Transportation Stress and Expression of Heat Shock Protein Affecting Pork Quality

The relationship between heat shock protein (Hsp) expression and meat quality were assessed in pigs. Carcasses from 2 h- and 6 h-transported pigs had higher temperatures and lower pH and water holding capacity values in the longissimus dorsi and gluteus maximus superficialis muscles. Long journeys were associated with increased creatine kinase (CK) levels. Higher CK levels are indicative of physical stress, as the enzyme is released from muscle fibers as a result of intense muscular exertion. These physiological and enzymatic changes were correlated with increased Hsp70 and decreased Hsp90 expression levels in both skeletal muscles. Animals whose cells contained high levels of Hsp may have had an advantage due to the protective role conferred by Hsp. Reduced Hsp levels were indicative of a higher meat quality and a good welfare of the transported pigs. The stress response declined over time in response to the same stress, such as a 6-h transport stress