초록 ▼

○ 연구결과
1)닭의 스트레스 관련 표지 물질 개발;HSP(HSP90,HMGCR)유전자 발현량,telomere함유율,혈액세포의 DNA 손상율 및 iNOS 등 일부 cytokine유전자 발현량을 가금의 스트레스 측정 표지로 개발
2)산란계 사육 형태에 따른 스트레스 정도 및 생산성 분석;개체의 생산 및 생리적 측면에서 방사사육이 케이지 사육에 비해 보다 바람직한 사육형태로 나타났고 각종 스트레스 마커를 이용하여 분석한 결과 닭의 케이지 사육 형태가 개체들에게 매우 큰 스트레스 요인으로 나타남
3)육계의 사육밀도에 따른

○ 연구결과
1)닭의 스트레스 관련 표지 물질 개발;HSP(HSP90,HMGCR)유전자 발현량,telomere함유율,혈액세포의 DNA 손상율 및 iNOS 등 일부 cytokine유전자 발현량을 가금의 스트레스 측정 표지로 개발
2)산란계 사육 형태에 따른 스트레스 정도 및 생산성 분석;개체의 생산 및 생리적 측면에서 방사사육이 케이지 사육에 비해 보다 바람직한 사육형태로 나타났고 각종 스트레스 마커를 이용하여 분석한 결과 닭의 케이지 사육 형태가 개체들에게 매우 큰 스트레스 요인으로 나타남
3)육계의 사육밀도에 따른 스트레스 반응과 생산성 분석;사육밀도가 증가됨에 따라 TNF-α,iNOS, IL-6,IFN-γ,IL-1β와 같은 친염증 유전자의 발현 증가되고,텔로미어의 함유율이 상대적으로 낮아지며,스트레스 관련 유전자인 HSP 및 HMGCR의 발현이 증가되어 사육밀도가 매우 큰 스트레스요인임을 입증
4)육계에 항산화 물질 첨가 급여에 따른 스트레스 반응과 생산성 분석;비타민 C를 급여할 경우 corticosterone농도가 현저하게 감소되는 것으로 나타나 감염스트레스를 완화하는 효과가 있는 것으로 보여지고,비타민 C 및 E의 첨가 급여가 스트레스 반응에 미치는 영향을 텔로미어 감축율, HSP 유전자 발현율 및 DNA 손상율로 분석한 결과 유의한 스트레스 저감 효과가 있는 것으로 나타남.

Abstract ▼

Ⅳ. Results
1. Telomeric DNA quantity, DNA damage and heat shock protein gene expression as physiological stress markers in chickens
In this longitudinal study with Single Comb White Leghorn chickens, we investigated the effects of stress conditions in birds that were subjected to a high stocki

