Neuroendocrine control of appetite in Atlantic halibut (Hippoglossus hippoglossus): Changes during metamorphosis and effects of feeding

The Neuroendocrine Regulation of Food Intake in Fish: A Review of Current Knowledge

“…Two CART isoforms have been identified in goldfish (Volkoff and Peter, 2001a) and common carp (Wan et al, 2012), and 4 in zebrafish (Akash et al, 2014) whereas, to date, only one form has been isolated for grass carp (Zhou et al, 2013; Liu et al, 2014), Characiformes [pirapitinga (serrasalmidae) (Volkoff, 2015a), pacu (serrasasalmidae) (Volkoff et al, 2017) and dourado (characidae) (Volkoff et al, 2016), red bellied piranha (serrasalmidae) (Volkoff, 2014a)], Salmoniformes [Atlantic salmon (Murashita et al, 2009a), rainbow trout (Figueiredo-Silva et al, 2012), Arctic charr (Striberny et al, 2015) and lake trout ( Salvelinus namaycush ) (Volkoff et al, 2007)], Siluriformes (channel catfish Kobayashi et al, 2008), Gadiformes (Atlantic cod Kehoe and Volkoff, 2007), Perciformes (cunner Babichuk and Volkoff, 2013), winter flounder (MacDonald and Volkoff, 2009a) and Atlantic halibut ( Hippoglossus hippoglossus ) (Gomes et al, 2015) (Pleuronectiformes), venomous toadfish Thalassophryne nattereri (Batrachoidiforme) (Magalhaes et al, 2006), rainbow smelt ( Osmerus mordax ) (Osmeriforme), pufferfishes ( Takifugu rubripes and Tetraodon nigroviridis , Tetraodontiforme) and stickleback Gasterosteus aculeatus (Gasterosteiforme) (cited in Murashita et al, 2009a). However, six forms of CART have been identified in the medaka (Beloniforme) (Murashita and Kurokawa, 2011) and seven forms in Senegalese sole Solea senegalensis (Pleuronectiforme), the highest number of CART genes reported to date in a vertebrate species (Bonacic et al, 2015).…”

“…However, in Arctic charr, CART hypothalamic expression is similar throughout the seasonal feeding cycles (Striberny et al, 2015) and fasting does not affect CART expression in either dourado (Volkoff et al, 2016), winter flounder (MacDonald and Volkoff, 2009a) or Atlantic halibut larvae (Gomes et al, 2015), and in lake trout, fish exposed to the pesticide tebufenozide and control fish have similar food intakes, despite higher CART mRNA brain expression levels in exposed fish (Volkoff et al, 2007). In winter skate, 2 weeks of fasting have no effects on brain CART expression (MacDonald and Volkoff, 2009b), suggesting that CART might not have a major feeding-regulating role in elasmobranchs.…”

“…However, in fasted halibut larvae, whole brain POMC-C mRNA expression is higher in unfed fish 30 min after re-feeding compared to continuously fed fish (Gomes et al, 2015), suggesting a short-term regulation of appetite. Given the small number of studies available, and the variation in experimental protocols (adults vs. larvae, pituitary vs. brain, long-term vs. short-term feeding), conclusions are difficult to drawn regarding the role of POMC in flatfish.…”

Orally administrated fatty acids enhanced anorectic potential but did not activate central fatty acid sensing in Senegalese sole post-larvae

“…capacities is likely as the operability of other mechanisms involved in the control of food intake, such as gastrointestinal remodelling, is also dependent on developmental stage (Kortner et al, 2011;Gomes et al, 2015). However, these results raise an interesting question: if FA-sensing systems are not responding to the intake of FAs, how do neuropeptides respond to FA administration?…”

“…However, it is of great importance to clearly establish when appetite regulation becomes functional in fish larvae, particularly in species of commercial interest to aquaculture. Very little is known concerning the neural regulation of feeding and appetite during early larval stages, with very few studies describing changes in the expression of brain neuropeptides (Kortner et al, 2011;Gomes et al, 2015). As far as we know, there are no available studies assessing the impact of specific nutrients on the regulation of food intake in fish larvae and post-larvae.…”