Fatty Acid Composition Of Larvae Research Articles

The influence of feeding media enriched with different oils on the fatty acid composition of the Black soldier fly (Hermetia illucens)

The black soldier fly (Hermetia illucens) has emerged as an interesting alternative protein source in animal feed due to its ability to grow on various substrates. Although it has many rearing benefits and possible applications, it has an unfavourable fatty acid profile if used for human consumption due to its high content of lauric acid and low content of polyunsaturated fatty acids. In order to investigate whether the lipid composition of black soldier fly larvae can be altered, the feeding media were supplemented with varying concentrations of fish, linseed or coconut oil (1, 2.5 and 5%). Two-week-old larvae were collected, measured and their tissue fatty acid composition was determined. The fatty acid profile of the larvae showed significant plasticity, depending on the life stage and the fatty acid composition of the feeding media. The addition of 2.5 and 5% of different oils significantly changed the fatty acid composition of larvae, depending on the type and percentage of oil. The n6/n3 ratio was considerably improved by supplementing fish and linseed oil. The addition of linseed oil increased the content of linolenic acid, but bioconversion to eicosapentaenoic and docosahexaenoic acids was low. In contrast, the addition of fish oil significantly increased the content of eicosapentaenoic and docosahexaenoic acids in the larvae. The content of lauric acid significantly increased after coconut addition. The trial showed that by using different oils, the lipid composition of black soldier fly larvae could be specifically changed to increase the beneficial long chain n3 polyunsaturated fatty acids, and the amount of lauric or linolenic acid.

Nutritional programming by maternal diet alters offspring lipid metabolism in a marine teleost

Nutritional programming - the association between the early nutritional environment and long-term consequences for an animal - is an emerging area of research in fish biology. Previous studies reported correlations between maternal provisioning of essential fatty acids to eggs and the whole-body fatty acid composition of larvae reared under uniform conditions for red drum, Sciaenops ocellatus. This study aimed to further investigate the nutritional stimulus and the consequences of nutritional programming by feeding adult red drum several distinct diets and rearing larvae under uniform conditions until 21days post-hatching when larval lipid and fatty acid compositions were assessed. Different maternal diets produced eggs with distinctive lipid and fatty acid compositions, and despite receiving the same larval diet for almost 3weeks, larvae showed differences in total fatty acid accumulation and in retention of highly unsaturated fatty acids (HUFA). Specifically, larvae reared from a maternal diet of shrimp generally showed elevated levels of fatty acids in the initial steps of the n-3 and n-6 HUFA biosynthetic pathways and reduced levels of fatty acid products of the same pathways, especially in triglyceride. Furthermore, the variations in larval fatty acid accumulation induced by maternal diet varied among females. Lipid metabolism altered by parental diet may have consequences for larval physiological processes and behavioral performance, which may ultimately influence larval survival.

Effects of Rotifers Enriched With Different Enhancement Products on Larval Performance and Jaw Deformity of Golden Pompano Larvae Trachinotus ovatus (Linnaeus, 1758)

This study evaluated the effects of rotifers enriched with three enhancement products (Nannochloropsis, S.presso, and Algamac 3080) on the body fatty acid composition, growth, survival, jaw deformity, and bone development-related gene expression of the golden pompano larvae. The rotifers enriched with Nannochloropsis were rich in EPA, and the rotifers enriched with S.presso and Algamac 3080 were rich in docosahexaenoic acid (DHA). The level of DHA in Algamac 3080 is higher than that in S.presso. The first feeding started at 3 DPH, and data were collected at 8 DPH. The results showed that the body fatty acid composition of the larvae was basically the same as that of the feeding rotifers. The specific growth rate of S.presso and Algamac 3080 treatment was significantly higher than the un-enriched treatment (P < 0.05). The survival rate of Algamac 3080 treatment was significantly lower than the other treatments (P < 0.05), and the jaw deformity rate of S.presso treatment was significantly lower than the Nannochloropsis and un-enriched treatment (P < 0.05). The expression level of BMP2 and BMP4 in golden pompano larvae were not significantly affected by the enhancement products (P > 0.05), and the expression level of RXRα decreased significantly in the S.presso and Algamac 3080 treatment (P < 0.05). This study indicates that S.presso was an enhancement product more suitable for rotifers for golden pompano larvae. This study provided reliable reference and guidance for the first feeding of golden pompano larvae and also provided more reference data for the study of the mechanism of diet on larval fish bone deformity.

