CENTRAL NEUROANATOMICAL SYSTEMS INVOLVED IN THE REGULATION OF FOOD-INTAKE IN BIRDS AND MAMMALS

The neural regulation of food intake seems to be quite similar in bird s and mammals. The ventromedial hypothalamic syndrome produced by lesi ons within the mediobasal hypothalamus of both birds and mammals is co mposed of several independent physiological and behavioral changes. Ot her neural sites known to be important in mammals for regulating food intake need to be examined in birds including the paraventricular nucl eus, nucleus tractus solitarius and parabrachial nucleus. Members of t he opioid and pancreatic polypeptide families are effective in stimula ting food intake in avian species. Both prolactin and growth hormone a re also efficacious in stimulating food intake. In contrast, cholecyst okinin inhibits food intake when administered intracerebroventricularl y. The autonomic and endocrine hypothesis developed to explain obesity in mammals appears to be quite applicable to genetic strains of comme rcial birds selected for meat production. Specifically the commercial broiler appears to display an imbalance of the autonomic nervous, syst em. The parasympathetic nervous system dominates as a consequence of i ntense genetic selection for growth rate.