Effects Of Dietary Phospholipids Research Articles

Suitable dietary phospholipids improve lipid deposition, but excessive dietary phospholipids disorder lipid metabolism in juvenile leopard coral grouper (Plectropomus leopardus)

Limited investigation has been available on the effects of dietary phospholipids in leopard coral grouper (Plectropomus leopardus), hindering its potential for aquaculture. This study was intended to investigate the impact of various levels (05 %) of dietary soy lecithin (SL) on juvenile P. leopardus over a 9-week feeding trial. Results indicated that dietary inclusion of 23 % SL enhanced the lipid content in liver, muscle, and whole-body. The fatty acid composition of muscle strongly reflected the dietary fatty acid profile. Furthermore, dietary inclusion of 3 % SL enhanced the activities of hepatic lipid synthesis enzymes [fatty acid synthase (FAS), glucose-6-phosphate dehydrogenase (G6PD)] and lipolytic enzymes [hormone-sensitive lipase (HSL), carnitine palmitoyltransferase-1 (CPT-1)]. Additionally, the inclusion of 23 % SL upregulated the relative expression of lipid synthesis-related genes [fas, sterol regulatory element binding transcription factor 1 (srebp1)] and lipid catabolism-related genes [hsl, cpt-1, and lipoprotein lipase (lpl)] in muscle. However, increasing dietary SL levels up to 45 % led to a reduction in muscle and whole-body lipid content, and an enhance in hepatic lipid content and hepatocyte vacuolization. Moreover, dietary inclusion of 5 % SL downregulated the relative expressions of hepatic lipid synthesis-related genes (g6pd and srebp1) and lipid catabolism-related genes (lpl and hsl). Overall, including 23 % SL in the diet improved lipid metabolism and thereby enhanced lipid deposition in juvenile P. leopardus, but excessive SL (45 %) disrupted lipid metabolism.

Effect of Dietary Phospholipid on the Behavior in C57BL/6J Mice

Effect of Dietary Phospholipid on the Behavior in C57BL/6J Mice

The Effect of Dietary Phospholipids on the Ultrastructure and Function of Intestinal Epithelial Cells.

Dietary composition substantially determines human health and affects complex diseases, including obesity, inflammation and cancer. Thus, food supplements have been widely used to accommodate dietary composition to the needs of individuals. Among the promising supplements are dietary phospholipids (PLs) that are commonly found as natural food ingredients and as emulsifier additives. The aim of the present study was to evaluate the effect of major PLs found as food supplements on the morphology of intestinal epithelial cells upon short-term and long-term high-dose feeding in mice. In the present report, the effect of short-term and long-term high dietary PL content was studied in terms of intestinal health and leaky gut syndrome in male mice. We used transmission electron microscopy to evaluate endothelial morphology at the ultrastructural level. We found mitochondrial damage and lipid droplet accumulation in the intracristal space, which rendered mitochondria more sensitive to respiratory uncoupling as shown by a mitochondrial respiration assessment in the intestinal crypts. However, this mitochondrial damage was insufficient to induce intestinal permeability. We propose that high-dose PL treatment impairs mitochondrial morphology and acts through extensive membrane utilization via the mitochondria. The data suggest that PL supplementation should be used with precaution in individuals with mitochondrial disorders.

Effects of dietary phospholipids on growth performance, fatty acid composition and lipid metabolism of early juvenile largemouth bass ( Micropterus salmoides )

Effects of dietary phospholipids on growth performance, fatty acid composition and lipid metabolism of early juvenile largemouth bass ( <i>Micropterus salmoides</i> )

Effects of dietary phospholipid and cholesterol levels on antioxidant capacity, nonspecial immune response and intestinal microflora of juvenile female crayfish, Procambarus clarkii

