Abstract: In this study the role of the glutamatergic system on feed intake in 24-hour-feed-deprived broiler cockerels was investigated. ICV injection of 0, 0.675, 1.25, and 2.5 nmol of glutamate reduced feed intake dose-dependently, and increased the latency time to start feeding. Pretreatment with 2.5 nmol HQCA, an ionotropic glutamate antagonist resulted in both an increase in feed intake and a decrease in latency of birds to start feeding. Pretreatment with 2nmol of MSPG, a metabotropic glutamate receptor antagonist, severely reduced feed intake and increased the latency to start feeding. These findings suggest, for the first time, that glutamate, acting as a neurotransmitter, is involved in feed intake regulation in broiler cockerels. This effect is probably mediated by both ionotropic and metabotropic receptors. It appears that both postsynaptic and presynaptic glutamate receptors are involved.
Key words: feed intake, broiler, glutamate, HQCA, MSPG