Composition and flavor of milk and butter from cows fed fish oil, extruded soybeans, or their combination.

Milk was collected from eight multiparous Holstein and four multiparous Brown Swiss cows that were distributed into four groups and arranged in a randomized complete block design with four 4-wk periods. The four treatments included a control diet of a 50:50 ratio of forage-to-concentrate; a fish oil diet of the control diet with 2% (on dry matter basis) added fat from menhaden fish oil; a fish oil with extruded soybean diet of the control diet with 1% (on dry matter basis) added fat from menhaden fish oil and 1% (on dry matter basis) added fat from extruded soybeans; and an extruded soybean diet of the control diet with 2% (on dry matter basis) added fat from extruded soybeans. Milk from cows fed control, fish oil, fish oil with extruded soybean, and extruded soybean diets contained 3.31, 2.58, 2.94, and 3.47% fat, respectively. Concentrations of conjugated linoleic acid in milk were highest in the fish oil (2.30 g/100 g of fatty acids) and fish oil with extruded soybean (2.17 g/100 g of fatty acids) diets compared with the control (0.56 g/100 g fatty acids) diet. Milk, cream, butter, and buttermilk from the fish oil, fish oil with extruded soybean, and extruded soybean diets had higher concentrations of transvaccenic acid and unsaturated fatty acids compared with the controls. Butter made from the extruded soybean diet was softest compared with all treatments. An experienced sensory panel found no flavor differences in milks or butters.     

Liquid holding capacity,texture and fatty acid profile of smoked fillets of Atlantic salmon fed diets containing fish oil or soybean oil

This study evaluates the effects of dietary vegetable oils on the liquid-holding capacity, texture properties and fatty acid composition of Atlantic salmon fillets. Three diets containing 100% of fish oil (FO), 100% of soybean oil (SO) or a 50/50 mixture of the two oils (FO/SO) as oil dietary source, were fed to triplicate groups of salmon. After slaughter, a third of the fish were studied fresh while the rest of fish were smoked and stored at two temperatures (4 °C or 14 °C) for 5 or 15 days. The liquid-holding capacity and the texture of fresh and smoked fillets were not significantly affected by dietary oil whereas the smoking yield increased with the inclusion of soybean oil. The fatty acid profile of fresh and smoked fillets reflected these of the diets, and no selective loss of fatty acids was observed after smoking and after storage. On the other hand, increased storage time and storage temperature reduced strongly the liquid-holding capacity of all smoked salmon particularly obvious as increased fat loss, irrespective of the diets. This study showed that an increase in storage time and temperature of smoked fillets of Atlantic salmon affected the liquid-holding capacity, irrespective of the diets.     

Effects of dry matter intake, addition of buffer, and source of fat on duodenal flow and concentration of conjugated linoleic acid and trans-11 C18:1 in milk

The primary objective of the study was to investigate the effects of DM intake, addition of buffer, and fish vs. soybean oil on duodenal flows and milk concentrations of conjugated linoleic acid (CLA) and trans-11 C18:1. Four ruminally and duodenally cannulated multiparous cows averaging 106 +/- 17 d in milk at the start of the trial were used in a 4 x 4 Latin square design with treatments as follows: 1) control=diet contained 2% fish oil and fed ad libitum, 2) buffer addition (BUFF)=control diet with 0.8% of NaHCO3 added, 3) low DM intake (LDMI)=DMI restricted to 80% of the control but concentration of fish oil was increased to 2.5% to provide for similar fatty acids (FA) intake, and 4) soybean oil (SBO)=same as control except 2% soybean oil was substituted for fish oil. The diets consisted of 36.2% forage and 63.8% concentrate. Each period consisted of 18 d, with the last 7 d devoted to data collection and the first 4 d used to determine the appropriate amount of feed to be offered to the cow on LDMI. Duodenal flows of CLA and trans-C18:1 were lower for SBO than for diets with fish oil. Feeding buffer did not affect ruminal pH or duodenal flows of trans-11 C18:1 and CLA. Restriction of DMI decreased duodenal flow of trans-11 C18:1 but did not decrease duodenal flow of CLA compared with control. In milk, CLA concentration was lower for SBO (24.5, 17.9, 18.5, and 10.1 mg/g of FA for control, BUFF, LDMI, and SBO, respectively). Cows fed fish oil had higher duodenal flow and milk concentration of n-3 polyunsaturated fatty acids than the cows fed SBO. Compared with SBO, fish oil is more effective in increasing duodenal flows of CLA and trans-11 C18:1, and thus, concentration of CLA in milk.     

