Pakistan
Journal of Nutrition, 6 (1): 20-27, 2007 ISSN 1680-5194
© Asian Network for
Scientific Information, 2007
Manipulation of Rumen Fermentation with
Organic Acids Supplementation in Ruminants Raised in the Tropics
Sittisak Khampa and Metha Wanapat*
Tropical Feed Resources Research and
Development Center (TROFREC), Faculty of Agriculture,
Khon Kaen University, P.O. Box 40002,
Khon Kaen, Thailand
Abstract: Locals feed resources
are prime importance for ruminants raised in the tropic particularly
low-quality roughages and agricultural crop-residues. Manipulating rumen
fermentation through treatment of roughage, concentrate and strategic
supplementation with organic acids could improve rumen efficiency by
maintaining higher pH, optimum ammonia-nitrogen (NH3-N),
thus reducing methane (CH4) and increasing
microbial protein synthesis and essential volatile fatty acid (VFAs), for
enhancing ruminant productivity in the tropics. The manipulation of rumen
efficiency through the use of organic acids especially malate with local feeds
would be an advantage. Indeed, organic acids potentially provide an alternative
to currently used antimicrobial compounds by stimulating rather than inhibiting
specific ruminal microbial populations. At the same time, local feed resources
especially cassava chip could be used effectively at high level as an energy
source for ruminants especially for beef and lactating cows. More recently, the
combined use of concentrates containing high level of cassava chip with
supplementation of sodium dl-malate and urea could improve rumen ecology and
subsequent performance in dairy steers receiving urea-treated rice straw as a
roughage. In addition, the high level of cassava chip in the diet resulted in
increase population of bacteria and fungi, decreasing protozoal populations,
and improving microbial protein synthesis and efficient microbial nitrogen
supply in the rumen. Under these circumstances, malate was also effective in
reducing the drop in ruminal pH normally seen 1 to 2 h after feeding a
high-grain diet and improved cows performance efficiency. In summary,
supplementation of organic acid like malate with local feed resources
especially cassava chip or other carbohydrate sources with high rumen
degradation would be a desirable alternative because there is no risk of
developing antibiotic resistance or having unwanted residues appear in either
meat or milk products as well as improving ruminal fermentation efficiency and
productivity in ruminants in the tropics.
Key words: Organic acids, malate,
feed resources, cassava chip, rumen fermentation, ruminants, tropics
