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Volume 9 (2009), Pages 1197-1205
Research Article

The Effects of Different Levels of Dietary Protein and L-Carnitine on Blood Sugar and Lipids of the New GIFT Strain of Juvenile Nile Tilapia (Oreochromis niloticus)

1College of Fisheries, Guangdong Ocean University, Zhanjiang 524025, China
2Guangdong South China Sea Key Laboratory of Aquaculture for Aquatic Economic Animals, Zhanjiang 524025, China

Received 20 April 2009; Revised 26 September 2009; Accepted 28 September 2009

Academic Editor: Micheal S. Allen

Copyright © 2009 Gang Chen et al.


The new GIFT (Genetically Improved Farmed Tilapia) strain of Nile tilapia is a popular cultivated fish in Asia, but intensive aquaculture using nutritionally imbalanced feed has led to disorder of lipid metabolisms. An 8-week feeding experiment was conducted in order to assess the effects of different levels of L-carnitine (0, 200, 400, 600, and 800 mg/kg) and dietary protein (22, 25, and 28%) on blood sugar and blood lipid contents of the new juvenile GIFT strain of Nile tilapia. Results showed that dietary protein and L-carnitine had significant influences on glucose (GLU), high-density lipoprotein–cholesterol (HDL-C), total cholesterol (TC), triglyceride (TG), and low-density lipoprotein–cholesterol (LDL-C) in the blood serum. The contents of GLU and HDL-C increased with the increases in dietary protein and L-carnitine levels, while the contents of TC, LDL-C, and TG decreased with the increases in dietary protein and L-carnitine levels. The interactive effect of both dietary protein and L-carnitine was most significant on GLU (p = 0.0001), followed by TG (p = 0.001), TC (p = 0.005), HDL-C (p = 0.056), and LDL-C (p = 0.109). These results suggested that high levels of dietary protein and L-carnitine supplementation reduce blood lipids and the burden of the fish liver.