• Korean Journal of Ichthyology
• /
• v.32 no.2
• /
• pp.78-83
• /
• 2020

This study aimed to investigate the effects of different water temperature (5, 8 and 11℃) on egg hatch and larval growth of walleye pollock Gadus chalcogrammus to improve rearing techniques for this species. Survival of eggs maintained at 5℃ was higher than that of eggs maintained at 8℃ and 11℃. The greatest hatching rate was obtained for larvae maintained at 8℃. However, time to first, 50% and 100% hatch of eggs maintained at 11℃ was shorter than at 5℃ and 8℃. A higher survival was observed in larvae reared at 5℃ compared to 8℃ and 11℃ and the greatest growth was observed in larvae reared at 11℃ compared to 5℃ and 8℃ during the feeding trial. This study demonstrated the importance of water temperature, as it affects culture performance of eggs and larval pollock. The results from this study provides valuable information for further development of pollock aquaculture.

• Parasites, Hosts and Diseases
• /
• v.54 no.3
• /
• pp.301-305
• /
• 2016

In order to determine the effect of various hosts on feeding performance of Rhipicephalus (Boophilus) microplus, we used 3 mammalian species as hosts, cattle (Qinchuan), sheep (Tan), and rabbits (Japanese white rabbit) for infesting ticks. Five hundreds of R. microplus larvae were exposed to each animal (3 animals/host species). Tick recoveries were 11.0%, 0.47%, and 5.5% from cattle, sheep, and rabbits, respectively. The averages of tick feeding periods were not significantly different on cattle, sheep, and rabbits, 28.8, 25.3, and 26.7 days, respectively. The average weights of individual engorged female from cattle, sheep, and rabbits were 312.5, 219.1, and 130.2 mg, respectively and those of egg mass weights each to 85.0, 96.6, and 17.8 mg. The highest egg hatching rate was in the ticks from cattle (96.0%), followed by those from rabbits (83.0%) and sheep (19.2%). These data suggest that rabbits could be as an alternative host to cultivate R. microplus for evaluating vaccines and chemical and biological medicines against the tick in the laboratory, although the biological parameters of ticks were less than those from cattle.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.11
• /
• pp.1562-1568
• /
• 2016

Monochromatic green light-emitting diodes (LED) light stimuli influences the posthatch growth performance of chicks. This study was undertaken with the following objectives: i) to examine whether the green LED light stimuli induces an overheating effect by determining weight loss rate of fertile eggs during incubation period; ii) to look for the development of eyes and other primary organs at different ages of embryos and newly hatched chicks. Arbor Acres fertile broiler eggs (n = 480) were randomly assigned to 3 incubation groups and exposed to continuous white light, green light, or a dark environment (control) from the first day to 19 d of incubation. The light sourced from LED lamps with the intensity of 30 lx at eggshell level. The results showed that either green or white light stimuli during incubation did not significantly affect the weight loss rate of fertile eggs, hatching time, hatchability, chick embryo, or body weight (BW), the weight percentage of heart, liver, and eyes, as well as obvious systematic abnormalities in eye weight, side-to-side, back-to-front, or corneal diameter from 15 d of embryogenesis to 6 d of posthatch (p>0.05). Compared with the dark condition, green light stimuli during incubation tended to increase feed intake (p = 0.080), improved the BW gain of chicks during 0 to 6 day posthatch (p<0.05), and increased the percentage of pectoral muscle to the BW on 3- and 6-day-old chicks. In addition, embryos or chicks in green light had lower weight percentage of yolk retention on 19 d of embryogenesis and 1 d of posthatch in comparison to those in dark or white group (p<0.05). These results suggest that providing 30 lx green LED light stimuli during incubation has no detrimental effect on the development of eyes, heart and liver of embryos and hatchlings, but does have potential benefits in terms of enhancement of the chick growth during the early posthatch stages. In addition, the fertile broiler eggs stimulated with 30 lx green LED light during incubation does not cause an overheating effect.

• Korean Journal of Poultry Science
• /
• v.48 no.1
• /
• pp.1-12
• /
• 2021

We investigated the effects of breed, laying age, and egg storage period on the vitality of chicks using the Hwanggalsaek Jaeraejong, Korean Rhode Island Red, and Korean White Leghorn chicken breeds. Their eggs were collected during the early laying period (27~29 weeks) and late laying period (50~52 weeks) and were stored for 3 days, 7 days and 14 days. After the eggs hatched, the hatching time, production performance, and organ weight of chicks were investigated. IL-6 gene expression level and relative length of telomeres were analyzed to determine the physiological activity of the chicks. HSP gene expression level and heterophil to lymphocytes ratio were also analyzed to examine the degree of stress response in the chicks. The results showed that breed and laying age influenced the vitality of chicks, but the egg storage period did not. Korean Leghorn chicks were considered the weakest breed in terms of vitality owing to their low survival rate, small heart size, low physiological activity, and high stress response level. Although the survival rate of chicks produced in the early laying period was low, their high physiological activity and low stress response indicated that they had a high vitality than the chicks produced in the late laying period. In conclusion, to obtain chicks with high vitality, it would be desirable to select a high vitality breed and avoid the use of chicks produced in the late laying period.

