대두박(大豆粕)의 처리방법과 요소첨가 수준이 반추위 미생물 단백질합성 및 영양소 소화율에 미치는 영향 : I. In vitro Continuous Culture System 에 의한 연구 I. A Study by in vitro Continuous Culture System = Effects of Urea Levels and Soybean Meal Treatment on the Rumen Microbial Protein Synthesis and Nutrient Digestibilities

국문 초록 (Abstract)

本 實驗은 反芻家畜의 주요 植物性 蛋白質 飼料인 大豆粕을 無處理, 高壓蒸氣 處理 및 乾熱處理하여 反芻胃內의 蛋白質 分解率을 각각 80.26, 74.28 및 60.38%로 低下시킴으로써 과다한 ammonia의 發生을 抑制하고 徵生物 蛋白質 合成에 必要한 부족된 nitrogen은 非蛋白態 窒素化合物인 尿素로 代贊 공급하여 飼料 蛋白質을 절약하고 그 利用性을 증진시키는데 목적이 있다.
따라서 本 硏究는 in vitro continuous culture system을 통하여 同窒素價로 飼料 蛋白質源의 일부를 尿素로 0, 1, 2 및 3% 代贊하였을때 大豆粕 蛋白質의 處理 方法에 따른 NH₃-N 利用性과 微生物 蛋白質 合成量의 變化 및 揮發性 脂肪酸 生成 등을 測定한 實驗 結果를 要約하면 다음과 같다.
1. NH₃-N 濃度(㎎/100㎖)는 尿素 0, 1, 2, 3%로 尿素 代贊율이 높아질수록 전처리구에서 NH₃-N 濃度가 증가하는 경향을 나타내었고 USBM에서 보다는 ASBM 및 DSBM에서 낮았다.
2. Nylon bag 蛋白質 소화율(%)은 尿素 代贊水準이 높아질수록 增加하여 3% 代贊시 最高値를 나타냈으나 處理區別로는 큰 差異가 없었다.
3. Nylon bag cellulose 소화율(%)은 모든 處理區에서 尿素 處理水準이 1∼2%에서 가장 높았으나 處理區間에 差異는 없었다.
4. Nylon bag 건물 소화율(%)은 尿素 代贊率이 높아질수록 增加하는 傾向이었으며 處理區別로는 큰 差異가 없었다(P>0.05).
5. 徵生物蛋白質 합성량(㎎/100㎖)은 尿素添加水準이 1%일때 가장 높았고 無處理 大豆粕(USBM)이 處理 大豆粕(ASBM과 DSBM)에서 보다 높았다.
6. 總 揮發性 脂肪酸 生成量(mM/ℓ)은 全 處理區 모두 尿素 1% 水準에서 最高値를 나타냈으며 또 無處理區 大豆粕에서 가장 높았다.

다국어 초록 (Multilingual Abstract)

Effects of urea levels (0, 1, 2, and 3%) and treatment of soybean meal on rumen microbial protein synthesis, VFA production and nutrient digestibilities were studied using in vitro continuous culture system.
Protein sources were commercial solvent-extracted untreated soybean meal(USBM), autoclaved soybean meal(ASBM) and dry heated soybean meal(DSBM), and 0, 1, 2 and 3% urea in a isonitrogenous basis. Degradabilities of USBM, ASBM and DSBM were 80.3, 74.2 and 60.4% for USBM, ASBM and DSBM, respectively.
The results which were obtained from this study are summarized as follows:
1. NH₃-N concentrations(㎎/100㎖) were increased as increasing urea levels and were lower in treated soybean meal as compared with untreated soybean meal.
2. Nylon bag protein digestibilities(%) in vitro, were increased as increasing urea levels, and were not statistically different among treatments.
3. Nylon bag cellulose digestibilities(%) were increased as increasing urea levels up to 1 or 2% in all treatment groups and were not different among treatment groups.
4. Nylon bag dry matter digestibilities(%) were also increased as increasing urea levels, but there were no differences among treatment groups.
5. Microbial protein yields(㎎/100㎖) were the highest when urea was added at 1% level and were higher in untreated soybean meal(USBM) than treated soybean meal(ASBM and DSBM).
6. Total VFA productions(mM/ℓ) were higher at 1% urea level in all groups and were the highest concentration in USBM than ASBM and DSBM.