Conjugated linoleic acid and other beneficial fatty acids in milk fat from cows fed soybean meal, fish meal, or both

Twelve multiparous Holstein cows at 48 +/- 8 DIM were used in a 4 x 4 Latin square with 21-d periods to determine the effect of replacing soybean meal with fish meal on feed intake, milk yield, and milk composition. Fish meal substituted for soybean meal on an isonitrogenous basis at 0, 25, 50, and 100% of supplemental protein. Total mixed diets were (DM basis) 25% corn silage, 25% alfalfa hay, and 50% concentrate mix. Intake of DM (27.9, 27.8, 26.1, and 25.8 kg/d for diets 1 to 4, respectively) was similar for all diets. Milk yield (37.5, 37.8, 37.2, and 37.7 kg/d) was not affected by diets. Milk protein percentages (3.23, 3.24, 3.31, and 3.35) increased with 100% fish meal supplementation and tended to be higher with 50% fish meal supplementation compared with 100% soybean meal diet. Milk fat percentages (3.18, 2.99, 3.04, and 2.87) and yield were lower with the 100% fish meal than with the 100% soybean meal diet. Concentration of n-3 fatty acids in milk fat (0.54, 0.56, 0.63, and 0.72 g/100 g fatty acids) increased as the proportion of fish meal in the diet increased. Concentrations of c9,t11 conjugated linoleic acid (CLA; 0.39, 0.44, 0.46, and 0.72 g/100 g fatty acids) and transvaccenic acid (TVA; 1.09, 1.19, 1.28, and 1.54 g/100 g of fatty acids) were higher with the 100% fish meal diet than with the 100% soybean meal diet. A total replacement of soybean meal with fish meal in the diet of lactating cows increased milk protein percentages and the beneficial fatty acids (CLA, TVA, and n-3 FA) in milk fat.     

EFFECTS OF STRUCTURED LIPID CONTAINING OMEGA-3 AND MEDIUM CHAIN FATTY ACIDS ON SERUM LIPIDS AND IMMUNOLOGICAL VARIABLES IN MICE

Diets supplemented with enzymatically produced structured lipid (SL) containing n-3 polyunsaturated fatty acids (eicosapentaenoic and docosahexaenoic) and caprylic acid or soybean oil (16.7 g/100 g) were fed to 4 to 6 week old female mice for 21 days. The effect of the diets on serum lipids (HDL-cholesterol, LDL-cholesteol. total cholesterol, triacylglycerol) and glucose concentrations were determined. The concentration of total cholesterol (49%), LDL cholesterol (35.4%) and triacylglycerol (53.2%) were significantly lowered in SL-fed group. The body weight gain in mice fed the soybean oil diet (control group) was significantly (p<0.05) greater than that in mice fed the SL diet after 21 days. The proportion of total T-cells (Thy 1.2⁺), T helper cells (CD⁴⁺), and T cytotoxic-suppressor cells (CD8⁺) in spleen were not significantly different between the two dietary groups as determined by flow cytometry.     

Effect of dietary fish oil on fatty acid composition, lipid oxidation and sensory property of chicken frankfurters during storage

Broilers fed with three levels of fish oil (0, 2 and 4%) for 6 weeks were used in the manufacture of chicken frankfurters. The meat samples were vacuum-packed and stored at 0°C for 0, 10, 20 and 30 days. Cooking yield, proximate and fatty acid composition, lipid oxidation, microbial and sensory properties of the meat products were measured. Cooking yield, moisture, fat, protein, ash and cholesterol contents of frankfurters were not affected (P>0.05) by levels of dietary fish oil. Frankfurters processed from chickens fed diets enriched with 2 and 4% of supplemental fish oil had a higher (P<0.05) level of n-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid), but had a lower level of n-6 fatty acids (P<0.05) than the controls (0% fish oil). TBA values and pH values of meat samples were not affected (P>0.05) by levels of supplemental fish oil in the diets, however, pH values of the vacuum-packaged chicken frankfurters decreased (P<0.05) as the storage time increased. No differences (P>0.05) in total anaerobic plate counts were observed among the fish oil treatments during storage. Supplementation of 2 and 4% fish oil in the diets did not increase (P>0.05) the intensity of fishy flavor in chicken frankfurters.     