• Clinical and Experimental Reproductive Medicine
• /
• v.26 no.2
• /
• pp.137-148
• /
• 1999

Purpose of the present study was to find the optimal ovulation induction medicine for the maturation and development of immature oocytes and culture media for 2-cell embryos in the mouse model. ICR female mouse aged 6 to 8 weeks, were stimulated with 5 IU PMSG injection. At 47 to 50 hour post-PMSG injection, ovaries were dissected out and oocytes-cumulus complexes were punctured. The oocyte-cumulus complexes were cultured in media containing various ovulation induction medicine, CC, HMG and Metrodin for 18 hours. Female ICR mice were stimulated with 5 IU PMSG and 48 hours later were injected 5 IU of hCG, then female and male mice were mated. At 48 hour post-hCG injection, oviducts were dissected out and 2-cell embryos were flushed. The 2-cell embryos were cultured in various media, Ham's F-10 media of milli-Q water $(3^{\circ})$, Ham's F-10 media of HPLC (high performance liquid chromatography, Baxter) water, Medicult media, HTF (human tubal fluid) media for 96 hours. The results were as follows. 1. When the oocytes-cumulus complexes were cultured in $10^{-9}{\mu}g/ml{\sim}10^{-8}{\mu}g/ml$ of CC, those were suppressed in meiotic maturation $(28.2{\sim}33.7%)$. Whereas the oocytes-cumulus complexes were cultured in $10^{-7}{\mu}g/ml{\sim}10^{-4}{\mu}g/ml$, these were not effected in meiotic maturation $(54.5{\sim}72.7%)$. 2. When the oocytes-cumulus complexes were cultured in $10^{-4}{\mu}g/ml{\sim}10^{-1}{\mu}g/ml$ of Metrodin, those were suppressed in meiotic maturation $(35.7{\sim}41.5%)$. Meanwhile the oocytes-cumulus complexes were cultured in $10^{-7}{\mu}g/ml{\sim}10^{-5}{\mu}g/ml$, those were not effected in meiotic maturation $(54.2{\sim}70.3%)$. 3. When the oocytes-cumulus complexes were cultured in $10^{-5}{\mu}g/ml{\sim}10^{-4}{\mu}g/ml$ of HMG, those were suppressed in meiotic maturation $(48.2{\sim}50.4%)$. As being cultured in $10^{-7}{\mu}g/ml{\sim}10^{-6}{\mu}g/ml$, increased in meiotic maturation $(75.8{\sim}80.7%)$. 4. When the 2-cell embryos were cultured in Ham's F-10 media of milli-Q water $(3^{\circ})$, Ham's F-10 media of HPLC (high performance liquid chromatograpy, Baxter) water, Medicult media, HTF (human tubal fluid) media, developmental rates to blastocyst and hatching for 96 hour were 50.0%, 45.2%, 71.5% and 95.6%, respectively.

• Journal of Life Science
• /
• v.19 no.11
• /
• pp.1547-1552
• /
• 2009

This study was carried out to evaluate the supplementation effect of dietary natural plant extracts (NP: $Coxynil^{(R)}$, $Growell^{(R)}$ and $Respowell^{(R)}$) on broiler chickens. Forty thousand male broilers with 7 days adaptation after hatching were fed experiment diets for 34 days. The supplementation effects of NP on growth performance, blood parameters and biopsy were examined with twenty thousand broilers as the treatment group. Twenty thousand broilers for the control group (CON) were fed the diet with salinomycin-6, clopidol-25, enramycin-1, and BMD-2.5. In the diet of the treatment group, the antibiotics were replaced with 0.03%, 0.035% and 0.03% of $Coxynil^{(R)}$, $Growell^{(R)}$ and $Respowell^{(R)}$, respectively. The weight gain of the treatment group was increased but the feed intake was decreased, indicating that feed efficiency was increased compared to the CON. The mortality of the NP group was also lower compared to the CON group (1,008 birds to 1,693 birds), showing positive dietary effects from natural plant extracts. In the activity of infectious bursal disease virus (IBDV) and new cattle disease virus (NDV) antibodies, the NP showed lower antibody titer levels for both of IBDV and NDV compared to the CON. The levels of total cholesterol, HDL-cholesterol, globulin, and IgG in blood did not show significant differences between the groups. In the microscopic tissue analysis, no significant differences were detected. These results may suggest that a complex of three natural plant extracts can be used as alternative antibiotics in broilers.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.47 no.1
• /
• pp.76-87
• /
• 2019

