Degradation of forage chicory by ruminal fibrolytic bacteria.
OBJECTIVE
Determine the susceptibility of forage chicory (Cichorium intybus L.) to degradation by ruminal fibrolytic bacteria and measure the effects on cell-wall pectic polysaccharides.


RESULTS
Large segments of fresh forage chicory were degraded in vitro by Lachnospira multiparus and Fibrobacter succinogenes, but not by Ruminococcus flavefaciens or Butyrivibrio hungatei. Cell-wall pectins were degraded extensively (95%) and rapidly by L. multiparus with a simultaneous release of uronic acids and the pectin-derived neutral monosaccharides arabinose, galactose and rhamnose. Fibrobacter succinogenes also degraded cell-wall pectins extensively, but at a slower rate than L. multiparus. Immunofluorescence microscopy using monoclonal antibodies revealed that, after incubation, homogalacturonans with both low and high degrees of methyl esterification were almost completely lost from walls of all cell types and from the middle lamella between cells.


CONCLUSIONS
Only two of the four ruminal bacteria with pectinolytic activity degraded fresh chicory leaves, and each showed a different pattern of pectin breakdown. Degradation was greatest for F. succinogenes which also had cellulolytic activity.


CONCLUSIONS
The finding of extensive removal of pectic polysaccharides from the middle lamella and the consequent decrease in particle size may explain the decreased rumination and the increased intake observed in ruminants grazing forage chicory.
Sun
X Z
XZ
Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
Joblin
K N
KN
Andrew
I G
IG
Hoskin
S O
SO
Harris
P J
PJ
D000818:Animals; D001089:Arabinose / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism*; D018651:Cichorium intybus / Q000378:metabolism*; D015169:Colony Count, Microbial; D005455:Fluorescent Antibody Technique; D005690:Galactose / Q000378:metabolism; D010368:Pectins / Q000378:metabolism; D012210:Rhamnose / Q000378:metabolism; D012417:Rumen / Q000382:microbiology*; D014574:Uronic Acids / Q000378:metabolism
D014574:Uronic Acids; D010368:Pectins; D001089:Arabinose; D012210:Rhamnose; C003181:polygalacturonic acid; D005690:Galactose