The objective of this study was to assess the effect of monosodium glutamate (MSG) on broiler performance, blood chemistry and the brain tissues. A total of 120 day-old Lohman broiler chicks were randomly divided into four groups with 3 replicates (30 birds per treatment). Four approximately isonitrogenous and isocaloric diets with different levels of MSG viz. 0, 0.25, 0.5 and 1.0% were formulated. Feed and water were provided ad libitum throughout the experimental period of 49 days. The results revealed that total feed intake was significantly higher (P≤0.05)  in  chicks  fed  1%  MSG compared to other three groups. Final body weight gain was significantly (P≤0.05) lower in chicks fed 0.25 and 0.5% MSG compared to control group. Feed conversion ratio, serum total proteins and cholesterol levels were not affected by the dietary treatments. Serum lipids level decreased significantly (P≤ 0.01) by dietary MSG. Significant increase (P≤0.01) in serum uric acid level was observed in birds fed 0.5% MSG. Light microscopic examination of brain sections showed histopatholgical lesions in midbrain and cerebellum in birds fed 1% MSG. Midbrain sections showed neuron angulations, chromatolysis, fibrolamellation and gliosis. Cerebellum sections showed spongy degeneration and haemorrhagic foci. It concluded that high level of MSG (1%) has adverse effect on the nervous tissue of broiler chicks.

Key words: Monosodium glutamate, serum, biochemistry, brain tissue, broilers.