Effects of dietary <Emphasis Type="Italic">n</Emphasis>-3 fatty acids on Toll-like receptor activation in primary leucocytes from Atlantic salmon (<Emphasis Type="Italic">Salmo salar</Emphasis>)

The shortage of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the international markets has led to increasing substitution of fish oil by plant oils in Atlantic salmon (Salmo salar) feed and thereby reducing the EPA and DHA content in salmon. However, the minimum required levels of these fatty acids in fish diets for securing fish health are unknown. Fish were fed with 0, 1 or 2% EPA or DHA alone or in combination of both over a period, growing from 50 to 400 g. Primary head kidney leucocytes were isolated and stimulated with Toll-like receptor (TLR) ligands to determine if EPA and DHA deficiency can affect expression of important immune genes and eicosanoid production. Several genes related to viral immune response did not vary between groups. However, there was a tendency that the high-level EPA and DHA groups expressed lower levels of IL-1β in non-stimulated leucocytes. These leucocytes were also more responsive to the TLR ligands, inducing higher expression levels of IL-1β and Mx1 after stimulation. The levels of prostaglandin E2 and leukotriene B4 in serum and media from stimulated leucocytes were lower in both low and high EPA and DHA groups. In conclusion, leucocytes from low EPA and DHA groups seemed to be less responsive towards immunostimulants, like TLR ligands, indicating that low levels or absence of dietary EPA and DHA may have immunosuppressive effects.     

Effects of dietary vegetable oils and varying dietary EPA and DHA levels on intestinal lipid accumulations in Atlantic salmon

High dietary content of vegetable oil (VO) has been associated with increased intestinal lipid accumulations in fish. The extent of this in aquacultured Atlantic salmon (Salmo salar L.) and its health effects are not certain. Samples were therefore collected from two separate feeding trials to investigate the effect of high dietary VO on intestinal lipid accumulations in Atlantic salmon. In the first trial, the fish were fed diets high in plant protein and with fish oil or ~80% of the fish oil replaced with either olive oil, rapeseed oil or soybean oil in a land‐based experimental set‐up. The second trial was performed in sea cages under commercial production conditions, and the fish were fed two dietary concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (9.7% or 5.5% EPA + DHA of total fatty acids). Neither dietary VO nor variations in EPA and DHA led to any significant effects on intestinal health or lipid accumulations. There were, however, indications of a delayed lipid transport in the rapeseed oil‐fed fish of the first trial, possibly caused by high dietary ≥18‐carbon fatty acids and low dietary 16:0 fatty acid and cholesterol.     

Effects of dietary levels of 20:5n-3 and 22:6n-3 on tissue lipid composition in juvenile Atlantic salmon, Salmo salar, with emphasis on brain and eye

Four dietary groups of juvenile Atlantic salmon, Salmo salar L., each with three replicates, were fed diets with increasing levels of docosahexaenoic acid (22:6n-3; DHA) and eicosapentaenoic acid (20:5n-3; EPA). Fatty acid composition of brain and eye was determined at the start and approximately every 3 weeks during the experimental period, and fatty acid composition of liver and fillet was determined in fish from the final sampling. Lipid class composition of brain and eye, and fatty acid composition of these lipid classes was determined at the end of the experiment. There was no effect of increasing dietary DHA content on fatty acid composition, lipid class composition or DHA levels in the lipid classes in the juvenile Atlantic salmon brain. The increasing dietary EPA content, however, was reflected in both the total fatty acid composition and in the EPA content in neutral lipids, phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI). A minor effect of the increasing dietary DHA content was found in the lipid composition of the juvenile salmon eye. Both EPA and 18:2n-6 levels in eye, however, clearly reflected the increasing and decreasing, respectively, dietary levels of these two fatty acids. The dietary EPA levels also affected the EPA levels in neutral lipids, PC, PE, PI and PS (phosphatidylserine) in the juvenile salmon eye. The results demonstrate that these dietary levels of DHA had no effect on brain lipid composition and only a minor effect on eye lipid composition. Furthermore, the dietary EPA levels significantly affected the lipid composition of both brain and eye. The fillet fatty acid composition reflected the dietary fatty acid composition, except for the DHA/EPA ratio, which was reversed in fillet compared with that in the diets. The liver fatty acid composition was also affected by the increasing dietary EPA and DHA levels.     

