Adaptation of the maternal intestine during lactation.

One of the most dramatic adaptations to lactation is a large increase in the size and complexity of maternal intestine. Although there are few data on changes in intestinal size, intestinal enlargement has been observed in many taxonomic groups. In this review I describe the morphological and physiological changes in the intestinal mass of lactating animals and discuss their functional significance. The observed increases maintain the digestive efficiency of the food, as well as insure adequate absorption of nutrients in the face of the increased energy demand that accompanies lactation. The extent of the increase in size is proportional to the increase in energy demand. It is clear that if the intestine did not accommodate during lactation mothers would not have the capacity to absorb the nutrients need to maintain their energy demand.