Effects Of Dietary Lipid Sources Research Articles

Effect of dietary lipids on fatty acid composition and metabolism in juvenile green sea urchins ( Strongylocentrotus droebachiensis)

Relatively little is known of the nutritional requirements of sea urchins, especially at the juvenile stages. One of the costly restrictions on feed formulation for marine fish species is the requirement for fish oils to supply the essential n-3 highly unsaturated fatty acids (HUFA). This study investigated the effects of different dietary lipid sources on the fatty acid composition and metabolism of juvenile green sea urchins ( Strongylocentrotus droebachiensis). Kelp ( Laminaria longicruris) served as a reference diet. Experimental diets contained 5% of: corn oil (high in 18:2n-6), linseed oil (high in 18:3n-3), menhaden oil (high in n-3 HUFAs 20:5n-3 and 22:6n-3), or 1:1 mixtures of corn oil and linseed oil, or corn oil and menhaden oil or linseed oil and menhaden oil. Unlike marine fish, the sea urchins exhibited ample ability for elongation and desaturation of shorter chain (18 carbon) polyunsaturated fatty acids (PUFA) to longer chain (20 carbon) n-3 and n-6 HUFA. Thus 18:2n-6 from corn oil in the diet resulted in high levels of 20:4n-6 in the sea urchin and similarly 18:3n-3 in the diet resulted in high levels of 20:5n-3. Even when fed kelp or diets with menhaden oil, the sea urchins did not incorporate high levels of 22:6n-3 into their lipids. In addition to the effects of dietary lipid sources on fatty acid composition of the lipids of total soft tissues of sea urchin, there were great differences in fatty acid composition among different tissues and among lipid classes of these tissues. For example, the test (shell) and associated tissue membranes, which are in constant contact with the seawater, incorporated much higher proportions of 20:4n-6 than the gonad or gut tissues. This may reflect an important role of 20:4n-6 in ion transport and osmoregulation. The sea urchins also synthesized a number of 20 and 22 carbon non-methylene-interrupted dienes (NMID) and the concentration of the major NMID was directly related to the tissue levels of 18:2n-6 and inversely proportional to the dietary and tissue levels of n-3 PUFA and HUFA. The significance of these and other interesting aspects of fatty acid metabolism in sea urchins are discussed.

Effects of dietary lipid sources on flavour volatile compounds of brown trout (Salmo trutta L.) fillet

Summary The high cost and unpredictable availability of fish meal and fish oil (FO) forced feed mill companies to look for alternative ingredients for aquafeeds. In this study, the effects of alternative dietary lipid sources [FO as control, canola oil (CO), oleine oil (OO), poultry fat (PF) and pork lard (PL)] in trout feed on flavour volatile compounds occurring in brown trout (Salmo trutta L.) fillet were evaluated after 70 days of feeding (rearing temperature 14.6� C). Total amounts of volatile compounds identified were higher for fillets of fish fed diets containing only FO as lipid sources. Total amount of alcohols and aldehydes of the fillets were linearly directly related to the percentage content of polyunsaturated fatty acids (PUFA) n-3 of brown trout flesh. The use of alternative dietary lipid sources, modifying the fillet fatty acids composition, affect the total amount of volatile compounds and, changing the relative amount of each volatile compound, affect the flavour of the fish flesh.

Effect of dietary essential fatty acids on growth, body composition and blood chemistry of juvenile starry flounder ( Platichthys stellatus)

A 10-week feeding experiment was conducted to investigate the effects of dietary lipid source and n-3 highly unsaturated fatty acids (n-3 HUFA) level on growth, body composition and blood chemistry of juvenile starry flounder. Three replicate groups of fish (average weight 1.9 g) were fed diets containing different n-3 HUFA levels ranging from 0.0% to 2.7% adjusted by either lauric acid as sole lipid source or different proportions of corn oil, linseed oil and squid liver oil at 10% of total lipid. Survival was not affected by dietary lipid source or n-3 HUFA level. Weight gain, feed efficiency and protein efficiency ratio of fish fed the diets containing squid liver oil were significantly higher than those fed the diets containing lauric acid, corn oil or linseed oil as the sole lipid source. However, there were no significant differences in weight gain, feed efficiency and protein efficiency ratio among fish fed the diets containing different n-3 HUFA levels ranging from 0.6% to 2.7%. Dietary n-3 HUFA requirement when using a broken line model was estimated at 0.9% for weight gain of fish. Crude lipid content of fish fed the diet containing lauric acid was significantly lower than that of other groups. Fatty acid compositions of neutral and polar lipid of fish were directly reflected by dietary fatty acid composition. The highest 14:0, 18:2n-6, 18:3n-3 and n-3 HUFA contents were observed in fish fed the diets containing lauric acid, corn oil, linseed oil and squid liver oil, respectively. The contents of n-3 HUFA in fish linearly increased with increasing dietary squid liver oil. Plasma cholesterol concentration and aspartate aminotransferase activity were affected by dietary lipid sources. These results indicate that dietary n-3 HUFA are essential and a value of at least 0.9% of n-3 HUFA in the diet could be recommended for optimum growth and efficient feed utilization of juvenile starry flounder.

