Genetic and genomic study of intake and feed efficiency in Nellore (Bos indicus) cattle

Author(s)

Miguel Henrique de Almeida Santana

• Document type: Doctoral Thesis
• Press: Pirassununga.
• Institution: Universidade de São Paulo (USP). Faculdade de Zootecnica e Engenharia de Alimentos (FZE/BT)
• Defense date: 2013-12-13

Examining board members

José Bento Sterman Ferraz; Luiz Lehmann Coutinho; Paulo Roberto Leme; Paulo Rossi Junior; Luis Felipe Prada e Silva

• Advisor: José Bento Sterman Ferraz

Abstract

The aim of this study was to evaluate the genetic parameters and correlations of intake and feed efficiency with performance and carcass traits, and perform the genome-wide association study (GWAS) for dry matter intake (DMI), residual feed intake (RFI) and average daily gain (ADG) in Nelore cattle (Bos indicus). Data from 1,058 animals phenotyped for DMI, feed conversion ratio (FCR), RFI, residual body weight gain (RG), residual intake and body weight gain (RIG), average daily gain (ADG) and carcass traits were used. Genetic parameters of DMI, FCR, RFI, RG and RIG and their correlations with ADG and carcass traits were estimated using Bayesian approach. Four SNPs (Single Nucleotide Polymorphism), located in genes related to appetite control (NPY and PDE3B) and ion transport (TRPM3 and ITPR1), were associated with performance, intake and feed efficiency traits. Additionally, the animals were genotyped in two different chips (Illumina Bovine HD and Illumina BovineSNP50) and genotypic information were combined by imputation. The hundreds of thousands of SNPs were used for GWAS of DMI, RFI and ADG by GRAMMAR-Gamma association test. The heritability of DMI, RFI and RIG was 0.40, 0.38 and 0.54, respectively. No associations were found in SNPs in genes TRPM3, NPY and ITPR1, however, the SNP in PDE3B gene was significantly associated (P≤0.05) with DMI, RFI and RIG. The SNPs most associated with DMI and RFI, in GWAS, are located on chromosomes 4, 8, 14 and 21 in genomic regions associated with ion transport and appetite regulation. The GWAS pointed chromosomes 3, 6 and 10 as those containing more associated markers for ADG. Feed intake and feed efficiency are amenable to genetic selection, especially the RIG. The PDE3B gene should be further studied thus appears to be related to these phenotypes. Finally, this work shows genomic regions by genome-wide association, related to DMI, RFI and ADG, believed to be the first study of its kind for these phenotypes in Nellore cattle. (AU)

• FAPESP's process: 12/03551-5 - Genomic study for intake and feed efficiency in Nellore cattle
• Grantee: Miguel Henrique de Almeida Santana
• Support Opportunities: Scholarships in Brazil - Doctorate