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1.
The lipid‐regulating effects of astaxanthin (ASTX) have been widely reported in terrestrial animals. However, little relevant information has been available in fish although ASTX has been used as exogenous pigment and antioxidant in fish feed. A 74‐day feeding study was conducted to investigate the effects of dietary ASTX on lipid accumulation in the marine teleost tiger puffer. Four experimental diets differing only in ASTX supplementation, that is, 0 (control), 50 (ASTX50), 100 (ASTX100) and 500 (ASTX500) mg kg‐1, were randomly assigned to 12 tanks of juvenile tiger puffer. Compared to control, the liver lipid content in group ASTX50 was significantly higher, while those in groups ASTX100 and ASTX500 were lower. The muscle lipid contents in group ASTX500 were significantly higher compared to control. Group ASTX50 had the best growth performances, while diet ASTX500 seemed to have adverse effects. In the liver, compared to control, groups ASTX50 and ASTX100 showed significantly lower mRNA expressions of genes related to triglycerol synthesis and fatty acid synthesis, transport and uptake, but higher expressions of genes related to β‐oxidation and monoglycerol hydrolysis. In the muscle, compared to control, ASTX100 showed higher expressions of genes related to β‐oxidation. ASTX50 resulted in higher contents of saturated and monounsaturated fatty acids but lower contents of n‐3 polyunsaturated fatty acids in fish. In conclusion, astaxanthin in diets for tiger puffer differentially regulated the lipid accumulation in the liver and muscle, both in dose‐dependent manners. Excess dietary astaxanthin (500 mg/kg) had adverse effects on tiger puffer.  相似文献   

2.
This study evaluates the effects of dietary mannan oligosaccharides (MOS) on growth, tissue composition, fatty acid profiles and liver morphology of European sea bass (Dicentrarchus labrax) fed diets containing either soybean oil (SBO; SBOMOS) or fish oil (FO; FOMOS) as unique oil source for 8 weeks. Results showed that MOS supplementation enhanced specific growth rate, regardless of the oil source used, and that dietary oil source reduced fish length, regardless of dietary MOS supplementation. Dietary MOS favoured lipid accumulation in muscle and anterior intestine when supplemented in FO‐based diets compared to fish fed SBO diet and reduces it in liver in relation to lower hepatocyte area, particularly in fish fed SBOMOS diet. Dietary MOS favoured liver and not muscular ∑n‐3 PUFA, DHA, EPA and ARA deposition, when combined with FO but not when included in SBO‐based diets. Thus, MOS dietary supplementation favours fish performance and helps to minimize the side effects derived from high dietary SBO supplementation on liver lipid accumulation and hepatocyte vacuolization, which could be of especial interest on long‐term feeding trials; however, the effects on favoured deposition ∑n‐3 PUFA are limited to FO‐based diets.  相似文献   

3.
Present study aimed to determine the optimum dietary lipid level in snakehead murrel channa striatus broodstocks. Triplicate groups of fish were fed for 240 days with isonitrogenous experimental diets with increasing lipid levels (100, 140, and 180 g kg?1), using fish oil and soybean oil as the lipid sources with the ratio of (1:1). Weight gain, GSI, fecundity, oocyte diameter and number of mature oocyte were found to be significantly higher in the group fed with diet containing 180 g kg?1 lipid level. Muscle fatty acid profile showed a significant increase in LA (18:2n‐6), LNA (18:3n3), total PUFA, n‐6 and ArA (20:4n‐6) in fish fed with diet containing 180 g kg?1 lipid. Increasing lipid level up to 180 g kg?1 resulted in significant increase in PUFA (LA & LNA), lc‐PUFA (EPA, DHA, ArA), total PUFA, n‐3 and n‐6 series in ovary and liver of female C. striatus.  相似文献   

