Article

Effect of dietary lipid level on growth performance, lipid deposition, hepatic lipogenesis in juvenile cobia (Rachycentron canadum). Aquaculture

Institute of Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, 135 Xinggang West Road, Guangzhou 510275, PR China
Aquaculture (Impact Factor: 1.88). 09/2005; 249(1-4):439-447. DOI: 10.1016/j.aquaculture.2005.04.038

ABSTRACT

A study was undertaken to evaluate the effect of the dietary lipid level on growth, feed utilization, lipid deposition and lipid metabolism by cobia juveniles. Three isonitrogenous diets containing 47% crude protein with increasing dietary lipid levels 5%, 15% and 25% (DM, dry matter) were fed to satiety to triplicate groups of 20 fish (7.71 g) for 6 weeks. At the end of the feeding trial, fish fed diets containing 5% and 15% lipid showed a higher growth than those fish fed with 25% lipid. Though daily feed intake (DFI) decreased with increasing dietary lipid, there was no significant difference in daily energy intake (DEI) among treatments. As dietary lipid level increased, energy retention (EI), daily energy gain (DEG), daily lipid intake (DLI), daily lipid gain (DLG), viscerosomatic index (VSI), intraperitoneal fat ratio (IPF) and body lipid content increased dramatically and the 25% group had the highest values. Hepatosomatic index (HSI) and muscle lipid content were higher at 25% lipid group than 5% lipid group, but no significant different was found between 15% and 25% lipid group. Activities of G6PD and ME were reduced with increasing lipid intake, but activities of IDH and 6PGDH did not change among groups. In conclusion, high dietary lipid levels above 15% produced little practical benefit because of higher fat accretion in cobia.

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    • "This particular study was carried out during the winter time (12/11/2014 to 02/05/ 2015) and may partly explain the slow growth observed, although it may also be a particular characteristic of this species, because, coincidentally , the study with C. othonopterus was also carried out during the winter time (01/13/2012 to 03/09/2012). In the present study, increased lipid deposition as a result of increasing dietary lipid was evident in whole fish, muscle and liver of C. parvipinnis (Table 4), coinciding with a number of observations reported for sciaenids like S. ocellatus, meagre A. regius, cuneate drum Nibea miichthioides, mulloway Argyrosomus japonicus, C. othonopterus and T. macdonaldi (McGoogan and Gatlin, 1999;Chatzifotis et al., 2010;Wang et al., 2006;Woolley et al., 2010;Perez-Velazquez et al., 2015a;González-Félix et al., 2015), as well as for non-sciaenids such as Atlantic salmon Salmo salar, Japanese flounder Paralichthys olivaceus, grouper Epinephelus malabaricus, cobia R. canadum, mullet Liza macrolepis, and common dentex Dentex dentex (Hemre and Sandnes, 1999;Lee et al., 2000;Shiau and Lan, 1996;Wang et al., 2005;Rangaswamy et al., 1998;Skalli et al., 2004). In addition to dietary lipid level, also the replacement level of FO by SO oil significantly affected the deposition of fat in muscle of C. parvipinnis and the moisture content, as reported for blackhead seabream Acanthopagrus schlegeli (Peng et al., 2008), S. aurata (Martinez-Llorens et al., 2007), white seabream Diplodus sargus (Taşbozan et al., 2015), and other Table 8Fatty acid composition (mg FA g −1 wet weight) of liver of Cynoscion parvipinnis fed diets with three levels of dietary lipid and three levels of replacement of fish oil by soybean oil after 8 weeks., 2011). "
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    ABSTRACT: This study evaluated the effect of various dietary lipid levels for the shortfin corvina Cynoscion parvipinnis when provided as fish oil (FO), and the degree to which FO may be replaced by soybean oil (SO) without significantly affecting its biological performance or the nutritional value of the fillet for the consumers. Three levels of dietary lipid, 8, 12, and 16%, and three levels of inclusion of FO, 100% FO, 75% FO–25% SO, and 50% FO–50% SO, were evaluated in an 8-week feeding trial with a 3 × 3 factorial design, on growth, feed utilization and body composition of this species. Juveniles (initial mean body weight: 97.47 g) were stocked into circular tanks of 250 L in a recirculating system at a density of 6 fish tank− 1, assigning each dietary treatment to four replicate tanks. At the end of the trial, no significant differences were observed for either the main effects or their interaction in any of the growth parameters evaluated. The crude fat content of muscle was significantly affected by the dietary lipid level and by the level of FO replacement, ranging from 1.33% in fish fed 8% lipid, to 1.81% in fish fed 16%, and from 1.25% in fish fed 100% FO, to 1.88% in fish fed 50% FO–50% SO. Linoleic acid content increased (0.65 to 1.43 mg g− 1) as dietary SO replaced FO, while the eicosapentaenoic (0.67 to 0.55 mg g− 1) and docosahexaenoic (1.49 to 1.26 mg g− 1) acids decreased. The atherogenicity index (AI) ranged from 1.07 to 1.16, while the thrombogenicity index (TI) ranged from 0.18 to 0.29, and the n − 3/n − 6 ratio was significantly reduced from 2.65 in muscle of fish fed the 100% FO diet, to 1.43 in those fed the 50% FO diet. Thus, from an economic perspective, it would be desirable to limit the FO inclusion and to keep the total dietary lipid at 8% when dietary protein is provided at 44% in aquafeeds for the growout stage of this species. Moreover, up to 50% of FO can be replaced by SO with no adverse effects on growth, and, even though the fatty acid profile of the muscle was significantly modified by the replacement, the health lipid indices and n − 3/n − 6 ratios confirmed that the muscle still conserved the functional properties of nutraceutics for human health, and the fillets are valuable in a healthy diet as a source of essential fatty acids.
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    • "In addition, in modern aquaculture HF diets have been widely used in many economic fish species to save dietary protein as an energy source and increase feed efficiency (Hillestad et al. 1998; Boujard et al. 2004). However, HF diets commonly caused excess fat accumulation in the liver or visceral fat tissue in farmed fish, accompanied by low growth, survival and resistance to pathogens and environmental stresses (Regost et al. 2001; Wang et al. 2005a), suggesting impaired lipid homeostasis. So far, people have known that the liver, adipose tissues, or muscle have the capability to store lipid in fish (Lin et al. 1977; Ando et al. 1993; Kaneko et al. 2013), and a number of lipid-metabolismrelated genes in some farmed fishes have been cloned and the preliminary functions have also been illustrated (He et al. 2014). "
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    Full-text · Article · Aug 2015
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    • "However, fish can utilize dietary lipids up to a certain level beyond which a retarded growth may be achieved due to reduced feed consumption (Daniels and Robinson, 1986; Ellis and Reigh, 1991; Watanabe, 1982). Also, an excess amount of dietary lipid can result in some side effects including feed manufacturing problems, production of fatty liver, body lipid deposition, and lower carcass quality (Chatzifotis et al., 2010; López et al., 2006; Luo et al., 2005; Wang et al., 2005). Therefore, it is very important to optimize dietary protein and lipid levels for formulation of nutritionally balanced cost-effective practical diets of fish. "
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