Diets different in crude protein (CP) and undegraded intake protein (UIP) contents were offered to sheep in a metabolism study to describe their effects on nutrient digestibility and nitrogen (N) metabolism. Six Corriedale sheep (body weight=56.2±2.3 kg) were divided in random within a Latin square design (replicated) to 1 of 3 diets: 1) a low-CP diet (LP; 12.2% CP with 35.1% UIP), 2) high CP with low UIP diet (HPLU; 14.9% CP with 33.7% UIP), and 3) high CP with high UIP diet (HPHU; 15.5% CP with 45.8% UIP). High-protein dried distillers grain and soybean meal were the main CP sources for the adjustment of UIP:DIP in the diets. No significant differences were found in feed consumption and nutrient digestibility; however, a greater proportion of CP was digested in sheep fed the HPLU diet (69.4%; P=0.04). Although N intake was greater in sheep receiving HPLU and HPHU diets, loss of N through fecal or urinary route was not different among sheep, which resulted in the highest (12.7 g/d) and lowest N retention (7.40 g/d) in HPHU- and LP-fed sheep, respectively. In conclusion, although CP or UIP content had marginal effects on feed consumption and whole-tract digestibility of the majority of nutrients, with the increased CP and UIP levels in the diet, the efficiency of N utilization was improved with regard to increased N retention with minimal differences in N excretion, which is important from an economic and environmental standpoint.

주야온 25/20℃, 상대습도 70%로 조절된 생육상내에서 명기 시간과 암기 시간의 비를 1 : 1 로 일정하게하고 광주기를 24h(명기 12시간 : 암기 12시간)와 6h(명기 3시간 : 암기 3시간)로 설정하여 토마토와 고 추 묘의 양분흡수 및 탄소대사 특성을 조사하였다. 토마토에서는 처리후 15일 6h에서 건물중, 초장, 엽면적, 엽록소함량 및 수분흡수량 감소와 함께 황화현상이 나타났으나, 고추에서는 6h에서 엽록소함량이 약간 낮았을 뿐 처리간 생장 차이는 없었다. 전체 처리 기간을 통해 NO3, P, K, Ca 및 Mg의 흡수량은 광 주기의 영향을 받지 않았으나, Fe의 흡수량은 두 작물 모두 처리후 10 일부터 6h가 24h에 비해 적었다. 이러한 경향은 엽록소함량이 가장 낮았던 처리후 15일과 토마토에서 현저하게 나타났다. 한편, 엽중 sucrose 함량은 토마토의 6h에서 높았으나 glucose는 24h에서 더 높았다. 본 실험 결과는 광주기 단축에 의한 엽중 엽록소함량 저하와 황화현상은 Fe 흡수량 부족 및 엽중 sucrose 축적과 관련이 있음을 시사해 주었다.