Feeding fish meal and extruded soybeans enhances the conjugated linoleic acid (CLA) content of milk

Twelve multiparous Holstein cows averaging 65 (33 to 122) DIM were used in a 4 x 4 Latin square for 4-wk periods to determine whether feeding fish oil as fish meal would stimulate increased amounts of milk conjugated linoleic acid (cis-9, trans-11 C18:2; CLA) and transvaccenic acid (trans-11 C18:1; TVA) when the cows were fed extruded soybeans to supply additional linoleic acid. Treatment diets were 1) control; 2) 0.5% fish oil from fish meal; 3) 2.5% soybean oil from extruded soybeans; and 4) 0.5% fish oil from fish meal and 2% soybean oil from extruded soybeans. Diets were formulated to contain 18% crude protein and were composed (dry basis) of 50% concentrate mix, 25% corn silage, and 25% alfalfa hay. Intake of DM was not affected by diet. Milk production was increased by diets 2, 3, and 4 compared with diet 1 (control). Milk fat and milk protein percentages decreased with diets 3 and 4. Milk fat yield was not affected by treatments, but yield of milk protein was increased with supplemental fish meal and extruded soybeans or their blend. When diets 2, 3, or 4 were fed, concentrations of cis-9, trans-11 CLA in milk fat increased by 0.4-, 1.4-, and 3.2-fold, and TVA concentrations in milk fat increased by 0.4-, 1.8-, and 3.5-fold compared with the control milk fat. Increases in TVA and cis-9, trans-11 CLA were 91 to 109% greater when a blend of fish meal and extruded soybeans was fed than the additive effect of fish meal and extruded soybeans. This suggested that fish oil increased the production of CLA and TVA from other dietary sources of linoleic acid such as extruded soybeans.     

Milk production and composition from cows fed small amounts of fish oil with extruded soybeans

Eight Holstein (189 ± 57 DIM) and 4 Brown Swiss (126 ± 49 DIM) multiparous cows were used in a replicated 4 × 4 Latin square with 28-d periods to determine the minimal dietary concentration of fish oil necessary to maximize milk conjugated linoleic acid (CLA) and vaccenic acid (VA). Treatments consisted of a control diet with a 50:50 ratio of forage to concentrate (dry matter basis), and 3 diets with 2% added fat consisting of 0.33% fish oil, 0.67% fish oil, and 1% fish oil with extruded soybeans providing the balance of added fat. Dry matter intake (23.1, 22.6, 22.8, and 22.9 kg/d, for control, low, medium, and high fish oil diets, respectively) was similar for all diets. Milk production (21.5, 23.7, 22.7, and 24.2 kg/d) was higher for cows fed the fat-supplemented diets vs. the control. Milk fat (4.42, 3.81, 3.80, and 4.03%) and true protein (3.71, 3.58, 3.54, and 3.55%) concentrations decreased when cows were fed diets containing supplemental fat. Concentration of milk cis-9,trans-11 CLA (0.55, 1.17, 1.03, and 1.19 g/100 g of fatty acids) was increased similarly by all diets containing supplemental fat. Milk VA (1.12, 2.47, 2.13, and 2.63 g/100 g of fatty acids) was increased most in milk from cows fed the low and high fish oil diets. Milk total n-3 fatty acids were increased (0.82, 0.96, 0.92, and 1.01 g/100 g of fatty acids) by all fat-supplemented diets. The low fish oil diet was as effective at increasing VA and CLA in milk as the high fish oil diet, showing that only low concentrations of dietary fish oil are necessary for increasing concentrations of VA and CLA in milk.     

