Linking coping styles and enzymatic activity of energy metabolism in the wedge sole (Dicologlossa cuneata)

Abstract

Knowledge of individual behavioural variations (coping styles) can be a very useful tool for aquaculture, since it could allow to adapt the culture conditions to the different behavioural traits and, thus, to reduce the stress in the fish getting in this way a better production. The objective of this work was the identification of coping styles and their possible association with energy metabolism enzyme activities in the wedge sole (Dicologlossa cuneata). After submitting the fish to different tests (Feeding Recovery, Novel Object, Aggression and Restraining), the results showed a high individual variation, especially in the adaptation to a new environment (CV = 90.92 %), latency to escape (CV = 114.14 %) and plasma cortisol levels (CV = 105.56 %), thus showing the existence of coping styles in this species. Two different personalities were defined: the CS1 group (reactive individuals) and the CS2 group (proactive individuals). The CS1, unlike the CS2, presented a shorter latency to escape, higher number of escape attempts, a longer duration of escape attempts, and higher plasma cortisol levels after an acute stress. In addition, significant differences were detected for Glycogen phosphorylase (GPase) that acts in glycogenolysis, presenting the group CS1 the highest values (0.80 ± 0.17 vs. 0.48 ± 0.02 U mg prot−1). In conclusion, this study demonstrates for the first time the existence of coping style in D. cuneata, proving effective the tests applied for this identification. Two different groups were observed with specific behavioural and physiological responses that fit the proactive and reactive patterns. Furthermore, these groups showed differences in the energy metabolism of carbohydrates in basal state.