Oxidative stability of salmon and herring roe lipids and their dietary effect on plasma cholesterol levels of rats

ABSTRACT:   The oxidative stability of lipids from salmon roe and herring roe was compared with those of commercial fish oils originated from sardine and tuna. Both fish roe lipids contained high amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Total EPA and DHA was more than 35% of total fatty acids in both roe lipids. On the basis of oxygen consumption, fish roe lipids showed the higher oxidative stability than both fish oils. This tendency in oxidative stabilities was also confirmed by the determination of propanal formation during oxidation. Analyses of lipid compositions suggested that the higher oxidative stabilities of fish roe lipids would be mainly due to the presence of phospholipids in them. Dietary effects of salmon and herring roe lipids were also determined. Little increase in total cholesterol level was observed in plasma lipids in rats fed salmon and herring roe lipids, although cholesterol content in fish roe lipids were 6.3% and 9.7% of total lipids for salmon roe and herring roe.     

Growth performance,feed utilization and product quality in slaughter size Atlantic salmon (Salmo salar L.) fed a diet with porcine blood meal,poultry oil and salmon oil

In a 17‐week experiment with Atlantic salmon (2.3–5.2 kg) in sea cages, a diet containing European animal by‐products and salmon oil (ABP) was compared with a control diet based on fish and plant ingredients, with respect to performance and product quality. Fish fed with the ABP diet had similar growth rates, but slightly improved feed conversion ratio (feed: gain; 1.08 versus 1.14) compared with the control. No differences were seen in fish length, live weight or condition factor. Final body composition was similar and retention of nitrogen and energy did not differ between diets. Higher DPA (C22:5 n‐3) content in the ABP diet apparently inhibited conversion of EPA (C20:5 n‐3) to DPA, resulting in higher EPA retention in muscle and whole body. Muscle and whole body DHA (C22:6 n‐3) level and n‐3 : n‐6 ratio were higher in the ABP group, corresponding with dietary levels. There were no differences in slaughter yield, quality classification, gaping score or fillet texture between diets. The feed with ABP contained less astaxanthin, possibly because of degradation catalyzed by iron in blood meal, and this resulted in lower muscle colour score and astaxanthin concentration (4.6 versus 6.4 mg kg⁻¹). A sensory test did not reveal any differences in odour, flavour, or texture.     

Dietary fish oil replacement with palm or poultry oil increases fillet oxidative stability and decreases liver glutathione peroxidase activity in barramundi (Lates calcarifer)

Complete dietary fish oil replacement with palm or poultry oil in barramundi (Lates calcarifer) had no detrimental effects on growth or hepatosomatic index of juvenile fish up to an average size of ~50 g. However, it significantly decreased the omega-3 (n-3) long-chain polyunsaturated fatty acid content of the fish muscle (fillet) lipids. This was particularly true for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) which are recognised for their health beneficial effects in the human diet. As a result of their decreased EPA and DHA content, the peroxidation index of the muscle lipids was also decreased. This was associated with increased simulated retail storage shelf life as indicated by decreased thiobarbituric acid reactive substances in muscle samples from fish fed the palm or poultry oil-based diets. Concomitantly, glutathione peroxidase (GPx) activity, but not glutathione S-transferase (GST) activity or reduced glutathione concentration, was significantly reduced in the liver of barramundi fed the palm or poultry oil-based diets as compared with the fish fed the fish oil-based diet. Furthermore, GPx and GST activity were very low in muscle, much lower than in gastrointestinal tract, liver or swim bladder. Therefore, we propose that liver GPx activity may be a good predictor of fillet shelf life in barramundi and other fish species.     

Polyunsaturated fatty acid metabolism in Atlantic salmon (Salmo salar) undergoing parr-smolt transformation and the effects of dietary linseed and rapeseed oils

