Table 6.
The effects of genotype of the capn1_187 SNP on the tenderness phenotype, myofibril fragment length (MFL) of representative purebred South African beef bulls during three to 20 days of ageing and on the muscle protease enzyme system during the first 20 h post-mortem.
| capn1_187 | *TT (n = 76) | CT (n = 57) | CC (n = 33) |
p-Value (Simplified) |
Genotype Effect |
|---|---|---|---|---|---|
| MFL (d 3) | 32.54 ± 0.64 c | 35.33 ± 0.76 b | 44.32 ± 2.10 a | 0.0090 | −26.6% |
| MFL (d 9) | 24.30 ± 0.43 c | 26.23 ± 0.51 b | 29.71 ± 1.40 a | 0.0047 | −18.2% |
| MFL (d 14) | 22.25 ± 0.40 | 24.38 ± 0.47 | 26.65 ± 1.30 | 0.1270 | − |
| MFL (d 20) | 20.61 ± 0.32 | 21.80 ± 0.38 | 24.02 ± 1.06 | 0.1885 | − |
| calpastatin (1 h) | 2.00 ± 0.04 | 2.04 ± 0.04 | 1.96 ± 0.12 | 0.2181 | |
| calpastatin (20 h) | 1.73 ± 0.04 z | 1.69 ± 0.05 z | 1.61 ± 0.14 z | 0.0640 ! | # variable |
| calpastatin/calpain-1 (1 h) | 1.38 ± 0.02 z | 1.44 ± 0.03 z | 1.63 ± 0.08 y | 0.0909 | −15.5% |
| calpastatin/calpain-1 (20 h) | 1.63 ± 0.05 | 1.69 ± 0.06 | 1.84 ± 0.16 | 0.1571 | |
| calpastatin/calpains (1 h) | 0.81 ± 0.01 | 0.83 ± 0.01 | 0.90 ± 0.04 | 0.1989 | |
| calpastatin/calpains (20 h) | 0.79 ± 0.01 | 0.80 ± 0.02 | 0.85 ± 0.04 | 0.5493 |
*TT—the genotype that favored tenderness; least squares means (LSM) ± standard errors (SE) that were significantly different within rows or ageing periods (p ≤ 0.05) were indicated with different ascending letter superscripts (a, b, c), and those that tended to be significantly different (p ≤ 0.10) with different descending letter superscripts (z, y). # Responses of the *TT genotype were variable between breeds and not always tenderizing, ! false positive association; MFL—myofibril fragment length.