Adaptations of lipid metabolism and food intake in response to low and high fat diets in juvenile grass carp (Ctenopharyngodon idellus)

Dietary nano‐selenium enhances antioxidant capacity and hypoxia tolerance of grass carp Ctenopharyngodon idella fed with high‐fat diet

“…According to previous studies, suitable lipid level in juvenile grass carp diet is 40 g/kg (Xiao et al, ; Yuan et al, ). Hence, high‐fat diets were formulated to contain 96 g/kg crude lipid in the present study (Li et al, ). Five experimental diets were formulated with gradually increased levels of Nano‐Se (0, 0.3, 0.6, 0.9 and 1.2 mg/kg), and the final estimated Se concentrations of experimental diets were 0.3, 0.6, 0.9, 1.2 and 1.5 mg/kg, respectively.…”

“…The intensive farming model of fish is based on the utilization of artificially formulated feed to achieve continuous increase in their production (Zhao et al, ). In recent years, high‐fat diet is commonly used in grass carp diet to economize the protein source, even though about 40–50 g/kg of lipid in diet can meet the growth demand of grass carp (Du, Clouet, Huang, et al, ; Li et al, ; Xiao et al, ; Yuan et al, ). However, excessive dietary lipid contents exhibited huge negative effects on grass carp, such as growth depression and unwanted hepatic fat deposition (Du, Clouet, Degrace, et al, ; Du et al, ; Li et al, ).…”

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

“…Whereas in mammals, leptin acts as an adipostat and its plasma levels are proportional to the amount of body fat, there is little evidence for such a role in fish. In topmouth culter Culter alburnus (Cyprinoforme), leptin mRNA expression is lower in wild populations, who have more muscle fat content than cultured fish (Wang et al, 2013), in grass carp, fish fed high fat diets have higher leptin expression (Li A. et al, 2016) than control fish, and in medaka, leptin receptor null-mutants have higher food intake and larger deposits of visceral fat than that of wild-type fish (Chisada et al, 2014), suggesting a correlation between leptin levels and fat. However, results from other studies seem to contradict this hypothesis: leptin receptor null adult zebrafish do not exhibit increased feeding or adiposity (Michel et al, 2016); In rainbow trout, leptin levels are higher in lean fish than fat fish (Salmeron et al, 2015; Johansson et al, 2016; Pfundt et al, 2016), and in Arctic charr, neither hepatic leptin expression nor plasma leptin levels correlate with fish adiposity (Froiland et al, 2012; Jørgensen et al, 2013); In murray cod Maccullochella peelii peelii (Perciforme), fish fed different experimental diets containing fish oil with or without vegetable oil have similar leptin levels (Ettore et al, 2012; Varricchio et al, 2012); In yellow catfish (Siluriforme), IP injections of human leptin reduce hepatic lipid content and the activities of lipogenic enzymes (Song et al, 2015) but Zn deficiency, which tends to increase hepatic and muscle lipid contents, does not affect leptin mRNA levels (Zheng et al, 2015).…”

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

“…This occurred for instance in rainbow trout (Peragón et al, 2000; Rasmussen et al, 2000; Gélineau et al, 2001; Forsman and Ruohonen, 2009; Figueiredo-Silva et al, 2012c; Saravanan et al, 2013), chinook salmon (Silverstein et al, 1999), polka-dot grouper (Williams et al, 2006), Senegalese sole (Bonacic et al, 2016) or grass carp (Li et al, 2016). Moreover, enhanced lipid storage is also usually associated with a reduced food intake (Shearer et al, 1997; Silverstein et al, 1999; Johansen et al, 2002, 2003).…”

“…High content of lipids in the diet reduce lipogenic potential and increases β-oxidation in the liver of many fish species (Dias et al, 2004; Figueiredo-Silva et al, 2010; Borges et al, 2013; He et al, 2015; Librán-Pérez et al, 2015b; Li et al, 2016). Furthermore, dietary lipid level affects glucose metabolism inducing hyperglycaemia, and reducing glycolytic capacity and increasing gluconeogenic potential in liver, as described in several fish species like rainbow trout (Gélineau et al, 2001; Panserat et al, 2002a; Figueiredo-Silva et al, 2012a,b), other salmonids (Mazur et al, 1992; Hemre and Sandnes, 1999), grouper (Cheng et al, 2006), sunshine bass (Hutchins et al, 1998), and Senegalese sole (Borges et al, 2014).…”