Effect of temperature on fatty acid composition and development of unfed Siberian sturgeon (A.baerii) larvae

The fatty acid metabolism in fish is influenced by various factors, including fish species, water temperature, water environment and diet supply. The aim of present work is to investigate the fatty acid composition of yolk-stage Siberian sturgeon larvae reared at three different temperatures. Fertilized Siberian sturgeon eggs were transferred to the Lodi Aquaculture Research Center of the University of Milan, divided in three aquaria, each containing three incubators and incubated at 16°C. After hatching the temperature was switched to 16, 19 and 22°C. Larvae sampling was performed at the end of yolk sac reabsorption. No feed was dispensed during the trial. Eggs and larvae were weighed and fatty acid profile was determined by GC-FID analysis after lipid extraction by chloroform/methanol mixture and fatty acid transesterification by methanolic hydrogen chloride. The fertilized eggs had a weight of 23.27 mg and a lipid content of 2.67 mg/egg. At hatching, the weight was 12.2 (0.17 SD) mg and lipid content 1.9 (0.6 SD) mg/larva. At the end of the trial, larvae mean weight was 33.6 (3.6 SD), 34.7 (1.8 SD) and 36.9 (1.1 SD) mg, while lipid content was 2.0 (0.3 SD), 2.1 (0.3 SD) and 2.0 (0.2 SD) mg for larvae reared at 16, 19 and 22°C respectively, without statistically significant difference. Larvae subjected to the highest water temperature showed a faster yolk-sac absorption. No differences were found across temperatures regarding survival rates and regarding ontogenic development. The fatty acid composition of larvae was affected by the temperature. Larvae reared at 16°C had the lowest amount of saturated fatty acids, mainly due to a lower palmitic acid content, that was offset by a higher level of linolenic and linoleic acid, if compared with larvae reared at 19°C and 22°C. The study suggests that at a lower temperature sturgeon spare unsaturated fatty acid consuming preferably saturated fatty acids, increasing our knowledge of the fatty acid metabolism in this species.

Effects of different mono, bi and trispecific microalgal diets on survival, growth, development, settlement and fatty acid composition of mussel Mytilus galloprovincialis (Lamarck, 1819) larvae

Abstract Based on the microalgae Isochrysis galbana clone T-iso (Ti), Chaetoceros gracilis (Cg) and Tetraselmis suecica (Ts), in the present investigation 8 different feeding regimes were trialed for Mytilus galloprovincialis larval culture: starvation, 3 monospecific diets (Ti; Cg; Ts), 3 bispecific diets (Ti + Cg; Ti + Ts; Cg + Ts) and the trispecific diet Ti + Cg + Ts. The effect of these feeding regimes on several culture parameters (survival, growth, development, competency and settlement) was assessed, and total lipid and fatty acid composition of larvae were analyzed. Our results revealed that specimens were not able to feed on Ts during their earliest development phases, and cultures deprived of ingestible food showed signs of starvation at 8–9 days post fertilization. The diets Ti + Cg, Cg + Ts and Ti + Cg + Ts showed better results than the rest in one or more culture parameters. Although the presence of Cg in a mixed diet seemed to be advantageous, the monospecific diet Cg entailed unexpected larval crushes as well as competency and settlement impairments. The comparative analysis of fatty acid compositions of larvae and diets provided showed that: (i) larvae have a certain capacity for fatty acid regulation, including some de novo biosynthesis; (ii) larvae seem to gain new synthesis capacities with metamorphosis, and (iii) the lack of some polyunsaturated fatty acids (especially docosahexaenoic acid), together with excessive levels of arachidonic acid, might have caused the poor results obtained with the monospecific diet Cg.

