SNPs of Leptin, IGF-1 and NPY genes in dairy and beef cattle of Tandil, Argentina

MILANO, GUILLERMO D.; BAKKER, MARÍA L.; NADIN, LAURA; QUINTANA, SILVINA; FERRAGINE, MARÍA DEL CARMEN

Foz do Iguaçu

Congreso; 54th Annual Meeting of the Brazilian Society of Animal Science; 2017

Sociedade Brasileira de Zootecnia

Genetic variants named Single Nucleotide Polymorphisms (SNPs) have been associated with differences in animal performance, partially explained by effects on body metabolism but also animal behaviour. Research studies with beef cattle, the majority in feedlot, have shown that it is possible to discriminate animals with lower Residual Feed Intake (RFI), an index of better feed efficiency, by genotyping favorable alleles of certain SNPs. A recent study in Uruguay showed that SNPs of Leptin (AF120500-198, favorable allele C), IGF-1 (AF017143-512, favorable allele C) and NPY (AY491054-666, favorable allele G) were strongly associated with lower RFI also under grazing. In the present report, alleles of these SNPs were genotyped in 18 dairy (Holando Argentino (HA), 175 ± 15 kg LW) and 12 beef (10 Aberdeen Angus and 2 Hereford (AA-H), 230 ± 20 kg LW) calves from herds of Tandil, Argentina (37° 19? S, 59° 08? W). Blood was obtained by jugular venipuncture in heparinized tubes and stored at -20°C. Control DNA from cattle with known allelic variants were obtained from Ana Trujillo (Facultad de Agronomía, Universidad de la República, Uruguay) for validation. Genotyping was performed by real time PCR using EvaGreen as intercalating fluorescent dye and High Resolution Melting analysis in a Rotor Gene Q thermocycler. The allelic frequency of favorable alleles for NPY, Leptin and IGF-1 were, respectively, 0.94, 0.60 and 0.60 in HA, and 0.42, 0.25 and 0.45 in AA-H. In this preliminary study, despite of the small sample, it was interesting however to note: firstly, the higher allelic frequency of favorable allele G for NPY in HA (0.94) in comparison with AA-H (0.42) and, conversely, the higher frequency of unfavorable allele T for Leptin (0.75) in AA-H in comparison with HA (0.40). The proportion of total sampled animals found favorable homozygous for one, two, and the three SNPs altogether was 0.17, 0.17 and 0.17 in HA and 0.27, 0.00 and 0.00 in AA-H. The possible presence of a high proportion of unfavorable alleles for these SNPs and its implications on RFI in beef cattle under different feeding systems in Argentina should be further investigated.