Rotifer Diet Research Articles

Performance and skeletal abnormality of striped trumpeter Latris lineata larvae and post larvae fed vitamin A enriched Artemia

Several nutritional studies have found that excess or reduced dietary vitamin A (VA) causes skeletal malformations in marine fish larvae. Feeding VA enriched rotifers to striped trumpeter (Latris lineata) from 6 to 18 days post hatch (dph) has been shown to affect vertebral column malformations but not jaw malformation. Our study examined the effect of dietary VA during the later Artemia feeding period on the prevalence of malformations. Larvae were initially reared in a 3000 l tank and fed a diet of Algamac-3050 enriched rotifers from 2 to 16 dph. At 16 dph, larvae were transferred to 24 × 300 l tanks and fed Artemia enriched with one of six doses of retinyl palmitate (VA) four times per day from 19 to 44 dph. Enrichment with emulsions containing 0 (control), 795, 1558, 3174, 4911 and 10,518 ng retinyl palmitate mg− 1 emulsion resulted in an average VA in Artemia of 0, 6, 7, 27, 30 and 55 ng retinyl palmitate mg− 1 dry weight (DW). The retinoid content of L. lineata at 44 dph was positively correlated with the enriched Artemia they fed on. Growth in length (15.91 ± 0.31 mm, mean ± SD) and dry weight (5.08 ± 0.32 mg), and survival (26.1 ± 2.9%), were not significantly affected at 44 dph by increasing dietary doses of retinyl palmitate. Retinyl palmitate enrichment in Artemia did not affect jaw malformation in L. lineata, which is contrary to other studies on a range of marine fish species treated with increased doses of dietary VA. By the end of the study, 54 ± 10% and 18 ± 6% of the post larvae across treatments had short lower and open jaws, respectively. Severe jaw malformations affected 50 ± 11% of the post larvae. Early culture of larvae in a larger tank was likely to reduce overall prevalence of jaw malformations compared to previous studies as interaction with tank walls was reduced. The prevalence of vertebral column malformations in 44 dph post larvae (58 ± 4%) were also not affected by dietary VA. The study suggests that the window of influence for dietary VA is during earlier development of bone structures in L. lineata.

The use of preserved copepods in sea bream small-scale culture: biometric, biochemical and molecular implications

Considering the well-known problems arising from the use of rotifers and Artemia as live prey in larval rearing in terms of fatty acid deficiencies, the aim of this study was to evaluate a partial or complete replacement of traditional live prey with preserved copepods during the larviculture of gilthead sea bream (Sparus aurata). Sea bream larvae were randomly divided into 4 experimental groups in triplicates: group A larvae (control) fed rotifers followed by Artemia nauplii; group B fed a combined diet (50%) of rotifers–Artemia and preserved copepods; group C fed rotifers followed by preserved copepods; and group D fed preserved copepods solely. Survival and biometric data were analysed together with major molecular biomarkers involved in growth, lipid metabolism and appetite. Moreover, fatty acid content of prey and larvae was also analysed. At the end of 40 days treatment, a stress test, on the remaining larvae, was performed to evaluate the effects of different diets on stress response. Data obtained evidenced a positive effect of cofeeding preserved copepods during sea bream larviculture. Higher survival and growth were achieved in group B (fed combined diet) larvae respect to control. In addition, preserved copepods cofeeding was able to positively modulate genes involved in fish growth, lipid metabolism, stress response and appetite regulation.

