This research determined the effect of monosodium glutamate (MSG) on selected tissue lipids and haematological indices of neonatal and adult Wistar rats. Pups were administered 4 mg/kg MSG on postnatal days 2, 4, 6, 8, and 10, raised for 32 weeks, and afterwards divided into 3 groups (n = 7) and administered saline, 5 and 10 mg/kg body weight of MSG, respectively, for 6 weeks. Two other groups, not exposed to MSG at neonatal age, were similarly administered 5 and 10 mg/kg body weight of MSG, respectively, for 6 weeks. The control received saline. Serum and brain lipids and haematology were determined and compared. Body weight was found to decrease (P<0.05) in animals exposed to MSG. The brain weights and lipids were found to increase but non-significantly, relative to normal control. Serum lipids decreased in groups previously exposed to MSG at the neonatal stage. Wistar rats exposed to MSG at the adult stage only showed an increased level of serum lipids. The red blood cells, haemoglobin and haematocrit decreased in groups exposed to MSG at both neonatal and adult stages. The white blood cells, lymphocytes, granulocytes, and platelets revealed increased levels in all MSG-exposed rats. In sum, the effects of adult and neonatal exposure to MSG were similar–both caused weight disorientation and dyslipidaemia, increased tendency to induce anaemia and tissue inflammation. Hence the biochemical basis for which neonates rather than adult rats are used in MSG-obesity induction may not reside in lipid metabolism and the haematopoietic system.