Essentiality of Dietary n‐3 Highly Unsaturated Fatty Acids in Juvenile Japanese Flounder Paralichthys olivaceus

AbstractThis study was conducted to confirm the essentiality of dietary n‐3 highly unsaturated fatty acids (n‐3 HUFA) and to investigate the effects of dietary lipid sources on growth performance, liver, and blood chemistry in juvenile Japanese flounder. Three replicate groups of fish (average weighing 3.0 g) were fed experimental diets containing lauric acid ethyl ester, soybean oil, soybean and linseed oils mixture, and squid liver oil as lipid sources for 13 wk. No significant difference was observed in survival among all groups (P >0.05). Weight gain, feed efficiency and protein efficiency ratio of fish fed the squid liver oil diet containing high n‐3 HUFA level were significantly higher than those of fish fed the other diets (P 0.05). Saturated and monounsaturated fatty acids of liver polar and neutral lipid fractions in fish fed the diet containing lauric acid tended to increase compared to those of the other groups. Fish fed the diets containing soybean and/or linseed oils, which contained high contents of 18:2n‐6 and 18:3n‐3, respectively, showed the highest contents of 18:2n‐6 and 18:3n‐3 in both lipid fractions of the liver (P 0.05). Significantly higher content of n‐3 HUFA was observed in both lipid fractions of the liver from fish fed the diet containing squid liver oil than for fish fed the other diets (P 0.05). Total cholesterol, glucose, and glutamic‐oxaloacetic acid transaminase in plasma were significantly affected by dietary lipids (P 0.05). Histologically, the liver of fish fed the diet containing squid liver oil had a clear distinction between nuclear and cytoplasm membranes; however, cytoplasm of fish fed the diets containing lauric acid and soybean oil was shrunken, and the hepatic cell outline was indistinguishable. It is concluded that the dietary n‐3 HUFA is essential for normal growth, and that the dietary lipid sources affect growth performance, liver cell property, and blood chemistry in juvenile Japanese flounder.

Effect of alternative lipid sources on long-term growth performance and quality of Atlantic salmon (Salmo salar L.)

The present study investigates the impact of replacing at least 50% of the fish oil in high-energy salmon diets with other types of oils. Triplicate groups of Atlantic salmon (Salmo salar L.) were fed six diets differing only in dietary lipid source for 12 months in sea water. The experimental oils were combinations of fish oil and one or two of the following oils: rapeseed, soybean, linseed, palm or poultry oil. Fish oil constituted 40%−50% of the oil mixtures. The fish grew from an average weight of 120 g to 2000 g during the 12 month trial. Except for minor differences in the lipid concentration of trimmed fillets, no significant effects of dietary lipid source were found on growth, survival, body traits or fillet quality. The main dietary effect was observed in the muscle fatty acid composition, which clearly reflected that of the diets. These results show that high-energy diets where 50%−60% of the fish oil is replaced by other lipid sources can produce similar results to diets containing 100% fish oil during the grow out phase of Atlantic salmon in sea. The importance of fillet fatty acid composition on processing and sensory characteristics requires further evaluations.

Effect of dietary lipid sources on odour‐active compounds in muscle of turbot (Psetta maxima)

AbstractOdour‐active compounds in muscle of turbot (Psetta maxima) fed experimental diets containing fish oil (FO), soybean oil (SO) or linseed oil (LO) were investigated by a gas chromatography/olfactometry technique. Thirty‐one areas associated with odours were detected in muscle extracts. Among the compounds responsible for these odours, 23 were formed by oxidation of unsaturated fatty acids. Independently of diet, (E)‐2‐penten‐1‐ol and (E)‐3‐hexen‐1‐ol contribute strongly to the odour of turbot. (E,Z)‐2,6‐Nonadienal, (E)‐2‐pentenal and (E,E)‐1,3‐(Z)‐5‐octatriene seem to contribute strongly to the odour of turbot fed diets containing high levels of n‐3 PUFA (FO and LO groups). Hexanal and decanal show a high detection frequency in turbot fed diets containing vegetable oils. Odorous compounds which are not formed by lipid oxidation (methional, 1‐acetyl pyrazine, 4‐ethyl benzaldehyde and 2‐acetyl‐2‐thiazoline) were not affected by dietary lipid sources.© 2001 Society of Chemical Industry

Lipoprotein lipase and lipogenic enzyme activities in adipose tissue from rats fed different lipid sources.

