INFLUENCE OF PH ON THE PROPORTION OF UNIONIZED AMMONIA IN RUMEN
Keywords:
free ammonia, ionized ammonia, pHAbstract
Protonation and deprotonation of ammonia provides a mechanism for movement of
the molecule across membranes and they make ammonia an important intermediate
in acid-base regulation as well as N metabolism. Only unionized ammonia
molecules are able to penetrate the rumen wall proportional to their concentration.
Rising pH dramatically increases the percentage of unionized ammonia. The ratio
of the ammonium ion, NH4
+
, to ammonia, NH3 is inversely related to pH. The study
had in view to establish the content of free and ionized ammonia in the rumen fluid
under the influence of nutritional factors (slow release urea, sugar, live yeasts and
premix) in five periods. Each increase in pH by 0.5 units further increases free
ammonia percentage by the average factor of 3.27. The decrease in pH with 0.5
units from 6.8 to 6.3 induces an increase in the NH4
+
proportion from 99.0% to
99.7% while the decrease in pH with 0.5 units from 6.3 to 5.8 induces an increase in
NH4
+
proportion from 99.7% to 99.9%.
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