Ontogenetic patterns of growth and lipid composition changes of blue swimmer crab larvae: insights into larval biology and lipid nutrition

Blue swimmer crab, Portunus pelagicus, is a commercially important crab throughout the Indo-Pacific region, that plays an important role in the food chains of coastal ecosystems. P. pelagicus undergoes four pelagic zoeal stages and a post-larval megalopal stage before settling as benthic juvenile; however, very limited information is available on larval biology and lipid nutrition of this species. The present comprehensive study investigated survival, growth and ontogenetic changes in lipid composition of P. pelagicus larvae under laboratory conditions. Larvae were fed rotifers (zoea I), rotifers and Artemia (zoea II) and enriched Artemia (zoea III – megalopa), consecutively. Among five larval stages of P. pelagicus, zoea I and II had the shortest durations (2.2–2.3 days), whereas megalopa had the longest duration (4.7 days). As larvae developed, their wet weight, dry weight and carapace length increased exponentially. Lower mortality occurred during zoea II (12.5%) and zoea III (14.3%), coincidental with the lower percentage increments in dry weight and specific growth rate of dry weight during these two stages. Generally, fatty acid composition of larvae can reflect that of their diets. However, increases in mono-unsaturated fatty acids, 20 : 4n-6 and 22 : 6n-3 in megalopa and the first crab compared with zoea IV might suggest that the later larvae were still deficient in essential fatty acids, and that 20 : 4n-6 and 22 : 6n-3 were preferentially accumulated. Therefore, measures of ontogenetic patterns of growth and lipid composition will provide valuable insights for better understanding of larval biology and lipid nutrition of P. pelagicus.

Fatty acids in anopheline mosquito larvae and their habitats

Larvae of the three important Central American malaria vectors, Anopheles albimanus, An. vestitipennis, and An. darlingi, are found in distinctly different habitats broadly defined by hydrology and aquatic vegetation, but little is known about the actual food quality and quantity of these habitats. Polyunsaturated fatty acids (PUFA) are of special interest, because mosquitoes require 20:5ω3 (EPA), 20:4ω6 (ARA), and 22:6ω3 (DHA) and without an adequate supply of these PUFAs they are not able to complete their life cycle. We collected samples of larvae and their corresponding habitats and analyzed their fatty acid (FA) composition to reveal if there are any species-specific and habitat-specific differences in FA composition, and if habitat FA differences can be linked to differences in the mosquito FA pattern and, ultimately, mosquito performance. We also assessed how FA of wild larvae compare to the laboratory-reared larvae. Habitats were generally low in essential PUFAs and there were no significant differences among the FA composition of habitat samples. There were significant differences in FA composition of larvae. An. darlingi contained significantly higher amounts of FA, specifically a higher content of ω-6 PUFA, represented mainly by the linoleic acid (18:2ω-6). Large differences were found between field-collected and laboratory-reared An. vestitipennis larvae, especially in the content of PUFAs. The laboratory-reared larvae contained significantly more of the total FA, ω3 PUFA, and MUFA. The laboratory-reared larvae contained three to five times more essential PUFAs, EPA, and DHA. However, there were no differences in the total dry weight of the 4(th) instar larvae between the wild vs laboratory-reared larvae. Total FA in both larvae and habitats of An. albimanus and An. darlingi were positively correlated with the concentration of particulate organic carbon and nitrogen (POC, PON) in their respective habitats, but no such correlation was found for An. vestitipennis. PUFA are a good indicator of nutritional quality, although factors controlling the success of anopheline development from larval habitats are likely to be more complex and would include the presence of predators, pathogens, and toxins as interacting factors.

