Effects of total replacement of dietary fish oil on growth performance and fatty acid compositions of hybrid tilapia ( O
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Effects of total replacement of dietary fish oil on growth performance and fatty acid compositions of hybrid tilapia (Oreochromis niloticus 3 O. aureus) C.-Y. Han • Q.-M. Zheng • L.-N. Feng
Received: 15 May 2012 / Accepted: 7 January 2013 / Published online: 16 January 2013 Ó Springer Science+Business Media Dordrecht 2013
Abstract The aim of this study is to evaluate the effects of total replacement of fish oil (FO) with pork lard (PL), soybean oil (SO), or tea seed oil (TO) on growth and fatty acid compositions of hybrid tilapia (Oreochromis niloticus 9 O. aureus). Four diets were formulated to contain 4.5 % of each of the different lipid sources. Each diet was assigned to triplicate groups of 15 hybrid tilapia with the same initial body weight (4.6 ± 0.5 g). After a 10-week feeding, the FO, SO, and TO groups had similar final body weight. The mean hepatosomatic index in the FO group was significantly lower than the other groups (2.5 vs 2.9–3.0; P \ 0.05). Whole-body lipid levels were highest in the TO group (5.2 ± 0.4 %) and lowest in the FO group (4.3 ± 0.5 %). Total n-3 polyunsaturated fatty acids (PUFA) concentrations were greater in the SO and FO groups (5.5 ± 0.1 and 7.1 ± 0.2, respectively) than in the PL and TO groups (1.7 ± 0.1 and 1.4 ± 0.1, respectively). The FO group had a 2- to 4-fold reduction in the n-6/n-3 PUFA ratio relative to the other groups. The concentrations of both docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were significantly (P \ 0.05) higher in the FO group than in the other groups. Our data demonstrate that total replacement of dietary FO with SO or TO has little effects on growth of hybrid tilapia but reduces the contents of health-benefiting DHA and EPA in fish body. Keywords Body composition Cichlid Fish oil Lipid nutrition Polyunsaturated fatty acids Introduction At present, fish oil (FO), which is produced from small wild fish, is widely used in formulated diets for farmed fish, not only providing energy and essential fatty acids but also improving the palatability of the feed. However, the wild fisheries resource is limited and cannot meet the vast demand of industrial aquafeeds. Thus, many attempts have been made to find ecologically sustainable alternatives to FO (Bell et al. 2001; Noffs et al. 2009; Karalazos et al. 2011; Morais et al. 2011). C.-Y. Han (&) Q.-M. Zheng L.-N. Feng Department of Biology, Jiaying University, Meizhou, China e-mail: [email protected]
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Aquacult Int (2013) 21:1209–1217
A wide range of alternative oils, especially vegetable oils, have been tested for their potential to replace FO in aquafeeds (Richard et al. 2006; Leaver et al. 2008; Noffs et al. 2009; Morais et al. 2011). It has been documented that FO in formulated diets can be replaced by up to 100 % of canola oil and by up to 50 % of linseed oil without significantly affecting the growth of Murray cod (Maccullochella peelii peelii), an Australian native freshwater fish (Francis et al. 2006). In red hybrid tilapia (Oreochromis sp.), the substitution of d
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