International Journal of Poultry Science1682-83561994-7992Asian Network for Scientific Information10.3923/ijps.2017.1.5PerdamaianA. B.I.SaragihH.T. S.S.G.DaryonoB. S.12017161Objectives: The aims of this study were to investigate the effect of crude protein and energy level in feed on insulin-like growth factor-I (IGF-1) expression level in a hybrid chicken (female Layer chicken×male Pelung chicken). Methodology: To study the correlation between feed type and IGF-1 expression level. Day-old chick (DOC) hybrids were divided into four groups and each group comprised 10 individuals. First group was fed with feed A [22% Crude Protein (CP) and 3100 kcal kg1 Metabolizable Energy (ME)], second group was fed with feed B (20% CP and 3300 kcal kg1 ME), third group was fed with feed C (21% CP and 2800 kcal kg1 ME) and fourth group was fed with standard feed after starving for 3 days post hatching. Chickens were observed from post-hatch to the 7th day and weighed (at 0, 3 and 7 days) and five individuals were sacrificed at the 7th day for IGF-1 analysis. Total RNA was isolated from the liver for gene expression analysis. Real-time PCR was used to study the IGF-1 expression profiles of each group after being normalized with β-actin. Results: The highest body weight was recorded for group 1, followed by group 2, 3 and 4. The IGF-1 expression level was noticeably high for feed A, B and C groups by 4.82, 3.82 and 1.9 fold, respectively, compared with the starved group. The weight highly correlated with IGF-1 expression level (R2 = 0.8). This moderate growth response to nutrition makes the hybrid chicken a suitable meat-type chicken. Conclusion: The result suggested that feed containing 22% CP and 3100 kcal kg1 ME is a promising starter for the Indonesian hybrid chicken.]]>Giachetto, P.F., E.N. Guerreiro, J.A. Ferro, M.I.T. Ferro, R.L. Furlan and M. Macari,200338697702Kaput, J. and R.L. Rodriguez,200416166177Fekete, S. and D. Brown,200755229239Damayanti, D.,20152015Nawaz, H., T. Mushtaq and M. Yaqoob,200643388393Resnawati, H. and I.A.K. Bintang,20052005Iskandar, S.,20052005Lin, S., H. Li, H. Mu, W. Luo and Y. Li et al.,20122012Livak, K.J. and T.D. Schmittgen,2001-ΔΔCT method.]]>25402408Benjamini, Y. and Y. Hochberg,199557289300SPSS.,2006Morris, T.R., 19689285295Kim, J.W.,20102316681676Saragih, H.T.S.S.G., R.T. Utomo, A.B.I. Perdamaian, U.E. Puspita and I. Lesmana et al.,2016Gallus gallus domesticus).]]>2016Kamran, Z., M. Sarwar, M. Nisa, M.A. Nadeem, S. Mahmood, M.E. Babar and S. Ahmed,200887468474Rosa, P.S., D.E. Faria Filho, F. Dahlke, B.S. Vieira, M. Macari and R.L. Furlan,20079117122Emler, C.A. and D.S. Schalch,1987120832883Scacchi, M., A.I. Pincelli and F. Cavagnini,200324200224Garcia-Tornadu, I., G. Risso, M.I. Perez-Millan, D. Noain and G. Diaz-Torga et al.,2010385969