Blood amino acids and milk composition from cows fed soybean meal, fish meal, or both

Twelve multiparous Holstein cows at 48 +/- 8 d in milk were used in a 4 x 4 Latin square with 21-d periods to determine the effect on feed intake, milk yield, milk composition, and blood amino acids when soybean meal was replaced with fish meal. Fish meal substituted for soybean meal on an isonitrogenous basis at 0, 25, 50, and 100% of supplemental protein. Total mixed diets were (dry matter basis) 25% corn silage, 25% alfalfa hay, and 50% concentrate mix. Intake of dry matter (27.9, 27.8, 26.1, and 25.8 kg/d for diets 1 to 4, respectively) was similar for all diets. Milk yield (37.5, 37.8, 37.2, and 37.7 kg/d) was not affected by diets. Milk protein percentages (3.23, 3.24, 3.31, and 3.35) increased with 100% fish meal supplementation and tended to be higher, with 50% fish meal supplementation compared with 100% soybean meal diet. Milk fat percentages (3.18, 2.99, 3.04, and 2.87) and yields were lower with the 100% fish meal than with the 100% soybean meal diet. Molar proportions of ruminal volatile fatty acids and ammonia were not greatly affected by diet. Fish meal supplementation slightly improved Met status, as shown when blood amino acid data were evaluated. Both extraction efficiency and transfer efficiency of amino acids from the blood by the mammary gland indicated that Met, Lys, and Phe were the most limiting amino acids in all diets. Replacing as much as 50 or 100% of dietary soybean meal with fish meal may improve the amino acid balance and increase the protein content in milk; however, feeding 100% fish meal will likely decrease milk fat percentages.     

Influence of dietary fish oil on conjugated linoleic acid and other fatty acids in milk fat from lactating dairy cows

Lactating cows were fed menhaden fish oil to elevate concentrations of conjugated linoleic acid, transvaccenic acid, and n-3 fatty acids in milk. Twelve multiparous Holstein cows at 48+/-11 DIM were assigned randomly to a replicated 4 x 4 Latin square. Each treatment period was 35 d in length, with data collected d 15 to 35 of each period. On a dry matter (DM) basis, diets contained 25% corn silage, 25% alfalfa hay, and 50% of the respective concentrate mix. Fish oil was supplemented at 0, 1, 2, and 3% of ration DM. Linear decreases were observed for DM intake (28.8, 28.5, 23.4, and 20.4 kg/d) and milk fat (2.99, 2.79, 2.37, and 2.30%) for 0 to 3% dietary fish oil, respectively. Milk yield (31.7, 34.2, 32.3, and 27.4 kg/d) increased as dietary fish oil increased from 0 to 1% but decreased linearly from 1 to 3% dietary fish oil. Milk protein percentages (3.17, 3.19, 3.21, and 3.17) were similar for all treatments. When the 2% fish oil diet was fed, concentrations of conjugated linoleic acid and transvaccenic acid in milk fat increased to 356% (to 2.2 g/ 100 g of total fatty acids) and 502% (to 6.1 g/100 g), respectively, of amounts when 0% fish oil was fed. There were no additional increases in these fatty acids when cows were fed 3% fish oil. The n-3 fatty acids increased from a trace to over 1 g/100 g of milk fatty acids, when the 3% fish oil diet was fed. Fish oil supplementation to diets of dairy cows increased the conjugated linoleic acid, transvaccenic acid, and n-3 fatty acids in milk.     

Effects of Dietary Supplementation with Camelina Oil on Porcine Blood Lipids

ABSTRACT: The effects of dietary supplementation with camelina oil on porcine plasma fatty acid composition and on serum cholesterol/triglyceride concentrations were investigated and compared with the effects of fish oil. The diets consisted of a control diet and diets supplemented with 5% camelina oil, 10% camelina oil and 5% fish oil. The camelina and fish-oil diets increased plasma ω3 fatty acids and reduced plasma ω6 fatty acids. Plasma eicosapentaenoic acid (C20:5ω3, EPA) was increased more by the fish oils diet than the camelina-oil diets. Serum triglyceride levels were reduced by the camelina-oil diets.     

