Article

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
Aquaculture (Impact Factor: 1.83). 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.

0 Followers
 · 
215 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: An 8-week feeding trial was conducted to evaluate the effects of varying dietary protein and lipid levels on growth, feed utilization, and body composition of brown-marbled grouper (Epinephelus fuscoguttatus)and giant grouper (Epinephelus lanceolatus) hybrid. Eight diets were formulated to contain four protein levels (40, 45, 50 and 55% crude protein) and two lipid levels (7 and 14% crude lipid). Seven hundred and twenty juvenile grouper averaging 2.55 ± 0.10 g were randomly allotted to 24 cages (8 treatments in triplicate groups) and fed the test diets to apparent satiation three times a day. The results showed significant (P b 0.05) enhancement of weight gain and specific growth rate with increasing dietary protein from 40 to 50%, and a reduced growth was obtained by further increase of dietary protein to 55%. Increasing dietary lipid level from7 to 14% did not significantly affect growth performance (P N 0.05). Feed efficiency was significantly improved by increasing dietary protein and lipid levels. Also, the results revealed the significant increase of protein efficiency ratio by increasing dietary lipid. Significant reduction in daily feed intake was observed by increment of dietary protein and lipid levels. Whole-body lipid content increased with increasing dietary lipid and inversely correlated with whole-body moisture content. Dietary protein, lipid, and their interaction had a significant effect on liver protein content. Significant changes in dorsal muscle and liver fatty acid compositions were observed by variation of dietary protein and lipid levels. According to these results, a diet containing 50% protein and 14% lipid with protein to energy ratio of 23.9 mg kJ−1 is recommended for efficient growth of juvenile hybrid grouper.
    Aquaculture 05/2015; 446:283-289. DOI:10.1016/j.aquaculture.2015.05.019 · 1.83 Impact Factor
  • Source
  • 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 04/2013; 44(2):259-266. DOI:10.1111/jwas.12023 · 0.93 Impact Factor

Preview

Download
2 Downloads
Available from