TY - JOUR
T1 - Oxalate balance in fat sand rats feeding on high and low calcium diets
AU - Palgi, Niv
AU - Ronen, Zeev
AU - Pinshow, Berry
N1 - Funding Information:
Acknowledgments We thank Regina Goldin-Tzirkin, Ilana Dolev and Ahuva Vonshak for technical assistance. We thank two anonymous referees whose comments helped to improve this paper. This research was partly supported by a Sigma Xi grant-in-aid-of-research and by a student support grant from the Mitrani Department of Desert Ecology (MDDE), both to NP. This is publication 598 of the MDDE.
PY - 2008/7/1
Y1 - 2008/7/1
N2 - Oxalate reduces calcium availability of food because it chelates calcium, forming the sparingly soluble salt calcium-oxalate. Nevertheless, fat sand rats (Psammomys obesus; Gerbillinae) feed exclusively on plants containing much oxalate. We measured the effects of calcium intake on oxalate balance by comparing oxalate intake and excretion in wild fat sand rats feeding on their natural, oxalate-rich, calcium-poor diet with commercially-bred fat sand rats feeding on an artificial, calcium-rich, oxalate-poor diet of rodent pellets. We also tested for the presence of the oxalate degrading bacterium Oxalobacter sp. in the faeces of both groups. Fat sand rats feeding on saltbush ingested significantly more oxalate than fat sand rats feeding on pellets (P < 0.001) and excreted significantly more oxalate in urine and faeces (P < 0.01 for both). However the fraction of oxalate recovered in excreta [(oxalate excreted in urine + oxalate excreted in faeces)/oxalate ingested] was significantly higher in pellet-fed fat sand rats (61%) than saltbush-fed fat sand rats (27%). We found O. sp. in the faeces of both groups indicating that fat sand rats harbor oxalate degrading bacteria, and these are able, to some extent, to degrade oxalate in its insoluble form.
AB - Oxalate reduces calcium availability of food because it chelates calcium, forming the sparingly soluble salt calcium-oxalate. Nevertheless, fat sand rats (Psammomys obesus; Gerbillinae) feed exclusively on plants containing much oxalate. We measured the effects of calcium intake on oxalate balance by comparing oxalate intake and excretion in wild fat sand rats feeding on their natural, oxalate-rich, calcium-poor diet with commercially-bred fat sand rats feeding on an artificial, calcium-rich, oxalate-poor diet of rodent pellets. We also tested for the presence of the oxalate degrading bacterium Oxalobacter sp. in the faeces of both groups. Fat sand rats feeding on saltbush ingested significantly more oxalate than fat sand rats feeding on pellets (P < 0.001) and excreted significantly more oxalate in urine and faeces (P < 0.01 for both). However the fraction of oxalate recovered in excreta [(oxalate excreted in urine + oxalate excreted in faeces)/oxalate ingested] was significantly higher in pellet-fed fat sand rats (61%) than saltbush-fed fat sand rats (27%). We found O. sp. in the faeces of both groups indicating that fat sand rats harbor oxalate degrading bacteria, and these are able, to some extent, to degrade oxalate in its insoluble form.
KW - Calcium
KW - Fat sand rats
KW - Oxalaobacter
KW - Oxalate
KW - Saltbush
UR - http://www.scopus.com/inward/record.url?scp=44849121639&partnerID=8YFLogxK
U2 - 10.1007/s00360-008-0252-1
DO - 10.1007/s00360-008-0252-1
M3 - Article
AN - SCOPUS:44849121639
SN - 0174-1578
VL - 178
SP - 617
EP - 622
JO - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
JF - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
IS - 5
ER -