The current study is conducted to evaluate the interactive effects of different phospholipids (PL) and cholesterol (CH) levels on the immune response and intestinal microbiota of juvenile female red swamp crayfish, Procambarus clarkii. A total of 270 healthy crayfish with an average initial weight of 5.92 ± 0.03 g were fed nine semi-purified diets containing three different levels of PL (0, 20 and 60 g/kg of diet) and CH (0, 5 and 10 g/kg of diet, as a 3 × 3 experiment design) for 60 days. The superoxide dismutase (SOD) activity in serum was enhanced by dietary supplementation of PL and CH (P < 0.05), and the activity of alkaline phosphatase (AKP) and phosphatase (ACP) decreased significantly with increasing dietary PL levels (P < 0.05). There was a significant interaction between PL and CH on malondialdehyde (MDA) content, catallase (CAT), total antioxidant capacity (T-AOC) and glutathione peroxidase (GPx) activities (P < 0.05). Optimal dietary PL and CH levels could significantly improve the abundance of intestinal microflora, change and optimize the intestinal flora composition and decrease pathogenic bacteria relative abundance. When CH addition level at 5 g/kg, the Bacteroidetes abundance was the highest and the relative abundance of Candidatus Bacilloplasma was the lowest compared with the other groups (P < 0.05). Considering antioxidant capacity, nonspecial immune response and microbial community structure, the optimal PL and CH requirements were estimated to be 60 g/kg and 5 g/kg for juvenile female P. clarkii, respectively.

Effects of Dietary Phospholipid and Cholesterol Levels on Growth, Molting Performance, and Ovary Development in Female Juvenile Crayfish (Procambarus clarkii)

The interaction between phospholipid (PL) and cholesterol (CH) on growth performance, molting rate, hepatopancreas fatty acid composition, and ovary development of the female red swamp crayfish (Procambarus clarkii) was investigated. Nine diets containing three PL levels (0, 20, and 60 g/kg) and three CH levels (0, 5, and 10 g/kg) were included in the study. Female crayfish (initial weight: 5.92 ± 0.03 g) were reared for 60 days. There was no significant interaction between dietary PL and CH levels ( P &gt; 0.05 ). However, the best growth performance and ovarian development were observed in crayfish receiving the 60 g/kg PL and 10 g/kg CH diet. High PL levels promoted CH transport in the hepatopancreas, and long-chain unsaturated fatty acid (C20:4n-6, C20:5n-3, and C22:6n-3) content of the hepatopancreas increased with the addition of PL in the diet. The molting rate increased with increasing CH levels in the diet containing 60 g/kg PL. Real-time quantitative polymerase chain reaction revealed that dietary CH enhanced the molting rate by improving the ecdysone receptor genes at transcription. This study showed that crayfish fed a diet containing 10 g/kg CH and 60 g/kg PL obtained maximum growth, molting rate, and ovary development.

Effects of dietary phospholipids on early stage Atlantic Salmon (Salmo salar) performance: A comparison among phospholipid sources

The present study aimed to confirm that additional phospholipids are needed in Atlantic Salmon (Salmo salar) fry diet for optimal performance. Furthermore, comparisons were made among soy lecithin and two marine-based phospholipids- krill oil and marine phospholipids extracted from fishmeal. First feeding salmon juveniles had significantly reduced mortality and increased growth when marine-based phospholipids (both krill and fish-sourced) were supplemented to high fishmeal diets (baseline control diet and a low phospholipid control diet). Fish fed diets with added soy lecithin had lower but not significantly different growth rates compared to fish fed diets supplemented with marine-based phospholipids, however, growth was also not significantly different than the baseline control. Thirty days after first feeding, differences in growth were no longer significant among supplemented diets and the control diet. However, both survival and growth for the low phospholipid baseline control remained poor, indicating a lowered but still present requirement for dietary phospholipids at this stage. Results show marine-based phospholipids, despite original source (fish versus krill), perform similarly, while soy lecithin has a tendency to perform slightly lower in the first-feeding juvenile stage. Marine-based ingredients are sustainable, but limited; therefore, it is important that many numerous, effective ingredient sources are available for the aquaculture industry.

Phospholipids improve the performance, physiological, antioxidative responses and, lpl and igf1 gene expressions in juvenile stellate sturgeon (Acipenser stellatus)