Effects of calanoid copepod Schmackeria poplesia as a live food on the growth, survival and fatty acid composition of larvae and juveniles of Japanese flounder, Paralichthys olivaceus

Zooplankton constitutes a major part of the diet for fish larvae in the marine food web, and it is generally believed that copepods can meet the nutritional requirements of fish larvae. In this study, calanoid copepod Schmackeria poplesia, rotifer Brachionus plicatilis and anostraca crustacean Artemia sp. were analyzed for fatty acid contents, and were used as live food for culturing larval Japanese flounder, Paralichthys olivaceus. The total content of three types of HUFAs (DHA, EPA and ARA) in S. poplesia was significantly higher than that in the other two live foods (P<0.01). Three live organisms were used for raising larvae and juveniles of Paralichthys olivaceus respectively for 15 and 10 d. Then the growth, survival and fatty acid composition of the larvae and juveniles were investigated. The results showed that the larvae and juveniles fed with copepods (S. poplesia) had significantly higher growth rate than those fed with the other two organisms (P<0.01). The survival of the flounder larvae fed with copepods was significantly higher than that of the others (P<0.01), and the survival of the juvenile fish fed with copepods was higher than that fed with Artemia (P<0.05). The contents of three types of HUFAs (DHA, EPA and ARA) and the ratio of DHA/EPA in larval and juvenile flounder P. olivaceus were analyzed. The results showed that the contents of DHA, EPA and ARA in the larvae and juveniles fed with S. poplesia were higher than those fed with a mixed diet or Artemia only, and the ratio of EPA/ARA in larvae and juveniles of P. olivaceus fed with S. poplesia was lower than that in the case of feeding with a mixed diet or Artemia only. The present data showed that copepod is the best choice for feeding the larvae and juveniles of fish considering its effects on the survival, growth and nutrition composition of the fish.

Fatty acid composition of larvae of the sand dollar Dendraster excentricus (Echinodermata) might reflect FA composition of the diets

Fatty acid (FA) requirements of echinoderm larvae were examined by a study of the FA composition, growth, and development of Dendraster excentricus larvae fed a microencapsulated diet, and two algal diets. Larvae were assigned to three treatments with three replicates per treatment, a microencapsulated diet, a single algal diet of Dunaliella tertiolecta and a mixed algal diet of Isochrysis galbana and Dunaliella tertiolecta. The percentage of saturated fatty acids (SAFA), short and long chain polyunsaturated fatty acids (PUFA) differed significantly among the algal diets and the microencapsulated diet. Differences in dietary FA composition influenced larval tissue FA composition. Eight day-old sand dollar larvae fed the single and mixed algal diets had a significantly higher percentage of the SAFA myristic acid (14:0), while eight day-old larvae fed the microencapsulated diet had a significantly higher percentage of the SAFA palmitic acid (16:0). Sixteen day-old competent larvae fed all three diets did not differ significantly in the percentage of myristic or palmitic acid. The algal diets had a higher percentage of the short chain PUFAs linolenic (LNA, 18:3n-3) and stearidonic acid (SDA, 18:4n-3) while the microencapsulated diet had the highest percentage of the long chain PUFAs eicosapentanoic acid (EPA, 20:5n-3) docosahexanoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6). The percentage of short chain PUFAs, though high in the algal diets, was low in the larval tissues, while the percentage of long chain PUFAs, though low in the algal diets, was high in the larval tissues. Competent larvae fed the two algal diets had up to ten times the percentage of EPA and AA than those fed the microencapsulated diet. Unexpectedly, despite a high percentage of DHA and EPA in the microencapsulated diet, the percentage of these long chain PUFAs in the tissues of larvae fed this diet was extremely low. Eight day-old larvae fed the three diets did not differ significantly in total larval length. Competent larvae fed algal diets had significantly longer larval arms, bigger stomachs and larger rudiments than those fed the microencapsulated diet. This study indicates that early larval growth and development of Dendraster excentricus were not discernibly affected by differences in dietary FA composition of microencapsulated and algal diets but the competent larval stages were. Similar growth and development of competent echinoderm larvae fed microencapsulated or algal diets might be obtained by enriching the microencapsulated diets with the short chain PUFAs LNA and SDA, and the long chain PUFAs EPA and AA. This is an important research tool as microencapsulated feeds can be used to establish nutritional requirements of fatty acids for echinoderm larval development.

