Effects of dietary lipid level on liver and muscle lipid deposition in juvenile haddock, Melanogrammus aeglefinus L.

Abstract

The effects of dietary lipid levels on growth, feed utilization, hepatosomatic index (HSI), liver lipid deposition and tissue fatty acid composition in haddock were investigated. Triplicate tanks of juvenile haddock (6.9 g) were fed graded levels of herring oil to supply 14, 16, 19 and 22% lipid (DM, dry matter) in ®sh meal-based, isonitrogenous diets. Growth and feed conversion ratio of juvenile haddock was not signi®cantly (P < 0.05) affected by increasing the lipid content of the diet. A signi®cant increase in HSI (9.8±12.1%), total liver lipid (63.2±69.0%) and whole body gross energy content (6.03±6.39 kcal g ±1 DM) were observed in haddock fed 14% vs. 22% lipid. Although the HSI of these cultured haddock was high in comparison to wild gadoids, histological analyses of these haddock livers did not reveal any overt pathology. Muscle lipid levels (1.0%) did not increase signi®cantly with dietary lipid. Liver fatty acid levels mirrored dietary fatty acid (FA) composition. The muscle consisted mainly of polar lipid (84.3 T 2.5% of total lipid) and a large proportion (52.6 T 0.8%) of polyunsaturated FA. A dietary lipid level of 14% DM or less is recommended for juvenile haddock.

Effects of dietary lipid levels on growth performance, feed utilization and fatty acid composition of juvenile Japanese seabass (Lateolabrax japonicus) reared in seawater

“…Given the relatively large size of the fillet (nearly 55% of body mass), muscular mass might also play the important contribution to body fat deposit in the present study for Japanese seabass. This result is different from that observed in other fishes fed high lipid diets (Nanton et al 2001;Lee et al 2002;López et al 2009), but similar to reports in eel (Otwell and Rickards 1981), salmon (Hemre and Sandnes 1999) and cobia (Wang et al 2005). 18:0 5.9 ± 0.3 a 4.7 ± 0.4 b 3.5 ± 0.7 c 4.3 ± 0.2 bc 5.7 ± 1.2 a 6.6 ± 0.9 a 20:0 0.8 ± 0.0 c 0.9 ± 0.1 bc 0.8 ± 0.1 c 1.0 ± 0.3 b 1.1 ± 0.1 b 1.3 ± 0.2 a SFA 24.2 ± 1.1 b 17.8 ± 1.3 c 17.2 ± 0.9 c 18.9 ± 1.8 c 23.9 ± 1.7 b 27.6 ± 3.4 a 16:1n-7 2.5 ± 0.1 c 3.5 ± 0.8 a 2.6 ± 0.5 c 2.9 ± 0.3 b 3.1 ± 0.1 b 3.5 ± 0.5 a 18:1n-9 8.2 ± 0.4 b 6.8 ± 0.6 c 5.1 ± 0.4 d 7.3 ± 0.3 c 8.4 ± 0.8 b 9.2 ± 0.7 a 18:1n-7 3.8 ± 0.6 ab 2.2 ± 0.2 d 2.6 ± 0.…”

Lipid and fatty acid compositions of cod (Gadus morhua), haddock (Melanogrammus aeglefinus) and halibut (Hippoglossus hippoglossus)

“…Haddock liver had significantly high lipid content, which was almost double that of cod and halibut liver. The result for haddock liver lipid level (67.2%) in the present study was in agreement with the previously published data (63.2%−69.0%, Nanton et al, 2001). However, lipid content of cod liver (36.9%) in our study was lower than that (50%−60%) reported by Lie et al (1986), and lipid content of halibut liver (30.7%) in this study was higher than that (7%−19%) reported by Hatlen et al (2005).…”

“…In fat fish flesh, triglycerides are the major lipid form, but the structural phospholipids exceeding the high energy triglycerides in lean fish muscle has been observed in previous work (Ackman, 1989;Santos et al, 1993;Nanton et al, 2001). Results of this study were in accordance with those previously reported.…”

“…Cod and haddock are typical lean fish; lipid content of their muscle was lower than 1% in the present study, which agreed well with the previous data (Santos et al, 1993;Nanton et al, 2001). Halibut is a low-fat fish and is ranked between lean fish and medium-fat fish like Atlantic salmon (Ackman, 1989).…”

Estimation of Male Reproductive Success of Marine Fisheries

“…and shrimp (Pandalus sp.). Prepared dry and moist pellet diets that require less labour are also options, though they are more removed from their natural diet, and due to a relatively high fat content, lead to enlarged livers (Nanton et al, 2001;Lambert and Thorsen, 2003). Fish should be tagged (external or internal) to maintain record of their growth and reproductive history while in captivity.…”