Effect of intracerebroventricular (ICV) injection of antimicrobial peptide expressed in the body-2 (LEAP-2) and its interaction with cannabinoid and ghrelin systems on food intake in broiler chickens

Liver-expressed antimicrobial peptide 2 (LEAP-2), initially identified as an antimicrobial peptide which endocannabinoid and ghrelin action may occur via changes in Leap2 expression. This study aimed to determine effect of ICV injection of LEAP2and its interaction with cannabinoid and ghrelin systems on food intake in broiler chickens. In the present study 4 experiments were conducted, each containing 4 experimental groups. In experiment 1, chicken injected with group 1 ICV injection of saline, group 2 with LEAP2 (0.75 nmol), group 3 with LEAP2 (1.5 nmol) and group 4 with LEAP2 (3 nmol). In experiment 2, chicken received ICV injections as group 1: saline, group 2: (D-Lys-3)-GHRP-6 (0.5 nmol), group 3: LEAP2 (3 nmol) and group 4 with co injection of the (D-Lys-3)-GHRP-6 + LEAP2. In experiment 3 chiken received ICV inejctions as: group 1: saline, group 2: SR141716A (6.25 µg), group 3: LEAP2 (3 nmol) and group 4 with co injection of the SR141716A + LEAP2. In experiment 4 chiken received ICV inejctions as: group 1: saline, group 2: AM630 (1.25 µg), group 3: LEAP2 (3 nmol) and group 4 with co injection of the AM630 + LEAP2. Immediately following the infusions, the broilers were returned to their respective boxes, where they were provided with pre-weighed meal and fresh water ad libitum. The cumulative meal consumption was subsequently measured at intervals of 30, 60, and 120 min post-administration. According to the results, ICV injection of the LEAP2 (1.5 and 3 nmol) significantly decreased food intake (P<0.05). Co-injection of the (D-Lys-3)-GHRP-6 + LEAP2 significantly decreased LEAP2-induced hypophagia (P<0.05). Co-injection of the (D-Lys-3)-GHRP-6 + LEAP2 significantly increased hypophagic effect of the LEAP2 (P<0.05). Co-injection of the SR141716A + LEAP2 significantly amplified LEAP2-induced hypophagia compared to control group (P<0.05). Co-injection of the AM630 + LEAP2 significantly amplified LEAP2-induced hypophagia compared to control group (P<0.05). These results suggested that LEAP2-induced hypophagia mediates via ghrelin and CB₁ and CB₂ receptors in neonatal chicken.