Increasing the levels of the essential trace elements Se, Zn, Cu and Mn in rotifers (Brachionus plicatilis) used as live feed

Rotifers are a common first feeding diet for rearing marine fish larvae. However, the levels of Mn, Cu, Zn, Se and iodine found in rotifers are low and may be insufficient to meet larval fish requirements. This study investigates increasing the concentration of Mn, Cu, Zn, Se and iodine simultaneously in rotifers (Brachionus plicatilis) in both short term enrichments (3h) or during batch cultures (6days), using either organically bound or inorganic mineral sources. This study demonstrates that rotifers can simultaneously be produced with Mn, Cu, Zn and Se concentrations up to and higher than the known requirements of fish, while increasing the level of iodine in rotifers was ineffective at the concentrations tested. To produce rotifers with copepod levels of Mn, Cu, Zn and Se, only 6% of a commercial rotifer enrichment diet had to be replaced with organically bound minerals, leaving a large percentage of the rotifer diet free to deliver other important nutrients such as lipid and proteins. Rotifers enriched to copepod mineral levels and stored for 18h retained 75–110% of their Se, Zn and Mn and 50% of their Cu. Overall, increasing rotifer mineral levels appears to be most effective when the mineral is available in an insoluble and hence ingestible form.

Abnormal elongation of the lower jaw in juvenile Japanese flounder: combined effects of a rotifer diet enriched with Nannochloropsis preserved by various methods and parentage

To elucidate possible causes of skeletal malformations in larval Japanese flounder, we reared larvae fed rotifers enriched with three types of preserved Nannochloropsis (fresh, refrigerated, and frozen). The incidence of malformations at 50 days post hatch ranged from 14.5 to 38.5 % within the three experimental groups, and elongation of the lower jaw (LJ) was the most frequently observed malformation, ranging from 68 to 89 % of total malformations. We also investigated larval parentages using microsatellite markers. Parentage analysis of the fresh Nannochloropsis group showed that one sire and a pair generated significant numbers of LJ-elongated individuals. In the refrigerated Nannochloropsis group, one dam and two sires generated significant numbers of LJ-elongated individuals. In the frozen Nannochloropsis group, no broodstocks or pairs generated significant numbers of LJ-elongated individuals. Our results suggest that LJ elongation in Japanese flounder likely results from the application of different types of preserved Nannochloropsis during rotifer feeding stage. However, there is also some level of genetic influence associated with this deformity.

Performance of Larval Florida Pompano Fed Nauplii of the Calanoid Copepod Pseudodiaptomus pelagicus

AbstractThe Florida pompano Trachinotus carolinus is a highly prized marine fish species, the larviculture of which currently includes the feeding of live rotifers and nauplii of brine shrimp Artemia spp. However, no previous studies have evaluated the feeding of copepod nauplii. In this study, the growth and survival of Florida pompano larvae fed nauplii of the calanoid copepod Pseudodiaptomus pelagicus were compared with those of larvae fed the standard reference diet of enriched rotifers Brachionus plicatilis. Experiments were conducted during the first 7–9 d posthatch (DPH), a period preceding the provision of Artemia nauplii. Treatments included feeding only copepod nauplii during the first day, the first three days, and on all days, as well as copepod nauplii mixed with rotifers during the entire experiment. In addition, the dietary effects on larval fatty acid composition were examined. Feeding copepod nauplii at a density of 2.0–3.5 nauplii/mL during the first day or the first three days of feeding had advantages over feeding only rotifers. However, after approximately 3 DPH, increased quantities of nauplii were needed to provide sufficient nutrients for growth. This was demonstrated in larvae fed copepod nauplii for the entire trial, for which survival was significantly higher than for the other treatments but for which growth was significantly reduced. Larvae fed a mixture of rotifers and nauplii for the entire trial had survival similar to that of larvae fed only rotifers (∼40%); however, growth was greater in larvae fed the mixed diet, suggesting that there is a nutritional advantage to including copepods in the diet. Fatty acid analyses revealed that increased levels of docosahexaenoic acid were associated with larvae fed copepods, which probably contributed to the observed higher survival and growth. These results indicate that there are multiple benefits to feeding copepods to Florida pompano larvae.Received June 6, 2010; accepted August 10, 2010

Preserved copepods as a new technology for the marine ornamental fish aquaculture: A feeding study

