Abstract
Previous studies have demonstrated that DNAJA1 could be a good indicator of beef toughness in Longissimus thoracis muscle from Charolais young bulls. This study aimed to check if relationship between DNAJA1 expression and beef tenderness is valid in two muscles, which differ in toughness from Angus steers with or without electric stimulation at different times of post-mortem ageing. Electric stimulation did not significantly affect DNAJA1 expression at the time of slaughter. But, RNA degradation soon after slaughter was a major factor, which affected the assessment of DNAJA1 expression, even at 3 h post-mortem. Correlation of DNAJA1 expression at slaughter with shear force values varied according to ageing time (24 h, 3, 7, 14 or 21 days post-mortem) or according to the use of electric stimulation and was not significantly correlated with any of these shear force peak values despite a few high correlation values (-0.60 or +0.34). In conclusion, DNAJA1 is not an omnipotent marker of beef toughness with this particular data set since the correlation of its expression level with shear force values varies according to slaughtering conditions and ageing time.