The effect of short chain fatty acids on calcium flux rates across isolated rumen epithelium of hay-fed and concentrate-fed sheep.
The present in vitro experiment was conducted to study the effect of two concentrations of short chain fatty acids [SCFA: 0 (control), 40 and 100 mmol/l in the buffer solution on mucosal side] on calcium ion (Ca2+) transport across the isolated rumen epithelium of two groups of sheep. One group was subjected to hay ad libitum, whereas the other to concentrate feed (800 g per day in equal portion at 7.00 and 15.00 hours and hay ad lib). The conventional Ussing chamber method was used for measuring the Ca2+ transport rates (45Ca), short-circuit current (Isc) and tissue conductance (GT) of isolated rumen epithelium. The SCFA significantly increased Isc of the epithelia of concentrate-fed sheep. In both hay- and concentrate-fed animals, 45Ca flux rates showed an almost linear increase in net flux rate () with rising concentrations of SCFA, as a result of a combined effect of a large increase in mucosal-to-serosal flux rates () and an almost linear, but small, decrease in serosal-to-mucosal flux rate (). In concentrate-fed sheep and were significantly higher in tissues incubated with SCFA compared with hay-fed animals. The well-known adaptable morphological and functional changes in the rumen epithelium attributable to concentrate feeding obviously include Ca2+ transport; such feeding therefore may be considered as a possible prophylactic measure in the prevention of milk fever.
D000222:Adaptation, Physiological; D000821:Animal Feed; D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism* / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000378:metabolism; D005232:Fatty Acids, Volatile / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D010319:Parturient Paresis / Q000517:prevention & control; D011247:Pregnancy; D011897:Random Allocation; D012417:Rumen / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D012756:Sheep / Q000378:metabolism*; D012757:Sheep Diseases / Q000517:prevention & control
D005232:Fatty Acids, Volatile; D002118:Calcium