Table 7.

Summary of the main histological evidences, molecular traits and differential expression of genes triggering and related to an altered Ca²⁺ homeostasis in Pectoralis major muscles exhibiting myopathic conditions.

Main findings	References
Histological evidences
hypercontracted fibers	Kuttappan et al., 2013; Sihvo et al., 2014; Velleman and Clark, 2015
≠ anchoring of the contractile filaments	Liu et al., 2020
↓ Ca2+ sensitivity of the fibers	Liu et al., 2020
Molecular traits
↑ Ca2+ concentration	Soglia et al., 2016b; Tasoniero et al., 2016; Zambonelli et al., 2016
↑ calpain activity and ↑ post-mortem degradation of myofibrillar proteins	Soglia et al., 2018; Hasegawa et al., 2020
Gene expression
≠ expression of genes involved in Ca2+ transport either in 3-weeks old or in marketable age broilers	Zambonelli et al., 2016; Papah et al., 2018; Marchesi et al., 2019
↑ genes involved in calcium signaling pathway and ↑ cytosolic Ca2+ concentration	Marchesi et al., 2019
↑ genes as a response mechanism to counteract ↑ intracellular Ca2+ and stop hypercontraction	Mutryn et al., 2015; Zambonelli et al., 2016; Marchesi et al., 2019
↓ genes suggesting a ≠ Ca2+ metabolism and ↓ excitation-contraction coupling	Pampouille et al., 2019