어유와 Casein의 급여가 병아리의 혈액 및 조직의 지방대사에 미치는 영향 = Effects of dietary fish oil and casein on lipid metabolism of plasma and tissues in young chicks

다국어 초록 (Multilingual Abstract)

This study was designed to investigate any interactions between the mechanisms for hypercholesterolemic effect of dietary casein and hypocholesterolemic effect of dietary fish oil(Marinol containing EPA 24.8% and DHA 10.1%) in young chicks. Dietary factors such as casein vs. soy protein(isolated), fish oil vs. soy-bean oil and exogenous cholesterol added at a level of 0.3% of the diets were compared in terms of their effects on plasma and tissue cholesterol levels. Feeding trials were conducted 4 times using Single Comb White Leghorn males of about one-week old. They were fed the test diets for 4 weeks except trial 2 in which the period was 2 weeks. Fourth trial was a duplicate of trial 3 except the way of feeding the diets. Chicks in the former trial were paired-fed to equalize the amount of consumption of the diets containing soy protein on the basis of the ingestion of the casein diets. Measurements were made for feed intake, body weight gain, weight of organs such as liver, heart and kidney for all trials. Plasma levels of triglyceride, various fractions of cholesterol including total, HDL, LDL and VLDL, and fatty acids, as well as levels of total lipids, total cholesterol and fatty acids of various organs were also measured.
Consumption of casein, compared to that of soy protein, led to a remarkable decrease in feed intake and body weight gain as well as feed/gain ratio. However, no significant differences were observed between performances of chicks fed the diets containing fish oil or soybean oil. Liver weight was tended to be heavier in chicks fed the diets containing casein compared to those of soy protein group, and also heavier in dietary groups fed fish oil compared to those of soybean oil groups. Weight of heart and kidney appeared to be less affected by the dietary factors than that of liver. Although chicks paired-fed consumed similar amount of diets, body weight gains of the birds fed the casein diets were still significantly less than those of the soy protein groups(p < 0.05). The weight of organs expressed in terms of 100g body weight was of the same tendency as those of the ad libitum fed groups.
Consumption of casein diets caused significant increase in total cholesterol levels in plasma and that was primarily due to the increase in LDL-cholesterol. Ingestion of the diets added with cholesterol led to a severe hypercholesterolemia mainly due to the increase in the level of plasma VLDL-cholesterol. This reponse was most remarkable in the chicks fed the casein diets. An interesting observation made in this case was that fish oil intake appeared to alleviate extent of hypercholesterolemia significantly at a level of p < 0.05 compared to intake of soybean oil. However, this hypercholesterolemic effect of casein was not obaserved in the chicks fed diets without supplemental cholesterol. Plasma HDL-cholesterol levels were not affected by dietary sources of protein or fat.
Feeding fish oil raised significantly levels of omega-3 fatty acids, particularly of 20:5w3(EPA), in plasma and liver in all feeding trials, meanwhile consumption of soybean oil led to an increase in levels of omega-6 fatty acids, mainly that of 18:2w6. Another interesting observation was that levels of plasma omega-3 fatty acids were much higher in the chicks fed diets added with fish oil and casein compared to the groups on the diets including fish oil and soy protein, which can not be explained at this moment.
It is not clear yet from this study that if there is any interaction between the mechanisms causing hypercholesterolemia by casein and hypocholesterolemia by fish oil consumption. A further study is also needed to elucidate the effect of dietary protein sources such as casein or soy protein on plasma omega-3 fatty acid levels.

목차 (Table of Contents)

• 목차
• 1. 서론 = 1
• 2. 실험내용 및 방법 = 4
• 2-1. 실험목적 = 4
• 2-2. 실험설계 = 5
• 2-2-1). 실험 I = 5
• 2-2-2). 실험 II = 5
• 2-2-3). 실험 III = 7
• 2-2-4). 실험 IV = 9
• 2-3. 실험방법 = 9
• 2-3-1). 실험동물의 사육 및 배치 = 9
• 2-3-2). 사료섭취량 = 11
• 2-3-3). 체중 = 11
• 2-3-4). 사료효율 = 11
• 2-3-5). 사료채취 및 보관 = 11
• 2-3-6). 혈액, 간, 심장 및 신장내 cholesterol함량의 분석 = 12
• 2-3-7). 혈액, 간, 심장 및 신장내 Triglyceride 함량의 분석 = 14
• 2-3-8). 조직내의 총지방함량의 분석 = 16
• 2-3-9). 혈액 및 간의 지방산함량의 분석 = 16
• 2-3-10). 실험 data의 통계 처리 = 17
• 3. 실험 결과 = 18
• 3-1. 실험 I = 18
• 3-2. 실험 I = 18
• 3-3. 실험 I = 25
• 3-4. 실험 I = 36
• 4. 고찰 = 48
• 5. 적요 = 63
• 6. 참고문헌 = 65
• 7. Appendix = 75