4.
The effect of varying dietary lipid and n‐3 polyunsaturated fatty acids (PUFAs) on growth, feed efficiency, protein and energy utilization, carcass quality, and nonspecific immune functions was investigated in rainbow trout reared at two different water temperatures (7.5 and 15 C). Six diets were formulated to contain 47% digestible protein and 21 MJ/kg digestible energy. Three of the diets were formulated to contain increasing lipid levels (10, 16, and 18%) and three additional diets formulated to 18% lipid with different lipid sources. Varying dietary lipid and n‐3 PUFA levels had little effect on growth and on protein and energy utilization. Diet composition only had limited effect on susceptibility of the flesh to rancidity and on the nonspecific immunity of the fish. Increasing lipid levels did not affect fish carcass or fillet proximate composition. Replacing half of fish oil with beef tallow resulted in lower n‐3 PUFAs in fish fillet but did not affect nutrient digestibility or growth performance of fish even at 7.5 C. Increasing dietary n‐3 levels using a fish oil concentrate resulted in significant enrichment of n‐3 PUFAs and elevated n‐3 : n‐6 ratio of the whole body and carcass. Water temperature significantly affected apparent digestibility coefficient (ADC) of protein and energy but did not affect the ADC of lipid, nor did it affect nitrogen and energy retention efficiencies. The study suggests that highly saturated fats, such as beef tallow, can be used to partially replace fish oil without negative effect on digestibility and growth even at low water temperature. High dietary n‐3 PUFAs levels can be used to enrich n‐3 PUFAs of the flesh without negative effect on the immune response.  相似文献   

5.
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6.
Effects of dietary fatty acid composition on the growth of the tiger puffer Takifugu rubripes were examined. Eight experimental diets were formulated with fish meal and casein as the major ingredients, providing 45.0–48.2% crude protein. Pollack and squid liver oils were used for the control diet while experimental diets contained three levels of EPA-DHA concentrated (C-HUFA) oils, soybean oil, linseed oil, and combinations of them, providing 0.5–5.5% n-3 HUFA and 5.0–11.1% crude lipid. Triplicate groups of fish with a mean body weight of 18.7 g per dietary treatment were fed the diets twice daily to apparent satiation, 6 days per week for 8 weeks. The final body weight and weight gain of the fish fed the soybean oil diet without C-HUFA oils were significantly lower than those fed the control diet. Both parameters were not statistically different among the other dietary groups, although the values obtained for the linseed oil diet without C-HUFA oils were lower. Similar trends were seen for SGR and feed efficiency. However, significantly lower PER values compared to the control were observed for the lower C-HUFA and the vegetable oil without C-HUFA oil groups. These results indicate that tiger puffer can be produced successfully with diets containing more than 1.5% n-3 HUFA.  相似文献   

7.
Three diets in which the lipid component was supplied either as fish oil (FO), linseed oil (LO) or olive oil (OO) were fed to duplicate groups of juvenile turbot (Scophthalmus maximus) of initial weight 1.2 g for a period of up to 12 weeks. The latter two diets resulted in a significant reduction in specific growth rate and an increased mortality compared to the FO (control) fed fish. A liver histopathology was evident in around half of the fish fed the LO and OO diets but was absent in fish fed FO. The lesion showed indications of cellular alterations consisting of foci of densely basophilic cells but without evidence of inflammatory activity. The total lipid fatty acid composition of the carcass from fish fed LO had increased percentages of 18:2n-6 and 18:3n-3, but decreased percentages of all other polyunsaturated fatty acids (PUFA) including the physiologically important 20:4n-6, 20:5n-3 and 22:6n-3, compared to fish fed FO. Almost 2/3 of the total fatty acids in the carcass of OO-fed fish were monounsaturated while the percentages of total saturated fatty acids and all other PUFA, except 18:2n-6, were significantly reduced compared to fish fed FO. Broadly similar effects on total lipid fatty acid composition were observed in liver. In the liver glycerophospholipid classes of fish fed LO, percentages of 18:2n-6, 18:3n-3 and 20:3n-3 were significantly increased whereas all C20 and C22 PUFA, with the exception of 20:5n-3 in PI, were significantly reduced compared to fish fed FO. The liver glycerophospholipids of fish fed OO all showed significantly increased total monounsaturates, 18:2n-6, 20:2n-6, 18:2n-9 and 20:2n-9 as well as reduced percentages of 20:4n-6 and 22:6n-3, compared to fish fed FO. The brain glycerophospholipids showed broadly similar changes in response to dietary treatment although the magnitude of fatty acid alterations was less than those observed in liver. The greater mortalities in the OO-fed fish compared to the LO-fed fish suggests that incorporation of 18:3n-3 into tissue phospholipids can offset losses of long-chain PUFA more effectively than incorporation of 18:1n-9. However, levels of dietary long-chain PUFA must be optimised to allow normal growth and development. We conclude that the very low flux through the fatty acid desaturase/elongase pathways in turbot is not up-regulated by diets deficient in 20:5n-3 and 22:6n-3.  相似文献   

