저단백질식이와 환경적 보충이 흰쥐의 성장 및 혈청 단백질 수준에 미치는 영향

Effects of low protein diet and environmental enrichment on growth and serum protein level in rats

  This study was undertaken to investigate the effect of low protein diet and environmental enrichment on the growth and serum protein conent in rats during four weeks of growing period. Twenty eight male rats of Sprague-Dawley strain were divided into four groups according to content of casein, 8% or 25% and rearing condition, isolated or enriched. Rats treated with environmental enrichment were placed in a large box containing many different toys along with six animals of the same group for a 3-hour play period 6 days a week. They received foods ad libitum.   The results were summarized as follows:   1. Food intake and body weight gain in 25% casein groups were significantly higher than those in 8% casein groups. The group of environmentally enriched 25% casein diet showed higher food intake, body weight gain, and feed efficiency ratio than that of same diet without enrichment. There were no difference between 8% casein groups with or without enrichment.   2. There were no significant difference among groups in brain weight. In case of liver, heart, and spleen, low protein diet decreased the weight of them and environmental enrichment increased it between controls. However, the weight of kidney and testis was decreased and was not significantly affected by environment.   3. Serum protein content in control diet group with environmental enrichment was significantly higher than others.   Above findings support that the environmental enrichment has profound effect in nutritionally sufficient condition rather than in deficient state.