Duplicate groups of Atlantic salmon parr were fed diets containing either fish oil (FO), rapeseed oil (RO), linseed oil (LO) or linseed oil supplemented with arachidonic acid (20:4n-6; AA) (LOA) from October (week 0) to seawater transfer in March (week 19). From March to July (weeks 20–34) all fish were fed a fish oil-containing diet. Fatty acyl desaturation and elongation activity in isolated hepatocytes incubated with [1-¹⁴C]18:3n-3 increased in all dietary groups, peaking in early March about one month prior to seawater transfer. Desaturation activities at their peak were significantly greater in fish fed the vegetable oils, particularly RO, compared to fish fed FO. Docosahexaenoic acid (22:6n-3:DHA) and AA in liver and gill polar lipids (PL) increased in all dietary groups during the freshwater phase whereas eicosapentaenoic acid (20:5n-3; EPA) increased greatly in all groups after seawater transfer. The AA/EPA ratio in tissue PL increased up to seawater transfer and then decreased after transfer. AA levels and the AA/EPA ratio in gill PL were generally higher in the LOA group. The levels of 18:3n-3 in muscle total lipid were increased significantly in the LO, LOA and, to a lesser extent, RO groups prior to transfer but were reduced to initial levels by the termination of the experiment (week 34). In contrast, 18:2n-6 in muscle total lipid was significantly increased after 18 weeks in fish fed the diets supplemented with RO and LO, and was significantly greater in the FO and RO groups at the termination of the experiment. Gill PGF production showed a large peak about two months after transfer to seawater. The production of total PGF post-transfer was significantly lower in fish previously fed the LOA diet. However, plasma chloride concentrations in fish subjected to a seawater challenge at 18 weeks were all lower in fish fed the diets with vegetable oils. This effect was significant in the case of fish receiving the diet with LOA, compared to those fed the diet containing FO. The present study showed that during parr-smolt transformation in Atlantic salmon there is a pre-adaptive increase in hepatocyte fatty acyl desaturation/elongation activities that is controlled primarily by environmental factors such as photoperiod and temperature but that can also be significantly modulated by diet. Feeding salmon parr diets supplemented with rapeseed or linseed oils prevented inhibition of the desaturase activities that is induced by feeding parr diets with fish oils and thus influenced the smoltification process by altering tissue PL fatty acid compositions and eicosanoid production. These effects, in turn, had a beneficial effect on the ability of the fish to osmoregulate and thus adapt to salinity changes.     

Dietary docosahexaenoic acid to eicosapentaenoic acid (DHA/EPA) ratio influenced growth performance,immune response,stress resistance and tissue fatty acid composition of juvenile Japanese seabass,Lateolabrax japonicus (Cuvier)

A 10‐week feeding experiment was conducted to investigate the effects of dietary DHA/EPA ratio on juvenile Japanese seabass reared in sea floating cages. Six practical diets were formulated differing only in DHA/EPA ratio: 0.55 (Diet D/E0.55), 1.04 (D/E1.04), 1.53 (D/E1.53), 2.08 (D/E2.08), 2.44 (D/E2.44) and 2.93 (D/E2.93). All diets had the same contents of total n‐3 long‐chain polyunsaturated fatty acid (LC‐PUFA) and arachidonic acid (ARA). The results showed that the final weight and specific growth rate significantly increased with increasing dietary DHA/EPA ratio from 0.55 to 2.08 and thereafter declined. Activities of lysozyme and superoxide dismutase in serum in groups with DHA/EPA of 1.53–2.93 was significantly higher compared to group D/E0.55 while the activity of serum alternative complement pathway in group D/E2.93 was significantly lower compared with group D/E1.53. However, no difference was observed in activities of both respiratory burst of head kidney macrophage and serum catalase among dietary treatments. The per cent survival after air exposure in group D/E1.53, D/E2.08 and D/E2.93 was significantly higher compared with group D/E0.55. The fatty acid composition of whole body and tissues reflected closely those of diets, while fish accumulated more DHA than EPA in fish tissues, especially in muscle. These results suggested that at the same dietary contents of n‐3 LC‐PUFA (appr. 18% of TFA) and ARA (appr. 0.7% of TFA), moderate dietary DHA/EPA ratios of 1.53–2.08 significantly enhanced growth performances, certain innate immune responses, and the stress tolerance of Japanese seabass, in accordance with the preferential incorporation of DHA into fish tissues.     

半滑舌鳎不同家系肌肉中脂肪酸含量的分析

为了研究半滑舌鳎(Cynoglossus semilaevis)不同家系肌肉中脂肪酸的组成与含量,并选育出高营养品系的半滑舌鳎家系,用气相色谱法对同一养殖环境中的半滑舌鳎15个不同家系(164个样本)肌肉中的脂肪酸的组成和含量进行了检测和比较分析,同时对高EPA、DHA、EPA+DHA含量的家系进行筛选,并研究了半滑舌鳎性别与EPA、DHA含量的关系。结果表明:(1)15个家系肌肉中脂肪酸种类没有区别,但脂肪酸的组成和含量存在若干差异。其特征均为多不饱和脂肪酸(PUFA)饱和脂肪酸(SFA)单不饱和脂肪酸(MUFA)。PUFA以ω-3系脂肪酸为主,且ω-3系脂肪酸与ω-6系脂肪酸比值达到4.16~5.03,其中的2种重要ω-3系脂肪酸EPA和DHA在15个家系中均具有显著性差异,且DHA含量远大于EPA含量;筛选出了3个高EPA、DHA、EPA+DHA含量家系,分别为F13012、F13023及F13031。(2)EPA的含量与半滑舌鳎性别不具有显著性相关关系。本研究对于选育半滑舌鳎优良品种家系具有重要意义。     

