Consequências do aleitamento complementar com leite de vaca para o desenvolvimento de ratos e ratas wistar

Abstract

In humans, complementary feeding should be started after 6 months; the introduction of any food or water before this time is considered early weaning, which is associated with health problems in adulthood. Cow s milk is a common food introduced to children less than 6 months that has an inadequate nutritional composition, mainly due to a worse casein:whey protein ratio compared to human milk. We hypothesized that suckling rats fed with cow s milk, which is rich in protein and bioactive peptides, develop further metabolic dysfunction. From postnatal day (PN) 14 to 20, Wistar rat pups were divided into 3 groups: rat milk (RM), in which pups received rat milk orally in a syringe; cow s milk (CM), in which pups received cow s milk; and CM with high protein (CM-H), in which pups received CM with twice the amount of protein as rat milk. Pups were killed on PN21 and PN180. At PN21, CM males had lower visceral fat mass compared with other groups. Serum corticosterone was higher in CM-H males, despite no change in glucocorticoid metabolism in liver and visceral fat. At PN180, CM and CM-H females had greater fat depots and hyperphagia, although there was no alteration in leptinemia and leptin signaling in the hypothalamus. CM-H females had a trend of hypoinsulinemia and a significant decrease in HOMA-β, suggesting lower insulin secretion. Males from the CM-H group had only lower total body protein mass. CM males had hypercorticosteronemia associated with lower expression of 11βHDS1 in visceral fat. In conclusion, early introduction of cow s milk in neonate rats leads to gender-dependent differences in metabolic and endocrine parameters in the short- and long-term.