The effects of dietary phospholipids (PL) on the performance of juvenile stellate sturgeon (Acipenser stellatus) was evaluated in terms of growth and feed efficiency parameters, muscle and liver fatty acid profiles, activity of digestive and antioxidative stress enzymes, and expression of lipoprotein lipase (lpl) and insulin-like growth factor (igf1). For this purpose, seven isoproteic (44% crude protein) and isolipidic (17% crude fat) diets containing graded levels of soybean lecithin (0, 1, 2, 4, 6, 8 and 10%) were prepared, resulting in 0.3, 0.9, 1.6, 2.7, 3.9, 5.3 and 5.4% of dietary PLs, respectively. At the end of the nutritional study (75 days), we found that there was a positive quadratic polynomial response between growth performance parameters and dietary PLs; somatic growth increased with increasing dietary PL levels up to 3.9% when growth parameters remained stable. Dietary PLs reduced the accumulation of fat stores in the liver and up-regulated the expression of the lipoprotein lipase gene, confirming the important role of this enzyme in incorporating plasma lipids into tissues, whereas the activities of CAT and SOD showed a positive linear increase with dietary PL levels. Increasing dietary PLs from 0.9 to 3.9% promoted the activity of gastric (pepsin) and pancreatic (trypsin, chymotrypsin, bile salt-activated lipase and α-amylase) enzymes, whereas higher inclusion levels of PLs did not provide any advantage in terms of A. stellatus digestive capacities. The analysis of fatty acid profiles in diets and selected tissues (liver and muscle) showed the capacity of A. stellatus juveniles to desaturate and elongate linoleic (C18:2n–6) and alpha-linolenic (C18:3n–3) acids to arachidonic (C20:4n-6), eicosapentaenoic (C20:5n-3) and docosahexaenoic (C22:6n-3) acids. Based on the results of growth performance, feed efficiency and physiological parameters, the inclusion of 3.9% of PLs in compound diets for juvenile stellate sturgeon are recommended.

Effects of dietary phospholipid and cholesterol levels on growth and fatty acid composition of juvenile swimming crab,Portunus trituberculatus

The objective of this study was to evaluate the effects of different phospholipids (PL) and cholesterol (CH) levels on the growth, moulting and fatty acid composition of juvenile swimming crab, Portunus trituberculatus. Six diets were designed to contain three PL levels (0, 10 and 20 g/kg) and two CH levels (2 and 8 g/kg). Juvenile swimming crabs (3.48 ± 0.02 g/crab) were reared for 8 weeks. The weight gain (WG) was significantly (p .05). The moulting frequency (MF), protein efficiency ratio (PER) and feed efficiency ratio (FCR) were not significantly (p > .05) affected by the dietary treatments. The serum total cholesterol (TCH) significantly (p > .05) increased with increasing dietary PL level. The C20:4n-6 and C20:5n-3 content of the whole body of crabs increased with the addition of PL to the diet containing 2 g/kg CH of diet. An interaction was observed between PL and CH on certain saturated and unsaturated fatty acid concentrations of body.

Effects of dietary phospholipid on lipase activity, antioxidant capacity and lipid metabolism-related gene expression in large yellow croaker larvae (Larimichthys crocea).

It was previously shown that lipid content of the whole larvae body fed the phospholipid (PL)-devoid diet was significantly lower than that of larvae fed PL-supplemented diets (P<0.05) (Feng et al., unpublished results). The mechanisms involved remain unclear and were explored from the perspective of fatty acids delivery, uptake, synthesis and oxidation in the present study. Besides, this study was also designed to investigate the effect of dietary PL on antioxidant capacity in large yellow croaker larvae (Larimichthys crocea). Triplicate groups of larvae (initial body weight: 3.86±0.24mg) were fed three isonitrogenous and isolipidic diets with increasing levels of PL (2.53%, 6.32% and 12.7%) eight times daily for 30days. Results showed that the specific activities of superoxide dismutase and catalase were significantly higher in 12.7% PL group compared to those in 2.53% PL group (P<0.05), while an opposite trend was observed for MDA content (P<0.05). The specific activity of lipase and the mRNA abundance of fatty acids delivery and uptake-related genes, including lipoprotein lipase, hepatic lipase and fatty acids translocase (cluster of differentiation) were significantly higher in 12.7% PL group than those in 2.52% group (P<0.05). Compared to 2.53% PL group, the transcript levels of fatty acid synthase and stearoyl-CoA desaturase I were significantly lower in 6.32% PL group (P<0.05), while peroxisome proliferators-activated receptor α, carnitine palmitoyl transferase-I and acyl CoA oxidase mRNA expression levels were significantly higher in 12.7% PL group (P<0.05). These results indicated that dietary PL could enhance antioxidant capacity of larvae. Dietary PL might regulate lipid metabolism in large yellow croaker larvae by modulating fatty acids delivery, uptake, synthesis and oxidation at transcriptional level and improved fatty acids delivery and uptake might be responsible for higher body lipid content in 6.32% and 12.7% groups.

