Effectiveness of Aspergillus oryzae fermentation culture to improve digestion of fibrous feeds

Studies regarding the use of living microorganisms as supplement have been done in the last two decades to improvedigestion process in the rumen. Many factors affect the use of the supplement, such as ration composition and physiologicalstatus of the animals. Materials used in this experiment are Aspergillus oryzae (AO) derived from ‘tauco’ (salty fermentedsoybean) and soybean sauce processing factories located in Bogor, Cianjur, and Sukabumi districts (15 sources), and also AOculture collections of the Indonesian Res. Inst. for Anim. Prod. (2 strains) and one strain from Indonesian Res. Inst. for Vet. Sci.in Bogor. The fungus was first isolated in potato dextrose agar (PDA), incubated at room temp. (26-300C) for 5 days forpurification. The AO from PDA then inoculated into cooked rice enriched with mineral mix, oven-dried (40-450C), then groundand kept in refrigerator as a stock culture for further use. To produce more AO (scaling-up), the culture is inoculated in two basalmedia, i.e. soybean meal and ‘onggok’ (tapioca processing waste) enriched with mineral mix, dried and ground, then kept inrefrigerator as A. oryzae fermentation culture (AOFC). Ground-dried King grass was used for in vitro digestion trials using sheeprumen fluid, which was not supplemented (control) or supplemented with the AOFC (10% w/w) from various sources. Threebest AOFC (by origin) were chosen and used for further digestion study. The study was run using 2 (media) x 3 (AOFC origin)factorial experiment based on a completely randomized design and Duncan’s MRT was applied to test differences amongtreatment means. Preliminary results indicated of the AOFC-SP66, -F172, and -CT4 used, the best AOFC was SP66, as it increased(P<0.05) fiber (NDF) digestion (10.5% better than the control). Total VFA productions were similar, but acetate content in therumen fluid was lowered (P<0.05), while propionate and butyrate levels were alleviated (P<0.05) by the AOFC-SP66. Ammoniacontent was not affected by addition of AOFC. No differences were detected on digestion parameters between the two mediaused for AO cultivation, therefore, it is suggested to use ‘onggok’ for producing AOFC in large scale. VFAs composition patternsuggests that AOFC was more suitably used for meat rather than for milk production.