Appetite regulating factors in pacu (Piaractus mesopotamicus): Tissue distribution and effects of food quantity and quality on gene expression

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

“…Indeed, in goldfish, hypothalamic orexin mRNA expression levels peak when fish are active prior to a scheduled meal (Hoskins and Volkoff, 2012) and in zebrafish, increased locomotor activity is associated with increased activity of hypothalamic orexin neurons (Naumann et al, 2010) and larvae overexpressing orexin are hyperactive (Woods et al, 2014). Similarly, orexin expression decreases post-feeding in Characiformes [cavefish (Wall and Volkoff, 2013), dourado ( Salminus brasiliensis ) (Volkoff et al, 2016) and pacu ( Piaractus mesopotamicus ) (Volkoff et al, 2017)] and is higher at mealtime in orange-spotted grouper (Yan et al, 2011) and tilapia (Chen et al, 2011) (Perciformes), as well as Atlantic cod (Gadiforme) (Xu and Volkoff, 2007). In cod, orexin levels are also higher during daylight hours, when animals are active (Hoskins and Volkoff, 2012).…”

“…Postprandial increases in CART brain expression have been shown in Senegalese sole (CART1a, CART 2a and CART4) (Bonacic et al, 2015), pacu (Volkoff et al, 2017), dourado (Volkoff et al, 2016), channel catfish (Peterson et al, 2012) but not in cod (Kehoe and Volkoff, 2007). …”

“…Fasting increases orexin brain mRNA expression in Cypriniformes (goldfish Abbott and Volkoff, 2011 and zebrafish Yokobori et al, 2011), Characiformes (cavefish Wall and Volkoff, 2013, dourado Volkoff et al, 2016, pacu Volkoff et al, 2017, and red-bellied piranha Volkoff, 2014a), and Pleuronectiformes (winter flounder Buckley et al, 2010 and Barfin flounder Amiya et al, 2012). In the mouth-brooding Astatotilapia burtoni (Perciforme), brain orexin mRNA levels increase in non-feeding females carrying eggs (Grone et al, 2012).…”

“…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).…”

“…Fasting/food restriction decreases CART brain expression in Cypriniformes (goldfish Volkoff and Peter, 2001a, zebrafish Nishio et al, 2012; Guillot et al, 2016 and common carp, Wan et al, 2012), most Characiformes (red-bellied piranha Volkoff, 2014a, and pacu Volkoff et al, 2017), most Salmoniformes (Atlantic salmon, Murashita et al, 2009a; Kousoulaki et al, 2013, rainbow trout Figueiredo-Silva et al, 2012), Atlantic cod (Kehoe and Volkoff, 2007), cunner (Perciforme) (Babichuk and Volkoff, 2013), medaka (CART3) (Murashita and Kurokawa, 2011), and Siluriformes (channel catfish Kobayashi et al, 2008, African sharptooth catfish Clarias gariepinus Subhedar et al, 2011), suggesting an anorexigenic role for CART in teleost fish. Postprandial increases in CART brain expression have been shown in Senegalese sole (CART1a, CART 2a and CART4) (Bonacic et al, 2015), pacu (Volkoff et al, 2017), dourado (Volkoff et al, 2016), channel catfish (Peterson et al, 2012) but not in cod (Kehoe and Volkoff, 2007).…”