• Science of Emotion and Sensibility
• /
• v.2 no.1
• /
• pp.137-145
• /
• 1999

열 두 명의 피험자가 안정상태 일 때, 백색 소음에 노출되었을 때, 백색 소음 하에서 기억과제에 주의를 기울일 때, 백색 소음 하에서 기억 검사를 받을 때, 기록된 뇌파에 대해 relative power spectrum 분석을 하였다. 뇌파는 전두, 측두, 후두 영역에서 단극 유도법으로 기록되었다. 분석 결과, 백색 소음에만 노출되었을 때나, 백색 소음 하에서 기억과제에 주의를 기울일 때나 비슷한 전기피질(electrocortical) 반응이 나타났다. 즉, delta power의 증가, 알파 blocking, fast beta power의 증가, 스트레스를 일으킨다고 피험자들이 평정한 배색 소음 하에서 기억검사를 받을 때에도 동일한 뇌파 패턴이 나타났지만 그 크기가 유의하게 컸다. 정보를 지각할 때 전형적으로 나타나는 반응을 유발하는 스트레스원에 수동적으로 노출되었을 때("intaki"상황)의 생리 반응과 스트레스 상황에 적극적으로 대처할 때("rejection")의 생리 반응을 구분하는 이론 틀 아래서 데이터를 해석하였다. 스트레스 후 기간에 대부분의 뇌파 변수들이 기저선 수준으로 회복된 것으로 보아 사용한 스트레스 유발 모델은 단기적 스트레스 반응만을 유발한 것으로 보인다. 이는, 더 장기적으로 지속되는 스트레스원을 사용하게 되면, tonic상태의 전기피질 반응이 나타날 것을 시사한다.기피질 반응이 나타날 것을 시사한다.

• Korean Journal of Poultry Science
• /
• v.47 no.4
• /
• pp.219-227
• /
• 2020

As the earth's average temperature rises, crop and livestock productions are at risk. Chickens are sensitive to heat stress, and increased temperatures may have adverse effects on their production performance and animal welfare. Reliable stress measurements are crucial for heat stress adaptation. Therefore, various measurement methods and biomarkers are used to evaluate poultry stress levels. Heat shock proteins (HSPs) are heat sensitive biological markers that are highly expressed under stress, thereby acting as a cellular thermometer. HSPs also have chaperone activity, which protects cells from heat stress. This review details the role of HSP70 as a molecular chaperone and biomarker for heat stress, which is important for breeding climate-adaptable, thermo-tolerant poultry.

• Korean Journal of Poultry Science
• /
• v.42 no.2
• /
• pp.157-167
• /
• 2015

We compared the degrees of stress response of 12 domestic purebred chicken strains that have been bred at National Institute of Animal Science, RDA, Korea since 1980. As a physiological marker of stress response, the expression levels of heat shock protein (HSP)-70, HSP-$90{\alpha}$, HSP-$90{\beta}$, hydroxyl-3-methyl-glutaryl coenzyme A reductase (HMGCR) genes and telomere length were measured by quantitative real-time polymerase chain reaction using the lymphocytes of 1,101 chickens. There was significant difference in HSP-70, HSP-$90{\alpha}$, HMGCR expression and telomere length among the strains. There was also significant difference in HSP-$90{\alpha}$, HSP-$90{\beta}$, and HMGCR expression between male and female chickens. Different age groups of chicken exhibited different expression levels of HSP-70, HSP-$90{\alpha}$ and telomere length. The results of the HSPs expression level suggested that, the strains of R, L and Y were highly resistant to stress, whereas the strains of S, O and W were susceptible to stress. Although the statistical differences in some of HSPs gene expression existed between genders, the HSP expression results varied in different strains that some opposed to the others, and there might be interaction between strains and genders, which conclude that there was no difference in stress response between male and female chickens. Moreover, despite of significant difference in some of HSPs expression level, it was considered that there was no difference in stress response between ages due to the inconsistent trends among HSP markers.

• Korean Journal of Poultry Science
• /
• v.46 no.2
• /
• pp.77-86
• /
• 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 the Korean Applied Science and Technology
• /
• v.35 no.3
• /
• pp.807-815
• /
• 2018

This study was investigated the effect of dietary probiotic mixture on blood biomarkers, immune responses, caecal microorganism and productivity in broiler chickens under heat stress (HS). A total of 400 broiler chick males (Ross 308) were divided into four groups of 100 heads each, group C (control, room temperature $25^{\circ}C$), HS (heat stress $33^{\circ}C$) and HSP (HS plus probiotic mixture 500, 750 mg/kg of diet), respectively. Broiler body weight gain, feed intake, feed conversion ratio and immune organ weight increased in the HSP group compared to the HS group. The concentrations of blood IgG and lymphocyte were increased in the HSP group compared to the HS group, and the heterophil:lymphocyte (H:L) ratio, corticosterone concentration and mortality were low. Lactobacillus in the cecum increased in the HSP group compared to the HS group, but was lower in Escherichiacoli (E. coli), coliform bacteria and aerobic bacteria. These results indicate that feeding probitic mixture including three strains such as B. subtilis, S. galilaeus and Sphingobacteriaceae to broiler exposed to heat stress can improve production with lowering mortality by improving immune response and microbial balance.

