Dietary Phospholipid Levels Research Articles

Effects of dietary phospholipid level in cobia (Rachycentron canadum) larvae: growth, survival, plasma lipids and enzymes of lipid metabolism

A study was conducted to determine the effects of dietary phospholipid (PL) levels in cobia (Rachycentron canadum) larvae with regard to growth, survival, plasma lipids and enzymes of lipid metabolism. Fish with an average weight of 0.4 g were fed diets containing four levels of PL (0, 20, 40 and 80 g kg(-1)dry matter: purity 97%) for 42 days. Final body weight (FBW), weight gain (WG) and survival ratio were highest in the 8% PL diet group and mortality was highest in PL-free diet group. We examined the activities of lipoprotein lipase (LPL) and hepatic lipase (HL) in liver, lecithin-cholesterolacyltransferase (LCAT) in plasma as well as plasma lipids and lipoprotein. LCAT activity showed a decrease of more than two-fold in PL-supplemented diet groups compared with the PL-free diet group. HL activity was highest in the 8% PL diet group and the other three groups showed no difference. LPL activity was significantly higher in the PL-supplemented diet groups than in the PL-free diet group. The dietary intervention significantly increased plasma phospholipids and total cholesterol (TC) levels, and the higher free cholesterol (FC) level contributed to the TC level. However, the fish fed PL exhibited a significantly decreased plasma triglyceride (TG) level. The lipoprotein fractions were also affected significantly by the PL. The PL-supplemented diet groups had significantly higher high-density lipoprotein (HDL) compared with the PL-free diet group, but showed a marked decrease in very low-density lipoprotein (VLDL). The results suggested that PL could modify plasma lipoprotein metabolism and lipid profile, and that the optimal dietary PL level may well exceed 80 g kg(-1) for cobia larvae according to growth and survival.

Effects of dietary phosphorus and phospholipid level on growth, and phosphorus deficiency signs in juvenile Japanese flounder, Paralichthys olivaceus

A growth experiment was carried out to investigate the effect of dietary phosphorus (P) and phospholipid (PL) concentration, as well as their potential interaction, on growth, feed intake, survival and lipid class composition of whole body and liver in juvenile Japanese flounder. Calcium monophosphate and purified PL (Soybean lecithin acetone insoluble, 88.6% purification) were the P and PL sources, respectively. Nine semi-purified diets were supplemented with 3 levels of inorganic-P (IP) and purified PL, and growth performances were monitored in a 40 day growth trial by using 1 g fish. Results indicated that final weight, weight gain and feed intake significantly increased with increasing P and PL level in the diet. No significant interaction between the two factors on growth, feed intake and survival was observed. Fish fed the diet containing 1.65% P and 5.2% PL gave maximum growth. Ash and P content of whole body decreased in the fish fed the lower P diets. Malformations were observed in opercula of fish fed the non-IP supplemented diets with or without PL supply. Based on scanning electron microscopy observations, the fish fed P-deficient diet showed relatively more perforated spongy area compared to those fed P-sufficient diet. The present study demonstrated that there was no interaction between dietary P and PL on the parameters measured, and dietary PL supplementation is beneficial for growth of juvenile Japanese flounder (1 to 18 g). Phosphorus deficiency signs were characterized by poor growth, deformed operculum, decreased bone mineralization and increment in whole body lipid content in juvenile Japanese flounder.

Effect of dietary phospholipid level on the development of gilthead sea bream (Sparus aurata) larvae fed a compound diet

The aim of the study was to determine the influence of dietary phospholipid (PL) levels on survival and development of first feeding gilthead sea bream (Sparus aurata) larvae. Larvae were fed from day 4 to 23 posthatching with an isoproteic and isolipidic formulated diet with graded levels of PL from 90-150 g kg(-1) dry matter (DM). A dietary PL content of more than 90 g kg(-1) DM seems to be necessary for sustaining growth of first feeding sea bream larvae. The survival rates of larvae fed the formulated diets (31-40% at day 23) were similar to those generally observed in marine aquaculture hatcheries with live prey feeding sequence. However, this high survival rate was not associated with high growth and the larvae showed, at the end of the study, a high proportion of individuals with abnormal liver and calculi in the urinary bladder. It is concluded that although the diets used here cannot be used in total replacement of live preys, they constitute a solid starting point for further nutritional studies with first feeding gilthead sea bream larvae.

