Kaolinite ingestion facilitates restoration of body energy reserves during refeeding after prolonged fasting.
Résumé
Clay consumption is a spontaneous behavior currently observed in animals and humans, particularly during undernutrition. Often regarded as intestinal care products, ingested clays also enhance food efficiency, notably by increasing intestinal lipid uptake. Clay complementation could then optimize the reconstitution of energy reserves in animals with low lipid stocks consecutive to intensive fasting. The aim of this study was therefore to observe the effects of voluntarily kaolinite complementation during the refeeding of fasted rats to determine whether body mass, food uptake, lipid and mineral contents as intestinal morphology and protein profile were modified. This study examined two types of refeeding experiments after prolonged fasting. Firstly, rats with ad libitum access to food were compared to rats with ad libitum access to food and kaolinite pellets. Animals were randomly put into the different groups when the third phase of fasting (phase III) reached by each individual was detected. In a second set of experiments, rats starting phase III were refed with free access to food and kaolinite pellets. When animals had regained their body mass prior to fasting, they were euthanized for chemical, morphological, and proteomic analyses. Although kaolinite ingestion did not change the time needed for regaining prefasting body mass, daily food ingestion was seen to decrease by 6.8% compared with normally refed rats, without affecting lipid composition. Along the intestinal lining, enterocytes of complemented animals contained abundant lipid droplets and a structural modification of the brushborder was observed. Moreover, the expression of two apolipoproteins involved in lipid transport and satiety (ApoA-I and ApoA-IV) increased in complemented rats. These results suggest that kaolinite complementation favors intestinal nutrient absorption during refeeding despite reduced food uptake. Within the intestinal lumen, clay particles could increase the passive absorption capacity and/or nutrient availability that induce mucosal morphological changes. Therefore, clay ingestion appears to be beneficial for individuals undergoing extreme nutritional conditions such as refeeding and limited food supplies.