Fatty Acid Composition Of Rotifers Research Articles

L-carnitine can promote the growth performance of rotifers (Brachionus rotundiformis) by improving their feeding behavior and nutrient composition

Rotifer are important food resources in aquaculture hatcheries, and several studies have shown that L-carnitine (LC) can promote the growth performance of rotifers. The aim of this study was to investigate the nature of beneficial effects of LC on rotifer Brachionus rotundiformis. The feeding behavior of rotifers were evaluated at different LC concentrations (0, 1, 10 and 100 mg L−1). Meanwhile, the effects of LC on growth performance, free LC content, amino acid and fatty acid composition of rotifers were analyzed. The results indicated that LC (10 and 100 mg L−1) treatments significantly improved the filtration and ingestion rates of rotifers fed microalgae or baker’s yeast, In addition, LC (10 and 100 mg L−1) not only significantly accumulated in rotifers, but also significantly improved the rotifer growth performance. After 48 h of LC treatment, the rotifer population density significantly increased. Concerning the biochemical composition of rotifers, 100 mg L−1 LC can increase the carbohydrates content, decrease the protein and lipid content in the rotifers. And the LC treatment could significantly decrease the total SFA content of rotifers, while significantly increase the total HUFA content of rotifers. Moreover, the levels of LC supplementation were positively correlated with the contents of Thr, Gly, Ala, Leu, Tyr, Phe, Lys, His, Arg and Pro in rotifers. Overall, adding LC could not only accumulate in rotifers, but also promote the growth performance of rotifers by improving their feeding behavior and their nutritional value.

Effects of Live Food enrichment on Yellowtail Amberjack Seriola lalandi dorsalis (Gill 1863) Larvae

Our study examined the effect of live food enrichment on the rearing performance of yellowtail amberjack Seriola lalandi dorsalis from day 3 posthatch (DPH) to 12 DPH. Three rotifer enriched treatments, 1) Nannochloropsis sp, 2) S.presso® (INVE Aquaculture) half dose (Sp1/2), and 3) S.presso® full dose (Sp1) were administered. Growth of yellowtail amberjack larvae was not significantly affected by these enrichments (P>0.05) but final survival rates were significantly affected (P<0.05). Jaw malformation of fish fed with only Nannochloropsis sp. enriched rotifers was significantly higher than those fed S.presso enriched rotifers. Fatty acid composition of rotifers was significantly affected by the enrichment treatments (P<0.05). Arachidonic acid (ARA, 20:4n-6) and Eicosapentaenoic acid (EPA, 20:5n-3) were highest in rotifers enriched with Nannochloropsis. Docosahexaenoic acid (DHA, 22:6n-3) level was highest in Sp1 treatment. Total saturated fatty acids in rotifers was not significantly affected (P>0.05), but total polyunsaturated fatty acid content was significantly affected (P<0.05) by enrichment. DHA/EPA ratio in rotifers was significantly affected by the enrichment (P<0.05). Highest total polyunsaturated fatty acids were observed in rotifers enriched with Sp1. On 12 DPH, fatty acid composition in the larvae was significantly affected by the nutrient enhancement (P<0.05). ARA and EPA levels were highest in the larvae fed with Nannochloropsis sp. enriched rotifers; highest DHA/EPA ratio in fish larvae was found in Sp1 treatment. Total polyunsaturated fatty acid in the larvae enriched with Sp1/2 and Sp1 was similar to the amount observed in fertilized eggs of yellowtail amberjack (P>0.05). Results indicate that enriched live feed can significantly affect rearing performance of yellowtail amberjack larvae; S.presso full dose enrichment is suitable for their initial rearing stages.

오징어(Todarodes pacificus) 간유와 광합성세균을 주원료로 한 동물먹이생물 영양강화제의 지질 영양강화 효과

We investigated the effects of enrichment with oil or bacteria on the fatty acid composition of rotifers and Artemia as live prey. One enrichment(oil source) was mainly composed of squid Todarodes pacificus liver oil; the other(photosynthetic-bacterial source) was primarily made up of Schizochytrium sp. The enrichments were intended to enhance the nutritional value of the live prey, such as their EPA, DHA and n-3 HUFA contents. The lipid content as EPA and DHA of rotifers was higher when enriched with the oil source rather than the photosynthetic-bacterial source. The DHA content of Artemia nauplii after enrichment differed significantly, depending on the type of enrichment used(P<0.05). When the Artemia nauplii were enriched with the oil source, the DHA content was increased to 16.8%, whereas it increased only to 1.1% when enriched with the photosynthetic-bacterial source. These results indicate that selection of the enrichment is important for Artemia nauplii but not for rotifers.