8.
Nile tilapia juveniles (8.35 ± 0.80 g) were fed on four levels (0.0%; 0.5%; 1.0%; 2.0%, 4.0%) of Aurantiochytrium sp. meal (ALL‐G‐RICH?), a source of docosahexaenoic acid (DHA). The 1% Aurantiochytrium sp. meal diet was compared to a control diet, which contained the same amount of DHA as cod liver oil (CLO) at 1.7% diet. Groups of 25 fish were stocked in 100 L tanks and fed twice daily until apparent satiation, for 57 days, at 28°C. Increasing dietary Aurantiochytrium sp. meal reduced the body retention of DHA and n‐3 polyunsaturated fatty acids (n‐3 PUFA) but increased the body retention of alpha‐linolenic (α‐LNA), linoleic (LOA) and n‐6 polyunsaturated fatty acids (n‐6 PUFA). Fatty acid profile in tilapia muscle was affected by increasing dietary inclusions of Aurantiochytrium sp. meal, with an increase in DHA, α‐LNA, n‐3 PUFA and n‐3 long chain‐polyunsaturated fatty acids (n‐3 LC‐PUFA) but a decrease in monounsaturated fatty acids (MUFA), n‐6 PUFA and n‐6 long‐chain polyunsaturated fatty acids (n‐6 LC‐PUFA). There was a larger body retention of DHA, α‐LNA, LOA, n‐3 PUFA and n‐6 PUFA fatty acids and a higher percentage of DHA, n‐3 PUFA and n‐3 LC‐PUFA in muscle fatty acid profile in fish fed on CLO diets than in those fed on 1% Aurantiochytrium sp. Therefore, Aurantiochytrium sp. meal is an alternative source of DHA for Nile tilapia diets.  相似文献   

9.
Three isonitrogenous (320 g kg?1 crude protein, casein and gelatine) semi‐purified diets with 80 (L8), 130 (L13) and 180 (L18) g kg?1 lipid (sunflower oil at increasing levels and cod liver oil fixed at 50 g kg?1) at three digestible energy levels (12 096, 13 986 and 15 876 kJ kg?1 dry weight) and were tested, in triplicate, on rohu fingerlings (3.2 ± 0.08 g) at two different temperatures (21 and 32 °C). Fish were fed to apparent satiation, twice daily, at 09.00 and 15.00 h, 7 days a week for 56 days. Maximum growth was obtained at a lipid level of 80 g kg?1 (L8) at 21 °C (439.37%) and 130 g kg?1 (L13) at 32 °C (481.8%). In general growth rate was higher at 32 °C than at 21 °C at all lipid levels. Tissue monounsaturated fatty acid (MUFA) contents decreased with increasing lipid level at 32 °C, but the reverse occurred at 21 °C. At 21 °C, Polyunsaturated fatty acid (PUFA) level increased significantly (P > 0.05) over initial values, but was affected insignificantly by dietary lipid level. At 32 °C, fish fed diet L13 had more n‐3 fatty acid (FA) in liver and muscle than the other two dietary groups while at 21 °C, both liver and muscle FA profiles exhibited significant change (P > 0.05) in n‐3 and n‐6 FA content which corresponded to variation in percent addition of dietary lipid. However, n‐3/n‐6 ratio was higher for fish fed diet L13 at 32 °C and diet L8 at 21 °C and may be correlated with fish growth.  相似文献   