Effect of lipid type on growth performance,meat quality and the content of long chain n − 3 fatty acids in pork meat

The aim of the present study was to produce pork with enhanced nutritive value for humans, both in terms of fatty acid profile (mainly long chain n − 3 fatty acids by feeding fish oil) and selenium. Forty-eight female pigs were allocated to one of six treatment groups: animal by-products and plant feedstuffs with tallow, plant feedstuffs with a blend of soybean oil and linseed oil with or without a supplement (CLA, selenium, vitamin E and vitamin C), plant feedstuffs with tallow and supplement, plant feedstuffs with fish oil and supplement. The diets containing the fish oil were fed up to either 49 days or 28 days before slaughter. The dietary treatments had no significant effects on growth performance, carcass characteristics and meat quality. When fish oil was included in the diet, higher levels of EPA, DPA and DHA were measured in the subcutaneous fat (up to 3.74%).     

Fish oil and extruded soybeans fed in combination increase conjugated linoleic acids in milk of dairy cows more than when fed separately

Eight multiparous Holstein and four multiparous Brown Swiss (78 +/- 43 DIM) cows were used in a 4 x 4 Latin square with 28-d periods to evaluate if feeding fish oil with a source of linoleic acid (extruded soybeans) would stimulate additional amounts of conjugated linoleic acid in milk. Four treatments consisted of a control diet with a 50:50 ratio of forage to concentrate (DM basis), a control diet with 2% added fat from either menhaden fish oil or extruded soybeans, or a combination of fish oil and extruded soybeans each adding 1% fat. DM intake (24.3, 21.6, 24.5, and 22.5 kg/d, for control, fish oil, extruded soybeans, and combination diets, respectively), milk production (32.1, 29.1,34.6, and 31.1 kg/d), and milk fat content (3.51, 2.79, 3.27, and 3.14%) were lower for cows that consumed either fish oil-containing diet, especially the 2% fish oil diet. The proportion of n-3 fatty acids in milk fat increased similarly among all three fat-supplemented diets. Concentrations of transvaccenic acid (1.00, 4.16, 2.17, and 3.51 g/100 g of fatty acids) and cis-9, trans-11 conjugated linoleic acid (0.60, 2.03, 1.16, and 1.82 g/100 g of fatty acids) in milk fat increased more with fish oil than with extruded soybeans. When fed the combination diet, these fatty acids were approximately 50% higher than expected for Holsteins, whereas concentrations were similar for Brown Swiss compared with feeding each fat source separately. These data indicated that fish oil modifies ruminal or systemic functions, stimulating increased conversion of linoleic acid into transvaccenic and conjugated linoleic acids.     

Protein sources evaluated for ruminating Holstein calves

Fifty calves were fed a basal diet of 11.6% crude protein or one of four diets (15.5% crude protein) containing added soybean meal, corn gluten meal, cottonseed meal, or fish meal. Diets were calculated 75% total digestible nutrients. Body weight gain increased an average of 17% with added protein. Fish meal and soybean meal generated highest rates of gain. Ruminal ammonia-nitrogen was higher for soybean meal and cottonseed meal than other diets, indicating greater rates of degradability. Molar proportions of rumen volatile fatty acids were not different among diets, but concentration was lower for fish meal. Serum urea nitrogen was lowest for the basal and fish meal diets. Microbial nitrogen in the abomasum was 33.6% of total nitrogen for corn gluten meal and 42.8% for soybean meal. Apparent dry matter and nitrogen digestibilities were greater for corn gluten meal and fish meal diets than for soybean meal or cottonseed meal diets. Rumen degradability of feedstuffs, as determined by dacron bag technique, ranged from 38.1% for corn gluten meal to 71.3% for soybean meal. Degradability of mixed diets reflected those of the protein supplement present in each diet except for diet containing cottonseed meal. Fish meal and soybean meal were better protein sources for growth of ruminating calves than were corn gluten meal or cottonseed meal.     