The predominance of polyunsaturated fatty acids in the butterfly Morpho peleides before and after metamorphosis

We hypothesized that the polyunsaturated fatty acids of the butterfly were probably derived from the diet and that there might be a great loss of body fat during metamorphosis. To substantiate these hypotheses, we analyzed the fatty acid composition and content of the diet, the larva, and the butterfly Morpho peleides. Both the diet and the tissues of the larva and butterfly had a high concentration of polyunsaturated fatty acids. In the diet, linolenic acid accounted for 19% and linoleic acid for 8% of total fatty acids. In the larva, almost 60% of the total fatty acids were polyunsaturated: linolenic acid predominated at 42% of total fatty acids, and linoleic acid was at 17%. In the butterfly, linolenic acid represented 36% and linoleic acid represented 11% of total fatty acids. The larva had a much higher total fatty acid content than the butterfly (20.2 vs. 6.9 mg). Our data indicate that the transformation from larva to butterfly during metamorphosis drastically decreased the total fatty acid content. There was bioenhancement of polyunsaturated fatty acids from the diet to the larva and butterfly. This polyunsaturation of membranes may have functional importance in providing membrane fluidity useful in flight.

Stable isotopes and fatty acids reveal thatChironomus ripariusfeeds selectively on added food in standardized toxicity tests

During long-term standardized toxicity tests with Chironomus riparius, food additions are a prerequisite for normal development and to avoid false-positive results. Consequently, larvae may selectively feed on added food rather than on contaminated sediment, which may confound toxicity test results. We designed a feeding study and estimated the degree of feeding on different food resources by using stable isotope and fatty acid (FA) analyses. In one treatment, larvae were offered both artificial sediment (peat, kaolin clay, sand, and calcium carbonate) and added food (TetraPhyll), whereas larvae in the two other treatments had access to either one of these potential food items. The highest biomass and survival were found among larvae with access to both artificial sediment and TetraPhyll. Two-source mixing models revealed that larval Chironomus that were offered both TetraPhyll and artificial sediment obtained 94 +/- 6.9% of their carbon and 90 +/- 4.3% of their nitrogen from added TetraPhyll. Larvae with access to only sediment had lower delta13C and delta15N (-23.34 +/- 0.56 per thousand and 0.33 +/- 0.52 per thousand) than those that were offered both sediment and TetraPhyll (-20.95 +/- 0.13 per thousand and 7.45 +/- 0.36 per thousand) or only TetraPhyll (-20.17 +/- 0.20 per thousand and 7.82 +/- 0.15 per thousand). In addition, FA composition of larvae that were offered both artificial sediment and TetraPhyll closely resembled that of those fed exclusively TetraPhyll. These results show that larval Chironumus strongly prefer added food, rather than artificial sediment in long-term toxicity tests. This preferential feeding behavior affects exposure pathways and ultimately toxicity test results.

First feeding of winter flounder ( Pseudopleuronectes americanus) larvae: use of Brachionus plicatilis acclimated at low temperature as live prey

Brachionus plicatilis are used as live prey for rearing winter flounder larvae at first feeding. This rotifer is grown between 20 and 25 °C (its optimal growth temperature) and then introduced into the 10 °C water in which larvae are reared. The rapid thermal difference between the two media is thought to reduce B. plicatilis quality and consequently affect larval rearing efficiency. In order to optimize larval rearing, a study was conducted to compare the effects of two different diets on larval growth performance and nutritional condition: (1) larvae fed B. plicatilis reared at 24 °C and (2) larvae fed B. plicatilis reared at 24 °C but acclimated overnight at 10 °C. Comparisons were undertaken using morphometric measurements, nucleic acid (RNA/DNA) ratios, total protein content, trypsin activity, and triacylglycerol/sterol ratios. Fatty acid composition of larvae was also studied with a focus on the levels and ratios of three essential fatty acids (docosahexaenoic acid or DHA, eicosapentaenoic acid or EPA, and arachidonic acid or AA). Unique information regarding trypsin activity and lipid components (phospholipid, triacylglycerol, and sterol) of winter flounder larvae is provided in this study. Trypsin activity was detected very early in larvae and was not affected by acclimation of prey. Phospholipid, triacylglycerol, and sterol composition showed no significant difference between the two diets tested and was characterized by high phospholipid content as well as low triacylglycerol and sterol contents. EPA, DHA, AA, DHA/EPA, and DHA/AA decreased from days 12 to 26. Interestingly, DHA content was significantly higher in larvae fed acclimated rotifers and AA content decreased significantly in 26-day-old larvae fed acclimated B. plicatilis. Overall results indicate that overnight acclimation of B. plicatilis at 10 °C is not important for optimizing the rearing of winter flounder larvae although it does influence the fatty acid composition.

