Fig. 1.

Influence of thermal acclimation on the connective tissue content of trout ventricular myocardium quantified using Masson's trichrome staining. (A) The hearts of cold acclimated male trout had significantly more connective tissue in the spongy layer than that of either control or warm acclimated male fish. (B) Cold acclimation of male trout caused an increase in connective tissue content in the compact layer compared to controls while warm acclimation of male trout caused a decrease in connective tissue content, compared to controls. The amount of connective tissue is presented as arbitrary units (A.U.) representing the ratio of connective tissue present in the compartment in relation to muscle. Values are mean ± SEM. Brackets, if present indicate a significant difference between sexes within an acclimation group. Different letters above the bars indicate a significant difference between acclimation groups. Different letters within the bars indicate significant differences between acclimation temperatures when each sex is analyzed separately (p < 0.05). Figure modified from (Klaiman et al., 2011).