Physiologic changes in acetylcholinesterase, specific acetylcholinesterase and total protein concentrations in the brain of domestic fowl (Gallus domesticus) cocks fed dietary monosodium glutamate
The objective of this study was to determine the effect of varied levels of monosodium glutamate (MSG) on acetylcholinesterase, specific acetylcholinesterase and total protein concentrations in the brain regions of chicken cocks. Three hundred cocks of 5 months old were used for the trial and they were randomly allotted to six dietary treatments: A, B, C, D, E and F containing 0.00 (control), 0.25, 0.50, 0.75, 1.00 and 1.25 g MSG/kg diet respectively. Two birds were housed per cell in the cage for the feeding trial in a completely randomised designed and the experiment lasted 12 weeks. At the end of the feeding trial, three cocks/replicate were sacrificed and brain dissected into different regions. The different regions of the brain studied were medulla oblongata, olfactory lobe, optic lobe and cerebellum. Samples were collected from these regions and homogenised to determine acetylcholinesterase, specific acetylcholinesterase and total protein concentrations. Result showed that the acetylcholinesterase activity in the olfactory lobe and pineal gland brain regions were not significantly (P≥0.05) influenced by the dietary MSG among the treatments when compared with the control diet. The cerebellum and medulla oblongata were only significantly (p<0.05) influenced when fed above 0.50 g MSG/kg diet while optic lobe was significantly (p<0.05) influenced at an inclusion level above 0.75 g MSG/kg diet. The total protein concentrations were significantly (p<0.05) higher in olfactory lobe and cerebellum of the brain regions of cocks fed 0.25 and 0.50 g MSG/kg and control diet than those fed other diets. Total protein concentration in the pineal gland and optic lobe regions of the brain in cocks fed the control diet were not significantly (P≥0.05) different among the treatment diets. This study suggests that dietary MSG above 0.50 g/kg diet increased the activities of acetylcholinesterase concentration in the optic lobe, cerebellum, pineal gland, medulla oblongata and reduced the total protein in the olfactory lobe, cerebellum and medulla oblongata regions of the brain with tendency to impair brain function.