10.
A 8‐week feeding trial was conducted to determine the effect of substituting fish oil with palm oil‐laden spent bleaching clay (SBC), a by‐product from crude palm oil (CPO) refining, on growth, feed utilization, fatty acid composition and heavy metal accumulation in the muscle of Nile tilapia, Oreochromis niloticus. Four isonitrogenous and isolipidic practical diets were formulated to contain 0, 100, 200 or 300 g kg?1 SBC. Growth performance of Nile tilapia was significantly better in fish fed the 100 g kg?1 SBC diet compared with fish fed the 0, 200 or 300 g kg?1 SBC diet. Growth and feed utilization efficiency of fish fed 200 or 300 g kg?1 SBC were similar to fish fed the control diet without added SBC. Whole‐body composition, body‐organ indices and haematocrit of tilapia were not affected by dietary treatments. Fatty acid compositions in the muscle lipid of Nile tilapia were strongly influenced by dietary treatments with progressively elevated levels of total saturates and n‐6 PUFA because of the dietary influence of these fatty acids from residual CPO adsorbed onto SBC. A gradual decrease in total n‐3 PUFA concentrations were also observed with the ratio of n‐3 to n‐6 fatty acids in muscle lipids decreasing from 4.75 to 4.41, 3.23 or 2.37 after 8 weeks on the 0, 100, 200 or 300 g kg?1 SBC diet, respectively. The arsenic, cadmium and lead concentrations in the experimental diets increased with increasing dietary levels of SBC but the concentrations of these heavy metals in the whole body and bone of Nile tilapia were not significantly different among fish fed the various diets. The present 8‐week study showed that in fishmeal‐based diets for Nile tilapia, palm oil‐laden SBC can totally replace added fish oil. The use of this presently discarded waste product from palm oil refining in tilapia diets will greatly contribute to reducing the impact of rising feed costs in the culture of tilapia in many tropical countries. Other potential benefits may include acting as a feed binder, removal of mycotoxins in fish feeds as well as adsorbing toxic substances present in the culture water.  相似文献   

11.
Replacing dietary fish oil with DHA‐rich microalgae Schizochytrium sp. and EPA‐rich microalgae Nannochloropsis sp. for olive flounder (Paralichthys olivaceus) was examined. Three experimental isonitrogenous and isolipidic diets with lipid source provided by 50% fish oil (F50S50), 50% (M50F25S25) and 100% microalgae raw material (M100) respectively were compared with a soybean oil (S100) diet as control. Triplicate groups of olive flounder juveniles (16.5 ± 0.91 g) were fed the experimental diets, and a group was fed the control diets for 8 weeks in a recirculation system. Results showed feed efficiency and growth performance were not significantly changed when fish oil (FO) was totally substituted by soybean oil (SO) or microalgae raw material (MRM). The whole‐body composition, lipid content of liver and muscle, and lipid composition of plasma were not significantly influenced by the total substitution of FO by MRM. The polyunsaturated fatty acids (PUFA) content of muscle and liver declined in fish fed S100 diet, whereas it was not significantly reduced in fish fed M50F25S25 and M100 diets. The total substitution of FO by MRM not only maintained the levels of arachidonic acid, EPA or DHA but also increased n‐3/n‐6 ratio. In conclusion, MRM as the sole lipid source is sufficient to obtain good feed efficiency, growth performance and human health value in olive flounder juveniles.  相似文献   

12.
This study investigated effects of linseed or fish oil–enriched finishing diets on the polyunsaturated fatty acids (PUFA) composition in dorsal muscle tissues of pond‐cultured common carp (Cyprinus carpio). After 180 days of dietary exposure to cereal diet containing vegetable oil (1%), carp were exposed to 7% linseed (LO) or 7% fish oil–enriched (FO) finishing diets for 30 days. FO supplied 17 and 20 mg fish?1 day?1, respectively, of the long‐chain n‐3 fatty acids eicosapentaenoic and docosahexaenoic acid for 30 days and doubled long‐chain PUFA concentrations in carp of the FO pond. The increased supply of short‐chain PUFA in LO resulted in higher short chain, but not long‐chain PUFA, showing that there was very little PUFA conversion. Thus, dietary short‐chain PUFA could not compensate for the low levels of dietary long‐chain PUFA in LO. However, moderate supply of dietary long‐chain PUFA in finishing diets for 30 days is very efficient in increasing nutritionally important long‐chain PUFA concentrations in carp.  相似文献   

