Effects of peripheral administration of ghrelin antagonist D-Lys3-GHRP-6 on growth performance and blood biochemical indices in broiler chickens

摘要

In the present study, possible effects of peripheral administration ofghrelin antagonist [D-Lys]-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 withintraperitoneal (IP) injection of 50 ng per 100 g body weight (BW) of D-Lys peptide on day 21; group 3(G100), chickens with IP injection of 100 ng per 100 g BW of D-Lys peptide on day 21; group 4 (G150), chickens with IP injection of 150 ng per 100 gBW of D-Lys peptide on day 21; and group 5 (G200), chickens with IP injection of 200 ng per 100 g BW of D-Lys peptide on day 21. On days 21 (post-injection) and 42 (post-rearing), blood samples were obtained from theanimals for laboratory analyses. Experimental groups administered the GHS-Rantagonist showed less feed intake – i.e., administration of greater doses ledto less feed intake (  0.01). Daily weight gains within groupsG150 and G200 decreased (  0.01) in comparison with thecontrol. The feed conversion ratio (FCR) did not differ among the groups. Therewas a significant difference between control and experimental groups forglucose, total cholesterol and phosphorus levels (  0.01) inpost-injection samples. In post-injection and post-rearing blood samples, thethyroid hormone (T and T) in 6 h increased in treated groups in comparison with the control (  0.01). The infusion of ghrelin antagonist [D-Lys]-GHRP-6 reduces feed intake and body weight. With regard to increase in T level, it can be inferred that [D-Lys]-GHRP-6 may increase metabolic rate, lipolysis and weight loss, which is similar to results obtained in mammalian species.