Ⅳ. Results
1. Telomeric DNA quantity, DNA damage and heat shock protein gene expression as physiological stress markers in chickens
In this longitudinal study with Single Comb White Leghorn chickens, we investigated the effects of stress conditions in birds that were subjected to a high stocking density with feed restrictions on 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. The telomere length and telomere shortening rates were analyzed by quantitative fluorescence in situ hybridization on the nuclei of lymphocytes. The DNA damage rate of lymphocytes was quantified by the comet assay. The expression levels of HSP70, HSP90 and HMGCR genes were measured by quantitative real-time polymerase chain reaction in lymphocytes. The telomere-shortening rate of the lymphocytes was significantly higher in the stress group than the control. The DNA damage also increased in birds raised under stress conditions, as compared to the control group. The stress conditions had a significant effect on the expressions of HMGCR and HSP90α in lymphocytes, but had no significance on HSP70 and HSP90β in blood. We conclude that the telomere length, especially the telomere-shortening rates, the quantification of total DNA damage and the expression levels of the HMGCR and HSP90α genes can be used as sensitive physiological stress markers in chickens.
2. Effect of housing systems of cage and floor on the production performance and stress response in layer
This study was conducted to investigate the effects of housing systems on the productivity and physiological response as stress indicators in White Leghorn chickens. The chickens subjected to the conventional cages had a significantly lower viability, hen-housed egg production, egg weight and body weight compared with those to the floor pens. However, the hens housed in the conventional cages had a shorter day of the first egg and a greater egg quality compared with those housed in the floor pens. In addition, this study was also investigated to identify biological markers for assessing the physiological response of chickens under stress conditions. As biological markers, the amount of telomeric DNA was analyzed by quantitative fluorescent in situ hybridization on the nuclei of cells. The DNA damage rate of lymphocytes was also quantified by the comet assay. The amount of telomeric DNA of the lymphocytes, kidney and spleen was significantly higher in the chickens under floor pens than those under conventional cages. The DNA damage also increased in chickens raised under conventional cages, as compared to the chickens under floor pens. As results, we conclude that the chickens housed in conventional cages have a greater stressful status than those housed in floor pens.
3. Effect of stocking density on the growth performance and the gene expressions associated with stress response in broiler chickens.
Stocking density showed no significant effect on body weight and feed conversion ratio among the different treatments. However, feed intake was significantly (P<0.05) high in the low density treatment. The weights of liver, spleen and thymus were not different among the treatments. The expression levels of cytokines, iNOS, IFN gamma, IL-1, IL-4, IL-6 and TNF alpha were not different among the treatment, but the expression levels of IL-10 was significantly (P<0.05) enhanced in high density treatment when blood, bursa, spleen and liver were analyzed. However the cytokines, iNOS, IFN gamma, IL-1, IL-4, IL-6 and TNF alpha were significantly enhanced in thymus for high density treatment. The expression of IL-4 decreased in low density treatment. In conclusion, high density has very little effect on the immune function. The effect of stocking density on telomere amount in blood, liver, lung, heart and testes tissues was investigated. We hypothesized that increased stocking density in broiler chickens causes increase in stress in the birds and hence would affect the amount of telomere amount in these birds. In results, we found that the amount of telomere decreases with increase in stocking density in blood lymphocytes. HSP70 and HMGCR gene expression levels showed the increasing trend with the increase in stocking density.
Though the expression levels were not significantly different among the low and standard group but were found to be significantly (p<0.05) high in high density stocked group. This clearly indicates that birds stocked at high density were experiencing stress when analyzed at transcription level.
4. Effect of dietary supplementation of vitamin C and E on the growth performance and the stress response in broiler chickens.
There is no significant difference among treatments in body weight, weight gain and feed intake.
The blood biochemical profiles, albumin, ALP, triglycerides (TG) and cholesterol in Vit C supplement groups significantly (P<0.05) increased compared to that of control group. The expression levels of cytokines (IFN gamma, IL-1beta, IL-10 and IL-4) of spleen and thymus were not different among the treated groups. However, the expression levels of IL-1beta, IL-6 and IL-18 in liver were significantly lower in Vit C supplemented birds. The telomere-shortening rate of the lymphocytes was significantly lower in the vitamin supplemented group than the control. The DNA damage also decreased in birds supplemented vitamins, as compared to the control group. The stress conditions had a significant effect on the expressions of HMGCR, HSP90-α and HSP90-β in lymphocytes, but had no significance on HSP70.

목차 Contents

• 표지 ... 1
• 제출문 ... 2
• 요 약 문 ... 3
• SUMMARY ... 9
• CONTENTS ... 13
• 목 차 ... 14
• 제 1장 연구개발과제의 개요 ... 15
• 1절 연구개발의 목적 ... 15
• 2절 연구개발 필요성 ... 15
• 3절 연구개발의 내용 및 범위 ... 15
• 제 2장 국내외 기술개발 현황 ... 18
• 1.세계적 수준 ... 18
• 2.국내수준 ... 18
• 3.국내․외의 연구현황 ... 18
• 제 3장 연구개발수행 내용 및 결과 ... 20
• 1절 닭의 스트레스 관련 표지 물질 개발 ... 20
• 2절 산란계 사육 형태에 따른 스트레스 정도 및 생산성 분석 ... 38
• 3절 육계 사육밀도에 따른 스트레스 관련 표지 물질의 발현 양상과 생산성 비교 분석 ... 60
• 4절 육계에 있어 항산화 물질 첨가 급여에 따른 스트레스 반응과 생산성 분석 ... 76
• 제 4장 목표달성도 및 관련분야에의 기여도 ... 92
• 1절 목표 달성도 ... 92
• 2절 관련 분야 기여도 ... 94
• 제 5장 연구개발 성과 및 성과활용 계획 ... 95
• 1절 연구 성과 ... 95
• 2절 성과활용 계획 ... 99
• 제 6장 연구개발과정에서 수집한 해외과학기술정보 ... 100
• 제 7장 참고문헌 ... 101
• 끝페이지 ... 105