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Reducing Greenhouse Gas Emissions from Livestock and Soils |
The objective of this study was to evaluate the
effect of mangosteen peel on
methane production in an in
vitro incubation, using a substrate
composed of molasses, Operculina turpethum meal and para grass,
with potassium nitrate or urea as source of non protein nitrogen.
Twelve treatments were arranged in a 4*3 factorial
with 3 replicates; mangossten peel (0, 0.5, 1.0 and 1.5% of substrate DM
basis); potassium nitrate (4 or 6% of diet DM basis) or urea (1.83% of diet DM
basis). The quantity of substrate was 2.5g to which were added 200ml of
buffer solution and 50ml of rumen fluid (from
a buffalo immediately after the animal was killed in the slaughter-house).
The incubation was for 48 h with measurements of total gas and percent methane
at intervals of from 0-6h, 7-12h, 13-24h,
25-36h and 37-48h, and determination of residual
unfermented substrate as well as ammonia-nitrogen (NH3-N) concentration
in rumen liquid after 48h of incubation.
Gas production was higher
for treatment without mangosteen peel than with mangosteen peel and was higher
for urea than for 4% or 6% of potassium nitrate as nitrogen source. Methane
concentration in the gas production at all incubation times was reduced by
mangosteen peel (Figure 1). and by potassium nitrate compared with urea. The
methane production per unit substrate fermented after 48h incubation, was lower
for 1.5% mangosteen peel than for other percentages of mangosteen peel and also
lower for nitrate (both 4% and 6% of potassium nitrate) than for urea at all
levels of mangosteen peel. The ammonia-nitrogen (NH3-N) concentration
in rumen liquid after 48h of incubation was not affected by mangosteen peel but
was reduced when urea rather than potassium nitrate was the nitrogen source.
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Figure 1. Effect of incubation time on methane percentage of the gas with 0, 0.5, 1 and 1.5% addition of mangosteen peel |
Figure 2. Effect of potassium nitrate or urea as source of fermentable nitrogen on methane production per unit substrate fermented in an in vitro system with substrate of molasses and Operculina turpethum meal with 0, 0.5, 1.0 and 1.5% addition of mangosteen peel (48h incubation |