Shahid Bahonar University of Kerman and Iranian Biotechnology Society Agricultural Biotechnology Journal 2228-6705 18 3 2026 08 23 Insulin-like growth factor binding protein gene polymorphisms and its effect on some productive and physiological traits of local Iraqi chicken Insulin-like growth factor binding protein gene polymorphisms and its effect on some productive and physiological traits of local Iraqi chicken 269 286 5415 10.22103/jab.2026.27008.1872 FA Bassam G. M. AL-Khatib Department of Animal Production, College of Agricultural Engineering Sciences, University of Baghdad, Baghdad, Iraq. 0000-0002-9439-6442 Alan A. Noori Department of Animal Production, College of Agricultural Engineering Sciences, University of Baghdad, Baghdad, Iraq. 0000-0003-1949-9502 H. A. Al-Mashhadani Department of Animal Production, College of Agricultural Engineering Sciences, University of Baghdad, Baghdad, Iraq. 0009-0007-9959-9656 Journal Article 2026 04 14 ObjectiveInsulin-like growth factor binding protein (IGFBP) plays a crucial role in the growth and development of chicken embryos and during the post-hatching stage. The aim of this study was to investigate IGFBP-2 gene polymorphisms and their effects on some productive and physiological traits of local Iraqi chicken.Materials and methodsThis study was conducted at the poultry farm of the College of Agricultural Engineering Sciences, University of Baghdad. One hundred local chickens before sexual maturity were used in this study. Blood samples were collected from the wing vein to extract DNA and molecular analysis and PCR amplification. Blood serum was also collected to measure biochemical parameters including total protein, glucose, lipid profile, albumin, and globulin concentrations. Production traits were recorded from the first egg production for a period of 100 days, which was divided into seven periods. These traits included number of eggs produced, mean egg weight, egg mass, age and body weight at sexual maturity, and mean feed consumption. The qualitative characteristics of the egg were also measured. PCR was performed to amplify a 386 bp fragment of the IGFBP-2 gene. The amplified fragments were then sequenced using the Sanger method. Results Three genotypes wild (TT), heterozygous (TC), and mutant (CC) were obtained, with two alleles T and C. The CC genotype showed a significantly higher frequency (p≤0.01) compared with TC and TT genotypes (59%, 30%, and 11%, respectively). Genotype had a significant effect (p≤0.05) on the number of eggs produced only in the third week. The TT had the superiority over CC (47.09 and 44.09) respectively. A significant effect (p≤0.05) was observed for eggshell weight, where the TC genotype was superior to CC (7.14 vs. 6.63 g). For yolk height, TT and TC genotypes showed significantly higher values than CC (19.09, 19.00, and 17.77 mm, respectively). For albumen height, the TT genotype showed a significant increase compared with CC (7.38 vs. 6.49 mm). A significant effect (p≤0.05) was also observed on serum albumin concentration, and the CC genotype showed a significantly higher value than TC (2.51 and 2.34 g/dL, respectively). No other significant effect was observed on blood serum biochemical characteristics.ConclusionOur results show that polymorphism in the IGFBP-2 gene can probably influence some production and egg quality traits in local Iraqi chickens. So, it can be considered as potential genetic marker for selection programs. ObjectiveInsulin-like growth factor binding protein (IGFBP) plays a crucial role in the growth and development of chicken embryos and during the post-hatching stage. The aim of this study was to investigate IGFBP-2 gene polymorphisms and their effects on some productive and physiological traits of local Iraqi chicken.Materials and methodsThis study was conducted at the poultry farm of the College of Agricultural Engineering Sciences, University of Baghdad. One hundred local chickens before sexual maturity were used in this study. Blood samples were collected from the wing vein to extract DNA and molecular analysis and PCR amplification. Blood serum was also collected to measure biochemical parameters including total protein, glucose, lipid profile, albumin, and globulin concentrations. Production traits were recorded from the first egg production for a period of 100 days, which was divided into seven periods. These traits included number of eggs produced, mean egg weight, egg mass, age and body weight at sexual maturity, and mean feed consumption. The qualitative characteristics of the egg were also measured. PCR was performed to amplify a 386 bp fragment of the IGFBP-2 gene. The amplified fragments were then sequenced using the Sanger method. Results Three genotypes wild (TT), heterozygous (TC), and mutant (CC) were obtained, with two alleles T and C. The CC genotype showed a significantly higher frequency (p≤0.01) compared with TC and TT genotypes (59%, 30%, and 11%, respectively). Genotype had a significant effect (p≤0.05) on the number of eggs produced only in the third week. The TT had the superiority over CC (47.09 and 44.09) respectively. A significant effect (p≤0.05) was observed for eggshell weight, where the TC genotype was superior to CC (7.14 vs. 6.63 g). For yolk height, TT and TC genotypes showed significantly higher values than CC (19.09, 19.00, and 17.77 mm, respectively). For albumen height, the TT genotype showed a significant increase compared with CC (7.38 vs. 6.49 mm). A significant effect (p≤0.05) was also observed on serum albumin concentration, and the CC genotype showed a significantly higher value than TC (2.51 and 2.34 g/dL, respectively). No other significant effect was observed on blood serum biochemical characteristics.ConclusionOur results show that polymorphism in the IGFBP-2 gene can probably influence some production and egg quality traits in local Iraqi chickens. So, it can be considered as potential genetic marker for selection programs. https://jab.uk.ac.ir/article_5415_3891b14b5d8cce2fdd8dcdb4ded28f6d.pdf