Chemical Composition, In vitro Digestibility and Drying Rate of Sugarcane Tops Using Different Curing Methods

Abstract

አህፅሮት

የሸንኮራ አገዳ ጫፍ በአገራችን በስኳር ፋብሪካዎች አከባቢና እና በአነስተኛ ሸንኮራ አገዳ አምራች ገበሬዎች ዘንድ የሚገኝ የእንስሳት መኖ ሀብት ነው፡፡ ይሁን እንጂ በሀገራችን እስካሁን የመኖ ጠቃሜታውን ለማሻሻልና በአያያዝ ጉድለት የሚመጣውን ብክነት ለመቀነስ የተካሄደ ጥናት በስፋት የለም። የዚህ ጥናት ዓላማም የርጥብ ሸንኮራ አገዳ ጫፍን ድርቆሽ በማዘጋጀት ሳይበላሽ ለረጅም ጊዜ ለማቆየት እንዲቻል ጥራቱን በተለያዩ የድርቆሽ አዘገጃጀት ዘዴዎች መፈተሽ ነው። ይህም በሳት የተቃጠለና (የተለበለበ) ያልተቃጠለ (ያልተለበለበ) የሸንኮራ አገዳ ጫፍን ሳይከረታተፍና ተከረታትፎ በፀሀይና በጥላ ሥር በማድረቅ ዘዴ የሚዘጋጀውን ድርቆሽ የንጥረ-ነገር ይዘት፣ የመፈጨት ደረጃውንና ለመድረቅ የሚፈጀውን ጊዜ ለመገምገም ነበር። የእያንዳንዱን አሰራር ዘዴ አምስት ጊዜ በመደጋገምና በተለያዩ ጊዜያት ናሙናዎች በመውሰድ አማካይ የድርቀት መጠናቸዉ 85 በመቶ ሲቃረብ በማቆም የናሙናዎች ኬየሚካለዊ ትንተና ተካሂደዋል። በተለበለቡና ባልተለበለቡ የሸንኮራ አገዳ ጫፍ መነሻ ናሙናዎች (fresh/original sugarcane tops) መካከል ያለው የመኖ ንጥረ-ነገር ይዘት ልዩነት የጎላ አልነበረም። ተከርትፈዉ በፀሀይ የደረቁት የሸንኮራ አገዳ ጫፍ ናሙናዎች ሦስት ቀናት ባልበለጠ ጊዜ የደረቁ ሲሆን፤ በአንፃሩ ያልተከረተፉት ናሙናዎች ለመድረቅ ከ45 እስከ 68 ቀናት ወስዶባቸዋል። በማድረቂያ ዘዴዎችና በሸንኮራ አገዳ ጫፍ ዓይነቶች መለየት ምክንያት በሚንራል(ash)፣ በቃጫ (NDF, ADL)፣በሟሚ ካርቦኃይድሬቶች (NFC)፣ በኃይል ሰጪ (ME)፣ በፎስፈረስ ይዘትና በተፈጭነት ደረጃ (digestibility) ልዩነት ማየት ተችሏል። የማድረቂያ ዘዴዎቹ መለያየት ከናሙናዎቹ ድርቀት(DM) እና ፕሮቲን ይዘት ዉጪ በሌሎች ንጥረ-ነገሮች ይዘቶች ላይ ልዩነት አልነበራቸዉም። በሌላ በኩል በፀሀይ የደረቀ ያልተከረተፈ-የተቃጠለ የሸንኮራ አገዳ ጫፍ ድርቆሽ የቃጫ(NDF) ይዘት አነስተኛና በፀሀይ ከደረቀው ያልተከረተፈ-ያልተቃጠለ ናሙና ልዩነት የለውም። በአንፃሩ የተከረተፉና በፀሐይ የደረቁ ናሙናዎች ሳይከረተፉ ከደረቁት ናሙናዎች በሟሚ ካርቦሀይድሬት፣ በቅባትና በሄማይሴሉለስ-ቃጫ ይዘት ከፍተኛ ሆነው በADF-ቃጫ ይዘት በእጅጉ ያነሱ ናቸዉ። በአጠቃላይ ከሸንኮራ አገዳ ጫፍ ድርቆሽ ለማዘጋጀት መከርተፍና በፀሀይ ማድረቅ የሚወስደዉን ጊዜ በእጅጉ ይቀንሳል፣ ብልሽትንና የንጥረ-ነገር ብክነትን በመቀነስ የመኖ ጠቀሜታውን ያጎላል።

Abstract

This study was conducted to evaluate effects of different drying methods on chemical composition, in vitro digestibility and drying rate of sugarcane tops (SCT). Treatments were set in factorial arrangement (2 SCT types (green and burnt) x 3 drying methods (shed and sun drying of intact SCT and sun drying of chopped SCT) in a completely randomized design. Each treatment was replicated 5 times and samples were dried at a swath density of 4 kg/m². Dry matter (DM) of samples was determined at time interval until the treatment average approached the safest content (≈ 85% DM) for storage. Fresh (samples at harvesting) and dried samples were chemically analyzed. The fresh burnt SCT had slightly higher DM, ash, EE, ADL, Ca, P, IVDMD, IVOMD and ME contents, but had lower CP and NFC contents than the fresh green SCT. The chopped burnt and green SCT dried at a rate of 19.8 and 20.7% per day, respectively. Rate of drying was highest in the 1^st week for all drying methods, then after decreased progressively. The lowest dehydration rate (0.92 and 0.99% per day), or longest drying time (68 and 60 days) was attained by shed dried intact green and burnt SCT, respectively. There were significant interaction effects (P<0.05) of drying methods and SCT types on ash, NDF, ADL, IVDMD, IVOMD, ME, NFC and P contents. Except for DM and CP, the drying methods had varied (P<0.0001) effect on nutrient content of SCT. The NDF content of burnt SCT was lower (P<0.05) for intact sun dried samples compared to other drying methods, but values for the green SCT did not vary (P>0.05) among the drying methods. However, ADF contents of sun- and shed dried intact SCT were not different (P>0.05), but were higher (P>0.05) than that of chopped sun-dried SCT. The sun-dried chopped SCT had higher (P<0.05) ether extract (EE) and hemicelluloses contents. However, sun-dried chopped green SCT had lower NDF and ADL than sun-dried chopped burnt SCT, but were similar (P>0.05) in DM, OM digestibility and ME contents. The NFC content was inversely related to the fiber fraction, being lower (P<0.05) for sun-dried chopped burnt SCT and shed-dried intact burnt SCT. The under shed dried intact green SCT had higher NFC content than sun dried chopped green SCT (P<0.05). In conclusion, the drying methods used in this study had variable effect on chemical composition, although lacks consistency in the trend. Chopping SCT clearly increases drying rate, shorten drying period and conserve nutrients that has been reflected in better in vitro digestibility and ME.