13.
To aid in development of nutritionally complete diets, a 12‐week experiment was conducted to identify appropriate sources of dietary lipid for bull trout. The basal diet was top‐coated with marine fish oil (MFO) (pollock liver oil), canola oil (CO), linseed oil (LO) or a mixture of canola and linseed oils (CLO) to produce four treatments. Each diet was fed to triplicate groups of fish initially averaging 1.6 g per fish. Weight gain, feed efficiency, survival and carcass proximate composition were not significantly different among fish fed the dietary treatments. However, whole‐body fatty acid percentages varied significantly among fish fed the four diets. Whole bodies of fish fed diets with vegetable oil (VO) contained significantly higher 18:2n‐6, 18:3n‐3 and total n‐6 polyunsaturated fatty acid percentages and significantly lower 20:5n‐3, 22:6n‐3 and total saturated fatty acid percentages compared with fish fed the MFO diet. Whole‐body fatty acid percentages also varied among fish fed VO diets. Despite similar 18:2n‐6 and 20:4n‐6 percentages in the VO diets, fish fed diet CO contained significantly lower 18:2n‐6 proportions and significantly higher 20:4n‐6 proportions compared with fish fed other VO diets. Results of this study suggest dietary fish oil is not required for short‐term rearing of bull trout.  相似文献   

14.
The replacement of dietary marine fish oil with vegetable oils was examined in fingerling humpback grouper, Cromileptes altivelis, over the course of an 8‐week growth trial. Five isolipidic (10%) and isoproteic (50%) fish meal‐based practical diets were formulated to contain iso‐ingredients but with different sources of lipids [crude palm oil (CPO), refined, bleached and deodorized, palm olein (RBDPO), soybean oil (SBO) or canola oil (CNO)], and their performance was compared with the control diet, which contained cod liver oil (CLO) as the added lipid source. The experimental diets were fed close to apparent satiation twice a day to triplicate groups of fish (10.6 ± 2.2 g). The grouper fingerlings were randomly distributed into groups of 12 fish in cylindrical cages (61 cm depth and 43 cm diameter) that were placed in a 150 tonne polyethylene seawater tank. There were no significant differences (P>0.05) in terms of growth, survival, feed conversion ratio, protein efficiency ratio, net protein utilization, hepatosomatic index and condition factor among fish fed the various dietary treatments. Similarly, the dietary lipid source did not significantly affect the whole body proximate composition of the fish. Muscle and liver fatty acid composition of fish was influenced by the experimental diets. Replacement of dietary CLO with CPO, RBDPO, SBO or CNO produced fish with lower n‐3 highly unsaturated fatty acids and increased levels of 18:2n‐6 in the muscle and liver. The n‐3:n‐6 fatty acid ratio in the muscle of fish fed the CLO‐based diet was 3.0 compared with 0.5–0.8 in the muscle of fish fed the various vegetable oil‐based diets. The present study demonstrated that various vegetable oils can be used in fish meal‐based dietary formulations for humpback grouper without compromising growth or feed utilization efficiency.  相似文献   

