| Titles |
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English :
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In vitro rumen fermentation of cereal straws as affected by the treatment with exogenous fibrolytic enzymes
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| Abstract |
Batch cultures of mixed ruminal microorganisms were used to study the effects of exogenous fibrolytic enzymes on the in vitro fermentation of three cereal straws (barley, wheat and rice). Three different enzymes preparations were tested: cellulase from Aspergillus niger (CEL; Cellulase 22178; Fluka Chemie GmbH), xylanase from rumen microorganisms (XYL; XylanaseM6; Megazyme International Ireland Ltd), and a 1: 1 mixture cellulase:xylanase (MIX). Samples of 500 mg of each cereal straw were accurately weighed into 120-ml serum bottles. Enzyme preparations were added directly into the bottles at two levels: 0 (control) and 10 units/g dry matter (DM) straw. Enzymes were applied directly into the bottle an d bottles were kept at room temperature for 24 h before incubation with ruminai fluid. Ruminal fluid was collected from 4 Merino sheep fed mediumquality alfalfa hay ad libitum and mixed with the buffer solution of Goering and Van Soest (1970) in a proportion 1:4 (v:v) at 39°C under continuous flushing with CO2, Fifty 50 ml of buffered rumen fluid were added into each bottle, bottles were sealed with rubber stoppers and aluminium caps and incubated at 39°C for 24 h. After 24 h of incubation the total gas production and the pH of the medium were measured, and samples for volatile fatty acids and ammonia-N analyses were taken. Finally, the content of the bottles was transferred to previously weighed filter crucibles to estimate DM and neutraldetergent fibre disappearance (NDFD). Four incubation runs were performed on different days, so that each treatment was conducted in quadruplicate. In each incubation run, two blanks were included to correct the gas production values for gas release from endogenous substrates and enzyme treatment. The treatment with enzymes increased (P<0.01) gas production after 24 h of incubation with barley and rice straw, but there were no significant differences (P>0.05) among the enzymatic preparations used. For all substrates, final pH, total volatile fatty acid production, acetate:propionate ratio and ammonia-N concentration were not affected (P>0.05) by the addition of enzymes. Although the treatment with enzymes increased NDFD with all straws by about 4 % (mean value for all enzymatic treatments) with all straws, the differences were only significant (P<0.01) for rice straw. The results indicate that pre-treatment of cereal straws with fibrolytic enzymes under the conditions of the present experiment contributed little, if any, to ruminal fibrolytic activity.
Key words: Rumen, Cellulase, Xylanase, Cereal straws, Batch cultures
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| Publication year |
2003
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| Pages |
299-302
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| Availability location |
معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى - الجيزة
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| Availability number |
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| Organization Name |
Animal Production Research Institute (APRI)
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| serial title |
Tropical and Subtropical Agroecosystems 3 (2003): 299-302
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| Author(s) from ARC |
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| External authors (outside ARC) |
Carro, M.D.
Leon University, Spain
Ranilla, M.J.
Leon University Spain
Tejido, M.L.
Leon University Spain
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| Agris Categories |
Animal feedingAnimal physiology - Nutrition
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AGROVOC
TERMS |
Cereal byproducts.
Enzymes.
Fermentation.
In vitro.
Rumen.
Straw.
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| Publication Type |
Journal
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