Effect of Leptin and IGFBP-3 Gene Polymorphisms on Serum IgG Level of Cattle Calves

Leptin and IGFBP-3 are two proteins that play an important role in growth and metabolism of the animals. They are also involved in the immune function of animals and, thus, are candidate genes for the study of association with immune functions. Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) of these two genes was done to screen 64 crossbred (Holstein Friesian${\times}$Hariana) female calves of one year of age. From each RFLPs (fragments) three genotypes were observed. In all the RFLPs the mutant homozygotes were very less in numbers and, hence, were excluded from the least squares analysis. The serum IgG level was estimated using SRID assay. The mean level of serum IgG was $28.83{\pm}2.73mg/ml$. The effect of these identified genotypes on serum IgG level of calves at one year of age was analysed using least squares analysis. The HaeIII RFLP-AB genotype had significantly (p<0.05) higher serum IgG level ($31.86{\pm}3.05$) than the HaeIII RFLP-AA ($25.62{\pm}2.96$) genotype. There was no significant effect of leptin genotypes on the IgG level. The present results indicated a role of the IGFBP-3 gene on serum IgG level of cattle calves.