Fig. 5

Effect of high density-induced stress on the Calpain/calpastatin system. Relative expression (fold change) of (a) calpain 1–2 and (b) the specific inhibitor calpastatin (short and long isoforms). Each gene was normalized using fau and β-actin. c Calpain enzymatic activity in relative fluorometric units (RFU). The results are shown as the means ± SEM (n = 5 per group). LD, low stocking density; HD, high stocking density. Significant differences are indicated with a line and an asterisk (* = P < 0.05; ** = P < 0.01)