Effects of dietary phospholipids and highly unsaturated fatty acids on the precocity, survival, growth and hepatic lipid composition of juvenile Chinese mitten crab, Eriocheir sinensis (H. Milne-Edwards)

Precocious puberty is one of the major constraints to the further development of Chinese mitten crab (Eriocheir sinensis) farming industry. Although dietary phospholipids (PL) and highly unsaturated fatty acids (HUFA) supplementation have been shown to enhance the growth of larval E. sinensis in other studies, it is still unknown whether this also leads to a higher precocity rate for juvenile E. sinensis. This study was conducted to investigate the effects of dietary PL and HUFA on precocity, survival, growth and hepatic lipid composition of juvenile E. sinensis. Two diets were formulated with PL [3.95% dry weight (DW)] and HUFA (0.98% DW) supplementation (diet A) and without PL and HUFA supplementation (diet B) and fed to juvenile E. sinensis. Although dietary PL and HUFA levels did not significantly affect the survival and growth performance of juvenile E. sinensis, compared with crabs fed diet A, a higher precocity rate was found among juvenile E. sinensis fed diet B (P=0.051). A higher total lipid content, but significantly lower levels of HUFA and PL (P<0.05) were found in the hepatopancreas of crabs fed diet B than in those fed diet A. Meanwhile, the precocious females had significantly lower hepatosomatic index, arachidonic acid (20:4n-6), eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3) contents in their hepatopancreas when compared with that of the normal immature juveniles (P<0.05). The results suggest that the occurrence of precocious puberty among farmed juvenile E. sinensis could be reduced by the inclusion of appropriate level of dietary PL and HUFA.

Dietary phospholipids affect growth and production of juvenile sea urchin Lytechinus variegatus

To facilitate sea urchin aquaculture, nutritionally-complete feeds are being developed for a number of species. In this study, the effects of dietary phospholipids from soy lecithin on weight gain and production were investigated to ascertain a potential dietary requirement for small juvenile sea urchins, Lytechinus variegatus. Laboratory-produced juvenile L. variegatus ( n = 16 per treatment, average 0.091 g ± 0.01 SE wet weight and 5.80 mm ± 0.09 SE diameter) were fed semi-purified formulated diets supplemented with 1, 2.5, 4, 5.2, 6.4, 7.6, or 8.8% phospholipids (as fed) from soy lecithin for 12 weeks. Under the conditions of this study, a negative correlation between dietary phospholipid level and weight gain was observed. By 6 wk and continuing through 12 wk, sea urchins fed the 1 to 6.4% supplemented phospholipid diet (SPLD) had significantly higher total wet weight than sea urchins fed either the 7.6 or 8.8% SPLD (final wet weight ranged from 10.53 ± 0.41 g to 7.42 ± 0.65 g, for the 1 and 8.8% treatments, respectively, P < 0.05). Feed intake and apparent dry matter digestibility coefficients were similar among the 1, 5.2, and 8.8% SPLD treatments. A requirement for greater than 1% dietary phospholipid derived from soy lecithin could not be determined. Gonad production was observed at 12 wk. No significant differences were observed for ovary wet or dry weight; however, testis wet weight was higher for males fed the 1% SPLD than males fed the 8.8% SPLD (ANOVA, P < 0.05). In the gut, nonpolar lipid levels were highest for individuals fed the 8.8% SPLD (4.6, 5.4, and 10.6% for 1, 5.2, and 8.8% SPLD, respectively), indicating conversion of phospholipid to nonpolar lipid, presumed to be stored as triacyglycerols. In the ovary and testis, polar lipid levels were similar among the three treatments tested (ovary, 9.2, 10.9, 10.3% and testis, 8.1, 9, and 7.6% for 1, 5.2, and 8.8% SPLD, respectively), but nonpolar lipid levels were highest for females and males fed the 8.8% SPLD (ovary, 9.4, 12, and 16.6% and testis, 3.7, 9.4, and 12.7%, respectively). These data suggest that dietary phospholipids are, in part, being metabolized and stored as neutral lipid in the gut and gonad.