Differences in the fatty acid composition of larvae and metamorphosing sea lampreys, Petromyzon marinus

This study was designed to evaluate biochemical changes in the fatty acid (FA) compositions of selected lipid depot (kidney and liver) and absorption (intestine) organs in larvae and metamorphosing sea lamprey, Petromyzon marinus. Palmitic or stearic acids were generally the predominant saturated fatty acids (SFA) before and during metamorphosis, but the greatest proportion of myristic acid occurred in renal triacylglycerol (TG). Monoenes, dienes, and polyenes consist mainly of 16:1, 18:1, and 20:1, 18:2 and 20:2ω6, and 18:4ω3, respectively. Alterations in these predominant fatty acids occurred during lamprey metamorphosis, but depended on tissue, lipid class, and developmental status. During metamorphosis, kidney TG and phospholipid (PL) classes tended to mobilize SFA and enhance the fatty acid unsaturation, as indicated by increased unsaturated/saturated ratio, unsaturation index (USI), and total mean chain length (MCL). There was a tendency to increase saturation in the fatty acids of liver TG and PL classes and intestine TG, FA and monoacylglycerol (MG) classes, but to increase unsaturation in the fatty acids of liver cholesteryl ester (CE), FA and MG classes and intestine PL and CE classes from larva or stage 3 to stage 7. Increased polyunsaturated fatty acids in kidney TG and PL from larvae to stage 5 transformers and intestine PL and CE from stage 3 to stage 7 transformers may reflect an osmoregulatory pre-adaptation. The presence of branched-chain SFA (BCSFA) and the odd number of fatty acids (ONFA) indicated a significant role of detritivores in the benthic larvae. Decreased abundance of BCSFA, ONFA, and 18:2 dienes occurred in the transformed intestine TG as non-trophic metamorphosis proceeded. These data suggest that sea lamprey metamorphosis may proceed in a habitat, dietary, osmoregulatory, energetic, and developmental pre-adaptation of fatty acid composition from benthic filter-feeding larvae to pelagic parasitic juveniles.

Fatty acid composition of herring (Clupea harengusL.) larvae off Western Norway

Abstract Herring larvae (Clupea harengus L.) were collected off western Norway in April 1991, 1992, and 1993. The larvae were length measured, staged and analysed individually for fatty acid content. Both absolute and relative amounts of individual fatty acids were used as input in principal component analyses (PCA), and the results revealed significant size and stage specific trends in composition. These differences were attributed to the same fatty acids all three years. Qualitative differences in the fatty acid composition of larvae with above average and below average total fatty acid content within respective developmental stages indicate possible maternal effects and effects of previous feeding history. The efforts on using fatty acid profiles as nutritional indices of the individual herring larvae will therefore be continued.

First feeding of Atlantic halibut ( Hippoglossus hippoglossus) using different combinations of Artemia and wild zooplankton

