Synergistic Effects of Leptin with Histamine, Melanocortin and Corticotropin on Control of Food Intake in Broiler Chickens

Appetite modulation is a set of physiological mechanisms that influence the various areas of the central nervous system. Melanocortin, corticotropin, and histaminergic systems have an important role in the central control of food intake in birds. On the other hand, leptin decreases food intake in birds. Therefore, the aim of this study was to explain the synergistic effects of melanocortin, corticotropin, and histaminergic systems with leptin on food intake in neonatal broiler chickens.

A total of one hundred and thirty-two neonatal chicks were randomly divided into three experimental groups. Each experiment had a control group and three treatment groups (n=11 in each group). In all experiments, 3-hour food-deprived birds received intracerebroventricular ‎injections of either control diluent or drug solution. Then, the birds had ad libitum access to the ‎food and fresh water, and then cumulative food intake (gr) was measured based on the ‎percentage of the body. In the first experiment, normal saline, leptin (2.5 µg), histamine (75 nmol) and leptin plus histamine were injected.‎ The other experiments were conducted as experiment 1, but in experiment 2, MTII (MC3/MC4 receptors agonist) (2.45 pmol) and in experiment 3, urocortin (CRF1/CRF2 receptors agonist) (0.1 µg) were injected instead of histamine, either alone or in combination with leptin.

The results of the present study showed that co-injection of histamine and leptin, MTII plus leptin, and urocortin plus leptin significantly reduced food intake in broiler chickens (P<0.001).

According to the results of the present study, there is probably a synergistic effect between melanocortin, corticotropin and histaminergic systems with leptin on food intake control of neonatal broiler chicks.