LOW DIETARY-PROTEIN IMPAIRS BLOOD-COAGULATION IN BHE CDB RATS/

The influence of dietary protein on blood coagulation tests was evalua ted in BHE/cdb rats. Three experiments were conducted in order to comp are effects of diets with low (8 g/100 g diet) or high (38 g/100 g die t) protein, to establish values for coagulation tests at intermediate (12-30 g/100 g diet) concentrations of dietary protein, and to compare feeding identical quantities of diets with 8 g protein/100 g diet vs. 18 g protein/100 g diet. After 4 wk of feeding the semipurified diets , bleeding time exceeded 15 min in the groups fed low protein diets, c ompared to a range of 3-6 min for the groups fed high protein diets. S everal in vitro tests of coagulation were abnormal in the rats fed low protein diets. For example, prothrombin time averaged 27 +/- 8 s in r ats fed 8 g protein/100 g diet plus beef tallow, but 17 +/- 1 s in rat s fed 38 g protein/100 g diet plus tallow. The coagulation deficit in rats fed low protein was not affected by fat source (tallow vs. menhad en oil), but fibrinogen was elevated in rats fed diets with menhaden o il. Conversely, no differences in coagulation tests were observed amon g rats fed 12-30 g protein/100 g diet. Bleeding times ranged from 7 to 9 min, and prothrombin time was 17-18 s. Significant differences in p lasma fibrinogen concentration and prothrombin time were observed in r ats fed 8 vs. 18 g protein/100 g diet at a fixed rate of 6 g/100 g bod y weight. Platelet and blood cell numbers were unaffected by dietary p rotein. The evidence for multiple deficits in the coagulation system s uggests that hepatic function in BHE/cdb rats may become impaired when the rats are fed low protein diets of the composition used here.