The aim of this study was to evaluate the potential use of preserved copepod as prey in Amphiprion clarkii larviculture. After hatching, A. clarkii larvae were divided in three experimental groups for feeding studies as follows: group A (control group) fed rotifers ( Brachionus plicatilis) followed by Artemia nauplii; group B fed a mixed diet of rotifers- Artemia salina nauplii and preserved copepods and group C fed preserved copepods solely. In this study we observed a positive effect of feeding preserved copepods in A. clarkii larviculture as a supplement food to the traditional diet based on rotifers and Artemia nauplii. In group B larvae, fed a combination of rotifers/ Artemia and copepods, a significant increase of insulin like growth factor I and II, peroxisome proliferator activated receptor α−β and thyroid receptor α and β gene expression together with a significant decrease of myostatin gene expression was evidenced by real time PCR compared to the other experimental groups. In this same group we also observed the best results in terms of growth (total length and weight) and survival. These preserved copepods may be considered a suitable food for marine fish larvae larviculture when used as a supplement to the traditional diet based on rotifers and Artemia nauplii.

The influence of dietary constituents on the molecular ontogeny of digestive capability and effects on growth and appetite in Atlantic cod larvae ( Gadus morhua)

Development of optimal nutrition feeding protocols is considered a major challenge in intensive marine fish larval rearing. There is a general lack of knowledge on the molecular basis underlying larval digestive capability and endocrine function, and relatively few studies have employed molecular biological techniques to study the ontogeny of digestive capability and effects of nutrients on growth and appetite of marine fish larvae. In this study, Atlantic cod larvae were fed either Acartia tonsa nauplii, rotifers grown on Rhodomonas baltica or a control rotifer diet, before weaning to formulated diet. Larvae were sampled at 5, 8, 16, 29 and 38 days post hatch. Larval dry weight and specific growth rate were measured, and gene expression patterns of trypsin, amylase, bile salt-activated lipase, phospholipase A2, Acyl CoA dehydrogenase, neuropeptide Y, cholecystokinin, growth hormone and thyroid hormone receptors α and β determined by quantitative PCR. We show that transcripts involved in appetite regulation and digestion were differentially expressed after different feeding protocols. Interestingly, several similar transcript profiles for genes coding for digestive enzymes and neural controlling factors were demonstrated. In addition, these relationships were partially reflected in larval specific growth rates, demonstrating for the first time in cod, that the ontogeny of digestive capability and its hormonal components may be tied directly to the type and quality of initial and early dietary constituents.

Prey selection and functional morphology through ontogeny of Amphiprion clarkii with a congeneric comparison

The relationship between the complexity of the feeding apparatus and prey selection through ontogeny was examined in Amphiprion clarkii larvae. Larvae were reared from 1 to 10 days post-hatch (dph) on a diet of rotifers, wild-caught plankton and newly hatched Artemia sp. nauplii. Results were compared with available data on the relationship between functional morphology and prey selection of Amphiprion frenatus to establish patterns of functional morphology and prey selection between the larvae of two species of coral-reef fishes. Larvae of both species exhibited an increase in selection of larger prey through ontogeny coincident with an increase in the complexity of the feeding apparatus. The first elements to ossify in larvae of both species were the pharyngeal teeth (A. clarkii: 5 dph, near +/-s.d. Standard length, L(S),4. 3 +/- 0. 2 mm; A. frenatus: 5 dph, L(S)5. 0 +/- 0. 4 mm) which, in combination with the development of a more functional feeding apparatus, may have permitted larvae to better process new types and sizes of prey. Prey items, however, were selected differentially between the two fish species, which could not be fully explained by the functional state of the feeding apparatus. While prey selection is influenced by the functional state of the feeding apparatus, all aspects of larval fish biology (morphology, behaviour and physiology) should be considered.

Can umbrella-stage Artemia franciscana substitute enriched rotifers for Cobia ( Rachycentron canadum) fish larvae?