Fatty Acid Composition of Rotifers Fed with Chlorella and Yeast

Fatty Acid Composition of Rotifers Fed with Chlorella and Yeast

Highly Unsaturated Fatty Acid Composition of Rotifers (Brachionus plicatilis) and Artemia Fed Various Enrichments

Highly Unsaturated Fatty Acid Composition of Rotifers (<i>Brachionus plicatilis</i>) and <i>Artemia</i> Fed Various Enrichments

Nutritional Properties of the Marine Rotifer Brachionus plicatilis Fed the Freshwater Microalgae Selenastrum capricornutum

AbstractThis study examined the effects of storage time on the fatty acid composition of freshwater Selenastrum capricornutum algal paste under 4 C refrigeration, the fatty acid composition of rotifers fed the fresh and stored algal paste, and the toxicological properties of the algal paste. Microalgae were produced in a hydraulically integrated serial turbidostat algal reactor (HIS‐TAR), harvested as a paste, refrigerated and analyzed every 2 wk. Fresh Selenastrum capricornutum paste had almost three times greater concentration of unsaturated fatty acids than saturated fatty acids. Over 50% of the unsaturated fatty acids were made up of n‐3 and n‐6 fatty acids. Total unsaturated, n‐3 group and n‐6 group fatty acids decreased (P 0.05) during storage, including the nutritionally important fatty acids (C20:4n6, C20:5n3, C22: 6n3). Rotifers fed 2– and 4‐wk‐old algal paste had a significantly lower (P 0.05) total unsaturated fatty acid percentage and significantly greater (P 0.05) total saturated fatty acids than those fed fresh algae. There were no significant changes in the n‐6 group fatty acid level in the 4‐wk‐old paste feeding study or for the n‐3 or n‐6 groups in the 2‐wk‐old paste feeding study as compared to fresh algae. The levels of the three nutritionally important fatty acids (C20:4n6, C20:5n3, C22:6n3) did not differ between rotifers fed fresh and stored algae. Stored algae did not present toxicity to rotifers and Daphnia at the normal feeding concentration. These results indicated that the use of refrigerated freshwater algal paste for production of rotifers results in live feed with adequate nutritional properties for marine larviculture. This could eliminate the costs associated with production of marine algae, which could be replaced with freshwater algae, and may provide an alternative to cryopreservation.

Development of hatchery technology for the silver pomfret Pampus argenteus (Euphrasen): effect of microalgal species on larval survival

The silver pomfret Pampus argenteus (Euphrasen) is a new candidate for aquaculture and there is not much information available on its larval rearing. Investigations carried out using microalgae alone in the culture system for the initial feeding of the silver pomfret larvae showed that Chlorella, Isochrysis and Nannochloropsis without rotifers are not conducive to the survival of newly hatched larvae. At 6 days after hatching (DAH), a maximum survival of 3% (1.8 ± 1.69%) was observed with Isochrysis followed by Nannochloropsis (0.35 ± 0.21%) and Chlorella (0.25 ± 0.21%). All control larvae died at 6 DAH without microalgae. Further investigations using the above microalgae with rotifers and a mixture of these same microalgae with rotifers showed that significantly higher (P < 0.05) survival could be achieved in the mixture of microalgae with rotifers in the culture system. At 12 DAH, the larval survival was 9.73 ± 1.39% in mixed species of algae compared with that of Isochrysis (6.93 ± 1.86%), Nannochloropsis (6.83 ± 0.61%), Chlorella (5.93 ± 2.76%) and seawater without microalgae or the control (0.73 ± 0.31%). The first incidence of feeding on rotifers at 4 DAH was significantly higher (P < 0.05) in all treatments with microalgae than that of the control. The incidence of feeding in mixed species of algae at 4 DAH (60.0 ± 0.00%) and in Isochrysis (55.0 ± 35.36%) was significantly higher (P < 0.05) than that of Chlorella (40.0 ± 0.00%) and the control (25.0 ± 7.07%). Prey consumption of individual larvae increased significantly (P < 0.01) at 8 DAH compared with that at 4 DAH. During this period, predation on rotifers by larvae was significantly higher (P < 0.05) in mixed species of algae (12.85 ± 5.73 rotifers larva−1) than that of the control (6.75 ± 1.20 rotifers larva−1). The fatty acid composition of rotifers used during this investigation shows that significantly higher (P < 0.05) ω3 HUFA was present in rotifers treated with mixed algae plus commercial enrichment media ‘Super Selco’ and ‘DHA Protein Selco’. Rearing of silver pomfret larvae up to the juvenile stage using mixed species of microalgae in the hatchery has been discussed. During 38 days of the larval rearing period, it was possible to achieve 3.6–4.2% larval survival with a mean of 3.9 ± 0.42%, which was considerably higher than in previous attempts (survival up to 1.5%).