Larvae of Atlantic halibut were offered different combinations of Artemia and wild Zooplankton during first feeding to examine the effects on feeding incidence, growth, survival and pigmentation. Free amino acid and fatty acid composition in feeds and fish larvae were also analysed. The free amino acid concentration in unenriched Artemia averaged 45 μmol/g w.w., compared to 116 μmol/ g w.w. in the wild Zooplankton. Super Selco ™ (Artemia Systems, Belgium)-enriched Artemia increased the concentration to 57 μmol/g w.w. on average, and also increased the lipid content in Artemia to approximately the levels found in wild Zooplankton (3.0% of wet weight), though with a much lower n − 3 PUFA content. Larvae fed 19 days on enriched Artemia (EA) were significantly larger than larvae fed wild Zooplankton (Z), wild Zooplankton for 7 days then unenriched Artemia (Z7) or unenriched Artemia (UA). The EA group also showed the best survival at day 19, 28.7% (19.9–34.4%) compared to 14.0% (13.2–14.7%) in the Z group and 13.6% (10.5–18.3%) in the Z7 group. Also the UA group had significantly higher survival 22.8% (18.8–25.5%) than the Z group, but showed slower growth. The fatty acid composition of larvae fed Artemia showed a development towards the composition of their feeds, while the fatty acid composition in the larvae fed wild Zooplankton remained relatively similar to that of prefed larvae. After 57 days of feeding, high frequencies of malpigmented juveniles were observed in the UA and EA groups (95.7 and 70.6%, respectively) as well as in the Z7 group (80.8%). All larvae fed wild Zooplankton or larvae transferred from an unenriched Artemia diet to a diet of wild Zooplankton from day 19 onwards, became normally pigmented. The present experiment showed that use of Artemia could be successful in providing growth and survival in the early larval stage of exogenous feeding in Atlantic halibut, but had negative effects on pigmentation later on. However, by introduction of wild Zooplankton prior to a critical stage (found to be beyond 19 days of feeding) these effects could be eliminated.

The Effects of Enriching Live Foods With Highly Unsaturated Fatty Acids on the Growth and Fatty Acid Composition of Larval Red Drum Sciaenops ocellatus

AbstractThree experiments were carried out to test the effects of enrichment of live food (rotifers) with varying levels of n‐3 highly unsaturated fatty acids (HUFA) on the growth rate and fatty acid composition of red drum larvae. Additionally, the fatty acid compositions of red drum eggs and day‐1 larvae were compared. The enrichment techniques were successful in that the levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were elevated in the rotifers fed the enrichment diet. Red drum larvae fed the control rotifers produced the highest growth rate of the three experiments. Larvae fed rotifers with no HUFA supplement (NHUFA) had a significantly lower growth rate than the controls for that experiment. The fatty acid compositions of the eggs and day‐1 larvae did not vary significantly and contained high levels of 16:0, 16:1 n‐7 and DHA (22:6 n‐3). Based on these data, the lack of DHA in the diet significantly reduced the growth rates of larval red drum. The 10‐day‐old red drum larvae had similar fatty acid profiles at the end of the experiments regardless of the diet they were fed, indicating that dietary inputs have little effect on the fatty acid composition of larvae during the first ten days of growth. Red drum larvae appear to have the ability, though limited, to bioconvert EPA to DHA since there was a significant increase in the levels of DHA from day 1 to day 10 in the NHUFA larvae. However, the efficiency of this bioconversion is not sufficient for optimal growth and supplemental DHA at least to the level found in the control rotifers (0.3–0.4mg/100mg tissue) is necessary to maximize growth. The exact role of EPA could not be determined from this study due to the inability to produce an EPA‐free rotifer.

The effect of monospecific algal diets on growth and fatty acid composition of Pecten maximus (L.) larvae

