Browsing by Author "Qiao, F"

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    Dietary oils modify lipid molecules and nutritional value of fillet in Nile tilapia: a deep lipidomics analysis.
    (Food Chemistry, 2018-11-02) Liu, Y; Jiao, J-G.; Gao, S; Ning, L-J.; Samwel Mchele Limbu; Qiao, F; Chen, Li-Qiao; Zhang, M-L; Du, Zhen-Yu
    The nutritional value of fish fillet can be largely affected by dietary oils. However, little is known about how dietary oils modify lipid molecules in fish fillets. Through biochemical and lipidomics assays, this study demonstrated the molecular characteristics of fillet lipids in Nile tilapia fed with different oils for six weeks. High 18:2n-6 and low 18:3n-3 deposition in phosphoglycerides resulted high 18:2n-6/18:3n-3 ratio in tilapia. Dietary n-3 VLCUFAs intake increased its deposition at sn-1/3 of triglycerides and at sn-2 of phosphatidylcholines. Irrespective of dietary oil, 16:0 was distributed preferentially at the outer positions of glycerol backbone. High 18:2n-6 accumulated at sn-2 position for fish fed with n-3 PUFA-enriched oils. High 18:3n-3 deposited at sn-1/3 in TG, sn-1 in phosphatidylethanolamines, while at sn-2 in phosphatidylcholines. Together, dietary oils change the composition and positional distribution of fatty acids on the glycerol backbone, and change nutritional value of fish for human health.
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    Functional differences between l- and d-carnitine in metabolic regulation evaluated using a low-carnitine Nile tilapia model. British Journal of Nutrition, 122(6): 625-638.
    (Cambridge University Press, 2019-08-14) Li, J.-M.; Li, L.-Y.; Zhang, Y.-X; Jiang, Z.-Y; Samwel Mchele Limbu; Qiao, F; Degrace, P.; Chen, L.-Q.; Zhang, M.-L.; Du Z.-Y.
    l-Carnitine is essential for mitochondrial β-oxidation and has been used as a lipid-lowering feed additive in humans and farmed animals. d-Carnitine is an optical isomer of l-carnitine and dl-carnitine has been widely used in animal feeds. However, the functional differences between l- and d-carnitine are difficult to study because of the endogenous l-carnitine background. In the present study, we developed a low-carnitine Nile tilapia model by treating fish with a carnitine synthesis inhibitor, and used this model to investigate the functional differences between l- and d-carnitine in nutrient metabolism in fish. l- or d-carnitine (0·4 g/kg diet) was fed to the low-carnitine tilapia for 6 weeks. l-Carnitine feeding increased the acyl-carnitine concentration from 3522 to 10 822 ng/g and alleviated the lipid deposition from 15·89 to 11·97 % in the liver of low-carnitine tilapia. However, as compared with l-carnitine group, d-carnitine feeding reduced the acyl-carnitine concentration from 10 822 to 5482 ng/g, and increased lipid deposition from 11·97 to 20·21 % and the mRNA expression of the genes involved in β-oxidation and detoxification in the liver. d-Carnitine feeding also induced hepatic inflammation, oxidative stress and apoptosis. A metabolomic investigation further showed that d-carnitine feeding increased glycolysis, protein metabolism and activity of the tricarboxylic acid cycle and oxidative phosphorylation. Thus, l-carnitine can be physiologically utilised in fish, whereas d-carnitine is metabolised as a xenobiotic and induces lipotoxicity. d-Carnitine-fed fish demonstrates increases in peroxisomal β-oxidation, glycolysis and amino acid degradation to maintain energy homeostasis. Therefore, d-carnitine is not recommended for use in farmed animals.