Influence of the Combination of Casein and Isolated Soyprotein with or without Methionine Supplementation on the Growth, Metabolism, and Body Composition of Growing Rats

카제인과 대두단백질(大豆蛋白質)의 혼합(混合) 및 Methionine보충(補充)이 흰쥐의 성장(成長), 체내(體內) 대사(代謝) 및 체조성(體組成)에 미치는 영향

This experiment was conducted to study effects of different sources of protein, and of the different combination ratios of the two protein supplemented or unsupplemented with methionine on the growth and body metabolism of the growing male rats. Casein and isolated soyprotein (ISP) were combined at different ratios of 100:0, 80:20, 50:50, 20:80 and 0:100 to supply the constant levels of dietary energy and protein of 3,600kcal/kg and 20%, respectively. Each combination was supplemented with either 0 or 0.3% methionine. Results obtained in these experiments were summarized as follows: The body weight and weight gain in the ISP diet were the lowest, but were increased with the increase of ratios of casein to ISP. The body weight gain in the ISP diet supplemented with methionine was similar to that in the combination diets of casein and ISP. The combination diets of casein and ISP supplemented with methionine had the higher weight gain than the casein diet. The food intake in the casein diet was the highest, and was increased with the increase of ratios of casein to ISP, and was lowered with methionine supplementation. The food intake in the ISP diet was the lowest and was not increased with methionine supplementation to the ISP diet. The food efficiency ratio of the combination diets of casein and ISP was improved compared to those of either the casein or the ISP diets. The food efficiency ratio was improved in the diet of either casein of ISP supplemented with methionine, but was not improved in the combination diets of casein and ISP with methionine supplementation. The gross energy intake had direct relation with the food intake of rats and the relation was increased either in the casein diet of with the increase of the ratios of casein to ISP. The energy efficiency and protein efficiency ratios were improved in the diet of either casein of ISP by the supplementation of methionine, and the effect of methionine supplementation of the energy efficiency and protein efficiency atio was increased with the increase of the ratios of ISP to casein. The nitrogen intake and urinary nitrogen excretion of the casein diet were the highest and those of the ISP diet were the lowest. They were increased with the increase of ratios of casein to ISP. The nitrogen balance and retention were not significantly among the treatments. The gross energy intake and fecal and urinary energy were the highest in the casein diet but the digestible and metabolizable energy and the digestibility and metabolizability of energy were not significantly different among the treatments. The body fat content of rats was increased by supplementation of methionine but the body protein content was decreased (r=-0.65, p<0.01). The body fat content of rats was negatively correlated with body moisture content (r=-0.83, p<0.01). The liver weight was highly correlated with the carcass weight (r=0.79, p<0.01), and was increased by the methionine supplementation and by the increase of the ratios of casein to ISP.

단백질(蛋白質)의 상호보충(相互補充) 및 제한(制限)아미노산 보충(補充)이 흰쥐(Sprague Dawley계(系) 이유(離乳)한 숫쥐)의 성장(成長), 체내대사(體內代謝) 및 체조성(體組成)에 미치는 영향(影響)을 규명하기 위하여 사양(飼養) 및 대사실험(代謝實驗)을 실시(實施)하였다. 실험사료(實驗飼料)의 에너지 및 단백질(蛋白質) 수준(水準)은 각각 3,600kcal/㎏ 및 20%로 고정하였고, 단백질(蛋白質)의 공급원(供給源)으로 카제인과 대두단백질(大豆蛋白質)을 택(擇)하여 각각 100:0, 80:20, 50:50, 20:80, 0:100의 비율(比率)로 혼합(混合)하였으며 각각에 methionine을 0% 또는 0.3%로 보충(補充)하였던 결과를 요약(要約)하면 다음과 같다. 흰쥐의 체중(體重)과 증체량(增體量)은 대두단백질(大豆蛋白質) 단독(單獨) 급여(給與) 때 가장 낮았고 카제인의 혼합비율(混合比率)을 증가(增加)시킬 수록 증가(增加)되었다. 대두단백질(大豆蛋白質)에 methionine을 보충급여(補充給與)했을 때 증체량(增體量)은 무보충(無補充) 혼합(混合) 급여(給與)했을 때와 동일(同一)했으며 카제인 단독(單獨) 급여(給與)때 보다 카제인 혼합(混合) methionine 보충(補充) 급여(給與)에서 증체량(增體量)은 더 높았다. 사료섭취량(飼料攝取量)은 카제인 단독급여(單獨給與) 때나 카제인의 혼합비율(混合比率)을 증가(增加)시킬 때 높았으나 meihionine을 보충(補充)했을 때 저하(低下)되었으며 대두단백질(大豆蛋白質) 단독급여(單獨給與)에서 낮았으며 methionine을 보충(補充)해도 증가(增加)되지 않았다. 사료효율(飼料效率)은 카제인이나 대두단백질(大豆蛋白質)의 단독(單獨) 급여(給與)때보다 두 단백질(蛋白質)의 혼합급여(混合給與) 때 더 높았으며 단독급여(單獨給與)에 methionine을 보충(補充)함으로써 사료효율(飼料效率)이 증가(增加)되었으나 혼합급여(混合給與)에 보충(補充)했을 때에는 같은 효과(效果)를 보이지 않았다. 성장실험기간중(成長實驗期間中) 총(總)에너지섭취량(攝取量)은 사료(飼料) 섭취량(攝取量)과 관계가 있었고 카제인 단독급여(單獨給與) 때나 그의 혼합비율(混合比率)을 증가(增加)시킬 때 증가(增加)했다. 에너지효율(效率)과 단백질효율(蛋白質效率)은 두 단백질(蛋白質)을 단독급여(單獨給與)할 때에는 methionine보충(補充)에 의해 증가(增加) 되었으며 또한 혼합급여(混合給與) 때에는 대두단백질(大豆蛋白質)의 비율(比率)을 증가(增加)시킬 수록 methionine에 의한 개선효과(改善效果)를 보였다. 질소섭취량(窒素攝取量) 및 카제인 뇨질소량(尿窒素量)은 단독급여(單獨給與) 했을 때 가장 높았고, 대두단백질(大豆蛋白質) 단독급여(單獨給與) 때 가장 낮았으며 카제인의 비율(比率)을 증가(增加)시킬 수로 증가(增加)되었다. 질소균형(窒素均衡) 및 축적율(蓄積率)은 처리(處理)에 의한 차이(差異)에 통계적(統計的) 유의성(有意性)은 없었다. 대사실험기간중(代謝實驗期間中) 총(總)에너지섭취량(攝取量)과 분(糞) 및 뇨(尿)에너지는 카제인 단독급여(單獨給與) 때 높았고, 가소화(可消化) 에너지와 대사(代謝)에너지, 에너지의 소화율(消化率) 및 리용율(利用率)은 처리(處理)에 의한 유의차(有意差)는 없었다. 체지방(體脂肪)은 methionine보충(補充)에 의해 증가(增加)되었으나, 체단백질(體蛋白質)은 감소(減少)했다(r=0.65, p<0.01). 체지방(體脂肪)과 체수분(體水分)과도 부(負)의 상관관계(相關關係)(r=-0.83, p<0.01)가 있었다. 간(肝)의 무게는 도체(屠體)의 무게의 변화(變化)와 일치(一致)했고 (r=0.79, p<0.01) methionine보충(補充)에 의해 증가(增加) 되었으며 카제인의 비율(比率)을 증가(增加)시킬 수록 증가(增加)되었다.