Rearing techniques for red porgy ( Pagrus pagrus) during larval development

Red porgy can be considered as a potential candidate to diversify aquaculture production of sparids, due both to the importance of red porgy fisheries and market within Europe, and to its phylogenetic closeness to gilthead seabream. Spontaneously spawned eggs were obtained from a broodstock of wild individuals captured in Canarian waters. Different rearing trials were conducted to study the success of: (a) different egg stocking densities (100, 150 and 200 eggs/l); (b) first feeding with rotifers enriched with different products (Powersh-fish oil, freeze-dried shark eggs and Selco supplemented with Nannochloropsis sp); and (c) supply of rotifers to larval cultures at different concentrations (5, 7 and 10 rotifers/ml). In all cases, larval feeding lasted for 14 days. Larval length was measured at the time of mouth opening, at day 10 of life, and at the end of the experiments. Larval survival was estimated at the end of each experiment by counting all the remaining live larvae. Total lipid and fatty acid composition of rotifers and larvae were analyzed and discussed in relation to larval growth and survival. In this study, egg densities between 100 and 150 eggs/l and the use of rotifers enriched with Powersh-W, containing a high level of 22:6 n−3, at concentrations of 5–7 rotifers/ml produced the best larval growth and survival.

Potential advantages of frozen algae ( Nannochloropsis sp.) for rotifer ( Brachionus plicatilis) culture

The eustigmatophyte Nannochloropsis is widely used in many aquaculture hatcheries to establish the initial step of an artificial food chain. The advantage of Nannochloropsis over other unicellular algae is primarily its unique fatty acid composition. Rotifers which consume the algae carry these fatty acids to the fish larvae. Cultivation of large quantities of algal biomass to support this food chain is a heavy burden in many hatcheries, and in many other locations it cannot be carried out all year round. In this study we examined the possibility of substituting frozen biomass for fresh Nannochloropsis as a sole food source for rotifer cultures or as an enrichment treatment prior to feeding the rotifers to the larvae. Relatively high reproductive rates were found in rotifers of three strains which were fed frozen Nannochloropsis biomass. Total fatty acid content of these rotifers and fatty acid distribution were related to the chemical composition of the algae. Although seasonal variations in biochemical composition and fatty acid distribution were found in the algal biomass, the quality of the long-term frozen algae was adequate to provide the rotifers with the essential fatty acids almost all year round. No differences were found in the fatty acid composition of rotifers fed with algae stored at − 20 °C or − 70 °C. The thawed algal biomass could be kept at 4 °C for 7 days and be used for rotifer feeding without a significant adverse effect on the fatty acid content and composition in the rotifers. The results of this study suggest that application of frozen Nannochloropsis biomass may promote easier management in biomass production of lipid-enriched rotifers. This provides the artificial food chain with essential fatty acids, which are crucial for the development and cultivation of fish larvae, with a relatively limited effort for algae production on the hatchery site.

Nutritional effects of algal addition in first-feeding of turbot ( Scophthalmus maximus L.) larvae

The effect which microalgal addition and rotifer enrichment with algae had on survival, growth rate and fry viability during first-feeding were examined for turbot ( Scophthalmus maximus L.). Addition of the microalgae Isochrysis galbana or Tetraselmis sp. together with rotifers Brachionus plicatilis, grown on yeast and oil emulsion, and Artemia greatly improved rearing success, whereas short-term enrichment of the rotifers with Tetraselmis sp. gave only improved viability. The algae modified the relative fatty acid composition of rotifers. Rotifers with I. galbana exhibited and increased level of 22:6 n-3 and a lower level of 20:5 n-3, whereas the opposite change occurred when Tetraselmis sp. was used. Addition of either of the two algal species at 1 mg cl −1 to the larval tanks resulted in a constant lipid level and high egg ratio of the rotifers, and thereby also high individual biomass content. Without algal addition, the lipid content of the rotifers decreased by 20% day −1 in the early phase, and their egg ratio became close to zero. In addition to improved nutritional conditions of the larvae, some other factor, e.g. some trigger mechanism or changed microbial or light conditions, also can operate to explain the increased early appetite of larvae with microalgae added and must be taken into consideration.