High n‐3 HUFA levels in the diet of Atlantic salmon affect muscle and mitochondrial membrane lipids and their susceptibility to oxidative stress

Atlantic salmon were fed one of four diets with increasing levels (11–58%of total fatty acids (FAs)) of n‐3 highly unsaturated FAs (HUFAs) in order to investigate the effect on muscle and mitochondrial membrane lipids and their susceptibility to oxidative stress. The high n‐3 eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) groups contained lower percentages of sphingomyelin and cardiolipin in total muscle than the intermediate n‐3 HUFA group. Cardiolipin and sphingomyelin are particularly susceptible to peroxidation, and a reduced percentage of these lipids showed that mitochondrial membranes had been damaged by oxidation. The intermediate n‐3 HUFA group had the highest level of mitochondrial integrity and tendencies of lower thiobarbituric acid reactive substances (TBARS) level than the other dietary groups. The high caspase‐3 activity, in addition to casp3a and bax gene expression levels, in the n‐3 DHA group also suggests that some degree of oxidative stress had occurred. Electron microscopy images showed a higher degree of myofibre–myofibre detachment in fish fed the high HUFA diets than in fish fed the intermediate n‐3 HUFA diet. Our findings show that intermediate levels of n‐3 HUFAs in salmon diets gave the best protection against oxidative damage of mitochondrial membranes and muscle structure.     

正常和白化褐牙鲆皮肤和肌肉中DHA和EPA含量的比较

利用气相色谱法对相同养殖条件下生长的正常和白化褐牙鲆(Paralichthys olivaceus)的皮肤和肌肉组织中的DHA和EPA含量进行了比较分析。结果显示，正常和白化褐牙鲆的皮肤和肌肉中EPA含量相近，但白化个体皮肤中DHA含量显著低于正常个体，约为后者的1／2。而两者肌肉中的DHA含量则没有显著差异。同时，白化个体皮肤和肌肉组织中的DHA／EPA比值略低于正常个体。这一结果证明白化褐牙鲆皮肤蓄积或利用DHA的能力要低于正常褐牙鲆。关于鲆鳔类白化现象同鱼体对饵料中脂肪酸类物质的利用率之间的关系有待深入研究。     

牙鲆幼鱼对EPA和DHA的营养需求

研究了EPA和DHA水平对牙鲆生长的影响,饲料中含0.5%EPA和1.0%～1.5%DHA能保证牙鲆幼鱼最适生长,鱼体水分最低,肝体指数最小,脂肪含量有较大幅度提高,肝脏极性脂中EPA和DHA达到最大积累;在肝脏和肌肉的非极性脂部分,各组间的脂肪酸组成没有显著变化,而极性脂部分能体现出饲料中n-3 HUFA含量对鱼体脂肪酸组成的影响,极性脂中的EPA和DHA含量远高于非极性脂;在肌肉和肝脏的极性脂和非极性脂中都含有较高的16:0和18:1n-9; 18:1n-9/n-3HUFA可以作为必需脂肪酸满足程度的一个判据,18:1n-9值的升高往往是缺乏必需脂肪酸的表现,在生长最佳时18:1n-9/n-3HUFA比值下降,为0.62和0.74.     