Four batches of Pecten maximus (L.) larvae were grown under hatchery conditions and fed the monospecific diets Pavlova lutheri Droop, Isochrysis aff. galbana Green (clone T-iso; termed Tahitian Isochrysis), Chaetoceros calcitrans Takano and Dunaliella tertiolecta Butcher which were selected on their very different polyunsaturated fatty acid (PUFA) profiles. Neutral and polar lipid PUFA compositions of larvae were influenced by diets. The constant level of ( n-3) PUFA in neutral lipids of larvae although very different in the diet indicated that neutral lipid composition was partially controlled by the larval metabolism. Similarly, the stability of total saturated, monounsaturated and PUFA levels (25, 15 and 55% of total fatty acids), as well as total ( n-3) PUFA level and the preferential incorporation of the 22:6( n-3) in polar lipids clearly indicated a metabolic regulation of the fatty acid composition. The 20:4( n-6) and 22:5( n-6) acids were also preferentially incorporated. The accumulation of 18:3( n-3) or 20:5( n-3) with depletion of 22:6( n-3) in neutral and polar lipids of larvae fed diets with high levels of the first two fatty acids but little or no 22:6( n-3), indicated that elongation-desaturation of dietary fatty acids was too low in P. maximus larvae to maintain high 22:6( n-3) levels in polar lipids. The selective incorporation of dietary long chain PUFA into neutral and polar lipids by acyltransferases may be the main mechanism controlling the fatty acid composition of larvae. These results indicate that P. maximus larvae have essential requirements for long chain ( n-3) and ( n-6) PUFA, similar to many other marine species.

Effect of broodstock diets on total lipids and fatty acid composition of larvae of gilthead sea bream (Sparus aurata L.) during yolksac stage

Total lipid content and total lipid fatty acid compositions were studied in larvae at the yolksac stage of gilthead sea bream from two different broodstocks. The two broodstock diets had the same total lipid content but were different with respect to their fatty acid levels.There were differences in the fatty acid composition of total lipids in the two groups of larvae, reflecting the influence of fatty acid levels in the diets fed to the broodstock. The main fatty acids in both larvae lots during yolksac stage were 16:0, 18:1n-9 and 22:6n-3.The desaturation index Δx = [P + Σ (n - x) - Σ (n - x) diet]/P allowed the determination of the relative importance of the Δ9, Δ6, Δ5 and Δ4 desaturations during the egg and larval yolksac stages.The levels of total lipid fatty acids in eggs and larvae during yolksac period were almost constant and very low desaturation and elongation activities were apparent.A competitive inhibition was observed between the fatty acids of the n-6 series with respect to the ones of the n-3 series in those eggs and larvae from broodstock whose diet contained a high proportion of linoleic acid and its derivatives.

Lipid content and fatty acid composition of larvae and adults of the velvetbean caterpillar, Anticarsia gemmatalis, as affected by larval diet

Eight fatty acids were found in the food, larvae and adults of the velvetbean caterpillar, Anticarsia gemmatalis, with C16:0, C18:0, C18:1, C18:2 and C18:3 accounting for over 90% of the total. Fatty acid composition of the larvae tended to reflect that of their food. The most striking differences were the high percentages of C18:1 and C18:2 and the low percentage of C18:3 in the artificial diet and artificial diet-reared larvae compared to the foliage of three species of legume food plants (soybean, Glycine max; pigeon pea, Cajanus cajan; and hairy indigo, Indigofera hirsuta) and foliage-reared larvae. Lipid content (%dw) declined during metamorphosis from mature larva to adult with diet-reared larvae and adults exhibiting significantly higher lipid contents than foliage-reared insects. Regardless of larval food, newly eclosed adults tended to exhibit a decrease in the % of C18:3, and increases in C16:0 and C18:1 compared to larvae. Larval diet clearly influenced the fatty acid composition of larvae and adults, but only the % of C18:2 did not change between food, larvae and adults.

Relationship of the oxidative pentose shunt pathway to lipid synthesis in Drosophila melanogaster.

The tissue activities of the oxidative pentose shunt enzymes, glucose-6-phosphate dehydrogenase (E.C. 1.1.1.49) and 6-phosphogluconate dehydrogenase (E.C. 1.1.1.44), in the larvae of Drosophila melanogaster are not dependent on the amount of flux through the oxidative pentose shunt pathway. An oxidative pentose shunt deficiency effects about a 40% reduction in the NADPH concentration in early third instar larvae, resulting in a six-fold difference in the NADPH/NADP+ ratio between wild-type and pentose-shunt-deficient larvae. The capacity of pentose-shunt-deficient larvae to synthesize triglyceride in response to a high concentration of dietary sucrose is only 73% of the wild-type level. Environmental temperature influences on the fatty acid composition of larvae are not altered by an oxidative pentose shunt deficiency.