This work was designed to study the effect of different lipid sources on the activities of lipoprotein lipase and lipogenic enzymes in adipose tissue from rats fed ad libitum or energy-controlled diets. Male Wistar rats were fed diets containing 40% of energy as fat (olive oil, sunflower oil, palm oil or beef tallow), for 4 wk. Under ad libitum feeding no differences were found among dietary fat groups in final body weight, adipose tissue weights and total body fat. Under energy-controlled feeding, despite isoenergetic intake, rats fed the beef tallow diet gained significantly less weight than rats fed the other three diets. Beef tallow fed rats showed the lowest values for adipose tissue weights and total body fat. When rats had free access to food no effect of dietary lipid source on lipogenic enzyme activities was found. In contrast, under energy-controlled feeding rats fed the beef tallow diet showed significantly higher activities of glucose-6-phosphate dehydrogenase and fatty acid synthase than rats fed the other three diets. Heparin-releasable lipoprotein lipase activity in perirenal and subcutaneous adipose tissues was not different among rats fed olive oil, safflower oil, palm oil or beef tallow. When comparing both adipose tissue anatomical locations, significantly higher activities were found in subcutaneous than in perirenal fat pad independently of dietary fat. In conclusion, under our experimental protocol, lipogenesis in rat adipose tissue does not seem to be affected by dietary fat type.

Effect of Dietary Lipid Source on Conjugated Linoleic Acid Concentrations in Milk Fat ,

Conjugated linoleic acids (CLA) found in ruminant milk fat are a byproduct of incomplete biohydrogenation of lipids by ruminal bacteria. We examined the effect of different dietary fat supplements and processing methods on CLA. In trial 1, dietary supplements of Ca salts of fatty acids from canola oil, soybean oil, and linseed oil increased CLA content of milk fat by three-to fivefold over the control diet. Trials 2 and 3 examined the effect of processing methods for heat treatment of full fat soybeans. In trial 2, extrusion, micronizing, and roasting resulted in two- to threefold greater concentrations of CLA in milk fat than the control diet (raw ground soybeans). In trial 3, different temperatures of extrusion (120, 130, and 14°C) increased the CLA content of milk fat to a similar extent; CLA averaged 19.9 mg/g of fatty acids for the extrusion treatments compared with 4.2 mg/g of fatty acids for the control diet (raw ground soybeans). Fish oil (200 and 400 ml/d) was examined in trial 4 and both levels resulted in CLA concentrations in milk fat that were about threefold greater than the control diet. In trial 5, grain and silage from a high oil corn hybrid increased the CLA content of milk fat; however, responses were modest with the CLA concentration (mg/g of fatty acids) averaging 4.6 and 2.8 for diets with high oil hybrid and normal hybrid, respectively. Similarly, dietary supplements of animal fat byproducts (tallow plus yellow grease; trial 6) resulted in modest increases in the CLA content of milk fat. Overall, several dietary manipulations involving lipid sources and processing methods were identified that allow for a marked increase in the conjugated linoleic acid content of milk fat.

Effect of dietary lipids on fatty acid composition and lipid peroxidation in sarcoplasmic reticulum of hybrid tilapia, Oreochromis niloticus×O. aureus

The effects of dietary lipid sources on the growth response of hybrid tilapia ( Oreochromis niloticus× O. aureus) were investigated. Enzymic lipid peroxidation in the sarcoplasmic reticulum (SR) of these fish fed different dietary lipids was also studied. Experimental fish were given diets containing no additional lipids (control), lard, soybean oil, menhaden fish oil and methyl esters of n-3 highly unsaturated fatty acids (HUFA) for 10 weeks. There was no difference in survival rates among test groups. Compared to fish supplied with dietary lipids, fish consumed control diet with trace lipids (0.02%) were low in final body weights and muscle lipids. The specific growth rates and weight gains of fish fed soybean oil and fish oil were significantly higher than other groups ( P<0.05). Fatty acid compositions of muscle and SR reflected the fatty acid compositions of dietary lipids. The thiobarbituric acid reactive substances produced by iron catalyzed NADH-dependent lipid peroxidation were significantly different ( P<0.05) among SR isolated from fish fed different dietary lipids. Lipid peroxidation activity of HUFA group was the highest, followed by fish oil, soybean oil, lard and control group.