Appropriate food of suitable nutritional value is crucial for first-feeding stages of the larvae of cobia Rachycentron canadum, a very fast growing marine fish species. Best survival and growth results in cobia larviculture have been reported with a starter diet of HUFA-enriched rotifers and –as mouth size permits – followed by freshly-hatched and eventually HUFA-enriched Artemia nauplii. Using the smaller-sized Vietnam Artemia franciscana (AF) strain instead of the Great Salt Lake A. franciscana strain, it has been shown that the rotifer-feeding period could be shortened with 3 days, resulting in significant improvements in larval survival and growth. This study verified the possibility to feed umbrella-stage Artemia for further shortening and eventually completely substituting rotifer start feeding. The experiment was conducted in 200-L tanks and lasted 18 days. AF umbrella Artemia was used as sole feed during the whole rotifer feeding period (UAF), compared to the use of enriched rotifers for the first 2 days followed by AF-umbrella (ER + UAF) and the use of enriched rotifers as control (ER). The feeding incidence of UAF treatments was significantly lower ( P < 0.05) in the 1st feeding day, however, the ingestion and digestion of AF were evident. Growth and survival as well as deformities at day 18 post-hatching were not significantly different for all treatments ( P > 0.05). The viability of cobia larvae after exposure to high salinity stress was lower in the ER treatment at day 8 post-hatching, but higher at day 18 post-hatching ( P < 0.05). The ability of cobia larvae to ingest and digest AF umbrella at first feeding as well as the nutritional suitability of AF umbrella is discussed. The possibility to use umbrella-stage Artemia opens an opportunity to simplify the rearing protocol and to reduce production costs of cobia larviculture.

Appropriate food type, feeding schedule and Artemia density for the zoea larvae of the mud crab, Scylla tranquebarica (Crustacea:Decapoda:Portunidae)

Scylla tranquebarica is an edible portunid crab with high commercial value. To develop hatchery techniques for juvenile production, the feeding requirements of the larvae were investigated. Experiments were carried out to identify food preferences, feeding schedule and optimum prey density. Larval diets of rotifer Brachionus sp, brine shrimp Artemia sp nauplii, and a combination of both were provided and survival, development, and metamorphosis to megalopa monitored. The timing for the withdrawal of rotifers from the larval diet and the timing of the introduction of brine shrimp nauplii, were also examined. The effect of varying densities of Artemia nauplii in the larval diet was also tested. Results showed that the best survival, most rapid development and highest metamorphosis to megalopa were found for larvae fed with a combination diet of rotifers and Artemia nauplii from Z1 to Z3, and Artemia nauplii only from Z4 onwards. Continued co-feeding with rotifers up to the last zoeal stage did not provide added benefit to the larvae. Larvae fed exclusively with rotifers all died at Z5 stage while those fed purely with Artemia nauplii had low survival to the megalopa stage. It was found that on Artemia density of 4.0 nauplii mL−1 given at Z1–Z2 stages, reduced to 2.0 nauplii mL−1 at Z3–Z4 stages, and further decreased to 1.0 nauplii mL−1 at Z5 stage, resulted in the best survival to the megalopa stage. These results advance the development of hatchery techniques for the mud crab, S. tranquebarica.

Breeding and rearing the longsnout seahorse Hippocampus reidi: Rearing and feeding studies