Dietary value of different vegetable oil in black tiger shrimp Penaeus monodon in the presence and absence of soy lecithin supplementation: Effect on growth, nutrient digestibility and body composition

Sunflower oil, peanut oil, palm oil and sardine oil were evaluated for their dietary value in juvenile Penaeus monodon in the presence or absence of soy lecithin (SL). Eight isonitrogenous and isocaloric diets were formulated to contain each of the oils as the lipid source. Evaluation was based on the growth performance of shrimp (for 42 days) and apparent digestibility coefficients (ADC). The ADC of the diets was determined by comparing concentrations of the digestibility marker, chromic oxide in the feed and faeces of the shrimp. Shrimps fed diets containing vegetable oil with SL had significantly higher values ( P < 0.05) than those fed diets containing the same oil without SL in all the performance parameters tested. No significant differences ( P > 0.05) were observed among SL supplemented dietary treatments, although weight gain and feed efficiency were higher in shrimp fed diets containing peanut oil (PNL) and sardine oil (FOL) respectively. Among the dietary treatments without SL, shrimp fed sardine oil diet (FO) had significantly ( P > 0.05) higher values than other diets in all the performance parameters tested which did not differ from those fed SL supplemented diets. There was no significant difference ( P > 0.05) in survival of shrimp among the dietary treatments. Though apparent dry matter digestibility (ADMD) was not significantly differed among dietary oils, there exists a significant difference in ADC for crude protein, crude lipid and energy. All SL supplemented diets showed a marked increase in apparent crude lipid digestibility (ACLD) than the diets without SL. A high correlation was found between dietary phospholipid (PL) level and ACLD ( r = 0.95; P < 0.05) of the experimental diets. Carcass composition of shrimp fed the different vegetable oil sources was similar. However, the lipid content was higher in the shrimp fed diets containing FO and FOL. The fatty acid composition of the test diets was reflected to a certain extent in the fatty acid composition of whole shrimp. The findings of the present work have shown that, shrimp fed vegetable oil supplemented with SL had significantly higher growth and nutrient digestibility comparable to that of sardine oil without SL.

Effect of dietary phospholipid level and phospholipid:neutral lipid value on the development of sea bass (Dicentrarchus labrax) larvae fed a compound diet.

The aim of the study was to determine the influence of dietary phospholipid concentration on survival and development in sea bass (Dicentrarchus labrax) larvae. Larvae were fed from day 9 to day 40 post-hatch with an isoproteic and isolipidic formulated diet with graded phospholipid levels from 27 to 116 g/kg DM and different phospholipid:neutral lipid values. The best growth (32 mg at the end of the experiment) survival (73 %) and larval quality (only 2 % of malformed larvae) were obtained in the larvae fed the diet containing 116 g phospholipid/kg DM (P<0.05). These results were related to the amount of phosphatidylcholine and phosphatidylinositol included in this diet (35 and 16 g/kg respectively). Amylase, alkaline phosphatase and aminopeptidase N activities revealed a proper maturation of the digestive tract in the two groups fed the highest phospholipid levels. Regulation of lipase and phospholipase A2 by the relative amount of their substrate in the diet occurred mainly at the transcriptional level. The response of pancreatic lipase to dietary neutral lipid was not linear. As in mammals 200 g triacylglycerol/kg diet seems to represent a threshold level above which the response of pancreatic lipase is maximal. The response of phospholipase A2 to dietary phospholipid content was gradual and showed a great modulation range in expression. Sea bass larvae have more efficient capacity to utilize dietary phospholipid than neutral lipids. For the first time a compound diet sustaining good growth, survival and skeletal development has been formulated and can be used in total replacement of live prey in the feeding sequence of marine fish larvae.

Maturation performance, offspring quality and lipid composition of Macrobrachium rosenbergii females fed increasing levels of dietary phospholipids.