The purpose of this study was to evaluate the performance of and to derive future maintenance-management measures of the constructed alternative habitat for the Kaloula borealis at the University of Seoul, examining the period between 2015-2017. The research was constructed in 2014 and in a $191m^2$ area. The performance evaluation was divided into maintaining the habitat of the target species, maintaining the population and reproduction rates of the target species, maintaining the habitat of the wild species, the resilience of natural ecosystems, and the harmony with the surrounding environment. In terms of maintaining the habitat of the target species, soil collected from the existing habitat of the Kaloula borealis and was the depth was increased to 30cm in the alternative habitat. An artificial water supply was required every year during the supporting the spawning and hatching of other amphibians along with the Kaloula borealis. The sources of water of the alternative habitat were both rain and tap water, as it cannot be maintained naturally. Additionally, the Kaloula borealis thrived because it inhabited the research site and the average temperature was $26.2^{\circ}C$ from April-June, which is when the Kaloula borealis spawns. In terms of maintaining the population and reproduction rates of the Kaloula borealis, they were evaluated to have stable rates of reproduction. In terms of maintaining the habitat of the wild species, studies on vegetation and the structure of the characteristics of prey or predators will be needed. Also, alien species, such as Humulus japonicus and Bidens frondosa needed to be removed to maintain the wetland ecosystem of the wild species. In the assessment of the resilience of the natural ecosystems, the mud was monitored, noting the changes in the depth of water, with steps taken to reduce the leakage of water. The mud collected from the Haneul Pond wetland, which is located around the research site was piled up. Also, partial mowing management and the inducement of a natural vegetation colony was required for vegetation management. It was also necessary to create porous spaces, such as old trees and tree branches to create a habitat with hiding places and feeding and spawning places for small organisms. In terms of the harmony with the surrounding environment, the following threat factors needed to be managed: amphibian roadkill by vehicles and pedestrians and artificial draining due to nearby user access. Based on the monitoring results, alternative habitat management measures presented the promoting various waterside structures, in which amphibians can spawn and hide in, managing the water environment consistently, managing the vegetation, focused on the habitat of the wild species, and managing the surrounding environment for the habitat. The creation of an alternative habitat should be managed through monitoring, reflecting the characteristics of the changes in the site. Also continuing efforts are also needed to improve the habitat of the target species.

• Korean Journal of Poultry Science
• /
• v.50 no.4
• /
• pp.303-310
• /
• 2023

The current study was conducted to compare the effect of crossbred on the body weight and laying performance of Korean native chicken from hatch to week 40. A total of 873 one-day-old chicks were divided into twelve crossbreds (i.e., CFCK, CFYC, CFYD, CKCF, CKYC, CKYD, YCYD, YCCF, YCCK, YDCF, YDCK, and YDYC) and commercial layer (Hy-Line Brown) were obtained as a counterpart in the study. All the birds are raised in battery cages (76 × 61 × 46 cm³) and then raised until 14 weeks and subsequently moved to layer battery cages (60 × 25 × 45 cm³) and raised until 16 weeks. The body weight and viability were measured biweekly from hatching to week 16. The week of 16, body weight range was about 1,010.24 to 1,411.77 g. The body weight of specific crossbreeds (i.e., CKCF, YCYD, and YDYC) was found to be comparable to that of Hy-Line Brown). The viability hatch to week 14 range was about 55 to 100% and however week 14 to 16 range was 80 to 100%. The crossbred (i.e., CKCF) recorded superior (P<0.05) viability throughout the whole experiment period, even compared with Hy-Line Brown (100% vs 96%). Our results are indicating that crossbreds Korean native chicken including CKCF, and YDYC has the potential to enhance key features of laying hens during the growing phase like optimal body weight and higher viability.

• Korean Journal of Ichthyology
• /
• v.31 no.1
• /
• pp.7-15
• /
• 2019

The present study aimed to investigate the influence of starvation on growth, survival and swimming ability of Pacific cod Gadus macrocephalus larvae. Notochord length, musculature height, body depth, gut height and volume of yolk of reared larvae were measured to determine the growth parameters. A significant difference was observed in all morphometric characteristics before 15 DAH (days after hatching). Body depth and volume of yolk of unfed larvae were significantly smaller than those of fed larvae from 9 DAH (P<0.05). Almost all yolk in fed group was consumed at 11 DAH. Survival and growth of larvae were observed to determine the effect of delayed initial feeding (2 DAH, 3 DAH, 4 DAH, unfed). All larvae in the unfed group died by 15 DAH and the larvae in other experimental groups survived until the end of the experiment to 21 DAH. Survival rate was not significantly different between the 2 DAH group ($17.5{\pm}4.27%$) and the 3 DAH group ($20.5{\pm}1.5%$) at 21 DAH (P>0.05). However, there was a significant difference in survival rate between the 3 DAH group and the 4 DAH group ($11.7{\pm}1.52%$) (P<0.05). There was no significant difference in notochord length among the groups fed from 2 DAH, 3 DAH and 4 DAH at 21 DAH (P>0.05). The swimming ability in fed group gradually increased in both cruising and burst swimming speeds, while those abilities in unfed group gradually decreased after reaching the peak at 6 DAH in both cruise ($18.7{\pm}6.56mm/s$) and burst swimming speed ($43.5{\pm}12.65mm/s$).