식이내 단백질과 Cu수준이 흰쥐의 체내대사에 미치는 영향

Abstract

This experiment was carried on to see the effect of dietary protein and Cu levels on the protein metabolism, Cu and Zn contents in the various tissues in the rats. Forty five male weanling rats of the sprague - Dawley strain weighing 61.45 1.28g were divided into nine groups and each group was given with one of the 9 different kinds of diets for four weeks. The three dietary protein levels used were 5, 20 and 40%s and Cu levels used were 0, 6 and 60 ppms. Throughout the experimental period, dietary intake and body weight gain were measured and feed efficiency ratio and protein efficiency ratio were caloulated. The urinary and fecal coatents of nitrogen, Cu and Zn were analyzed. The weights of Liver, Kidney and posterior crural region of lower hind Limb. (Soleus, Plantaris, Gastrocnemius) were measured. The tissue contents of nitrogen, DNA, RNA, Cu and Zn and serum concentrations of Cu and Zn were also determined. The results were summerized as following: 1. Food consumption, body weight gain and feed efficiency ratio in 20 and 40% of protein diet groups were significantly higher than 5% LP-groups. There was no significant difference with different Cu levels. 2. Protein efficiency ratios of SF-groups were higher than these of HP-and LP-groups. But the protein efficiency ratio of LP-HCu group was similar to these of SP-groups. With Cu level in the diet, there was no significant difference among groups. 3. The weights of Liver, Kidney and posterior crural region of lower hind Limb were different with the dietary protein level. Between SP-and HP-groups, there was no significant difference but they were significantly higher than LP-groups. 4. The total DNA contents of whole Liver in SP-and HP-groups were significantly higher than LP-groups. But the DNA contents per gram tissue showed no significant difference among all groups. The Liver RNA contents per gram tissue of - SCu groups tended to be higher than the other groups at the same level of dietary protein. The total RNA contents of whole Liver of SP-SCu group was highest and these of - SCu groups were high and these of LP-groups were low. The RNA/DNA ratios of SP-SCu and HP-SCu groups were higher than the others. 5. The DNA and RNA contents of Kidney showed the same tendency. LP-SCu and LP-HCu groups were Eromewhat high. The RNA contents of HP-SCu and HP-HCu groups were a little high. 6. In comparison the contents of Cu and Zn in tissues among groups, the Cu contents of LP-SCu groups were significantly high in liver, HP groups were a little high in Kidney, and LP-LCu group was the highest in the posterior crural region of Lower hind limb. There was no difference in tissue Zn contents among the nine groups. The Cu content in serum was high when the dietary protein level was low or the dietary Cu level was high. But there was no consistent tendency in the Zn content with dietary treatments. 7. The urinary Cu content of, - HCu groups were higher than the other six groups. There was signficant-difference in urinary Zn content with the level of dietary protein and these of SP-and HP-groups were comparatively high. The fecal Cu contents were shown to be proportional to the dietary Cu level and these of - HCu groups were highest and these of - LCu groups lowest.;본 연구에서는 식이내 단백질과 Cu수준을 달리하였을 때 흰쥐의 체내에서 단백질과 Cu및 Zn대사에 미치는 영향을 알아보고자 했다. 평균 체중이 61.45±1.28g인 Sprague-Dawley종 수컷 흰쥐 45마리를 식이 단백질 함량을 5%, 20%, 40%의 3수준으로하고 식이 Cu함량을 0ppm, 6ppm, 60ppm의 3수준으로 하여 모두 9군으로 나누어 4주간 사육하였다. 전체 실험기간에 각 실험군마다 식이 섭취량과 체중을 측정하였으며 사료효율과 단백질 효율을 산출하였다. 뇨와 변을 채취하여 질소함량과 Cu 및 Zn함량을 측정하였고, 간, 콩팥, 뒷다리 근육의 무게를 각각 측정하였으며, 각 조직내 질소 함량, DNA 및 RNA 함량과 Cu및 Zn농도를 측정하였다. 혈청내의 Cu및 Zn농도도 측정하였다. 그 결과를 요약하면 다음과 같다. 1. 식이섭취량, 체중증가량, 사료효율은 전 실험기간을 통하여 식이 단백질 수준이 20% 이상인 군들이 5%인 군들 보다 유의적으로 높은 경향을 보여주었으나 식이 Cu수준에 따라서는 별 차이가 없었다. 2. 단백질 효율은 식이 단백질 수준이 20%인 군들이 가장 높고, 그 다음이 40%군들, 5%군들 순서였으며, 식이 Cu수준에 따른 차이는 없었다. 3. 각 조직의 무게도 식이내 단백질 수준에 의해서 유의적인 차이를 나타내며, SP-군들과, HP-군들이 LP-군들보다 유의적으로 높았으며, 식이 Cu수준에 의한 차이는 없었다. 4. 간내 질소함량은 SP-군, HP-군들 사이에는 유의적인 차이가 없었으나 LP-군들에 비해 유의적으로 높았고 식이 Cu수준에 따른 차이는 없었다. 콩팥과 뒷다리 근육내 질소함량은 각군간에 별 차이가 없었다. 5. 뇨의 질소배설양을 보면 LP-군들, SP-군들 사이에는 유의적인 차이가 없이 비교적 낮은 값을 나타내었으나 HP-군들이 높은 함량을 나타내었고 변의 질소량은 식이 단백질 수준에 의한 차이가 다소 있었으며 HP-SCu군, HP-HCu군이 가장 높았으며, Lp-LCu군이 가장 낮았다. 식이 Cu수준에 의한 차이는 일정한 경향이 없었다. 6. 간 전체의 총 DNA는 LP-군에 비해 SP -, HP - 군들이 유의적으로 높았다. 간 단위g당 RNA함량은 -SCu군들이 동일 단백질 수준에서 -LCu, - HCu군들보다 높은 경향을 나타내었고 간 전체 총 RNA는 식이내 Cu수준, 단백질 수준에 의해 유의적인 차이를 보여주어 SP-SCu군이 가장 높으며, 동일 단백질 수준에서 볼 때 - SCu군들이 다소 높았으며, LP-군들이 비교적 낮게 나타났다. RNA/DNA비는 9군간에 유의적인 차이는 없었으나 SP-SCu군, HP-SCu군에서 비교적 높았다.