[The effect of 4'-galacto-oligosacchraide on sodium and potassium in growing rats]

The effect of 4'-galacto-oligosaccharide (4'-GL), fed at the 5% dietary level on sodium (Na) and potassium (K) absorption was investigated during four 3-day balance periods (days 15 and 17, 30 and 32, 45 and 47 and 60 and 62) of a 62-day feeding course in young male rats. The results obtained were as follows: 1) A decrease in urinary volume excretion and an increase in fecal weight were observed in the 4'-GL group, but growth rate was not affected by 4'-GL administration. 2) Fecal Na excretion, expressed either in milligrams or as a percent of intake, was significantly increased (p less than 0.05) in the 4'-GL group during the second (days 30 and 32) and third (days 45 and 47) balance periods. 3) Urinary K excretion, expressed either in milligrams or as a percent of intake, was significantly lower (p less than 0.05) in the 4'-GL group during the second and third balance periods. 4) While differences in Na and K retention between the two groups were not significant, a tendency for decreased Na retention and increased K retention was observed in 4'-GL group. 5) Rats fed the 4'-GL diet had heavier cecal weight, decreased Na concentration and increased K concentration in the cecum, than rats fed the control diet. 6) While no significant difference was found in Na or K concentration in plasma between the two groups, Na/K ratio in plasma was lower in the 4'-GL group.