고지방식이로 식이공급방법을 달리했을때 나이가 다른 흰쥐의 지방대사에 미치는 영향

Abstract

본 연구는 연령이 다른 흰 쥐의 체내 지방대사에, 지방의 중류를 달리한 고지방식이와 식이 공급 방법이 미치는 영향을 알아보고자 계획되었다. 실험동물은 Wistar종의 수컷 흰 쥐로 평균체중이 69.5±4.7g인 4주된 어린 쥐와 283.7± 14.4g인 6개월된 성숙한 쥐 모두 56마리를, 식사의 내용으로 동물성 급원인 버터군과 식물성 급원인 옥수수유군으로 나눈 뒤, 각 지방군에 식이 공급 형태로서 nibbling군과 meal feeding군으로 다시 나눈 뒤 4주간 사육하였다. 식이내 단백질 함량은 무게의 15 %로, 지방함량은 무게의 30 %로 고정하였다. 본 실험의 결과를 요약하면 다음과 같다. 식이섭취량은 성숙한 동물, 버터군, nibbling군이 각각 어린 동물, 옥수수유군, meal feeding군보다 높았으며, 체중증가량은 식이 섭취량과 같은 경향이었으나 어린 동물의 옥수수유군에서 meal feeding군이 nibbling군보다 높은 경향을 보여주었고, 사료효율과 열량효율은 비슷한 경향으로 어린 동물이 성숙한 동물 보다 높은 경향을 나타냈다. 신체내 축적되는 지방함량은 epididymal fat pad의 무게와 같은 경향으로 연령이 높을수록 많이 축적되었으며, 간장과 비장의 무게 그리고 epididymal fat pad내 총지방 함량도 성숙한 동물이 어린 동물에 비해 높은 수치를 나타내었고, efididymal fat pad내의 총콜레스테롤 함량과 변내의 총지방, 총콜레스테롤 및 triglyceride함량은 연령이나 식이 투여 방법에 상관없이 옥수수유를 성취하는 군이 버터를 섭취하는 군보다 높았다. 또한 일일 지방의 섭취량은 버터군이 높았으나 배설량은 옥수수유군이 높았으므로, 결과적으로 지방의 흡수율은 버터 군이 옥수수유군보다 높았으며, 그러한 현상은 어린 동물에게서 더욱 현저 하였다. 혈청내의 총지방, 총콜레스테롤 및 triglyceride함량은 모두 어린 동물에게서 높은 경향을 보여주었으며, 총지방과 triglyceride의 함량은 버터군, meal feeding군이 높았고 특히 버터를 meal feeding하는 군에 유의적으로 높은 반면, 간내 총지방 총콜레스테롤 및 triglyceride의 함량은 각 실험군에서 유의적인 차이가 없었으나, 혈청에서 높았던 버터를 meal feeding하는 군이 모두 낮은 경향을 보여주었다. 또한 혈청의 총콜레스테롤 함량과 low density lipoprotein (LDL)과 high density lipoprotein (HDL) fraction은 모두 각 군간의 유의적인 차이가 없었다. 이상에서 흰 쥐의 지방대사에, 어린 동물에게는 지방종류가 더 큰 영향을 미치고, 성숙한 동물에게는 지방종류와 식이 투여 방법이 모두 영향을 미친다고 할 수 있다.;The purpose of this study was to investigate the effect of the kind of dietary fat and feeding pattern on the lipid metabolism in young and old rats. 56 male rats of Wistar strain were divided into two age groups: young rats weighed 69.5±4.7g; 4 weeks, old rats weighed 283.7±14.4g; 6 months. Each age group were divided into again 2 groups of butter group and corn oil group by lipid source. And then each group were divided into 2 subgroups: meal feeding group and nibbling group by feeding pattern for 4 weeks. All experimental groups were fed with 15% (wt./wt.of diet) of protein and 30% (wt./wt.of diet) of lipid. The result of this study was summarized as following: Food consumptions were relatively high En old rats, butter group and nibbling group compared with young rats, corn oil group and meal feeding group respectively during experimental period. Body weight gains were low in meal feeding group except young rats which were fed corn oil. F.E.R and C.E.R. after four weeks in young rats were higher than old ones. There was high correlation between the weight of epididymal fat pad and body fat deposit. The amount of body fat accumulation by empty carcas was high in old rats compared with young ones. In regard to fat absorption ratio, Butter group revealed higher ratio of lipid absorption than corn oil group and this tendency was clear in young rats. Fecal total Lipid and total cholesterol were significantly higher in corn oil group than butter group irrespective of age and feeding pattern. But triglyceride content was a little higher in corn oil group than butter group. Serum total lipid, total cholesterol and triglyceride content were relatively higher in young rats than old ones. Butter group and meal feeding group were higher in total lipid and triglyceride than others. Irrespective of age in total lipid and triglyceride content, Butter group of meal feeding showed higher values. But there was no significant difference in total cholesterol content. While HDL portion of Lipoprotein faction in serum was high in young rats of corn oil group compared with butter group, LDL portion showed reverse state. But there was no statistical significance and this tendency was not found in old rats. HDL and LDL portion among serum total lipid were higher in old rats than young ones. The weights of liver and spleen of old rats were than young ones and there were no significant differences in lipid sources and feeding pattern. Hepatic total lipid, total cholesterol and triglyceride content were not different significantly in all experimental groups. But it was note worthy that butter group of meal feeding was a little lower than any other group in hepatic lipid composition. Total lipid of epididymal fat pad was relatively higher in old rats than young ones. Total cholesterol of epididymal fat pad was significantly high in corn oil group irrespective of age and feeding pattern. As is stated above, young rats are affected by only lipid source, while old rats are affected by lipid source and feeding pattern in Lipid the metabolism.