In vitro degradation of oxalate and of cellulose by rumen ingesta from sheep fed Halogeton glomeratus.

Abstract

The artificial rumen technique was used to study in vitro oxalate degradation and cellulose fermentation by rumen liquor obtained from a sheep before and after feeding IIalogeton glomeratus, an oxalate producing plant. Cellulose fermentation was inhibited when 240, 180, or 120 mg. of oxalate were added to 100 ml. of fermentation medium containing rumen liquor inoculum from a sheep that had not been fed halogeton. When 60 mg. of oxalate was added, the fermentation of cellulose was highly variable. When the inoculum for the in vitro fermentation was obtained from a sheep fed halogeton for three days, cellulose fermentation took place but at a slower rate and earlier in the fermentation period. Oxalate was degraded even when cellulose was not fermented. Degradation of oxalate did not take place until after four hours of fermentation when the rumen inoculum was taken from a sheep fed halogeton, but there was a delay of 8 hr. from rumen inoculum from the sheep not fed halogeton. Addition of calcium carbonate, calcium chloride, dicalcium phosphate, bonemeal or magnesium sulfate to the fermentation medium containing oxalate enhanced the fermentation of cellulose. The effect of calcium chloride was inverse to that of the other minerals. The in vitro data suggests that acute oxalate poisoning may involve impaired cellulose fermentation and rumen dysfunction.