Seasonal simulated photoperiods influence melatonin release and immune markers of pike perch Sander lucioperca

Abstract

Melatonin is considered as the time-keeping hormone acting on important physiological functions of teleosts. While the influence of melatonin on reproduction and development is well described, its potential role on immune functions has little been considered. In order to better define an immune modulation by the melatonin hormone, we hypothesized that natural variations of photoperiod and subsequent changes in melatonin release profile may act on immune status of pikeperch. Therefore, we investigated during 70 days the effects of two photoperiod regimes simulating the fall and spring in western Europe, on pikeperch physiological and immune responses. Samples were collected at 04:00 and 15:00 at days 1, 37 and 70. Growth, plasma melatonin levels, innate immune markers and expression of immune-relevant genes in head kidney tissue were assessed. While growth and stress level were not affected by the seasonal simulated photoperiods, nocturnal levels of plasma melatonin were photoperiod-dependent. Innate immune markers, including lysozyme, complement, peroxidase and phagocytic activities, were stimulated by the fall-simulated photoperiod and a significant correlation was made with plasma melatonin. In addition to bring the first evidence of changes in fish immunocompetence related to photoperiod, our results provide an additional indication supporting the immunomodulatory action of melatonin in teleosts.

Cadmium Accumulation and Depuration in the Muscle of Prussian Carp (Carassius gibelio Bloch) after Sub-Chronic Cadmium Exposure: Ameliorating Effect of Melatonin

“…While the present study found no clear impact of melatonin on the body weight of the fish studied, melatonin certainly improved the survival of the fish as no deaths were recorded in the Cd-exposed fish that received continuous-release melatonin implants. It may be assumed that the immunostimulating effect of melatonin helped reduce the mortality of the fish [ 31 ].…”

Melatonin as a Multipotent Component of Fish Feed: Basic Information for Its Potential Application in Aquaculture

“…The organization of the immune system in fish is strikingly interesting as it is devoid of bone marrow and lymph nodes (Manning, 1998). In fish, the primary lymphoid tissues for the production and development of B lymphocytes is the head kidney (pronephros) also known as lympho-haematopoietic tissue, whereas T lymphocytes are developed and matured in the thymus (Baekelandt et al, 2020). Spleen is considered as the secondary lymphoid organ in fish, and the scattered leucocyte populations in gills [gill-associated lymphoid tissue (GIALT)], skin [skin-associated lymphoid tissue (SALT)], and gut [gutassociated lymphoid tissue (GALT)] constitute the mucosalassociated lymphoid tissue (MALT) (Salinas, 2015;Baekelandt et al, 2020).…”

“…This inhibitory effect of MEL is operated through a pathway that involves adenylate cyclase (AC) and protein kinase A (PKA) by which MEL causes the inhibition of the phagocytic activity in C. punctatus (Roy et al, 2008). Very recently, in the case of pike perch (Sander lucioperca), a significant correlation between plasma MEL with innate immune markers has been explored (Baekelandt et al, 2020) (Table 2). Thus, the interpretations from different studies collectively supported that MEL can be used to modulate and improve fish immunity and resistance to certain pathogens in aquaculture.…”

“…Environmental stressors and disease susceptibility are the two important aspects, which have major impacts on sustainable fish aquaculture. Several studies on fish also demonstrated the role of MEL in regulating the status and rhythmic functions of immune cells (Cuesta et al, 2007(Cuesta et al, , 2008; Roy et al, 2008;Baekelandt et al, 2020). In the case of fish, external stressor-mediated MEL synthesis and the response of mealatonin to chronic stress are also known (Conde-Sieira et al, 2014;López-Patiño et al, 2014;Gesto et al, 2016).…”

Insights into early ontogenesis: characterization of stress and development key genes of pikeperch (Sander lucioperca) in vivo and in vitro

“…This also applies to the immune response, which is well investigated in percid fishes such as yellow perch (Perca flavescens) or Eurasian perch (Perca fluviatilis) but is poorly documented in pikeperch. Current studies mainly focus on humoral stress and immune markers under certain husbandry conditions (Baekelandt et al 2019;Baekelandt et al 2020;Żarski et al 2020), but alterations within gene expression during physiological changes of early ontogenesis have not been reported so far. In the present study, we investigated the transcription patterns of selected genes involved in stress and immune responses as well as the growth phase and the previously mentioned stages of early development.…”