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Stimulatory effect of trace elements on cellulose digestion by washed suspensions of rumen microorganisms

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Title Stimulatory effect of trace elements on cellulose digestion by washed suspensions of rumen microorganisms
Names Martinez, Andres (creator)
Church, D. C. (advisor)
Date Issued 1969-05-09 (iso8601)
Note Graduation date: 1969
Abstract The object of the present study was to investigate the stimulatory
or inhibitory effects of barium, boron, bromine, cadmium,
chromium, cobalt, copper, fluorine, iodine, iron, manganese,
molybdenum, nickel, rubidium, selenium, strontium, vanadium, and
zinc upon in vitro rumen microbial activity as measured by the amount
of cellulose digested. Washed suspensions of rumen microorganisms
were prepared by centrifuging intact rumen fluid at 1500 rpm (365 x g)
for two minutes and immediately centrifuging the resulting supernatant
at 8500 rpm for 20 minutes. The resulting sediment, consisting
primarily of bacterial cells, was resuspended in a M/15 phosphate
buffer and again centrifuged at 8500 rpm for 20 minutes. The twicewashed
cells of rumen microorganisms were then incubated at 39°C
for 24 hours in a medium containing 0, 2 percent purified cellulose
(Solka-Floc); M/15 phosphate buffer and basal mineral media in a 1 to .1
ratio; and the element being tested.
Ten levels of each of the 18 elements were added separately to
the incubation media. Each concentration of the test element was
duplicated in each of three trials (that is, six observations per
concentration) yielding a total of 1296 observations during an eightmonth
period. The elements and concentrations (in ppm) found to be
stimulatory to cellulose digestion included: (P = 01) I, 20; Mn,
5-20; Mo, 30-70; (P = . 05) Co, 3; Fe, 3-5; Rb, 20; Zn, 5-7; (P =
10) Cd, 5; (P = . 20) Cr, 2, and Sr, 10-15. Depression of cellulose
digestion (P = . 05) occurred at the following levels (in ppm): Ba, 30;
B, 300; Cd, 10; Cr, 7; Co, 7; Cu, 1; F, 0.5; Fe, 100; Mn, 100;
Ni, 0. 5; Se, 7; Sr, 200; V, 5, and Zn, 20. Bromine concentrations
of 1 to 1000 ppm had no effect on cellulose digestion. Levels up to
1000 ppm I, 500 ppm Mo, and 1000 ppm Rb had no significant
detrimental effect on cellulose digestion under the conditions tested.
Genre Thesis/Dissertation
Topic Rumen
Identifier http://hdl.handle.net/1957/46876

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