Open AccessMolecular adaptations of glucose and lipid metabolism to different levels of dietary carbohydrates in juvenile Japanese flounder Paralichthys olivaceus
Author(s) -
Yang Mengxi,
Deng Kangyu,
Pan Mingzhu,
Zhang Yue,
Sampath Wijerath Wiriduge Hasitha Aruna,
Zhang Wenbing,
Mai Kangsen
Publication year - 2020
Publication title -
aquaculture nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.941
H-Index - 79
eISSN - 1365-2095
pISSN - 1353-5773
DOI - 10.1111/anu.13013
Subject(s) - glucokinase , biology , phosphoenolpyruvate carboxykinase , gluconeogenesis , glycogen , olive flounder , carbohydrate metabolism , medicine , carbohydrate , paralichthys , endocrinology , hexokinase , flounder , pyruvate kinase , lipid metabolism , phosphofructokinase , glucose homeostasis , glut2 , malic enzyme , glycogenolysis , glycolysis , glucose transporter , metabolism , biochemistry , enzyme , insulin , fishery , fish <actinopterygii> , dehydrogenase , insulin resistance
Japanese flounder juveniles (initial body weight: 7.12 ± 0.02 g) were fed three diets containing 0, 120 and 200 g/kg of carbohydrates (C0, C120 and C200, respectively) for 10 weeks. Results showed that higher dietary carbohydrate intake enabled further deposition of glycogen and lipids in liver and muscle. The mRNA levels of glucokinase ( gck ), phosphofructokinase ( pfkl ) and hexokinase (HK) activity involved in glycolysis were significantly up‐regulated in C120 ( p < .05) but showed no further up‐regulation except for gck in C200. Besides, the gluconeogenic phosphoenolpyruvate carboxykinase 1 ( pck1 ) mRNA levels were down‐regulated significantly in fish fed the C120 ( p < .05). However, further increase in dietary carbohydrate levels increased the mRNA levels and activities of enzymes involved in gluconeogenesis and lipolysis ( p < .05). Additionally, plasma glucose remained unchanged in C120 ( p > .05) but significantly increased in C200 group ( p < .05). In conclusion, Japanese flounder was able to use carbohydrates efficiently through regulation of glucose and lipid metabolism when dietary carbohydrate was not higher than 120 g/kg, while 200 g/kg of dietary carbohydrate caused the deregulation of glucose homoeostasis.