The aim of this study was to evaluate the potential use of the harpacticoid copepod Tisbe spp as prey in Hippocampus reidi culture together with the effect of natural (14 L/10D) or prolonged (24 L/0D) photoperiod. After release, the juveniles were divided into four experimental groups as follows: group A (control group) fed rotifers ( Brachionus plicatilis) followed by Artemia nauplii subjected to 14 L/10D photoperiod; group B fed a mixed diet of rotifers and Tisbe spp nauplii followed by a combination of Artemia nauplii and Tisbe spp copepodites/copepods subjected to 14 L/10D photoperiod; group C fed rotifers ( B. plicatilis) followed by Artemia nauplii subjected to 24 L/0D photoperiod and group D fed a mixed diet of rotifers and Tisbe spp nauplii followed by a combination of Artemia nauplii and Tisbe spp copepodites/copepods subjected to constant light. We observed higher survival and better growth performance in juveniles fed a combined diet and subjected to an extended photoperiod respect to those fed a standard diet or exposed to natural photoperiod. In conclusion, we found that the harpacticoid copepod Tisbe spp may be considered a valuable live prey for H. reidi culture when used as a supplement to the traditional diet based on rotifers and Artemia nauplii and that photoperiod may play an important role in the successful culture of this species.

The use of harpacticoid copepods as live prey for Amphiprion clarkii larviculture: Effects on larval survival and growth

The aim of this study was to evaluate the potential use of the harpacticoid copepod Tisbe spp as prey in Amphiprion clarkii larviculture. After hatching, A. clarkii larvae were divided in four experimental groups for feeding studies as follows: group A (control group) fed rotifers (Brachionus plicatilis) followed by Artemia nauplii; group B fed a mixed diet of rotifers and Tisbe spp nauplii followed by a combination of A. nauplii and Tisbe spp copepodites/copepods; group C fed copepod nauplii solely followed by Tisbe spp copepodites and copepods; group D fed rotifers followed by Tisbe spp copepodites and copepods. In this study we observed a positive effect of feeding Tisbe spp copepods in A. clarkii larviculture as a supplement live food to the traditional diet based on rotifers and A. nauplii. In group B larvae, fed a combination of rotifers/Tisbe spp nauplii followed by a combination of A. nauplii/Tisbe spp copepodites-adults, a significant increase of IGF II and IGF I gene expression and a significant decrease of myostatin gene expression was evidenced by Real Time PCR compared to the other experimental groups. In this same group we also observed the best results in terms of growth (total length and weight) and survival.In conclusion, the harpacticoid copepod Tisbe spp may be considered a suitable live prey for marine fish larvae larviculture when used as a supplement to the traditional diet based on rotifers and A. nauplii.

Is ω6 docosapentaenoic acid an essential fatty acid during early ontogeny in marine fauna?

A thraustochytrid marine protist (Schizochytrium sp.) was fed to rotifers (Branchionus plicatilis), which in turn, were fed to cod larvae (Gadus morhua). Samples of larvae 1 and 11 d after hatch, the rotifer diet, and the enrichment were collected for molecular and isotope analyses of fatty acids. Schizochytrium sp. had unusually high proportions of ω6DPA (8.6% α 0.6%), which was reflected in the rotifers fed this protist (8.7% α 0.2%). This fatty acid was also unusually 13C‐enriched in both the protists (211.63% α 0.11%) and the rotifers (‐11.83% α 0.39%). The proportions of ω6DPA were very low in prefeeding cod larvae but they increased 30‐fold by d 11; however, ω6DPA showed the smallest δ13C change from the protist source. This, combined with reports of significantly higher growth rates in cod and scallops fed diets rich in this fatty acid, provide strong evidence for ω6DPA being essential at least in the early life stages of these two very different groups.

Trophic links in the lowland River Meuse (Belgium): assessing the role of bacteria and protozoans in planktonic food webs

30 of rotifers was low compared with that of phytoplankton (<30% of total carbon ingestion) except when phytoplankton biomass decreased below the incipient limiting level (ILL) of the main metazooplantonic species. In such conditions, protozoa (mainly ciliates) constituted � 50% of total rotifer diet. These results give evidence that microbial organisms play a significant role within the planktonic food web of a eutrophic lowland river, ciliates providing an alternative food for 35 metazooplankton when phytoplankton becomes scarce.

