Increased food intake in growth hormone-transgenic common carp (Cyprinus carpio L.) may be mediated by upregulating Agouti-related protein (AgRP)

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

“…In addition, transgenic zebrafish overexpressing AgRP exhibit obesity, increased growth and adipocyte hypertrophy (Song and Cone, 2007). GH-transgenic common carp Cyprinus carpio , which display increased food intake, have higher hypothalamic AgRP1 mRNA expression levels than non-transgenic fish, further suggesting an orexigenic action (Zhong et al, 2013). However, this is contradicted by another study in carp showing that brain AgRP mRNA expression decreases after fasting and increases after re-feeding (Wan et al, 2012).…”

“…The first direct evidence of the actions of CCK on feeding was provided by injections in goldfish (Himick and Peter, 1994), followed by cloning of goldfish CCK cDNA (Peyon et al, 1998) and the demonstration of periprandial variations in CCK mRNA expression levels (Peyon et al, 1999). Subsequently, a number of studies have characterized CCK in several fish, including other Cypriniformes (e.g., common carp Zhong et al, 2013; zebrafish Koven and Schulte, 2012; Tian et al, 2015; grass carp; blunt snout bream Ping et al, 2013; Ji et al, 2015), Characiformes (e.g., cavefish Wall and Volkoff, 2013, dourado Pereira et al, 2015; Volkoff et al, 2016, thin dogfish Oligosarcus hepsetus Vieira-Lopes et al, 2013, pirapitinga Volkoff, 2015a, red-bellied piranha Volkoff, 2014a, pacu Volkoff et al, 2017), Salmoniformes (e.g., Atlantic salmon Valen et al, 2011), Gadiformes (Atlantic cod Tillner et al, 2013), Perciformes [e.g., yellowtail (Furutani et al, 2013; Hosomi et al, 2014); Astatotilapia burtoni (Grone et al, 2012); cunner (Babichuk and Volkoff, 2013; Hayes and Volkoff, 2014); sea bass (Tillner et al, 2014); yellow croaker ( Larimichthys crocea ) (Cai et al, 2015); white sea bream, Diplodus sargus (Micale et al, 2012, 2014)], Pleuronectiformes (e.g., winter flounder (MacDonald and Volkoff, 2009a), Atlantic halibut Kamisaka et al, 2001, olive flounder Kurokawa et al, 2000) and Siluriformes (channel catfish Peterson et al, 2012). …”

Nutrient Sensing Systems in Fish: Impact on Food Intake Regulation and Energy Homeostasis

“…As for POMC, its mRNA abundance increased post-prandially in rainbow trout (Gong and Björnsson, 2014), medaka (Chisada et al, 2014), and Atlantic halibut (Gomes et al, 2015). The mRNA levels of AgRP increased with food deprivation in hypothalamus of goldfish (Cerdá-Reverter and Peter, 2003), zebrafish (Song et al, 2003), carp (Zhong et al, 2013), and sea bass (Agulleiro et al, 2013), though not in Atlantic salmon (Murashita et al, 2009) whereas no post-feeding changes occurred in medaka (Chisada et al, 2014). AgRP mRNA levels also increased in hypothalamus of GH-transgenic carp that also displayed increased food intake (Zhong et al, 2013).…”

“…The mRNA levels of AgRP increased with food deprivation in hypothalamus of goldfish (Cerdá-Reverter and Peter, 2003), zebrafish (Song et al, 2003), carp (Zhong et al, 2013), and sea bass (Agulleiro et al, 2013), though not in Atlantic salmon (Murashita et al, 2009) whereas no post-feeding changes occurred in medaka (Chisada et al, 2014). AgRP mRNA levels also increased in hypothalamus of GH-transgenic carp that also displayed increased food intake (Zhong et al, 2013). The mRNA abundance of NPY decreased post-feeding in grass carp (Zhou et al, 2013), goldfish (Kehoe and Volkoff, 2007), and zebrafish (Tian et al, 2015) but responses were contradictory in orange-spotted grouper (Tang et al, 2013), rainbow trout (Gong and Björnsson, 2014), and zebrafish (Chen et al, 2016).…”

Effects of growth hormone over-expression on reproduction in the common carp Cyprinus carpio L.

“…However, because of the potential ecological risk of transgenic fish, none of these fish have yet been produced for the intended goal of commercial use and human consumption (Devlin et al, 2006;Hu et al, 2006Hu et al, , 2007Hu and Zhu, 2010). The over-expression of GH causes numerous biological effects such as changes in growth rates, feeding behavior, swimming speed, energy metabolism, osmoregulation, and hypoxia tolerance (Almeida et al, 2013;Caelers et al, 2005;Duan et al, 2011;Guan et al, 2008Guan et al, , 2011Li et al, 2007;Lohmus et al, 2008;Mori et al, 2007;Rahman et al, 2001;Raven et al, 2008;Wang et al, 2001;Zhong et al, 2013Zhong et al, , 2012. Growth hormone over-expression could also affect reproduction.…”