Doktorarbeit Endversion - Stiftung Tierärztliche Hochschule Hannover

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Irle, Annika (2011): In vitro studies on the effects of two Clostridium strains combined
with grass silage containing conspicuously low true protein
contents on fermentation parameters in bovine ruminal fluid.
7 Summary
In the current study the effects of C. botulinum Typ C and C. perfringens Typ B in
different amounts [C. botulinum and C. perfringens, 1 mL (3 x 10 9 bacterias) and
2 mL (6 x 10 9 bacterias)] in combination with grass silages containing different
percentual true protein (TP) contents of crude protein [CP; (TP%/CP)] on
fermentation parameters in bovine rumen fluid in vitro using RuSiTec (Rumen
Simulation Technique) were investigated. Furthermore, a possible effect on the
ruminal protozoas caused by both Clostridia strains should be clarified. One grass
silage (K-01) with 50.5 TP%/CP was used as a control, the conspicuous grass
silages had 39.8 RP%/CP (S-11) and 42.0 TP%/CP (S-05).
In a total of eight, 28 days lasting experimental cycles the effects on fermentation
parameters in bovine ruminal fluid were reviewed. Additionally the actvity of ruminal
protozoas was tested and measured using light microscope by ingestion of different
stains and stained yeast and amylum.
Every experimental RuSiTec cycle began with an eight days lasting controlling phase
[daily addition of 10.5 g hay (dry matter) and 3.4 g concentrate (18 % CP) to the
fermenters]. Afterwards the hay was exchanged with grass silage (10.5 g dry
matter/day) for ten days (days 9-18). The daily given amount of concentrate
persisted. At the same time C. botulinum and C. perfringens were applied for five
days (days 10-18), in two experiments for nine days (days 10-18). In the following
phase of regeneration (ten days) the additions were the same as in the controlling
phase. Samples were taken once daily before loading the RuSiTec.
During addition of Clostridia the concentration of ammonia in bovine rumen fluid rose.
The amount and kind of Clostridia strains were important. The addition of
C. perfringens (1 mL) and C. botulinum (1 mL) combined with conspicuous grass
silages led to two phases with increased concentrations of ammonia; the first
between days 10 and 14, the second with lower concentrations between days 15 and
19. When C. perfringens (2 mL) combined with conspicuous grass silages was
added, ammonia concentrations rose at day ten and stayed on a high level till day
19. C. botulinum (2 mL) combined with conspicuous grass silages led to a first lower
increase of ammonia between days 10 and 14 and to a second higher rise between
days 15 and 18 (chart 6.1).
The composition of grass silage also influenced the dimension of ammonia increase:
combination of conspicuous grass silages and Clostridia generally led to a higher rise
of ammonia than the combination with control silage. There was only a marginal
increase when Clostridia were added to control silage. Other parameters of fermentation,
as well as the activity of protozoa, were not affected by the addition of
Clostridia.