Characterization of global hepatic gene expression profile associated with feed efficiency in Nelore cattle

Author(s)

Pâmela Almeida Alexandre

• Document type: Master's Dissertation
• Press: Pirassununga.
• Institution: Universidade de São Paulo (USP). Faculdade de Zootecnica e Engenharia de Alimentos (FZE/BT)
• Defense date: 2015-03-30

Examining board members

Joanir Pereira Eler; Luiz Lehmann Coutinho; Paulo Roberto Leme

• Advisor: Joanir Pereira Eler

Abstract

The selection of beef cattle to feed efficiency (FE) traits is very important not only from the productive and economic perspective but also for helping to reduce the environmental impact of livestock production. Being a multifactorial and expensive to measurement trait, the aim of this work was to analyze the liver global gene expression profile of animals with high feed efficiency (HFE) and low feed efficiency (LFE), to identify new genes, biological functions and regulatory genes associated to this phenotype. For this purpose, 98 Nellore cattle were evaluated regarding feedlot performance, FE measures, carcass ultrasound, serum biochemistry, biometric measures, carcass evaluation, meat tenderness and evaluation of ruminal fluid. In addition, 8 animals of HFE and 8 animals of LFE, selected by the measure of residual intake and body weight gain at the end of feeding trial, had liver transcriptomic profile data analyzed by three approaches: differential gene expression, co-expression and differential co-expression. It was observed that HFE and LFE groups showed equal performance for initial and final weight, weight gain, carcass yield and rib eye area. On the other hand, the animals of LFE had higher feed intake and increased deposition of subcutaneous and visceral fat. In addition, animals of LFE showed higher levels of cholesterol and GGT and transcriptomic profile analysis showed to be related to immune response, inflammation and lipid metabolism. Based on these results and research in humans we created the hypothesis that the LFE animals are more susceptible to bacterial infection in the liver in response to the change of pasture diet to feedlot diet. (AU)

• FAPESP's process: 12/14792-3 - Characterization of global gene expression associated with feed efficiency in Nelore cattle
• Grantee: Pâmela Almeida Alexandre
• Support Opportunities: Scholarships in Brazil - Master