Expression of genes involved in key metabolic processes during winter flounder (Pseudopleuronectes americanus) metamorphosis

Abstract

The aim of this study was to better understand the molecular events governing ontogeny in winter flounder (Pseudopleuronectes americanus (Walbaum, 1792)). The expression of seven genes involved in key metabolic processes during metamorphosis were measured at settlement (S0), at 15 (S15), and 30 (S30) days after settlement and compared with those in pelagic larvae prior to settlement (PL). Two critical stages were identified: (1) larval transit from the pelagic to the benthic habitat (from PL to S0) and (2) metamorphosis maturation, when the larvae stay settled without growth (from S0 to S30). Growth hormone (gh) gene expression significantly increased at S0. At S30, an increase in cytochrome oxidase (cox) gene expression occurred with a second surge of gh gene expression, suggesting that enhanced aerobic capacity was supporting growth before the temperature decrease in the fall. Expression patterns of pyruvate kinase (pk), glucose-6-phosphate dehydrogenase (g6pd), and bile salt activated lipase (bal) genes indicated that energy synthesis may be mainly supplied through glycolysis in PL, through the pentose–phosphate pathway at settlement, and through lipid metabolism at S30. The expression of the heat-shock protein 70 (hsp70), superoxide dismutase (sod), cox, and peroxiredoxin-6 (prx6) genes revealed that oxidative stress and the consequent development of antioxidative protection were limited during the PL stage, reinforced at settlement, and very high at S30, certainly owing to the higher growth rate observed at this period.

Essential Fatty Acid Requirements in Tropical and Cold-Water Marine Fish Larvae and Juveniles

“…The lipid composition of larvae and/or juveniles has been presented in detail for Florida pompano (Cavalin and Weirich, 2009;Hauville et al, 2014Hauville et al, , 2016Rombenso et al, 2016Rombenso et al, , 2017 Jackson et al, 2020) and for winter flounder (Mercier et al, 2004;Seychelles et al, 2011Seychelles et al, , 2013Vagner et al, 2013;Bélanger et al, 2018;Martinez-Silva et al, 2018). While these studies examined different developmental stages, we have merged the results for the purpose of comparison.…”

Anthropogenic boat noise reduces feeding success in winter flounder larvae (Pseudopleuronectes americanus)

“…Fertile males were available 106 at the wet lab facility. Egg fertilization and incubation were done according to the method 107 described by Vagner et al (2013). Upon hatching, larvae were reared according to the 108 standard procedures used in our laboratory (Vagner et al 2013;Martinez-Silva et al 2018).…”

“…What is the acclimation and the learning capacity at the larval stage, when energy is devoted to feeding to accumulating enough energy to undertake metamorphosis? larvae metamorphose above 6.6 mm length (Vagner et al 2013;Bélanger et al 2018).…”

Influence of the timing of weaning on growth and survival of juvenile winter flounder (Pseudopleuronectesamericanus)

“…A previous genomic study suggested that the first 30 days after settlement correspond to a metamorphosis maturation process where the larva stays settled without growth, and where an increase in aerobic capacity occurs with a switch from the pentose-phosphate pathway to lipid metabolism as an energy source for ATP synthesis to sustain juvenile growth (Vagner et al 2013). Here, the low level (< 5%) of accumulated TAG (the major energy storage form in marine fishes; Lochman et al 1995) by 30 days after settlement in the surviving juveniles could suggest a lack of sufficient energy reserves necessary to support metamorphosis.…”