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

Institute of Aquatic Economic Animals, School of Life Science, Sun Yat-sen University, 135 Xinggang West Road, Guangzhou 510275, PR China; College of Fisheries, Ocean University of China, Qingdao 266003, PR China
Aquaculture 01/2005; 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.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Culture density in excess of a critical threshold can result in a negative relationship between stocking density and fish production. This study was conducted to evaluate production characteristics of juvenile cobia, Rachycentron canadum, reared to market size in production-scale recirculating aquaculture systems (RAS) at three different densities. Cobia (322 ± 69 g initial weight) were reared for 119 d at densities to attain a final in-tank biomass of 10, 20, or 30 kg/m 3 . The specific objective was to determine the effects of in-tank crowding resulting from higher biomass per unit rearing volume independent of system loading rates. Survival was ≥96% among all treatments. Mean final weight ranged from 2.13 to 2.15 kg with feed conversion efficiencies of 65–66%. No significant differences were detected in growth rate, survival, feed efficiency, or body composition. This study demonstrates that cobia can be reared to >2 kg final weight at densities ≤30 kg/m 3 under suitable environmental conditions without detrimental effects on production. Interest in the culture of cobia, Rachycentron canadum, a migratory marine pelagic finfish, has increased greatly in the USA over the last 10 years. Cobia are of excellent food quality with high consumer appeal (Oesterling 2001; Shiau 2007) and possess a number of attributes desirable for commercial culture. Cobia exhibit extremely rapid growth (Chou et al. 2001, 2004; Weirich et al. 2004) and can attain weights of 4–6 kg in less than 1 yr (Shyu and Liao 2004; Benetti et al. 2010). They adapt well to con-finement and readily accept formulated feeds (Schwarz et al. 2004; Weirich et al. 2004). Cobia can be spawned in captivity, with or without hormonal induction (Franks et al. 2001;
    Journal of the World Aquaculture Society 01/2013; 44:259-266. · 0.75 Impact Factor
  • Source
    Latin American Journal of Aquatic Research 11/2012; 40(4):1017-1025. · 0.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present study aimed at determining the growth performance, body composition and digestive enzyme activities of pejerrey (Odontesthes bonariensis) juveniles fed with graded levels of dietary lipids: 6% (L6), 10% (L10) and 25% (L25). Following a 14-week growth trial, weight increase decreased in group L6. The protein productive value increased in groups L10 and L25, whereas group L10 showed the highest lipid productive value. Hepatosomatic and mesenteric fat indexes decreased in group L6. Body protein content decreased with the increase in dietary lipids (L6 > L10 > L25); whereas body lipid content, and nitrogen and energy retentions were the lowest in group L6. The muscle fatty acid composition was differentially regulated by the diets except EPA, DHA and n-3 PUFA contents. The total n-6 PUFA decreased in group L6. The n-3 PUFA tended to accumulate in the muscle of the fish; group L10 exhibiting the lowest accumulation rate. The total activity of neutral lipase was stimulated in group L25 whereas the specific activity of pancreatic lipase decreased in this same group. While group L6 showed the lowest total activity of alkaline proteases, group L10 showed the highest total activity of trypsin. A decrease in the specific activity of amylase in group L25 followed the decrease in dietary starch. In summary, 25% of dietary lipids did not have additional stimulatory effects on the digestive proteases activity compared to 10%, but negatively affected pancreatic lipase and trypsin activities. Moreover, the decrease of the latter in group L25 suggests that approximately 10% of dietary lipids might support the growth of pejerrey juveniles reared in captivity.
    Aquaculture 12/2013; 416-417:15-22. · 2.01 Impact Factor


Available from