Oral administration of lysine restores food intake and ventromedial hypothalamic dopamine in chicken on a lysine-free diet |
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| Authors: | MR Alam F Yoshizawa K Sugahara |
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| Institution: | 1. United Graduate School of Agriculture, Tokyo University of Agriculture and Technology , Tokyo 183-8509 , Japan;2. Department of Bio-productive Science, Faculty of Agriculture , Utsunomiya University , Utsunomiya 321-8505 , Japan;3. Department of Bio-productive Science, Faculty of Agriculture , Utsunomiya University , Utsunomiya 321-8505 , Japan |
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| Abstract: | 1. This study was conducted to examine whether oral administration of lysine solution affect food intake and the ventromedial hypothalamic (VMH) monoamines in chickens fed on a lysine-free diet. 2. Chickens were assigned to four treatment groups. Two groups of chickens were given two different doses of lysine solution (0·1?g and 0·07?g in 1?ml of saline) exogenously (orally) while being fed on a lysine-free diet, and these results were compared with a control diet plus saline group. Another group of chickens was fed on a lysine-free diet without lysine supplementation, and their results were compared with the lysine treated groups. The extracellular dopamine (DA), norepinephrine (NE) and serotonin (5-HT) in the VMH of freely moving chicken were measured by in vivo microdialysis. 3. There was no significant difference in food intake between the control diet and the lysine supplemented groups during the time-course of the experiments. Food intake significantly decreased at 4, 5 and 6?h in the lysine-free diet plus saline group compared with the lysine supplemented groups. Of the VMH monoamines, the DA concentration remained close to the baseline in the lysine supplemented groups. This DA concentration was significantly lower than the baseline in the lysine-free diet plus saline group at 3·5?h and thereafter. 4. No significant difference from the baseline was observed for NE in the lysine-free diet plus saline group. The 5-HT concentrations were close to the baseline for all groups throughout the experiments. 5. The findings suggest that oral administration of lysine solution to chickens fed on a lysine-free diet restored food intake which was associated with the variations of VMH DA concentration. |
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