Effects of dietary phospholipid and highly unsaturated fatty acid on the gonadal development, tissue proximate composition, lipid class and fatty acid composition of precocious Chinese mitten crab,Eriocheir sinensis

Precocious puberty is a major constraint to the economical rearing Eriocheir sinensis farming. Although dietary phospholipid (PL) and highly unsaturated fatty acids (HUFA) reportedly enhanced ovarian development in normal adult E. sinensis, it had opposite effects of reducing precocity in juveniles. This study investigated the effects of dietary PL and HUFA on survival, gonadal development and biochemical composition of precocious E. sinensis. Two diets with PL and HUFA supplementation (diet A) and deficient (diet B) were formulated and fed to precocious E. sinensis. Although no significant differences were found on survival and gonadosomatic index of crabs fed both diets, crabs fed diet B had significantly higher hepatosomatic index and hepatopancrean lipid content than crabs fed diet A. The percentages, 14:0, 18:1n-9, 20:5n-3 and 22:6n-3, in hepatopancreas, muscle and gonads were positively correlated to the diets. Interestingly, the crabs fed diet B accumulated significantly higher 18:2n-6 in gonads and muscle than those fed diet A. Furthermore, substantially higher 20:4n-6 was detected in the gonad and muscle than in the diets. These results suggested that dietary PL and HUFA had limited effects on male gonad biochemical composition. Meanwhile, the precocious E. sinensis may be capable of negating the negative effects of HUFA deficiency by enhanced tissue 18:2n-6 accumulation and converting 18:2n-6 to 20:4n-6.

Effect of Dietary Phospholipids on the Choline Requirement ofLitopenaeus vannamei Juveniles

AbstractAn 8‐wk feeding trial was conducted with a 3 ± 4 factorial design for evaluating the nutritional relationship between phospholipids (lecithin at 0, 1.5% or 3% of diet) and choline chloride (0, 1,000, 2,000, or 4,000 mg/kg diet) in juvenile Litopenaeus vannamei. In addition, diets with five graded levels of choline chloride (0, 500, 1,000, 2,000, and 4,000 mg/kg) without supplemental phospholipids or cholesterol were fed for determining the dietary choline requirement. Overall survival was 99% with no difference among the dietary treatments. The choline requirement was estimated to be 871 mg/kg diet without dietary phospholipids. No choline requirement was evident when lecithin was provided at 1.5% and 3% of diet. Shrimp growth significantly increased with incremental dietary phospholipids regardless of choline chloride level. These results indicate that lecithin could effectively provide choline. Conversely, synthesis of phospholipids from choline could not meet the phospholipids requirement of shrimp. Both dietary lecithin and choline chloride supplementation reduced lipid in shrimp muscle. However, only lecithin supplementation increased lipid in hepatopancreas, and dietary choline chloride decreased the level of other phospholipids (except phosphatidylcholine) in shrimp muscle.

Effect of Dietary Phospholipids on Digestion of Neutral Lipid by the Prawn Penaeus monodon

Abstract— Different amounts of dietary phospholipid were tested for their effect on the digestibility of total neutral lipids in the diet of the prawn Penaeus monodon. A purified source of the phospholipid, L‐α‐phosphatidylcholine, was included at 0. 5, 10, 20 or 40 g/kg in a purified diet containing 80 g/kg olive oil as the predominant neutral lipid source. The apparent digestibility of the neutral lipid (ADNL) in these diets was determined by comparing concentrations of the digestibility marker, cholestane in the feed and faeces of the prawns. ADNL (%) increased curvilinearly with increasing dietary phospholipid content (X, %) as described by the equation: ADNL = 80.4 + 9.08X ‐1.705X2 (P &lt; 0.05; R2= 0.71); the asymptote of 92.5% was achieved with a phosphatidylcholine value of 27 g/kg. These results demonstrate that phosphatidylcholine significantly increases the digestibility of neutral lipids by penaeid prawns. However, olive oil was used as the predominant neutral lipid source to examine the effects with a relatively poorly digestible lipid source. The effects of phosphatidylcholine on more readily digested lipid sources such as fish oils, may not be as great, but still be sufficient to improve the utilisation of these nutrients.

