Effects of peripheral administration of ghrelin antagonist [D-Lys&sup&3&/sup&]-GHRP-6 on growth performance and blood biochemical indices in broiler chickens

摘要

In the present study, possible effects of peripheral administration of ghrelin antagonist [D-Lys&sup&3&/sup&]-GHRP-6 on chicken performance, thyroid hormones level and serum biochemical parameters were investigated. Broiler chicks divided into five experimental groups were reared up to day 42. On day 21, a treatment was assigned to the five groups: group 1 (control), chickens without any administration of peptide or solution; group 2 (G50), chickens with intraperitoneal (IP) injection of 50?ng per 100?g body weight (BW) of D-Lys&sup&3&/sup& peptide on day 21; group 3 (G100), chickens with IP injection of 100?ng per 100?g BW of D-Lys&sup&3&/sup& peptide on day 21; group 4 (G150), chickens with IP injection of 150?ng per 100?g BW of D-Lys&sup&3&/sup& peptide on day 21; and group 5 (G200), chickens with IP injection of 200?ng per 100?g BW of D-Lys&sup&3&/sup& peptide on day 21. On days 21 (post-injection) and 42 (post-rearing), blood samples were obtained from the animals for laboratory analyses. Experimental groups administered the GHS-R antagonist showed less feed intake – i.e., administration of greater doses led to less feed intake (&i&P&/i&?&?0.01). Daily weight gains within groups G150 and G200 decreased (&i&P&/i&?&?0.01) in comparison with the control. The feed conversion ratio (FCR) did not differ among the groups. There was a significant difference between control and experimental groups for glucose, total cholesterol and phosphorus levels (&i&P&/i&?&?0.01) in post-injection samples. In post-injection and post-rearing blood samples, the thyroid hormone (T&sub&3&/sub& and T&sub&4&/sub&) in 6?h increased in treated groups in comparison with the control (&i&P&/i&?&?0.01). The infusion of ghrelin antagonist [D-Lys&sup&3&/sup&]-GHRP-6 reduces feed intake and body weight. With regard to increase in T&sub&4&/sub& level, it can be inferred that [D-Lys&sup&3&/sup&]-GHRP-6 may increase metabolic rate, lipolysis and weight loss, which is similar to results obtained in mammalian species.