of shrinkage. This study shows that a laser-assisted hole in ZP improves the hatching rate of blastocysts developed from frozen-thawed, in vitro cultured ICR mouse embryos.