No significant effect of additive ratios of docosahexaenoic acid to eicosapentaenoic acid on the survival and growth of cobia (Rachycentron canadum) juvenile

An experiment was conducted in the laboratory to investigate the effects of additive ratios of docosahexaenoic acid (DHA) to eicosapentaenoic acid (EPA) on the growth and survival of cobia (Rachycentron canadum) juveniles from August to October 2005. Three hundred and eighty cobia juveniles (56 days of age, body weight 6.9 ± 0.1 g, body length 9.2 ± 0.1 cm) were selected and 20 of them were freely taken for initial sample analysis in the week 0. Additional 360 juveniles were randomly assigned into eight groups with triplicate, total 24 tanks with 15 fish each. Cobia juveniles were reared in glass‐steel tanks (200‐L volume per tank) using filtered seawater with temperature 26–30.5 °C, salinity 25.4–33.0 g L^?1 and pH 7.8–8.0. Cobia juveniles were fed for 8 weeks using seven treatment diets (D‐1 to D‐7) with the same amount of DHA and EPA (15.0 ± 1.2 g kg^?1 of dried diet), but varying ratios of DHA to EPA (0.9, 1.1, 1.3, 1.5, 1.7, 1.9, 2.1, respectively) and a control diet (D‐0, DHA + EPA = 8.0 g kg^?1 of dried diet, DHA/EPA = 1.3). Five juveniles per tank were randomly taken for sample analysis at the end of weeks 4 and 8, respectively. The highest protein efficiency rate (PER; 1.5 in mean), average body weight (BW; 73.3 g per fish in mean) and the lowest feed conversion ratio (FCR; 1.6 in mean) were obtained in cobia juveniles fed the control diet at the end of week 8. These parameters were significantly different (P < 0.05) among juveniles fed the control and treatment diets; however, no significant difference (P > 0.05) was found among juveniles fed the treatment diets evaluated in this study. It was concluded that the survival and growth of cobia juveniles were not greatly influenced by additive ratios of DHA to EPA in our experimental conditions.     

Interactions between dietary docosahexaenoic acid and other long-chain polyunsaturated fatty acids on performance and fatty acid retention in post-smolt Atlantic salmon (Salmo salar)

A study with varying dietary inclusion levels (1, 5, 10, 15 and 20 g kg^?1) of docosahexaenoic acid (DHA; 22:6n-3) was conducted with post-smolt (111 ± 2.6 g; mean ± S.) Atlantic salmon (Salmo salar) over a 9-week period. In addition to the series of DHA inclusion levels, the study included further diets that had DHA at 10 g kg^?1 in combination with either eicosapentaenoic acid (EPA; 20:5n-3) or arachidonic acid (ARA; 20:4n-6), both also included at 10 g kg^?1. An additional treatment with both EPA and DHA included at 5 g kg^?1 (total of 10 g kg^?1 long-chain polyunsaturated fatty acids, LC-PUFA) was also included. After a 9-week feeding period, fish were weighed, and carcass, blood and tissue samples collected. A minor improvement in growth was seen with increasing inclusion of DHA. However, the addition of EPA further improved growth response while addition of ARA had no effect on growth. As with most lipid studies, the fatty acid composition of the whole body lipids generally reflected that of the diets. However, there were notable exceptions to this, and these implicate some interactions among the different LC-PUFA in terms of the fatty acid biochemistry in this species. At very low inclusion levels, DHA retention was substantially higher (~250 %) than that at all other inclusion levels (31–58 %). The inclusion of EPA in the diet also had a positive effect on the retention efficiency of DHA. However, EPA retention was highly variable and at low DHA inclusion levels there was a net loss of EPA as this fatty acid was most likely elongated to produce DHA, consistent with increased DHA retention with additional EPA in the diet. Retention of DPA (22:5n-3) was high at low levels of DHA, but diminished with increasing DHA inclusion, similar to that seen with DHA retention. The addition of EPA to the diet resulted in a substantial increase in the efficiency of DPA retention; the inclusion of ARA had the opposite effect. Retention of ARA was unaffected by DHA inclusion, but the addition of either EPA or ARA to the diet resulted in a substantial reduction in the efficiency of ARA retention. No effects of dietary treatment were noted on the retention of either linolenic (18:3n-3) or linoleic (18:2n-6) acids. When the total n-3 LC-PUFA content of the diet was the same but consisted of either DHA alone or as a combination of EPA plus DHA, the performance effects were similar.     

