식이내 함유된 동식물성 지방의 수준이 흰쥐의 체내대사에 미치는 영향(Ⅱ)

Abstract

In order to recommend dietary lipid content, this study was designed to elucidate fat metabolism in terms of fat accumulation in the body and serum lipid content on rats fed by different levels ana s ources of lipids contained in the experimental diets. Different levels of Lipid in the experimental diet were 3%, 6%, 9%, l2%, 15%, 18%, 21%, 24%, 30%, 36%, 42% respectively. Two different lipid sources, soybean oil, representing vegetable oil and soybean oil plus beef tallow in the proportion of 50: 50 representing mixed vegetable and animal sources were included in this study. Hundred sixty-one Sprague-Dawley rats weighing 72±0.2g were divided into two droops. One for soybean oil diet and the other for mired diet, soybean oil plus beeftallow, containing 77 rats each. Each group was subdivided into eleven different experimental groups, 7 rats each, according to the Levels of dietary lipid,3%, 6%, 9%, l2%, 15%, 18%, 21%, 24%, 30%, 36%, 42% respectively. Seven rats designed as initial group were sacrificed at the beginning of this study. Food consumption of experimental animals were controlled by pair-feeding in order to feed same amount of calories drived from eleven different Levels of lipid in the experimental diets resulting different calorie values of per gram of mixed diets. The duration of this experiment was ten weeks. The amount of food intake, calorie intaker and body weight gain were measured to calculate protein efficiency ratio and calorie efficiency ratio. And epididymal fat pad was measured. The ratio of fat absorption was calculated by the difference between fat intake and fat excretion in the feces. Total body carcass analysis was carried out to analyze body chemical composition such as protein, fat and water content expressed in percentage. Total Lipid and cholesterol in serum were also analyzed. The result of this study was summarized as follows ; A. Experimental animals fed soybean oil plus beeftallow diets at the el even different levels of Lipid showed higher in protein efficiency ratio value than the animal fed soybean oil diet. Protein efficiency ratio, body weight gain and calorie efficiency ratio s bowed statistically insignificant differences. B. In regard to fat absorption ratio calculated by differences between fat intake and excretion in the feces, soybean oil fed group revealed higher ratio of lipid absorption comparing these reapects of soybean oil plus beeftallow fed groups. The Levels of dietary Lipid content certainly effected absorption of lipid in the study. It was noteworthy that most of the animals fed more than 6% dietary soybean oil increased significantly lipid absorption ratio. In comparing the lipid absorption ratios between animals fed less than 6% and more than 6% dietary soybean oil. animals fed Less than 6% soybean oil groups showed only 80% lipid absorption ratio and the other were more than 90-97%. C. In contrast to the result of Lipid absorption ratio, the animal fed soybean oil plus beeftallow accumulated more total body lipid than animals fed soybean oil alone. Concerning the dietary level of lipid content, lipid accumulation didn't affect by fat consumption amount. In other word increasing the dietary level of lipid from 3% to 42% gradually didn't increase body fat accumulation. The weight of epididymal fat pad didn't reflect all the time the lipid content in the diet consumed. Author expected more protein accumulation in the body of the experimental animals fed by soybean oil diet to counterbalance of the body total composition. But these expectation turned out to be reversed. Still the animals fed by soybean oil plus beeftallow showed higher in the protein and the water content in the body as result of the total body composition. D. To observe circulating Lipid content in the experimental animals, serum total lipid and total cholesterol were analysed. When diet contained sole source of lipid such as soybean oil diet showed higher serum total lipid compared to the