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| Author(s): |
Luana Lelis Souza
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Jaboticabal. 2023-05-12. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal |
| Defense date: | 2023-03-13 |
| Advisor: | Josineudson Augusto II de Vasconcelos Silva; Maria Eugênia Zerlotti Mercadante |
| Abstract | |
Genetic selection to reduce methane emissions (CH4) by ruminants is a strategy to mitigate CH4 because the improvements are cumulative and permanent over generations. The objective of this study was to estimate the heritability and perform the genomic wide association study of CH4 emission traits in Nellore cattle. Data were collected in two genetic improvement programs (Instituto de Zootecnia (IZ) and Qualitas). The animals were evaluated in feed efficiency tests. Diets consisted of 60% roughage and 40% concentrate. Methane was evaluated in 751 Nelore (48 females from the IZ, 564 males from the IZ and 139 males from the Qualitas), for five consecutive days, using the flux hexafluoride technique as a tracer gas. Methane emissions in g/day (CH4gd), methane emissions per kg of DMI (CH4CMS), residual methane emissions (CH4R), methane emissions per kg of average live weight (CH4PVM) and methane emissions per average daily intake (CH4ADG). Data were analyzed by fitting a univariate animal model with the fixed effect of accelerator group, initial age at CH4 collection as a covariate, as well as the random effects of animal and error. This study included phenotypic information on the methane emission traits of 743 animals, in addition to genotypes originating from 6,239 genotyped animals. The total number of SNPs used in genomic-wide association analyzes with genotypes after imputation was 407,213. The pedigree file with 18,352 animals was included in the analysis. Gene identification was performed using BioMart/Ensembl (bovine genome ARS-UCD1.2). The estimate of heritability was 0.39 for CH4gd, 0.20 for CH4CMS, 0.36 for CH4GMD, 0.06 for CH4PVM, 0.20 for CH4R. The window 39697429 - 40695738 of chromosome 20 had a great participation in explaining the additive variance in most methane emission characteristics (CH4gd, CH4CMS, CH4PVM and CH4R). Several genes associated with methane emission were found, such as C1QTNF3, ACBD5, ADAMTS12, ANGPTL2, OSMR, NOS1, ERCC5, COL14A1. Genes are associated with fat deposition, carcass weight, growth and development, feed efficiency, heat stress, meat quality, marbling. The value of the heritability estimate for the methane trait emission demonstrates its potential use as a selection option in animal genetic improvement programs. In conclusion, traits related to methane emissions can be included in animal breeding programs. (AU) | |
| FAPESP's process: | 19/11738-7 - Phenotypic, genetic correlations and genomic wide association between feed efficiency and enteric methane emission of Nellore cattle |
| Grantee: | Luana Lelis Souza |
| Support Opportunities: | Scholarships in Brazil - Doctorate |