Abstract:
Bioavailability of three rumen protected Methionine
(Met) sources with different
protection methods (Mepron
®
M85, Evonik Industries, Germany; Methioplus
®
, Soda
Nutrition, Italy and Methilock
®
, Tehrandaneh Co. Iran) were evaluated in 2 experim
ents
with 6 canulated non-lactating Holstein cows. In ex
periment 1, the ruminal
in situ
and
mobile bag techniques were used for assessing rumin
al degradability and intestinal
digestibility of Met from the protected Met sources
. The rate of disappearance of Met
from Mepron
®
M85 was lower than Methioplus
®
(2.94
vs.
5.73 % h
-1
). Mepron
®
M85 had
more resistance to ruminal degradation than Methiop
lus
®
(82.78
vs.
68.51%), but the
higher intestinal digestibility of Methioplus
®
resulted in similar amounts of available Met
for two products. Because of high washing out loss
from
in situ
bags, ruminal degradation
was not estimated for Methilock
®
. In the second experiment, Met availability was as
sayed
by the blood Met response after 5 days feeding each
product in comparison to
pretreatment levels utilizing a 3×3 Latin square de
sign. Three Met sources increased
blood Met concentration significantly after 5 days
feeding (37.5, 52.23 and 44.39% for
Methilock
®
, Mepron
®
and Methioplus
®
respectively). Results of the present study showed
that the three RPM sources increased blood Met conc
entration. This study also suggests
that the
in situ
method may not adequately characterize the availab
ility of rumen
protected amino acids, especially those of small pa
rticle size.
Keywords:
Blood Response, Holstein cow, Intestinal Disappear
ance, Methionine, Ruminal
degradability.