The effects of increasing levels of dietaryphospholipids (PL) on the reproductive performance,egg and larval quality, and lipid composition offemales of the freshwater prawn Macrobrachiumrosenbergii were investigated. Three isolipidic dietscontaining similar amounts of highly unsaturated fattyacids but varying levels of PL (0.8, 2.4 and 4.6%)were fed during 180 days to three groups of eightfemales originating from Thai ponds. No significantdifferences were observed for fecundity, egg size andhatchability, starved larvae size, and size, survivaland tolerance to stress of 8 day-old larvae.Similarly, no major differences in the lipidcomposition of the midgut gland, ovaries and muscletissue of females could be detected. Results indicatethe lack of need of dietary supplementation of PL forM. rosenbergii broodstock, as previouslyreported for earlier life stages. It is suggested thatthe basal level of 0.8% dietary PL was sufficient tomeet the dietary demands of the prawn broodstock. ThePL requirements of M. rosenbergii broodstock, ifany, may be satisfied in commercial feeds through theinclusion of ingredients containing some phospholipidsendogenously.

Enhanced absorption of docosahexaenoic acid (DHA, 22:6n-3) in Artemia nauplii using a dietary combination of DHA-rich phospholipids and DHA-sodium salts

The effects of surface-active agents such as phospholipids (PL) and salts of long chain fatty acids in enrichment lipids on emulsification, and hence digestion and absorption of essential fatty acids (EFA) were studied. The advantages obtained by using a mixture of docosahexaenoic acid (DHA, 22:6n-3)-rich phospholipids (DHA-PL) and DHA-salts in the process of live feed enrichment are reported on. Enrichment diets at equal levels of DHA, but with varying proportions of DHA-rich triacylglycerols (DHA-TAG), DHA-PL and DHA-sodium salt (DHA-Na) isolated from heterotrophicaly grown Crypthecodinium sp . algae were fed to instar-II stage Artemia nauplii. Artemia nauplii survival and lipid content after 16 h of enrichment were 74.0±7.8% and 24.3±0.6% (dry weight) respectively, and not significantly affected ( P>0.05) with increasing dietary quantities of PL and DHA-salts (up to 40 and 30%, respectively). Artemia lipid class composition was independent of dietary phospholipid level. However, higher proportions of polar lipid fraction was evident in Artemia lipids with the addition of DHA-Na. Dietary inclusion of 20% PL or a mixture of 10% PL and 10% DHA-Na resulted in maximal ( P<0.05) absorption of dietary DHA by the Artemia (27.5±2.6 mg/g dry weight) with a DHA to eicosapentaenoic acid (EPA, 20:5n-3) ratio greater than 3. Furthermore, PL was the most efficient dietary fraction to deliver DHA to Artemia nauplii as compared to TAG or unesterified delivery forms.

Effects of dietary lipids, fatty acids, and phospholipids on growth and survival of prawn ( Penaeus japonicus) larvae

The effects of lipids, fatty acids, and phospholipids on growth and survival of larvae of the prawn, Penaeus japonicus, were examined using purified diets containing carrageenan as a binder. P. japonicus larvae did not metamorphose to post-larvae and died in 7 days when fed the diets containing no phospholipid. Growth and survival rate of the prawn larvae were improved by the addition of soybean phosphatidylcholine (PC) to the diets containing 18:1ω9 and essential fatty acids (EFA), or pollack liver oil (PLO) as lipid sources. These results suggest that P. japonicus larvae probably require dietary sources of some phospholipids for growth and survival. The efficacy of phospholipids in improving growth and survival varied with the kinds and sources of phospholipids. Bonito-egg PC, soybean PC, and soybean phosphatidylinositol (PI) had a high efficacy, whereas chicken-egg PC was ineffective. Ovine-brain phosphatidylserine, bonito-egg phosphatidylethanol-amine (PE), and ovine-brain PE improved slightly growth and survival of P. japonicus larvae. The PC and PI containing high proportions of ω6- and ω3-fatty acids as constituents were thought to be effective in improving growth and survival of the prawn larvae. The optimum level of soybean PC for P. japonicus larvae varied with the kinds of coexistent dietary lipids. The best growth and survival were attained on the diets containing 6.0% soybean PC when 18:1ω9 and 1.0% highly unsaturated fatty acids were used as basal lipids. But the inclusion of 3.5% soybean PC was enough to attain optimum growth and survival when PLO was used as the lipid source. The present study did not give a clear picture of the EFA requirements of P. japonicus larvae, although they seemed to vary with dietary phospholipid levels.