15.
The aim of this study was to determine the effects of replacing fish oil (FO) with laurel seed oil (LSO), as an alternative plant lipid source in diets on the growth and fatty acid composition of rainbow trout (Oncorhynchus mykiss; 111.47 ± 0.2 g mean individual weight). At the end of the feeding trial, survival was 100% in all treatments. No significant differences were seen in growth between the dietary groups (P > 0.05). The protein, lipid and ash contents were not significantly different among the groups (P > 0.05); however, there was a significant difference in protein and ash content between the treatment groups and the initial, and between the 50LSO group and the initial group, respectively (P < 0.05). The viscerosomatic index (VSI) and hepatosomatic index (HSI) values were not affected by increasing LSO percentages in the diets. The n‐6 polyunsaturated fatty acid (PUFA) concentration increased with increasing LSO levels in the diets. In contrast, the n‐3 PUFA levels decreased with increasing LSO levels in the diets. The liver and muscle were used for the analysis of fatty acids. The highest level of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) concentrations was recorded in fillet of fish fed the FO diet and the lowest in those fed the 50LSO diet. However, EPA and DHA ratios in the liver of fish fed the 75LSO diet were higher than those in fillet of fish fed the FO and 50LSO diets. No significant differences were seen in fatty acid composition between the dietary groups (P > 0.05). Based on the results of growth performance and fatty acid composition of the experimental fish in this study, it can be concluded that the 75% concentration of laurel seed oil performed best among the diets tested in the experiment.  相似文献   

16.
The effect of replacing fishmeal with soybean meal in the diet and also partial dietary protein replacement with carbohydrates, on sharpsnout sea bream (Diplodus puntazzo) total lipid fatty acid profile was studied. A group of sharpsnout sea bream of 200 g were fed a diet containing either 0%, 20%, 40% or 60% of protein from soybean meal. In a second experiment, fish (126 g) were fed diets with reduced protein and increased carbohydrate percentages. Fishmeal replacement with soybean meal increases the fish polyunsaturated fatty acids (PUFA) content, mainly due to linoleic acid, which is present in high quantities in soya. But as a consequence, the inclusion of soybean meal produces a significant decrease of the n‐3/n‐6 relationship (from 2.21±0.07 to 1.66±0.05). Replacement of protein with carbohydrate hardly modifies the diet fatty acid profile. As the fishmeal content decreases, there is a slight reduction of saturated fatty acids, the diet with lowest protein percentage having the highest monounsaturated fatty acids and lowest PUFA proportions. Fat quality indices are similar to those reported in previous studies, and in the case of fish under soy‐containing diets, they are favourables. However, fishmeal replacement causes a loss of n‐3 fatty acids that is important to compensate using other sources rich in this type of fatty acids.  相似文献   

17.
The study was conducted to investigate the effects of dietary tea polyphenols (TP) on growth performance, biochemical and antioxidants responses, fatty acid composition, and lipid metabolism‐related gene expressions of large yellow croaker (Larimichthys crocea). Four diets were formulated with different levels of TP (0.00%, 0.01%, 0.02% and 0.05%). Results showed that growth performance of L. crocea were not different among dietary treatments. Compared with the control group, fish in 0.02% TP group had lower body and hepatic lipid content and lower total cholesterol content. The minimum content of triglycerides and low‐density lipoprotein‐cholesterol were found in 0.05% TP group. Hepatic n‐6 PUFA and n‐3 PUFA were significantly higher in TP supplementation groups. Malondialdehyde content was lower in TP supplementation groups, and superoxide dismutase activity was higher in 0.01% TP group than the control group. The mRNA expressions of carnitine palmitoyltransferase1, acyl‐CoA oxidase and peroxisome proliferators‐activated receptor α were up‐regulated in 0.01% and 0.02% TP groups, while lipoprotein lipase expression was down‐regulated in TP supplementation groups than the control group. Results suggested that 0.01%–0.02% TP supplementation could reduce the deposition of liver lipid of L. crocea caused by high‐lipid diet, which might be due to the increase in lipid oxidation related gene expressions.  相似文献   

