Abstract #M98

# M98
Transcriptome analysis of muscular tissue in Nellore cattle divergently ranked for meat tenderness.
Larissa Fernanda Simielli Fonseca*1, Daniele Fernanda Jovino Gimenez1, Fernando Baldi1, Jesus Aparecido Ferro2, Rafael Espigolan1, Lucia Galvão Albuquerque1, 1Departamento de Zootecnia, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP, Brazil, 2Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias, UNESP, Jaboticabal, SP, Brazil.

The objective of the present study was to identify differential gene expression related to meat tenderness in Nellore cattle. Meat samples from 132 animals belonging to the same contemporary group were used. Meat tenderness was measured by shear force through Warner Bratzler method and 20 divergently ranked animals for this trait (10 with tough meat and 10 with tender meat) were selected. Means and the respective standard deviations for tough and tender meat groups were 7.4 ± 0.78 kg and 4.41 ± 0.40 kg, respectively. Total RNA was extracted from the selected samples and sequenced (RNA-Seq) using the HiSeq 2500 System (Illumina). The results were analyzed in the iPlant Collaborative platform. The workflow included: FastQC; TopHat2 and Cuffdiff. A total of 17 differentially expressed genes (q- value <0.05) were identified, and among them, 4 are highlighted. The genes Q3ZCJ1 (transmembrane protein 37), C1QTNF7 (C1q and tumor necrosis factor related protein 7) and BDH1 (3-hydroxybutyrate dehydrogenase, type 1), were more expressed in tough meat samples, whereas the gene ATP1A1 (ATPase, Na+/ K+ transporting, α 1 polypeptide) was more expressed in tender meat samples. The Q3ZCJ1 protein is involved in the same metabolic pathway of actin and myosin proteins that constitute the myofibrils, organelle which acts on muscle contraction. C1QTNF7 protein acts in complement and coagulation cascade metabolic pathway. This pathway is activated after an injury and the coagulation system is activated by exposed collagen after an injury. There is a direct link between collagen content and meat tenderness. The BDH1 enzyme is involved in the synthesis and degradation of ketone bodies that, if present, causes a decrease in muscle pH. The ATP1A1 enzyme is related to protons synthesis, which causes a decrease in intracellular pH during ATP degradation to ADP. Muscle pH decrease is related to meat tenderness during the post-mortem process. These genes seem to be involved in the meat tenderness process. This study was supported by São Paulo Research Foundation FAPESP (grants 2009/16118-5 and 2013/09190-7)

Key Words: RNAseq, differentially expressed gene, quality meat