In vitro evaluation of fibrolytic enzymes as additives for maize (Zea mays L.) silage II. Effects on rate of acidification, fibre degradation during ensiling and rumen fermentation

Dario Colombattoa, Fergus L Moulda, Mahalingeshwara K Bhatb, Richard H Phippsc, Emyr Owena

Author address: 

a Department of Agriculture, The University of Reading, Earley Gate, Reading RG6 6AR, UK b FMS Division, Institute of Food Research, Colney Lane, Norwich NR4 7UA, UK c Centre for Dairy Research, Department of Agriculture, The University of Read

Abstract: 

Abstract A study was carried out to determine the influence of fibrolytic enzymes derived from mesophilic or thermophilic fungal sources, added at ensiling, on time-course fermentation characteristics and in vitro rumen degradation of maize silage. The mesophilic enzyme was a commercial product derived from Trichoderma reesei (L), whereas the thermophilic enzyme was a crude extract produced from Thermoascus aurantiacus (Ta) in this laboratory. The fungus was cultured using maize cobs as a carbon source. The resulting fermentation extract was deionised to remove sugars and characterised for its protein concentration, main and side enzymic activities, optimal pH, protein molecular mass and isoelectric point. In an additional study, both enzymes were added to maize forage (333.5g DM/kg, 70.0, 469.8, 227.1 and 307.5g/kg DM of CP, NDF, ADF and starch, respectively) at two levels each, normalized according to xylanase activity, and ensiled in 0.5kg capacity laboratory minisilos. Duplicate silos were opened at 2, 4, 8, 15, and 60 days after ensiling, and analysed for chemical characteristics. Silages from 60 days were bulked and in vitro gas production (GP) and organic matter degradability (OMD) profiles evaluated using the Reading Pressure Technique (RPT), in a completely randomised design. The crude enzyme extract contained mainly xylanase and endoglucanase activities, with very low levels of exoglucanase, which probably limited hydrolysis of filter paper. The extract contained three major protein bands of between 29 and 55kDa, with mainly acidic isoelectric points. Ensiling maize with enzymes lowered (P
2003

abstract No: 

Page 129-143

Full conference title: 

2003 American Academy of Allergy, Asthma, and Immunology Annual Meeting
    • AAAAI 2003 (59th)