IGF-I gene polymorphism and its effect on feed consumption and egg production in inbred synthetic White Leghorn

An experiment was conducted on inbred progeny to confirm the inheritance of IGF-I gene polymorphism and its effect and association with feed consumption and egg production. Parent generation of Synthetic White Leghorn population, which was categorized into four different groups viz. High feed consumption and High egg production (HH), Low feed consumption and High egg production (LH), High feed consumption and Low egg production (HL), Low feed consumption and Low egg production (LL) to find out the effect of IGF-I gene polymorphism on feed consumption and egg production. Population was further propagated by sib mating to produce inbred progeny, which were identified according to their dam's group viz. HH, LH, HL and LL. A total of 124 inbred Synthetic White Leghorn chicks were generated and reared in deep litter system under standard feeding, managemental and health care practices. At 16th week of age, 40 females and 40 males were housed in individual California cage system. Important economic traits were recorded on individual birds. Genomic DNA was extracted from these 80 inbred birds, by John's method with some modification. Chicken gene specific primers were used for amplification of IGF-I gene and amplicon was digested with Hinf-I for RFLP analysis. Polymorphic patterns were found in IGF-I gene. Gene (A and B) and Genotypic frequencies of AA, BB and AB genotypes were estimated. In IGF-I gene, BB genotype showed significantly (P < 0.05) higher AFE in both female (160.86) and male (159.70) inbred progeny as compared to other genotypes. HH group showed significantly (P < 0.05) higher TEN64 in male inbred progeny (225.20) and significantly higher in parental generation (256.90) and significantly higher EN51–60 as compared to HL group in both male (47.67) and female (49.71) inbred progeny and parental generation (62.10). HH and HL groups showed significantly (P < 0.05) higher DFC51–60 in female inbred progeny (110.56) and (110.54), respectively and parental generation (134.45) and (129.45), respectively. HL group showed significantly (P < 0.05) higher FC/E51–60 in female (235.90) and male (316.92) inbred progeny and HL (210.00) and LL (250.04) groups showed significantly (P < 0.05) higher FC/E51–60 in parental generation as compared to other groups.