Phospholipid-rich butter milk decreases the gastro-intestinal survival and translocation of listeria in rats

Metabolites of phospholipids possess powerful biologic activity towards prokaryotic cells. For instance, they may cause surfactant-induced lysis of cells. Gram-positive bacteria are sensitive to the lyric action of surfactants. In this study we, therefore, investigated the effect of dietary phospholipids on the Gram-positive food-borne pathogen Listeria monocytogenes. Methods: The listericidal effect of lecithin and lysolecithin was tested in vitro by culturing techniques. In addition, male Wistar rats were fed purified diets based on lactase-treated skim milk powder (1.7 lamol phospholipids/g diet) or sweet butter milk powder (10.4 pmol phospholipids/g diet). After adaptation to these diets, animals were orally infected with 4 x 109 CFU Listeria monocytogenes 4B. Results: Lysolecithin, in contrast to lecithin, inhibited growth of Listeria in vitro. Infection parameters in vivo are summarized in the table (* P < 0.05).

Comparison of native, lyso and hydrogenated soybean phosphatidylcholine as phospholipid source in the diet of postlarval penaeus japonicus bate

Native and two modified forms of soybean phosphatidylcholine were used to study the nutritional effect of their fatty acids for postlarval Penaeus japonicus. Five semipurified and isolipidic diets were formulated using casein as a protein source. Three diets contained 1.5 % of different types of phosphatidylcholine (95 % purity), i.e. native soybean phosphatidylcholine, hydrogenated soybean phosphatidylcholine and 1‐acyl lyso soybean phosphatidylcholine, besides 1% of n‐3 highly unsaturated fatty acid formulated as triglycerides. Two negative control diets contained either triglycerides or ethyl esters as a source of n‐3 highly unsaturated fatty acids without phospholipid. The experiment was conducted during two successive phases of 20 d starting from 12‐d old postlarvae. Feeding the diet containing native soybean phosphatidylcholine resulted in significantly better growth and resistance to osmotic shock of P. japonicus postlarvae compared to the other diets. The total lipid content of the tissue was significantly increased by the supplementation of soybean phosphatidylcholine, whereas no significant difference was observed for the shrimp fed the modified phosphatidylcholine sources compared to the phosphatidylcholine‐free diet at the end of the experiment. Shrimp fed the diet containing soybean phosphatidylcholine exhibited a higher polar lipid fraction in the whole body total lipid mainly as a result of the increased proportion of phosphatidylcholine and to a lesser extent of phosphatidylinositol at the expense of free fatty acids, free sterols and sterol esters. The content of 20: 5n‐3, 22 : 6n‐3 and total n‐3 highly unsaturated fatty acids in the shrimp tissue were higher in shrimp fed the native soybean and hydrogenated soybean phosphatidylcholine diets compared to those fed the phosphatidylcholine‐free and 1‐acyl lyso soybean phosphatidyl‐choline‐based diets. The fatty acid profile of tissue phosphatidylethanolamine was more influenced by the type of dietary phosphatidylcholine than that of tissue phosphatidylcholine. In the absence of phospholipids in the diet, triglyceride fish oil and a mixture of ethyl ester concentrate arid coconut oil with similar n‐3 highly unsaturated fatty acids content were equivalent sources of n‐3 highly unsaturated fatty acids. The beneficial effects of dietary phospholipids may be due to a more efficient transport and utilization of dietary neutral lipids through a better lipid mobilization following absorption in the intestinal mucosa rather than due to a better emulsification of neutral lipid in the gut lumen. The functionality of phosphatidylcholine in the diet of postlarval P. japonicus requires the presence of unsaturated fatty acids and an intact fatty acid moiety.

Effect of dietary phospholipid on requirements for and incorporation of n − 3 highly unsaturated fatty acids in postlarval Penaeus japonicus Bate

Penaeus japonicus postlarvae were fed three dietary levels of n − 3 highly unsaturated fatty acids (HUFA) (0, 0.5 and 1%) with or without 1.5% soybean phosphatidylcholine (SPC; 95% purity). The experiment was conducted during two successive phases of 20 days starting with 12-day-old postlarvae. Supplying 1.5% of SPC and 1% n − 3 HUFA in the diet significantly improved the growth, survival and resistance to osmotic stress of postlarvae compared to those fed phosphatidylcholine (PC)-free and HUFA-free diets, respectively. A significant interaction between dietary SPC and n − 3 HUFA was only found for their effect on resistance to osmotic stress. A significant drop in stress sensitivity was obtained in the PC-deprived shrimp only when 1% n − 3 HUFA were present in the diet, whereas the shrimp fed SPC exhibited a drop of stress sensitivity already at a level of 0.5% n − 3 HUFA. Increasing the dietary levels of n − 3 HUFA resulted in increased concentrations in the shrimp tissue of total body lipid content, 20:5 n − 3 and 22:6 n − 3; and reduced levels of 18:2 n − 6 and total n − 6 polyunsaturated fatty acids. Also, the proportion of 20:5 n − 3, 22:6 n − 3 and total n − 3 HUFA significantly increased in the two major shrimp phospholipids, PC and phosphatidylethanolamine (PE), with increasing level of dietary n − 3 HUFA. The changes in whole body total lipid, lipid composition and fatty acid composition of total lipid, PC and PE due to the addition of soybean phospholipid depended on the dietary level of n − 3 HUFA.