Alternative vegetable lipid sources in diets for grouper, Epinephelus coioides (Hamilton): effects on growth, and muscle and liver fatty acid composition

The aim of this study was to investigate the effects of different oils on growth performance and lipid metabolism of the grouper, Epinephelus coioides. Five experimental fish meal‐based isonitrogenous and isolipidic diets were formulated containing either 5.5%‐added fish oil (FO), soybean oil (SBO), corn oil (CO), sunflower oil (SFO) or peanut oil (PO). Each diet was fed to triplicate groups of 20 fish (initial body weight 13.2±0.02 g) grown in seawater at 28.0–30.5 °C for 8 weeks. Fish were fed twice a day to visual satiety. No significant differences in the survival, weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio or hepatosomatic index were found between fish fed the FO or vegetable oils (VO) diets. Dietary lipid sources did not affect whole‐body composition among grouper fed the various diets. Muscle of fish fed the FO diet had significantly higher levels of 14:0, 16:0, 16:1n‐7, 20:5n‐3[eicosapentaenoic acid (EPA)] and docosahexaenoic acid (DHA)+EPA (except for PO fed fish) compared with those of fish fed VO diets. However, the levels of 18:1n‐9, 18:2n‐6 and DHA/EPA ratios in the muscle of fish fed FO diet were significantly lower than those of fish fed the VO diets. The liver of fish fed the FO diet had significantly higher levels of 18:0, 20:5n‐3, 22:6n‐3, n‐3 highly unsaturated fatty acids and DHA+EPA than those of fish fed the VO diets, whereas increases in 18:1n‐9, 18:2n‐6 and mono‐unsaturated fatty acid levels were observed in the liver of fish fed the VO diets.     

Lipid Oxidation and Omega-3 Fatty Acid Retention in Salmon and Mackerel Nuggets During Frozen Storage

The extent of lipid oxidation and retention of omega (ω)-3 fatty acids in milk protein concentrate (MPC)-added mackerel and salmon mince and nuggets during 4-months frozen storage were investigated in order to develop high ω-3 seafood products. Mechanically deboned fish mince formulated with MPC and other ingredients was formed into batter-breaded nuggets with or without par-frying. The addition of MPC at 4% resulted in significantly lower thiobarbituric acid reactive substances (TBARS) values and helped retain significantly (p < 0.05) higher amounts of docosahexaenoic acid (DHA) in both salmon and mackerel mince and eicosapentaenoic acid (EPA) in the mackerel mince. There were no significant differences in peroxide values (PV) and TBARS values between nugget products with and without par-frying. EPA and DHA were retained less in par-fried than raw nuggets probably due to oil leaching and thermal degradation during frying. The reductions of EPA and DHA in salmon were 67% and 53% for raw and 57% and 39% for par-fried nuggets, while in mackerel they were 63% and 73% for raw and 57% and 56% for par-fried nuggets, respectively. Results suggest that although MPC provided some protection against lipid oxidation, additional measures are needed to improve retention of ω-3 fatty acids in mince-based seafood products during frozen storage.     

Variation in Rainbow Trout,Oncorhynchus mykiss,to Biosynthesize Eicosapentaenoic Acid and Docosahexaenoic Acid When Reared on Plant Oil Replacement Feeds

To determine the potential for improving the conversion and deposition of the omega‐3 fatty acids docosahexaenoic acid (DHA; 22:6n‐3) and eicosapentaenoic acid (EPA; 20:5n‐3) in fish, 44 families of rainbow trout were fed a diet low in these components and then evaluated for their ability to convert and store plant oils that did not contain DHA and EPA in their muscle tissue. The range for EPA and DHA detected in the tissues of different families varied between 1.2 and 2.9%, and 3.8 and 7.1% total fatty acid, respectively. After adjusting for covariates, an averaged heritability of 0.78 ± 0.11 for DHA and 0.61 ± 0.17 for EPA was calculated. Expression analysis of genes related to the elongation and conversion of lipids were also analyzed, and significant differences were found in the expression of some genes between groups of families that were delineated as having relative high, medium, and low capabilities of depositing EPA and DHA in their muscle tissue after being reared on the mainly soy/flax oil containing diet. However, none of these genes showed a positive correlation with the high conversion/deposition group .     

波纹唇鱼肌肉中营养成分分析

通过对波纹唇鱼肌肉氨基酸、脂肪酸等营养成分的测定和分析,评估和讨论其肉质的风味特征。结果表明,波纹唇鱼Cheilinus undulates的含肉率为71.5%,肌肉中粗蛋白、粗脂肪、粗灰分、水分的含量分别为18.98%、1.56%、1.23%、76.33%;测定的18种氨基酸总量为878.1mg/g(干重),4种鲜味氨基酸含量为355.3mg/g(干重),是其美味的主要因素。DHA和EPA的含量分别为2.00和9.51mg/g,DHA和EPA含量占脂肪酸总量的12.76%。