Effects of central injection of liver-expressed antimicrobial peptide-۲ (LEAP۲) on feed intake in broiler chickens: interactions with opioidergic and serotonergic systems

Background: One of the factors influencing the regulation of food intake in birds and mammals is opioid and serotonergic receptors. The present study aims to investigate the role of the antimicrobial peptide expressed in the liver (Leap-۲) in regulating food intake in broiler chickens. Methods: This study was conducted on Ross ۳۰۸ broiler chickens kept in separate rooms with a ۲۴-hour light cycle, a temperature of ۳۱ _x۰۰۰۰_b۱ ۲_x۰۰۰۰_b۰C, and free access to water and starter diet. The intracerebroventricular injection was performed at the age of ۵ days. To administer the intracerebroventricular injection in chickens, the head of the chicken was fixed in a special stereotaxic device, and then the injection was performed using a Hamilton syringe. At the end of the experiment, the chickens were euthanized, and only data from chickens where the dye was correctly injected into the lateral ventricle were analyzed because Evans blue dye at ۰.۱% in normal saline was used as a marker. The drugs under investigation were dissolved or diluted in this solution. The injection volume in each group was ۱۰ microliters, and the number of chickens in each group was ۱۲. The chickens were deprived of food ۳ hours before the experiment, and after the injection, they were returned to their cages with free access to food and water. The cumulative food intake was measured at ۳۰, ۶۰, and ۱۲۰ minutes after the injection. Results: ICV injection of the antimicrobial peptide expressed in the liver (Leap-۲) significantly reduced food intake. Injection of the ۵-HT۲c receptor antagonist (SB۲۴۲۰۸۴) could not change the food intake at all experimental times. However, the simultaneous injection of SB۲۴۲۰۸۴ and Leap-۲ weakened the reduction in food intake caused by Leap-۲. Similarly, _x۰۰۰۳_-FNA + Leap-۲ weakened the reduction in food intake caused by Leap-۲. Conclusion: The effects of the antimicrobial peptide expressed in the liver (Leap-۲) on appetite regulation and food intake are mediated by the serotonergic and opioid systems (through ۵-HT۲c receptors and opioid receptors) in broiler chickens.

کلیدواژه ها:

Food intake ، broiler chickens ، opioid receptors ، serotonergic receptors ، Leap-۲