Amino acid composition of Brazilian surubim fish (Pseudoplatystoma coruscans) fed diets with different levels and sources of fat

Surubim (Pseudoplatystoma coruscans) is a river fish from the Brazilian São Francisco basin which presents a great potential for commercialization. The amino acid composition of carcasses of surubim fed isoproteic diets with variable levels and sources of fat were determined. The increase of soybean oil at levels of 4%, 8% and 12% in the rations promoted a corresponding increase in nitrogen fixation in the fish carcass, reflected by higher amino acid contents. However, the application of 12% added amounts of pig lard, corn oil, linseed oil or soybean oil, as different sources of fat, did not promote much variation in the fish amino acid fixation. The determination of the essential amino acid composition in the fish carcasses and the A/E ratios of individual amino acids provided a pattern of amino acid requirements of surubim fish.     

EFFECTS OF ANTIOXIDANTS AND PROCESSING ON STABILITY OF MUSCLE FROM HYBRID STRIPED BASS WITH OMEGA-3 FATTY ACIDS

Hybrid striped bass were fed four diets containing 0, 4, 8, and 12% menhaden fish oil (MFO) for 18 weeks during final growth to determine (1) omega-3 (n-3) fatty acid uptake and its effect on fish and postharvest quality, and (2) the effects of selected antioxidants on oxidation and sensory quality of fish enhanced with n-3 fatty acids. Lipid content was significantly higher in the two highest MFO treatments: 3.2, 3.5, 3.9 and 4.4% in the 0, 4, 8 and 12% MFO treatments, respectively. During this study EPA(eicosapentaenoic acid) significantly increased with increasing dietary MFO: 5.4 ± 0.93, 6.9 ± 0.15, 8.0 ± 0.45 and 8.1 ± 0.35 for the 0, 4, 8 and 12% MFO diets, respectively. The following fatty acids in muscle increased 1% or more in fish fed 12% MFO compared to fish fed 0% MFO: 14:0, 16:1n-7, 22:6n-3, and total polyunsaturates, total n-3, and the n-3/n-6 ratio. Changes in individual fatty acids in fish muscle reflected the concentrations of fatty acids in the diet. Hybrid striped bass fed 8 and 12% MFO had twice as much n-3 fatty acids (1.0 g/100 g tissue) as fish cultured on diets without MFO     

Fatty acid profiles of milk and rumen digesta from cows fed fish oil,extruded soybeans or their blend

Four fistulated primiparous cows (two Holstein and two Brown Swiss) averaging 102 DIM were used in a 4 x 4 Latin square with 3-wk periods to determine the effect of feeding fish oil, extruded soybeans, or their combination on fatty acid profiles of milk and rumen digesta. Experimental diets consisted of: 1) control diet; 2) a diet with 2% (DM basis) added fat from menhaden fish oil; 3) a diet with 2% added fat from extruded soybeans; and 4) a diet with 1% added fat from fish oil and 1% fat from extruded soybeans. All diets consisted of 25% corn silage, 25% alfalfa hay, and 50% concentrate. Milk yields (28.6, 29.7, 29.2, and 28.1 kg/d for control, fish oil, extruded soybeans, and combination diets, respectively) were similar for all fat supplements and control. Milk fat and protein percentages (3.49, 3.08; 3.25, 2.96; 3.47, 3.01; 3.48, 2.99 for diets 1, 2, 3, and 4, respectively) were not affected by fat supplements compared with control. Dry matter intake (23.0, 21.6, 22.7, and 21.6 kg/d) was reduced when diets containing fish oil were fed. Concentrations of conjugated linoleic acid [CLA; cis-9, trans-11 CLA, 0.40, 0.88, 0.87, and 0.80 g/100 g fatty acids (FA)] and transvaccenic acid (TVA, 1.02, 2.34, 2.41, and 2.06 g/100 g of FA) were increased in milk fat by all fat supplements, with no differences in milk CLA and TVA observed among fat supplements. As with milk fat, proportions of ruminal CLA (0.09, 0.26, 0.18, and 0.21 g/100 g of FA) and TVA (2.61, 4.56, 4.61, and 4.39 g/100 g of FA) increased with fat supplements. The effects of fat supplements on ruminal TVA and CLA concentrations were also reflected in rumen FA-salts, free fatty acids, and neutral lipids. The higher TVA to CLA ratio in the rumen compared with milk indicated that fat supplements increased milk CLA concentration mainly by increasing ruminal production of TVA, which also implied the significant role that mammary delta-9 desaturase plays in milk CLA concentrations.     