Fecundity, survival, and growth of the seahorse Hippocampus ingens (Pisces: Syngnathidae) under semi-controlled conditions

We studied fecundity, survival, and growth of the seahorse Hippocampus ingens under semi-controlled conditions. Three wild brood stock mature males of 14.8, 24.5, and 32.0 g released 1 598, 1 703, and 1 658 juveniles. Juvenile stocking densities of 12 were settled in 60-l aquariums in groups of 1, 12, and 20 days old organisms. The rate of survival was 21.5, 61.9, and 59.0 %, respectively, in 35 days. Juveniles were fed a mix diet of rotifers B. plicatilis and Artemia nauplii, then they were transferred to a cement tank of 100 000 l at a density of 50/1 000 l and fed with live adult Artemia for 60 days more. They grew from an average of 0.7, 1.5, and 2.7 to 4.5, 5.4, and 6.7 cm, respectively, in 95 days. The seawater temperature varied from 17 to 23 C°.

Improving Live Feeds: Effect of a Mixed Diet of Copepod Nauplii (Acartia tonsa) and Rotifers on the Survival and Growth of First‐Feeding Larvae of the Southern Flounder, Paralichthys lethostigma

Improving Live Feeds: Effect of a Mixed Diet of Copepod Nauplii (<i>Acartia tonsa</i>) and Rotifers on the Survival and Growth of First‐Feeding Larvae of the Southern Flounder, <i>Paralichthys lethostigma</i>

Diet-induced differences in the essential fatty acid (EFA) compositions of larval Atlantic cod (Gadus morhua L.) with reference to possible effects of dietary EFAs on larval performance

AbstractWe studied the performance of cod rearing in which live feed was given under three different essential fatty acid (EFA) enrichment regimes, using commercially available live-feed enrichments. We assessed the fatty acid profile [docosahexaenoic (DHA), eicosapentaenoic (EPA), and arachidonic acid (AA)] in larval somatic tissue, relative to its amounts in both rotifers and Artemia as well as to larval performance. Overall, percentage lipid level of each experimental diet for the trial was approximately 50%. Further, there were no significant differences in total fatty acid levels of larvae from each treatment at the end of the trial (mean = 444.76 μg fatty acid per mg lipid). However, during the rotifer phase, larvae from each treatment were able to incorporate comparable levels of %DHA, irrespective of levels in the diet. Despite this, the rotifer diet with more %DHA still promoted better larval growth than other treatments. Conversely, larvae from two of the treatments did not exhibit any accumulation of AA, reflecting levels found in the diet instead. However, between-tank differences in larval %AA showed improved growth during the rotifer period when larval %AA was high. Low ratios of EPA had no effect. During the Artemia phase, percentage levels of larval DHA decreased; there was no accumulation of DHA relative to dietary levels, which in Artemia were significantly lower than in rotifers (6 cf. 20–30%). However, DHA levels in larvae at the end of the experiment correlated positively with survival. Artemia contained lower levels of AA than rotifers (1.5 cf. 3.0%), yet comparable levels of AA were found in rotifer-fed and Artemia-fed larvae. This also differed significantly between treatments, and correlated positively with survival.

Effect of enriched rotifers on growth, survival, and composition of larval Atlantic cod (Gadus morhua)

AbstractRecently, the nutritional requirements of marine finfish larvae have received considerable attention, and studies have shown that docosahexaenoic acid (DHA) affects the growth and survival of marine finfish larvae. We investigated the effects of different rotifer diets containing variable amounts of DHA on the growth and survival of larval Atlantic cod (Gadus morhua L.). Four different commercial rotifer enrichment formulations were used: spray-dried whole cells composed of Crypthecodinium sp. (ED1), spray-dried whole cells of Schizochytrium sp. (ED2), an oil emulsion (ED3) and ED1, and dried Chlorella at a 7:3 ratio by weight (ED4). The resultant rotifers contained a similar concentration of DHA (1.1–1.6% DW), but the level of DHA differed in proportion to EPA for each enrichment, and was designated ER1–4. Twelve 30-l aquaria were used with three replicates per treatment. Larvae were fed with rotifers from 3 to 43 days post-hatch (dph) at 4000 prey l−1. At the end of the experiment, no significant differences were found in body length and dry weight between the larvae reared on ER1 and ER2. However, larvae reared on ER3 were significantly smaller (both in length and weight) than larvae reared on ER1 and ER2. Larval survival on the ER2 treatment at 43 dph was significantly higher than on the other three treatments. Our results showed a positive effect of rotifer DHA proportions on growth and survival of cod larvae, and demonstrated that Atlantic cod larvae require a high ratio of dietary DHA to EPA.