Increased docosahexaenoic acid levels in total and polar lipid of European sea bass ( Dicentrarchus labrax ) postlarvae fed vegetable or animal phospholipids

A 6-week feeding trial was conducted with 44-d-old European sea bass (Dicentrarchus labrax L.) in order to examine the effect of various dietary phospholipid (PL) sources on the incorporation of n-3 highly unsaturated fatty acids (HUFA) in tissue lipids. From weaning onwards the fish received diets prepared by coating different lipid fractions (7.5% diet) on an extruded basal diet (92.5% diet). The two PL-free control diets contained 0.5 and 2% of an emulsifier blend, respectively. Seven other diets contained 2% PL, differing by their purity and origin (vegetable or animal). All diets were rendered isolipidic by the addition of hydrogenated coconut oil. Feeding the PL-supplemented diets, except the diet containing hydrolyzed soybean PL (lyso PL), resulted in a higher survival and a 10 to 30% better growth as compared to the PL-free diets. No difference according to the PL origin was observed. The sea bass final lipid content increased with increasing body weight. Also the lipid class composition of the fish was clearly correlated with the final weight gain. Total neutral lipid increased from 51% of total lipid (initial fish) to 76% for fish fed the PL-free diets, and up to 88% for fish fed the sunflower PL. Weaning the fish on the experimental diets induced important changes in their fatty acid profiles characterized by a decrease in 18:3n-3, 20:5n-3 and 20:4n-6 and an increase in saturated fatty acids and 22:6n-3 (DHA). According to the fatty acid composition of both total and polar lipid, the weaned fish could be divided into three groups reflecting the dietary fatty acids: a group fed the vegetable PL, a group fed the animal PL and a PL-deprived group. An effect of dietary PL on the incorporation of dietary n-3 HUFA, more particularly DHA, was noticed. For a similar supply of DHA through the neutral lipids in the diet, fish fed PL-supplemented diets (except for the lyso PL diet) had 10 to 25% higher DHA levels in total and polar lipid than PL-deprived fish. This PL effect was already clear at the end of the weaning and was not related to the presence of n-3 HUFA in the PL source, as suspected in a previous study when feeding egg yolk PL. A better incorporation of DHA was not obtained by replacing the PL by an emulsifier or by lyso PL with higher emulsifying properties. Present results confirm a role of dietary PL in the absorption of dietary neutral lipids, by a mechanism other than emulsification.

Effect of dietary phospholipids and their constituents on bile composition in rats and hamsters.

The formation of cholesterol gallstones is a result of an interaction between bile lipid concentration, composition and other factors. The solubilization of cholesterol in bile is affected by the nature of the fatty acids and head groups of biliary phospholipids. In this study we tried to modulate the composition of biliary lipids in the rat and hamster by means of dietary supplementation of whole phospholipids or their constituents (at 3% to 5% of food weight). A striking effect of ethanolamine feeding in rats and hamsters was demonstrated: Biliary cholesterol concentration and cholesterol saturation index were significantly lower (p < 0.03). In rats, bile acid concentration was increased, contributing to decreased bile lithogenicity. Ethanolamine also increased biliary phospholipid output. Other test substances had less marked effects. The addition of lecithin to rat diet significantly increased phospholipid concentration (p < 0.05) compared with controls. Cholesterol and bile acid concentrations were reduced in palmitic acid-fed hamsters (NS). Choline supplementation insignificantly increased the cholesterol saturation index in hamsters. Despite the clear effect of ethanolamine on biliary lipid composition, no change could be demonstrated in the proportion of phosphatidylethanolamine in bile. It is postulated that ethanolamine was methylated in the liver to choline. Our data demonstrate that biliary lipid composition can be modulated by dietary phospholipids or their components.