Effects of dietary lipid source and energy restriction on the liver fatty acid profile in zucker rats (fa/fa)

Effects of dietary lipid source and energy restriction on the liver fatty acid profile in zucker rats (fa/fa)

Larval rearing of an African catfishHeterobranchus longifilis(Teleostei, Clariidae): effect of dietary lipids on growth, survival and fatty acid composition of fry

Legendre M., N. Kerdchuen, Ci. Corraze, P. Bergot. Aquat. Living Resour., 1995, 8, 355-363. With the aim of improving dry diets for first feeding of Heterobranchus long$lis larvae, the effect of dietary lipid sources on growth rate, survival rate and fatty acid composition of fry from 2 days up to 17 days of age was evaluated. Six feeding regimes were tested: Artemia nauplii which served as a reference, and 5 experimental dry diets diffenng only by the lipid source. The different oils used for the different expenmental diets were the following: cod liver oil, palm oil, copra oil, peanut oil and cotton seed oil. Each diet was tested on duplicate groups of 400 larvae placed in the 40 1 tanks of a recirculating system (27-29°C) and fed to excess six times per day every 4 hours. Separation and identification of the fatty acids of diets, eggs and fry were carried out by gas-liquid chromatography. After 15 days of feeding, survival rates were high for al1 treatments (71-87%) and did not differ significantly. By contrast, growth rates were largely influenced by the feeding regime. Fry fed with Artemia were significantly bigger (289 mg) than those fed artificial dry diets (79-1 15 mg). However, it was found that the specific growth rate of fry fed Artemia was supenor to that of fry receiving dry diets only for fish of less than 50 mg body weight, indicating that Artemia presents a nutritional advantage only for fry at their youngest stages of development (first 6 days of feeding). Among the artificial dry diets, the best results were obtained with diets containing palm or copra oil, the lowest growth rate being observed with the cod liver oil diet. Peanut and cotton seed oil diets led to intermediate results. The fatty acid composition of the whole fry reflected that of the experimental diets. Al1 together, the results indicated the existence of an optimal ratio between n-3 and n-6 fatty acids for covenng essential fatty acids requirement of the fry. Growth rates tended to be reduced by an excess of n-3 fatty acids (cod liver oil) or by an excess in n-6 fatty acids (cotton seed oil) as well. Evidence of the occurrence of HUFA (20:4n-6 and 22:6n-3) biosynthesis are given.

Effect of Dietary Lipid Sources on Production of Leukotriene B by Head Kidney of Channel Catfish Held at Different Water Temperatures

Abstract Separate and combined effects of dietary fatty acids and water temperature on the production of leukotriene B (LTB) by the head kidney of channel catfish Ictalurus punctatus were investigated. Fish were fed semipurified diets containing 7% lipid as beef tallow, corn oil, linseed oil, menhaden oil, or a mixture (1:1:1) of menhaden oil, beef tallow, and corn oil. At 28°C, fish fed corn oil produced the greatest amount of LTB, and fish fed beef tallow produced the least. At 17°C, production of LTB by fish fed the beef tallow diet was again lowest; production of LTB by fish fed the corn oil diet was highest but was not significantly different from that obtained with the mixed-oil or menhaden oil diet. Production of LTB for the other diets was intermediate. This is the first report that the head kidney of channel catfish produces LTB; this production was affected by dietary lipid sources but not by the two water temperatures tested. Production of LTB was not related to weight gain. Moreover, the patte...

Effects of Dietary Lipid Saturation on Prolactin Secretion, Carcinogen Metabolism and Mammary Carcinogenesis in Rats

Isoenergetic diets containing 20% corn oil, 20% beef tallow, or an equal mixture of 10% corn oil and 10% beef tallow (mixed fat) were fed to 30 rats per diet for 28 weeks following weaning. DMBA [7,12-dimethylbenz(a)anthracene] was administered (1.75 mg/100 g body weight) in a single oral dose after 4 weeks of feeding. After 28 weeks, 70% of the rats fed corn oil had mammary tumors versus 47% for mixed fat and 30% for tallow. Diet had no effect on the number of tumors per tumor-bearing rat or the proportion of tumors that were adenocarcinomas. Other rats assigned to each of the three diets were killed at the time corresponding to DMBA administration for examination of hepatic mixed-function oxidase activity. NADPH cytochrome c reductase activity and cytochrome P-450 content were higher in rats fed corn oil or mixed fat rather than tallow. However, no significant differences in aryl hydrocarbon hydroxylase, glutathione transferase, and uridine-diphosphoglucuronide transferase activities were observed. The effects of dietary fat saturation on enzyme activity failed to show a clear association with DMBA carcinogenesis. In other rats assigned to the three dietary treatments for 4 or 16 weeks, lipid saturation did not change serum prolactin (PRL) concentrations during diestrus or proestrus. PRL secretion was examined following a provocative stimulus (perphenazine) in rats fed the experimental diets for 4 or 10–22 weeks. Although perphenazine increased serum PRL and depleted the pituitary of PRL, differences in dietary lipid saturation caused no significant changes in these indices. These data show that the incidence of mammary tumors in rats fed high fat diets (20% by weight) was greater in those fed corn oil compared to beef tallow. The effect of dietary lipid source on tumorigenesis was not associated with changes in carcinogen-metabolizing enzyme activity or PRL secretion.