EFFECT OF FOOD RESTRICTION ON CECAL MICROBIOTA AND SHORT-CHAIN FATTY-ACID CONCENTRATIONS IN RATS

The effect of food restriction on the caecal bacterial and short-chain fatty acid (SCFA) concentrations in Wistar rats was studied since foo d restriction (FR) and the intestinal microbiota have effects on aging and other physiological processes of laboratory animals. Rats were fe d a purified diet ad libitum (control), and 80 per cent or 60 per cent of the control intake. FR resulted in increased numbers of bifidobact eria, Bacteroidaceae, and lactobacilli in proportion to the restrictio n rate. In particular, bifidobacteria significantly increased in the 6 0 per cent fed group (P<0.05); and Bacteroidaceae in the 60 per cent f ed group (P<0.001) and in the 80 per cent fed group (P<0.001). Enteroc occi and staphylococci did not change in concentration during FR. The number of enterobacteria decreased somewhat, but not significantly, in the 40 per cent FR. The total SCFA concentrations were reduced remark ably in proportion to the FR rate, especially butyrate which decreased strikingly compared with the other SCFAs. The present results suggest that FR may influence the physiological processes in age changes thro ugh alterations in the gut microbiota and its metabolic products.