Izvorni znanstveni članak
Relationships among Gas Production, End Products of Rumen Fermentation and Microbial N Produced in vitro at Two Incubation Times
Mirko Cattani
; Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
Laura Maccarana
; Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
Hanne H. Hansen
; Department of Large Animal Sciences, University of Copenhagen, Grønnegårdsvej 2, 1870 Frederiksberg, Denmark
Lucia Bailoni
; Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
Sažetak
This experiment compared linear relationships among end-products of rumen fermentation measured at the time (t.) at which a feed produces half of its asymptotic gas production) or at 48 h. Meadow hay and corn grain were incubated for t. (16 and 9 h, respectively) or for 48 h into glass bottles. Each bottle (310 ml) was filled with feed sample (0.5 g) and 75 ml of buffered rumen fluid, and incubated at 39.0°C. Gas production (GP) was measured using the ANKOMRF System, and gas accumulated in headspace of bottles was released at 3.4 kPa. At t. or 48 h, fermentation fluids were analysed for ammonia N (N-NH3), volatile fatty acids (VFA), residual NDF and N bound to residual NDF (N-NDF). Values of GP were also predicted from VFA. Microbial N (MN) was computed as the difference between N present at the beginning and at the end of incubation. At 48 h, the relationship between GP measured and predicted from VFA was weak (R2 = 0.67; equation not shown), whereas the linear relationship was better at t. (R2 = 0.94). At t., the relationship between N-NH3 and measured GP was strong (R2 = 0.84), as well as that between MN and measured GP (R2 = 0.92). Conversely, these variables were not well related at 48 h. At t., the valerate content in rumen fluid was negligible. However, relatively large amounts of valerate were measured after 48 h, probably the result of microbial lysis. Results suggest that relationships among end-products of rumen fermentation can be more accurately evaluated at a substrate-specific incubation time (t.) rather than at 48 h.
Ključne riječi
rumen; in vitro fermentation; end-products of fermentation; incubation time
Hrčak ID:
106908
URI
Datum izdavanja:
4.9.2013.
Posjeta: 747 *