• Proceedings of the KAIS Fall Conference
• /
• 2006.05a
• /
• pp.449-452
• /
• 2006

본 논문에서는 전장부품에서 중요한 연결 장치인 커넥터의 고장 모드를 분석하기 위한 방법으로 HALT(Highly Accelerated Life Test)를 이용해 관측된 고장 데이터를 기반으로 ReliaSoft사의 소프트웨어인 ALTA PRO를 이용하여 분석하고자 한다. 커넥터를 이루는 주재료는 플라스틱과 금속으로 구성되어 있어 습도에 대한 반응 보다 열 변화와 진동에 의해 고장이 발생 한다. 이러한 커넥터의 특성을 고려하여 HALT는 온도와 진동 스트레스를 이용한 복합 스트레스 시험을 실시하였다. HALT에 사용된 시료는 20핀 커넥터 5개로 74시간 동안 시험하였으며, 9개의 핀에서 부러지는 고장이 관측 되었다. 관측된 고장 데이터를 단일 스트레스에 의한 고장으로 분석하기위해 시험에 사용된 온도와 진동 스트레스를 개별 스트레스로 하여 ALTA PRO를 이용하여 분석하였다. 분석을 위한 수명-스트레스관계식은 스텝 스트레스에 적합한 Cumulative Damage 선택하였으며 Likelihood Function을 이용 최적 분포는 Weibull 분포임을 확인하였다, ALTA Pro를 이용한 분석 결과 열에 대한 Mean Life는 2444.03 시간이며, 진동에 대한 Mean Life는 1784.27시간으로 진동에 대한 Mean Life가 659.76 시간만큼 작은 것을 확인 하였다. 고장 데이터를 이용한 수명 예측에서 Mean Life가 작다는 것은 스트레스에 의해 고장이 빠르게 발생 했다는 것을 의미한다. 가속수명시험을 통해 관측된 커넥터의 고장은 핀이 부러지는 현상이며, 고장에 대한 주요 원인으로 온도 스트레스 보다 Mean Life가 낮은 진동 스트레스인 것으로 판단된다.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2017.10a
• /
• pp.58-58
• /
• 2017

• Korean Journal of Poultry Science
• /
• v.41 no.2
• /
• pp.115-125
• /
• 2014

With Single Comb White Leghorn (WL) and Korean Native Chicken (KNC) breeds, we compared the stress response with chicken breeds that were subjected to a high stocking density. Stress response was analyzed by the quantity of telomeric DNA, the rate of DNA damage and the expression levels of heat shock proteins (HSPs) and hydroxyl-3-methyl-glutaryl coenzyme A reductase (HMGCR) genes on tissues and blood. The telomere length and telomere shortening rates were analyzed by quantitative fluorescence in situ hybridization on the nuclei of lymphocytes and tissues. The DNA damage rate of lymphocytes was quantified by the comet assay. The expression levels of HSP70, HSP90-${\alpha}$, HSP90-${\beta}$ and HMGCR genes were measured by quantitative real-time polymerase chain reaction in lymphocytes. There was no significant difference between KNC and WL in body weight, weight gain, telomere shortening rate and DNA damage rate. However, the growth rate significantly decreased in chickens raised under high stocking density conditions, as compared to the control group. The telomere-shortening rate, DNA damage and HSPs expression of the lymphocytes were significantly higher in the high stocking density group than the control. The stress condition and breeds had a significant effect on the expressions of HSP70, HSP90-${\alpha}$ and HSP90-${\beta}$ in lymphocytes, except HMGCR. The stress response of WL was higher than that of KNC, as analyzed to the expression of HSP70 and HSP90-${\alpha}$. Therefore, we concluded that the chickens which were exposed to a high stocking density had increased the individual physiological stress response regardless of breeds, and White Leghorns are more susceptible to stress condition than Korean Native Chickens.

• Journal of the Korean Applied Science and Technology
• /
• v.35 no.3
• /
• pp.787-796
• /
• 2018

This study was conducted to investigate the effects of probiotic mixture on fecal ammonia, caecal microorganism, immune response, egg quality and production in layer under heat stress (HS).A total of four hundred 50 week olds Hy-Line Brown layers were randomly divided into four groups of 100 heads each: C (control, room temperature $25^{\circ}C$), HS (heat stress $33^{\circ}C$), PM (HS plus probiotic mixture 500, 750 mg/kg of diets). Egg production, egg quality, spleen weight, blood IgG and lymphocyte concentrations were increased in the PM group compared to the HS group, while mortality, the heterophil:lymphocyte (H:L) ratio, and corticosterone levelswere significantly decreased. Lactobacillus was increased in the PM group compared to the HS group, but E. coli, coliform bacteria and aerobic bacteria were significantly reduced. Fecal ammonia production was significantly increased in the HS group compared to the PM group. In conclusion, the results of this study that these mixed probiotics can reduce the heat damage of the summer laying hens and can be an effective nutritional strategy to reduce odor generation from feces, and to improve egg quality and laying production through immune response and caecal microbial balance.

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2004.05a
• /
• pp.272-273
• /
• 2004