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Effect of Brahman Genetic Influence on Collagen Enzymatic Crosslinking Gene Expression and Meat Tenderness

2014; Taylor & Francis; Volume: 25; Issue: 3 Linguagem: Inglês

10.1080/10495398.2013.846862

1532-2378

J. M. Gonzalez, D. D. Johnson, Mauricio A. Elzo, M. C. White, A. M. Stelzleni, Sally Johnson,

Coagulation, Bradykinin, Polyphosphates, and Angioedema

Abstract The objective of the study was to examine the effect of Brahman genetics on collagen enzymatic crosslinking gene expression and meat tenderness. Steers were randomly selected to represent a high percentage Brahman genetics (n = 13), Half-Blood genetics (n = 13), Brangus genetics (n = 13), and a high percentage Angus genetics (n = 13). Muscle samples from the Longissimus lumborum muscle were collected at weaning and harvest and reverse transcription quantitative PCR (qPCR) analysis was conducted to measure the mRNA expression of lysyl oxidase (LOX), bone morphogenetic protein 1 (BMP1), and cystatin C (CYS). Steaks from subject animals were collected at harvest, aged for 14 d and subjected to collagen analysis, Warner-Bratzler Shear Force (WBS) and trained sensory panel analysis (tenderness, juiciness, and connective tissue). Data indicated that Half-Blood and Brahman steers had greater (P<0.05) WBS values and tended to receive decreased (P < 0.06) panel tenderness scores than Angus and Brangus steers. Panelists tended to detect more connective tissue in Brahman and Half-Blood steaks when compared to Angus and Brangus steaks (P < 0.07). Crosslinking gene expression data revealed that at weaning Half-Blood steers had more (P < 0.05) mRNA expression of CYS and LOX than Angus and Brangus steers. At weaning and harvest, all genetic groups had similar mRNA expression of BMP1 (P > 0.10). At harvest, Brangus and Angus steers had greater LOX mRNA expression than Brahman cattle (P < 0.05). Pearson's correlation coefficients indicated that only weaning CYS mRNA expression was correlated to WBS, panel tenderness and connective tissue scores (P < 0.05). Expression of LOX was only correlated to these measures at harvest, and BMP1 was correlated to these traits at both time periods (P < 0.05). These results indicate that collagen crosslinking enzyme activity, as indicated by mRNA levels, early in an animal's life may account for some of the variation seen in steak tenderness due to Brahman genetic influence. Keywords: BrahmanCollagenCrosslinkingMeatTenderness Notes a Angus cattle contain 26/32 or greater Angus genetics. Brangus cattle contain 20/32 Angus genetics. Half-Blood cattle contain 14/32 to 18/32 Angus genetics. Brahman cattle contain 0/32 to 9/32 Angus genetics. b Warner-Bratzler Shear force. c 1 = extremely tough; 2 = very tough; 3 = moderately tough; 4 = slightly tough; 5 = slightly tender; 6 = moderately tender; 7 = very tender; 8 = extremely tender. d 1 = Abundant; 2 = Moderately abundant; 3 = Slightly abundant; 4 = Moderate; 5 = Slight; 6 = Traces; 7 = Practically none; 8 = None. e 1 = Extremely dry; 2 = Very dry; 3 = Moderately dry; 4 = Slightly dry; 5 = Slightly juicy; 6 = Moderately juicy; 7 = Very juicy; 8 = Extremely juicy. f 1 = Extremely bland; 2 = Very bland; 3 = Moderately bland; 4 = Slightly bland; 5 = Slightly intense; 6 = Moderately intense; 7 = Very intense; and 8 = Extremely intense. g 1 = Extreme off-flavor; 2 = Strong off-flavor; 3 = Moderate off-flavor; 4 = Slight off-flavor; 5 = Threshold off-flavor; 6 = No off-flavor. *, **, ***Values within a row are significantly different (P < 0.05). #, ##Values within a row with different letters tend to be different (P < 0.10). a All primers sequenced to ensure amplification of correct gene. b Housekeeping gene. Bovine 18 S gene expression used as housekeeping gene for computation of ▵CT values. 18 S gene expression did not differ between treatments of both muscle groups. a Angus cattle contain 26/32 or greater Angus genetics. Brangus cattle contain 20/32 Angus genetics. Half-Blood cattle contain 14/32 to 18/32 Angus genetics. Brahman cattle contain 0/32 to 9/32 Angus genetics. BMP1, Bone morphogenetic protein 1; CYS, Cystatin C; LOX, Lysyl Oxidase. a Warner-Bratzler shear force. **P ≤ 0.01; *P ≤ 0.05; † P ≤ 0.10. Contribution no. 12-397-J of the Kansas Agricultural Experiment Station, Manhattan 66506.