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.

This study aimed to investigate growth rate and nutrient consumption of Chlorella vulgaris according to different light irradiation interval. Applied light irradiation intervals were 12 hr, 4 hr, 1 hr, and 1 min. The light source was flexible LED(Blue:Red=1:1), light intensity was 200 PPFD and Light/Dark cycle was 1:1. As a result, growth rate and nutrient removal efficiencies showed no significant differences depending on the light irradiation interval. Considering the reproduction characteristics of applied microalgae cultures of this study, this is thought to be one of the possible reasons of above results. Because Chlorella vulgaris performs an asexual reproduction and it is known that there is no significant relationship between light irradiation interval and growth rate, including nutrient consumption in case of asexual reproduction.

페레니얼 라이그라스에서 질소의 공급형태 ( or ) 및 수준 (0.2, 1.0 and 6.0mM)에 따른 질소동화와 탄수화물 대사산물에 미치는 영향을 알아보기 위해 nitrate, nitrate reductase, sugar 농도와 Fructan 농도를 조사하였다. 공급구에서 잎의 생체량은 약간 증가하다가 같은 수준으로 유지되는 반면 공급구에서는 농도가 증가함에 따라 처음수준에 비해 약 25%에서 30% 증가하였다. 공급구에서 Nitrate 농도는 Ni

질소의 형태를 질산태(NO3 -N), 암모니아태(NH4 ＋-N) 그리고 질산태와 암모니아태(NO3 -N ＋ NH4 ＋-N)를 혼합한 양액 하에서 수경재배하여 담배의 생육단계별 질소이용에 따른 흡수 양상과 생육 및 nitrate reductase, glutamine synthetase 효소활성을 평가하여 질소 시비 유형에 따른 체내 질소대사의 기초자료를 제공하고져 축행한 결과는 다음과 같다. 질소의 형태별 생육은 NO3 -N, NH4 ＋-N 단독 처리구보다 혼합처리구에서 지상 및 지하부의 생육이 좋았고, NH4 ＋-N 처리구에서는 암모늄 독성에 의해 생육이 극히 불량하였다. 생육단계별 양액의 pH 변화는 NO3 -N 처리구에서 이식 초기부터 이식 후 40일까지 증가하였고 NH4 ＋-N 처리구에서는 이식 후 20일에 pH 3.42, 혼합처리구에서는 이식 후 30일에 pH 3.64까지 떨어졌다가 증가하였다. 혼합처리구의 질소흡수반응은 생육초기에서는 NH4 ＋-N의 흡수를 우선하고 생육중기부터 NO3 -N 흡수가 증가하여 흡수 양상을 달리하였다. 생육시기에 따라 흡수형태도 NO3 -N와 NH4 ＋-N 사이의 상대적인 비율에 의해 크게 영향을 미쳤다. 엽록소와 가용성 단백질은 혼합처리구에서 전질소는 NH4 ＋-N 처리구에서 높았고, 특히 NH4 ＋-N 질소를 시비하였을 때는 질소함량이 증가하였다. 질산함량이 증가하였다. 질산함량은 NO3 -N 처리구에서 암모니아함량은 NH4 ＋-N 처리구에서 높았고, 산소 활성은 혼합처리구에서 nitrate reductase와 glutamine synthetase 활성이 높았다.