PREVENTION OF COPROPHAGY DOES NOT ALTER THE HYPOCHOLESTEROLEMIC EFFECTS OF OAT BRAN IN THE RAT

Male rats were fed on either a non-purified rodent diet (JS) or choles terol-free purified diets containing wheat bran (WB) or oat bran (OB). Some animals were allowed normal access to their faeces for coprophag y (coprophagy+), while in others coprophagy was prevented by placement of a plastic cup over the anus (coprophagy-). Direct ingestion of fae ces from the anus was observed in the former groups. Food intake was u naffected by diet or coprophagy status and body weight gain was unchan ged with OB -and JS -- but was significantly lower with WB -. Plasma c holesterol was highest with WB and equally lower with OB and JS and wa s unaffected by coprophagy status. Plasma triacylglycerols were highes t with OB and were unaffected by coprophagy status. Caecal digesta mas s was highest with JS, intermediate with OB and lowest with WB. Digest a mass was unaffected by coprophagy status with WB and JS but was high er with OB -. Digesta moisture content was lowest with WB + but highes t with WB -. Digesta volatile fatty acid (VFA) concentrations were sim ilarly lower with OB + and OB -, but were significantly lower with JS- and WB- than in the corresponding coprophagy+ group. In all groups di gesta butyrate concentrations were reduced by coprophagy prevention. P ools of total VFA, acetate and butyrate in the digesta were highest wi th JS. Pools of total VFA in digesta were highest with JS +, OB + and OB - and lowest with WB + and WB -. The propionate pool was highest wi th OB , intermediate with OB +, and equally low in all other groups. T he pool of butyrate was highest with JS + and lowest with OB-. Effects of oats and wheat on plasma cholesterol in the rat do not seem to be mediated through faecal re-ingestion.