Chemical Composition and Ruminal In Situ Degradability of Spent Flammulina Velutipes Mushroom Substrates Fermented by Supplemental levels of Molasses
본 연구는 팽이버섯 수확 후 배지에 3% 개미산 처리와 당밀 첨가수준별(0%, 2%, 4%, 6%)로 각각 25일 및 45일 동안 발효시켰을 때, 화학적 조성과 반추위내 in situ 분해율을 조사함으로써 반추가축용사료로서 적절한 처리방법을 규명해보고자 수행되었다. 반추위 cannula가 장착된 한우암소 3두(평균체중 450kg)를 이용하여 반추위내 발효시간별(0, 3, 6, 9, 12, 24, 48 시간)로 각각 3반복으로 in situ 시험을 실시하였으며, 공시축은 시판 배합사료와 볏짚을 4:1의 비율로 섭취하였다. 개미산 처리 후 당밀을 첨가하여 발효시킨 팽이버섯 수확 후 배지의 pH는 4이하이었으며, 일반성분함량으로 볼 때, 중국산 대두피정도의 수준이었다. 시험사료의 건물 중, 반추위내에서 분해가 빠르게 일어나는 ‘a’부분은 당밀첨가수준이 높아질수록 증가하는 경향이었고, 반추위내에서 서서히 분해될 수 있는 ‘b’부분은 25일 동안 발효 시에는 당밀4% 첨가구에서 높았으며, 45일동안 발효 시에는 당밀 6% 첨가구에서 높게 나타났다. 건물의 유효분해도(r=0.06)는 평균 45%로 처리간 비슷한 수준이었다. 시험사료의 NDF 중 ‘b’부분은 25일 동안 발효 시에는 당밀 6%첨가구가 타 처리구에 비해 낮았으나 45일 동안 발효 시에는 당밀 6%첨가구에서 높았다. 당밀 6%첨가구에서 시간당 NDF 분해속도가 가장 느렸으며, NDF의 반추위내 유효분해도는 평균 39%(r=0.06)로 처리간 비슷한 수준이었다. 이상의 결과로 볼 때, 본 시험에 사용된 팽이버섯 수확후 배지는 반추가축용 사료로서 보관성 향상을 위하여 탈병 후 3% 개미산(HCOOH)만 처리하여 혐기발효시켜도 무방할 것으로 판단된다.
This study was conducted to determine the chemical composition and ruminal in situ degradability of eight spent mushroom substrates(Flammulina Velutipes) fermented by supplemental level(0, 2, 4, 6%) of molasses with 3% formic acid and fermentation period(25d, 45d). Three Hanwoo cows(average weight 450kg) cannulated in rumen were used for in situ trial and fed a commercial formula feed and rice straw(4:1). Nylon bags were suspended in the rumen for 0, 3, 6, 9, 12, 24 and 48 hrs with 3 replicates, respectively. The experimental spent mushroom substrates(SMS) were below pH 4 and were similar level with soy hull manufactured in china when evaluating by chemical composition. Fraction ‘a’, immediately degradable DM in the rumen, was inclined to increase with the level of molasses. Fraction ‘b’, potentially degradable DM in the rumen, was relatively high in the 4% molasses treatment when SMS was fermented for 25 days, however, was relatively high in the 6% molasses treatment when fermented for 45 days. Effective DM degradability in the rumen was average 45% assuming at 6% ruminal passage rate per hour(r=0.06) of experimental feeds without significant difference among treatments. Fraction ‘b’ of NDF was relatively low in the 6% molasses treatment when SMS was fermented for 25 days, on the contrary, was high in the 6% molasses treatment when fermented for 45 days. NDF degradation rate was relatively low in the 6% molasses treatment and effective degradability in the rumen was average 39% at r=0.06 without significant difference among treatments. Hence, this study showed that the SMS(Flammulina Velutipes) as a ruminant feed could be anaerobically fermented with 3% formic acid only without supplemental molasses for preservation.