Fish oil in feeds for entire male and female pigs: Changes in muscle fatty acid composition and stability of sensory quality

A total of 72 crossbred [(Norwegian Landrace × Yorkshire) × Duroc] male and female growing-finishing pigs were restrictedly fed diets containing fish oil to study the fatty acid composition of Musculus longissimusdorsi and sensory quality of belly and neck. Six diets were used: two low-fat diets with or without 0.5% fish oil added, and four medium-fat diets with palm kernel oil to fish oil in ratios given as % inclusion: 4.1:0.0, 3.9:0.3, 3.6:0.5 and 3.4:0.7. Feeding fish oil gave a dose-dependent response between fatty acids in the diets and in the M.longissimusdorsi and increased the level of very long chain n−3 fatty acids, especially the C22:5n−3 (DPA). A more efficient n−3 fatty acids deposition was obtained when given as a medium-fat diet rather than the low-fat diet. Female pigs had a significant higher percentage of monounsaturated fatty acids and C18:1 than males suggesting a gender related difference in the delta-9-desaturase activity. No significant differences were found in sensory attributes for short-term stored neck and belly. For pigs fed the highest level of fish oil (0.7%) long-term stored (12 months at −80 °C, 6 months at −20 °C) belly showed a slight increase in fish oil flavour. After warmed-over treatment, fish oil odour and flavour as well as rancid flavour were increased in this group. The results suggest levels of dietary fish oil up to 0.5% produce a healthier meat fatty acid composition, without negative effects on sensory attributes, even in long-termed stored belly.     

Identification of odour‐active compounds in muscle of brown trout (Salmo trutta) as affected by dietary lipid sources

The effect of fatty acid composition on odour‐active compounds in brown trout (Salmo trutta) muscle was evaluated. The fillets were obtained from three groups of fish fed experimental diets containing either fish oil (FO), soybean oil (SO) or linseed oil (LO). Muscle fatty acid composition was shown to be influenced by diet. Thirty‐one odorous compounds were detected by gas chromatography/olfactometry (frequency‐of‐detection method). Most of these compounds were formed by the oxidation of unsaturated fatty acids. Independently of diet, (E)‐2‐pentenal, (E)‐2‐pentenol and (E)‐2‐hexenol contribute strongly to the odour of brown trout. (E,Z)‐2,4‐Heptadienal was detected with high frequency in fish fed diets containing high levels of n‐3 PUFAs (FO and LO groups). Hexanal, (E)‐2‐hexenal and 2‐nonanol seem to contribute most to the odour of fish fed diets containing vegetable oils. Many odorous compounds were derived from the oxidation of mono‐ and di‐unsaturated fatty acids, which could be promoted by high levels of PUFAs. © 2002 Society of Chemical Industry     

Monola oil versus canola oil as a fish oil replacer in rainbow trout feeds: Effects on growth,fatty acid metabolism and final eating quality

Monola oil, a high oleic acid canola cultivar, and canola oil were evaluated as replacers of fish oil at three levels of inclusion (60%, 75% and 90%) in rainbow trout diets. After a 27-week grow-out cycle, the diet-induced effects on growth, fatty acid metabolism and final eating quality were assessed. Overall, no effects were noted for growth, feed utilisation or fish biometry, and the fatty acid composition of fish fillets mirrored that of the diets. Dietary treatments affected fillet lipid oxidation (free malondialdehyde), pigmentation and flavour volatile compounds, but only minor effects on sensorial attributes were detected. Ultimately, both oils were demonstrated to possess, to differing extents, suitable qualities to adequately replace fish oil from the perspective of fish performance and final product quality. However, further research is required to alleviate on-going issues associated with the loss of health promoting attributes (n-3 long chain polyunsaturated fatty acids) of final farmed products.