EFFECTS OF DIFFERENT LIPID SOURCES ON THE GROWTH, LIPID METABOLISM AND ANTIOXIDANT ABILITY OF BRACHYMYSTAX LENOK

A 52-day growth trial was conducted to evaluate the effects of different dietary lipids on the growth performance, lipid metabolism, and antioxidant ability of Brachymystax lenok. Fish with average initial weight of (22.19±1.10) g were fed with four experimental diets that contained fish oil (FO), colza oil (CO), palm oil (PaO), and soybean oil (SO), respectively. The lowest weight gain, specific growth rate, and the feed conversion ratio were observed with CO treatment, while the highest values of these parameters occurred at the experiments of FO and SO, with no significant differences between these two conditions (P>0.05). Crude protein and lipid in the muscle ofBrachymystax lenok were not affected by lipid sources (P>0.05). However, the DHA level ofBrachymystax lenok fed with SO increased, which indicated that Brachymystax lenok had the ability to desaturate and elongate from 18:3n-3 to 22:6n-3. Compared to which fed with FO, an increase of TG and decrease of TC were observed in the serum of Brachymystax lenok fed with plant oils. In addition, the mRNA expression of Δ6 Fad in the liver of those fed with plant oils also increased, but the mRNA expression of ACC1 and FAS decreased. The values of ROS, MDA, GPx and TBARS in liver were significantly affected by different lipid sources (P<0.05). The results suggest that FO and SO could be used in the diet for juvenileBrachymystax lenok, but CO and PaO are unsuitable as single lipid sources for juvenile Brachymystax lenok.