|Leeds, Timothy - Tim|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2007
Publication Date: 7/8/2007
Citation: Gervin, J.A., Zerby, H.N., Kuber, P.S., Moeller, S.J., Wick, M.P., Notter, D.R., Leeds, T.D., Mousel, M.R. 2007. Relationship between calpastatin activity and lamb carcass characteristics.. Journal of Animal Science Supplement. 85(1):21. Interpretive Summary: Tenderness is a major contributor to consumer perception of meat quality. Tenderness of lamb meat can be variable. To produce lambs that are consistently more tender, understanding the biological mechanism(s) behind the differences in tenderness is required. In cattle, calpastatin activity has been associated with meat tenderness. In this study, calpastatin activity in 40 lambs has been shown to be associated with more tender loin chops. In addition, calpastatin activity was not associated with intramuscular fat or back fat thickness. This implies that producers may be able to select for leaner animals without sacrificing tenderness.
Technical Abstract: The purpose of this study was to determine if calpastatin activity (CALP) was related to the amount of intramuscular fat (IMF) and Warner-Bratzler shear force (WBS) in lamb carcasses. Market wethers representing three sire lines (n = 40, average live weight of 68.9 kg) were harvested at the OSU Meat Science Laboratory. Longissimus thorasis (L) samples were taken 24 h postmortem (PM) for determination of CALP and IMF (Caviezel® method). Standard carcass measurements were collected to assess relationships among traits. Nine (2.5 cm) chops were removed from the L at approximately the 7th through the 12th rib location, utilizing both the left and right side of the rack. Chops were randomly assigned to one of three (24 h, 72 h, and 7 d PM) aging periods and WBS was measured. Correlations between CALP, IMF, WBS and carcass traits were calculated. Using a mixed model with fixed sire line, aging, and a sire line by aging interaction and a random animal within sire line effect, the force to shear samples decreased (P < 0.01) over time (24 h, 72 h and 7 d), with least squares means of 4.7 kg, 4.2 kg, and 2.7 kg, respectively. Percent intramuscular fat ranged from 2.9% to 8.5% with a mean of 5.8% (std. dev. 1.2%). Calpastatin was significantly (P < 0.03) and positively correlated with 24 h, 72 h, and 7 d WBS, r = 0.35, 0.40, and 0.40, respectively. Simple correlations of CALP with IMF (r = -0.22, P = 0.17), back fat (r = -0.07, P = 0.68) and body wall (r = .0002, P = 0.99) were not significant. Furthermore, IMF was not significantly correlated with 24 h (r = 0.08, P = 0.63), 72 h (r = 0.13, P = 0.41), or 7 d (r = 0.06, P = 0.72) WBS. These results are consistent with previous literature in lamb and beef reporting that CALP is positively correlated with WBS and in beef that IMF is not directly related to WBS. The correlation between CALP and IMF warrants further investigation.