Effects of α-tocopherol supplementation of rotifers on the growth of striped trumpeter Latris lineata larvae

The effect of dietary α-tocopherol (α-T; vitamin E) on the performance of striped trumpeter larvae was assessed using a dose–response design. Five tuna oil/lecithin/water emulsions containing between 0% and 4% (40 mg g −1) dry weight (DW) of α-T were fed to rotifers, resulting in rotifer α-T concentrations between 114 and 1040 μg g −1 DW. These rotifers or a reference diet of rotifers enriched with AlgaMac 2000 (AM) were fed to larvae from first feeding at 5 days post-hatch (dph) until 23 dph. In larvae fed the emulsion-enriched rotifers, tissue concentrations of α-T were correlated to dietary concentrations. Larvae at 5 dph contained 276 μg α-T g −1; concentrations in most larvae had reduced at 23 dph (to between 121 and 225 μg α-T g −1) except for those fed highest α-T, which contained 356 μg g −1. Larval weight at 20 dph, and length at 14 and 23 dph were positively correlated with dietary α-T concentration. Interpolation of data from the regression curves showed that higher dietary α-T (i.e. ≥437 μg α-T g −1) gave a maximum 7% increase in larval length and a maximum of 10% increase in weight. Larval survival was extremely variable (average 37.0±30.1%). Though not statistically significant, average survival was apparently higher (48.4±28.2%) in larvae fed diets containing ≥437 μg α-T g −1 than those fed diet with lower α-T, i.e. ≤144 μg α-T g −1 (25.6±30.3%), with larvae fed 221 μg α-T g −1 having intermediate survival (37.2±32.3).

Influences of dietary n-3 long-chain PUFA on body concentrations of 20:5n-3, 22:5n-3, and 22:6n-3 in the larvae of a marine teleost fish from Australian waters, the striped trumpeter (Latris lineata).

We determined the effect of dietary long-chain (> or = C20) PUFA (LC-PUFA), 20:5n-3 and 22:6n-3, on larval striped trumpeter (Latris lineata) biochemistry through early development and during live feeding with rotifers (Brachionus plicatilis). Rotifers were enriched using seven experimental emulsions formulated with increasing concentrations of n-3 LC-PUFA, mainly 20:5n-3 and 22:6n-3. Enriched rotifer n-3 LC-PUFA concentrations ranged from 10-30 mg/g dry matter. Enriched rotifers were fed to striped trumpeter larvae from 5 to 18 d post-hatch (dph) in a short-term experiment to minimize gross deficiency symptoms such as poor survival that could confound results. No relationships were observed between larval growth or survival with dietary n-3 LC-PUFA at 18 dph. The larval FA profiles generally reflected those of the rotifer diet, and significant positive regressions were observed between most dietary and larval FA at 10, 14, and 18 dph. The major exception observed was an inverse relationship between dietary and larval 22:5n-3. The presence of 22:5n-3 in elevated amounts when dietary 22:6n-3 was depressed suggests that elongation of 20:5n-3 may be occurring in an attempt to raise body concentrations of 22:6n-3. We hypothesize that accumulation of 22:5n-3 might be an early indicator of 22:6n-3 deficiency in larval fish that precedes a reduction in growth or survival. A possible role of 22:5n-3 as a biochemical surrogate for 22:6n-3 is discussed.