[The effect of single and intermittent fasting on cholesterolemia in rats of various ages]

Experiments studying the influence of single and repeated fasting on cholesterolaemia were performed in rats of both sexes and of our own breed (Wistar) aged 5, 10, 14 and 21 days of postnatal life and in adult rats. Cholesterol was determined by means of Lachema (CSSR) tests. The single fasting was realized in such way that one half of standard litter was separated from mother and nest for a period of 24 hours. Adult rats did not receive an appropriate diet for the same period. The repeated fasting was carried out as follows: in three successive days half of the litter was separated from mother for a period of 18 hours. For the remaining 6 hours the rats were returned to mother into the nest. Isolation was in both cases performed under optimal thermal conditions. Blood was taken by decapitation. Changes in total cholesterolaemia during ontogenesis (maximum up to 14 days of postnatal life) were confirmed. Fasting was found out to cause a significant decrease in cholesterolaemia in the first three age categories and in adult rats. In rats aged 21 days neither single nor repeated fasting caused a significant change in plasma cholesterol contents. In the first three age groups repeated fasting has a demonstrably higher effect, i.e. the decrease in cholesterolaemia is higher after this type of fasting than after the single one. The results are compared with our previous studies concerning the influence of fasting on the development of organism.