My stress, our stress: Blunted cortisol response to stress in isolated housed zebrafish

Chronic social isolation affects thigmotaxis and whole-brain serotonin levels in adult zebrafish

“…Previously, Parker et al [18] reported a decrease in anxiety in zebrafish isolated for 14-days. Giacomini et al [4] found similar changes after 15-days or 30-days of isolation. Together, these findings, along with reports of decrease or no difference in cortisol levels in isolated fish [18,19] suggest that social isolation has anxiolytic effects in zebrafish.…”

“…Social deprivation can be used as a tool to study regulation and consequences of social interaction and the dependence of social behaviors on presence of social stimuli. The effects of social isolation have been investigated in various model species including insects, birds, rodents, and non-human primates, where a wide range of behavioral and physiological effects have been reported [3,4].…”

“…In zebrafish, the behavior of isolated fish has been described as unpredictable and variable [1], with reduction in shoaling, locomotor activity, anxiety and stress reactivity [17,18]. Physiological indices showed that fish isolated prior to and/or during testing had reduced cortisol [4], decreased proliferating cells in sensory areas of the brain [19] and reduced serotonin in response to novelty [2,20]. For dopamine neurotransmission, conflicting reports exist.…”

On the proper rearing density in domesticated zebrafish to avoid unwanted masculinization. Links with the stress response

“…Surprisingly, and opposite to what happens with rodents, where universal husbandry protocols are available, the zebrafish community lacks universal rearing guidelines. Although many authors have focused on the different aspects of rearing conditions (Westerfield, 1995;Casebolt et al, 1998;Trevarrow, 2004;Lawrence, 2007;Pavlidis et al, 2013;Giacomini et al, 2015), a main variable such as rearing density is still not clearly established. Thus, it is urgent to clarify the influence of rearing density on zebrafish sex differentiation.…”

Divergent effect of fluoxetine on the response to physical or chemical stressors in zebrafish

“…In addition, physical stimuli elicit robust stress responses in fish (Perry, Reid & Salama, 1996). Physical stressors such as chasing have been used as standardized stressors (Abreu et al, 2014; Giacomini et al, 2015, 2016), and spatial restriction is used as a stress model for behavioral assessment in zebrafish (Piato et al, 2011; Ghisleni et al, 2012). Stressor stimulus can also be chemical, such as alarm substances, originally described in the minnow ( Phoxinus phoxinus ) (Frisch, 1941), which are produced and stored in epidermal “club” cells (Barbosa et al, 2012) and are released into the water after skin injuries as those provoked by predator attack (Chivers & Smith, 1998; Korpi & Wisenden, 2001).…”