Effect of polymorphisms linked to LEP gene on its expression on adipose tissues in beef cattle

In cattle, genetic markers at the leptin (LEP) gene and at those linked to the gene have been described as affecting calving interval (markers LEPSau3AI and IDVGA51), or daily weight gain (BMS1074 and BM1500). This work investigated the effect of these alleles on LEP mRNA levels in cattle subcutaneous and omental adipose tissues. A sample of 137 females of a Brangus-Ibage beef cattle herd was analysed to evaluate the distribution of the polymorphisms; then, animals having at least one of the IDVGA51*181 (allele 181 at marker IDVGA51; six animals), LEPSau3AI*2 (four), BMS1074*151 (13), BM1500*135 (six) alleles and a control group composed of animals without any of these alleles (four animals) were submitted to surgery to obtain omental and subcutaneous adipose tissues. Leptin mRNA expression was quantified by TaqMan RT-PCR, using 18S rRNA as internal control and adjusted for the effect of body condition score, through regression analysis. Omental fat had LEP gene expression 33% lower than the subcutaneous tissue. Carriers of IDVGA*181 and BMS1074*151 showed subcutaneous fat leptin mRNA levels higher than the controls. Leptin controls feed intake and coordinates reproduction; therefore, animals with higher LEP gene expression will probably have lower daily weight gain than others with similar forage offer and nutritional condition and probably will also have longer calving interval.