Influence of the biochemical composition of food on the biochemical composition of the rotifer Brachionus plicatilis

The influence was investigated of the biochemical composition of different kinds of food on the protein, lipid and carbohydrate content, protein composition and fatty acid composition of total, polar and neutral lipids, and alterations in these compounds during the secondary cultivation period (48 h) on the alga Monochrysis lutheri (the rotifers were originally fed with baker's yeast, Saccharomyces cerevisiae). Positive correlations between the protein and lipid content of rotifers and the content of these compounds in their food were noted. No correlations were established for carbohydrates. The most significant and the least alterations occurred in the content of lipids and proteins, respectively. No correlations were found between the amino acid composition of rotifers and that of their food. The total content of amino acids in proteins and their amino acid composition were constant. The concentration of diacylglycerols, monoacylglycerols and free fatty acids in rotifer lipids did not depend on the content of these compounds in food lipids, and was rather constant. We observed a positive correlation between the content of triacylglycerols and sterol esters in rotifers and in their food. Most significant alterations took place in the triacylglycerol content. As a whole, the fatty acid composition of rotifers was similar to that of their food. A greater degree of unsaturation of the fatty acids of the neutral lipids, and a greater variation in this fraction, as compared to polar lipids were observed. Alteration of the general biochemical composition begins with an increase in the lipid content after l h of feeding. The lipid content reaches a maximum after about 6 h of feeding, and then decreases to a level exceeding the primary one. The carbohydrate content begins to decrease after 6 h of feeding and reaches a minimum after about 24 h of feeding, then rises and becomes stable at a level lower than the primary one. The phospholipid content decreases insignificantly after 12 h of feeding, whereas the triacylglycerol content increases after 6 h much more than that of phospholipids. Changes in the sterol and sterol ester content appear after 12 h of feeding and disappear completely after approximately 36 h. Alterations of the lipid fatty acid composition begin with a change in polar lipids (after 1 h). Alterations of the fatty acid composition occur between 6 and 12 h of feeding and practically cease after 24–36 h.

Intensive rotifer cultures using chemostats

Continuous production of the rotifer Brachionus plicatilis rotundiformis (S-type) in an intensive chemostat culture system has been investigated. The production dynamics of rotifers in relation to different flow rates and feed regimes show that the growth rate and production depends on the type of algal feed and flow rate utilized in the culture system. It was possible to achieve a mean production of up to 318.84 × 106 rotifers m−3 d−1 at a flow rate of 6 1 h−1 in 100 1 chemostats and up to 261.21 × 106 rotifers m−3 d−1 at a flow rate of 40 1 h −1 while using 1 m3 capacity rotifer chemostats as production units. The ω 3 fatty acid composition of rotifers while using Chlorella and Nannochloropsis in the culture system has been described. The results of this investigation show that the rotifer productivity in the continuous culture system is considerably higher than in any of the conventional culture systems described to date for aquacultural purposes.

De novo synthesis of fatty acids in the rotifer, Brachionus plicatilis

The fatty acid composition of rotifer phospholipids is largely dependent on that of their food, indicating that the ingested lipids are hydrolysed in the gut, resorbed, metabolized and incorporated into body phospholipids. It is stable and does not change considerably after 1 or 2 days of starvation. Considerable differences were found in the fatty acid composition of rotifers fed baker's yeast (Saccharomyces cerevisiae), Chlorella or Isochrysis. Rotifers fed on baker's yeast for several generations contained considerable amounts of PUFA (1.6% of 22:6 ω3) although this yeast contains mainly 16:1 and 18:1 acids and is completely devoid of 16:3, C:20 and C:22 unsaturated and saturated fatty acids. This observation suggests that fatty acid synthesis and elongation had occurred. De novo synthesis of PUFA was further suggested by experiments in which 1- 14C acetate was incorporated into radioactive acids and was verified by chemical degradation. Upon decarboxylation, approximately 10% of the total radioactivity in the PUFA was recovered as 14CO 2, indicating that all the uneven C-atoms must contain 14C. Oxidative cleavage of all of the double bonds of PUFA yielded 14C-labelled propionic and hexanoic acid from the methyl end of the molecule. However, the rate of synthesis of these acids is rather low. Hence, in order to supply large amounts of PUFA to marine fish larvae, rotifers must be fed on PUFA-rich food.