18.
It is assumed that Florida pompano have dietary EPA (20:5n‐3) and DHA (22:6n‐3) requirements. However, it is unclear whether both are equally important in meeting demand for n‐3 long‐chain polyunsaturated fatty acids (LC‐PUFAs) or whether the requirement(s) can be influenced by other fatty acids. Accordingly, we assessed production performance and tissue composition of juvenile Florida pompano (41.0 ± 0.5 g) fed diets containing fish oil; beef tallow; or beef tallow partially or fully supplemented with EPA, DHA or both. After 8 weeks, no signs of fatty acid deficiency were observed. Although fish performance did not vary significantly among the dietary treatments, fish fed the DHA‐supplemented feeds exhibited numerically superior growth than those fed the other diets. Fillets of fish fed the beef tallow‐based diets contained reduced levels of n‐3 fatty acids and LC‐PUFAs and elevated levels of MUFAs and n‐6 fatty acids, although dietary supplementation with EPA and/or DHA attenuated these effects somewhat. Our results suggest that beef tallow is suitable as a primary lipid source in Florida pompano feeds and n‐3 LC‐PUFA requirements may be met by as little as 4 g/kg EPA and 4 g/kg DHA. However, there may be value in supplementing tallow‐based diets with DHA to enhance tissue levels and possibly growth.  相似文献   

19.
Copepod oil (CO) from the marine zooplankton, Calanus finmarchicus, is a potential alternative to fish oils (FOs) for inclusion in aquafeeds. The oil is composed mainly of wax esters (WE) containing high levels of saturated fatty acids (SFAs) and monounsaturated fatty alcohols that are poorly digested by fish at low temperatures. Consequently, tissue lipid compositions may be adversely affected in salmon‐fed CO at low temperatures. This study examined the lipid and FA compositions of muscle and liver of Atlantic salmon reared at two temperatures (3 and 12 °C) and fed diets containing either FO or CO, supplying 50% of dietary lipid as WE, at two fat levels (～330 g kg?1, high; ～180 g kg?1, low). Fish were acclimatized to rearing temperature for 1 month and then fed one of four diets: high‐fat fish oil (HFFO), high‐fat Calanus oil (HFCO), low‐fat fish oil (LFFO) and low‐fat Calanus oil (LFCO). The fish were grown to produce an approximate doubling of initial weight at harvest (220 days at 3 °C and 67 days at 12 °C), and lipid content, lipid class composition and FA composition of liver and muscle were determined. The differences in tissue lipid composition between dietary groups were relatively small. The majority of FA in triacylglycerols (TAG) in both tissues were monounsaturated, and their levels were generally higher at 3 °C than 12 °C. Polyunsaturated fatty acids (PUFA), particularly (n‐3) PUFA, predominated in the polar lipids, and their level was not significantly affected by temperature. The PUFA content of TAG was highest (～26%) in the muscle of fish fed the HFCO diet at both temperatures. Tissue levels of SFAs were lower in fish‐fed diets containing HFCO than those fed HFFO, LFFO or LFCO, particularly at 3 °C. The results are consistent with Atlantic salmon being able to incorporate both the FA and fatty alcohol components of WE into tissue lipids but, overall, the effects of environmental temperature on tissue lipids were more pronounced in fish fed the CO diets than FO diets.  相似文献   

20.
A 15‐wk study was conducted to evaluate the effect of supplemental menhaden fish oil levels and feeding duration on growth performance and tissue proximate and fatty acid (FA) compositions of juvenile channel catfish, Ictalurus punctatus. Dietary fish oil levels had no effect on final weight gain, feed efficiency, and survival of channel catfish. Tissue lipid contents were directly correlated to dietary lipid levels, while moisture contents were inversely related to dietary lipid levels. Fillet moisture contents progressively decreased, whereas fillet lipid increased with increasing feeding duration. Significant increase in saturated and total n‐3 FAs and decrease in monoenoic and total n‐6 FA in whole body and fillet were observed at each incremental level of dietary fish oil. Percentages of n‐3 and n‐3 highly unsaturated fatty acids in fillet of fish fed the control and 3% fish oil diets decreased with increasing feeding periods, whereas those of fish fed 6 or 9% added fish oil diets remained stable or increased. Ratios of n‐3/n‐6 were statistically comparable throughout the 15‐wk feeding. When expressed in terms of mg/g of fillet, the highest concentration of n‐3 was obtained in fillets of fish fed the 9% added fish oil diet for 15 wk.  相似文献   

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