mixed lipid, soybean oil plus beeftallow contrasting to the body accumulation of fat. If diet contained less than 6% of lipid, serum total lipid content showed less in the soybean oil fed animals than that in mixed oil fed animals. In case of sole source of lipid fed to the experimental animals, for example 9% soybean oil diet fed animals showed higher total serum lipid content than 18% soybean oil and beeftallow fed animals. These two groups of animals resulted to feed same amount of soybean oil. In other word mixed diet fed animals fed 9% soybean oil and 9% beeftallow. This result double amount of lipid feeding in addition to the same amount of soybean oil consumption in the beeftallow and soybean oil fed animals. Same result showed in the total serum lipid content, in other comparisons such as 12% soybean oil and 24% soybeanoil plus beeftallow, 15% soybean oil and 30% soybean oil plus beeftallow, 18% soybean oil and 36% soybean oil plus beeftallow and 21% soybean oil and 42% soybean oil plus beeftallow. When soybean oil alone is included as the dietary, lipid sources, the total serum lipid will increase and total body fat accumulation decrease at any levels of lipid in the diet of this experiment. Considering the results produced in this study, you can recommend two different aspects. If you want to decrease the serum total lipid, mixed lipid diet such as soybean oil plus beeftallow are recommendable. Meanwhile soybean oil only as dietary lipid source is recommendable to decrease body fat accumulation. Determinating the dietary lipid level, as soybean oil only, body fat accumulation, fat absorption ratio, and total serum lipid content showed the lowest value at dietary lipid level, 6% or less of total calorie intake. In case of mixed, animal and vegetable Lipids consumption, 3% or less dietary fat of total calorie intake is recommendable amount included in the diet. Fat accumulation is increased 3% and 6% or more, up to 42% of total calorie intake. Fat accumulation and total serum lipid picture have same metabolic ratio at any levels of dietary fat between this range of this study.;본 연구는 식이내 첨가된 지방의 종류 및 수준이 체내의 지방축적 및 지방대사에 미치는 영향을 비교 연구하여서 식사내에 함유시켜야 하는 지방의 권장량을 알아보고자 하는데 그 목적이 있었다. 그래서 Sprague-Dawley 종 수컷 흰쥐 161마리를 각 군당 7마리씩 23군을 나누어 식이내 지방의 종류를 달리하여 식물성 지방 단일 급원인 대두유군과 식물성과 동물성 지방이 50:50으로 섞인 대두유+우지군으로 나누고 식이내 지방이 차지하는 열량비를 3%에서부터 42%까지 11단계로 세분하여 총 10주 동안 pair-feeding으로 사육하여 식이내 함유된 지방의 양에 따른 체내 대사상의 여러 문제를 알아 보았다. 식이내 지방의 종류와 함유율에 따른 성장 효과를 관찰하기 위해 단백질 효율 열량효율 및 체중을 측정하였고 체내 지방 대사의 변화를 관찰하기 위해 변을 채취하여 지방 배설량과 지방 흡수율을 측정하였으며 실험 식이에 따른 체구성 성분의 영향을 알아보기 위해 체내 총지방량과 총단백질량, 총수분 함유율을 측정하였으며 체내 유동 지방을 알아보기 위해서 혈청내 총지방량과 총 Cholesterol 양을 측정하였다. 그 결과를 요약하면 다음과 같다. A. 단백질 효율은 대두유+우지군이 대두유군보다 동일 수준 지방군에서 다소 높은 경향을 보였으나 단백질 효율, 체중 증가량 및 열량 효율 모두는 각 실험군 간에 유의적인 차이가 없었다. B. 변의 양은 식이내 함유된 지방의 수준의 고하를 마론하고 거의 비슷했으며 같은 양의 변속에서 대두유+우지군이 대두유군에 비해서 많은 양의 지방을 함유하고 있어서 결과적으로 지방의 흡수율은 대두유군이 보다 현저히 높았고 식이내 지방의 함유 수준에 따라서도 그 증가 양상은 뚜렷하였다. C. 그러나 한편 대두유군이 대두유+우지군에 비해서 지방의 흡수율이 높은데도 불구하고 체내 총지방량은 그 반대로 대두유+우지군이 대두유군보다 높은 결과를 나타냈으며, 식이내 지방의 함량에 따라서 큰 차이가 나타나지 않았다. epididymal fat pad 무게 역시 지방의 함량이 높아진다고 반드시 높아지는 결과를 보여주지는 않았다. 체내 총단백질량 역시 대두유+우지군이 대두유군보다 높은 경향을 나타냈으나 유의적인 차이는 나타나지 않고 체내 수분 함유율도 모든 군에서 유의적인 차이는 나타나지 않았다. D. 혈청내 총지방량과 총 Cholesterol 양은 각 실험군 간에 유의적인 차이는 나타나지 않았으나, 대두유군에서는 혈청내 총지방량은 식이내 함유된 지방이 9%이상이 되면 그 이하와 비교해서 현저히 높은 값을 나타냈으며 또한 같은 수준 지방군에서는 대두유군이 대두유+우지군에 비해서 더 높은 경향을 나타내었다. 뿐만아니라 식이내 지방의 함량이 9%이상이 되면 단일 급원인 대두유만으로 섭취한 경우가 대두유+우지 즉 단일 급원으로 섭취한 양만큼의 대두유를 섭취하고 거기에 부과해서 동량의 우지를 또 섭취한 경우보다 혈청 지방량이 더 높게 나타났다. 위의 결과를 종합해보면 순 식물성 지방을 식사내 지방 섭취 급원으로 하면 체내 지방 축적율은 떨어지고 반면에 혈청내 총지방량은 증가하는 결과여서 혈청내 총지방량을 감소시키고자 할 경우에는 단일 급원으로 대두유나 우지만으로 섭취하기 보다는 식물성 지방과 동물성 지방을 혼합하여 섭취하는 것이 더 나은 것으로 나타났다. 또한 본 연구에서 목적하였던 식이내 지방의 함유 수준을 결정한다면 식물성 지방인 대두유만으로 식이내 지방 급원으로 할 경우 식이내 지방 함유량이 6%이하일 경우 지방의 신체내 축적율, 지방 흡수율, 혈청내 총지방량을 미루어 가장 낮은치를 보여 주었으며 그 이상의 식이내 지방 함유량을 섭취한 경우는 식이내 42%의 지방 섭취까지 별 차이가 없이 높게 나타났다. 동물성 지방을 함께 섭취할 경우에는 식이내 지방의 함량이 3%이하로 떨어질 때 순식물성 지방으로 식이내 지방 6%수준으로 섭취한 것과 비슷한 결과를 보여준다고 할수 있다.