Leptin Selectively Regulates Nutrients Metabolism in Nile Tilapia Fed on High Carbohydrate or High Fat Diet

Abstract

Leptin is known to inhibit appetite and promote energy metabolism in vertebrates. Leptin resistance (LR) commonly occurs in diet-induced obesity (DIO) in mammals. However, the roles of leptin in the energy homeostasis in DIO animals with LR remain unclear. Here we first verified the high expression of leptin in subcutaneous adipose tissue (SCAT) as in liver in Nile tilapia. Furthermore, we produced two types of DIO Nile tilapia by using a high-carbohydrate diet (HCD) or a high-fat diet (HFD), and confirmed the existence of LR in both models. Notably, we found that HCD-DIO fish retained leptin action in the activation of lipid metabolism and showed LR in glucose metabolism regulation, while this selective leptin action between lipid and glucose metabolism was reversed in HFD-DIO fish. Fasting the fish for 1 week completely recovered leptin actions in the regulation of lipid and glucose metabolism. Therefore, leptin may retain more of its activities in animals with LR than previously believed. Evolutionally, this selective regulation of leptin in nutrients metabolism could be an adaptive mechanism in animals to store surplus calories when different types of food are abundant.

Peroxisomal proliferator‐activated receptor α‐b deficiency induces the reprogramming of nutrient metabolism in zebrafish

“…The IPGTT was performed with slight modifications from the method described previously (Liu et al . 2018). It was conducted following a 24 h fast by i.p.…”

“…2018), saline containing Glu (2.5 μCi labelled Glu * per 50 g BW, 500 mg unlabelled Glu kg −1 BW) (Liu et al . 2018) and saline containing AA (2.5 μCi labelled AA * per 50 g BW, 500 mg unlabelled AA kg –1 BW) (Yang et al . 2018).…”

“…-amino acid mixture (AA * ) (PerkinElmer), respectively. The injection concentrations of 14 C-labelled nutrient, respectively, were DMSO containing PA (2.5 μCi labelled PA * per 50 g BW, 1 μmol unlabelled PA kg -1 BW) (Ning et al 2016;Yang et al 2018), saline containing Glu (2.5 μCi labelled Glu * per 50 g BW, 500 mg unlabelled Glu kg −1 BW) (Liu et al 2018) and saline containing AA (2.5 μCi labelled AA * per 50 g BW, 500 mg unlabelled AA kg -1 BW) (Yang et al 2018). The ratio of unlabelled AA was 2.7:2:1 and 1:1.3 for L-Lys: L-Arg:DL-Met and L-His:L-Val, respectively (Sigma) .…”

Dietary tea polyphenols change flesh quality with dose‐related manner in the GIFT tilapia fed with a high‐fat diet

“…Of note, tilapia is an omnivorous fish species and has higher dietary carbohydrate utilizing ability than other fish species, especially carnivorous fish (Boonanuntanasarn et al., 2018; Gominho‐Rosa et al., 2015). However, because the dietary level of carbohydrate in the practical feed of tilapia has been already high, and excess dietary carbohydrate (more than 400 g/kg) would also cause physiological impairments in tilapia (Liu et al., 2018; Luo et al., 2020), the requirement to increase dietary lipid utilization is increasing in tilapia feed production. During recent years, HFD is also widely used in tilapia aquaculture, and the adverse effects in disturbing metabolism had also been reported (Liu et al., 2018).…”

Differential Roles of Two Leptin Gene Paralogues on Food Intake and Hepatic Metabolism Regulation in Mandarin Fish

“…Leptin is involved in energy homeostasis and growth regulation as a satiety signal in mammals (31,32). However, the relationship between energy state and leptin has not been fully elucidated in fish (14).…”