Evolution of glycogen and blood metabolites after controlled suckling at two periods of lactation in young rabbits

In natural conditions young rabbit nurses once a day and therefore ingests the whole of his daily caloric intake during a single meal. The present work investigates glucose homeostasis during perinatal period in young rabbit by assessing blood glucose and glycogen stores before and after one single meal. Ponderal data, glycogen and blood metabolites were determined in 1-4 day- and 17-21 day-old rabbits before suckling and at different times (1, 3, 6, 9, 24, 48, 72 h) after controlled suckling. In "young" and "old" rabbits hepatic glycogen stores were exhausted after 48 and 72 h of fast. Within the first hours following milk ingestion, muscle and carcass glycogen did not vary until 9 h in the "young" and until 24 h in the "old" without notable variation of glycemia. From 24 to 72 h young rabbits were in a fasting period with low hepatic glycogen and a decrease of muscle and carcass glycogen, but glycaemia decreased only slightly at 48 and 72 h in "young" and at 72 h in "old" As blood alanine was decreased, it appears that gluconeogenesis was effective and that alanine-glucose and Cori cycles were operating in these conditions.