Rotifers enrichment

Fig. 5.4 Percentage content of neutral (NL) and polar (PL) lipids and of 20 4 n-6 (ARA), 20 5n-3 (EPA) and 22 6n-3 (DHA) in copepod adults (250-800 pm) and nauplii (80-150 pm) collected from an open Norwegian pond, rotifers enriched with Isochrysis and RotiMac and 1-day old Artemia nauphi enriched with DC-DHA Selco (data from van der Meeren ef a/., 2008) and from Acamatoma adults (A-Rho) and nauplii (N-Rho) grown in culture on Rhodomonas baltica (data from Stpttrup...

Fig. 5.5 Content of pigments and vitamins in copepod adults (250-800 pm) and nauplii (80-150 pm) collected from an open Norwegian pond, rotifers enriched with Isochrysis and RotiMac and 1-day old Artemia nanpUi enriched with DC-DHA Selco (data from van der Meeren ef al., 2008).

Effect of rotifer enrichment with herbal extracts on growth and resistance of red sea bream, Pagrus major (Temminck Schlegel) larvae against Vibrio anguilla-rum. Aquaculture Research 42 1824-1829. 

Thanks to this last characteristic, rotifers can be cultured on many feed sources (e.g. microalgae or yeast cells) and, even more important, their nutritional composition can be adjusted in a relatively short time (called enrichment) to better suit the nutritional requirements of the predator (e.g. fish or shrimp larvae). In the culture of fresh water rotifers, B. calyciflorus, pH is important due to the ammonia-ammonium equilibrium. 

Baker s yeast is also a common feed. However, yeast contains less highly unsaturated fatty acids (HUFA), which results in rotifers with inferior nutritional quahty for the larvae compared to microalgae fed rotifers (Con-geicao et /., 2010). This is especially important for marine larvae as marine fish are not able to synthesize eicosapentaenoic acid (EPA) and docosa-hexaenoic acid DHA themselves from linolenic acid (for a review see Tocher, 2010). The nutritional composition of the rotifers can be adjusted through enrichment (i.e. inclusion of specific nutrients/chemicals essential to the larvae). There are many formulated feeds on the market that are... 

The composition of rotifers can be modified in a relatively short time by presenting particles within a suitable range (0.3-21 pm Vadstein et all, 1993 Hotos, 2002). These will be ingested due to their filter-feeding nature resulting in nutritional enrichment. 

Although bacteria present in rotifer cultures can provide vitamin B (Yu et al, 1989) and microalgae such as Chlorella sp. and I. galbana provide vitamin C (Merchie et al, 1995), extra enrichment of thiamine (as thiamine HCl) and vitamin E (as DL-alpha-tocopherol) led to an increased concentration in the rotifers after four days. On the other hand, addition of vitamin A (as retinyl palmitate) in the diet did not lead to a significant increase in vitamin A content (Srivastava et al, 2011). As copepods and their naupUi are the natural food for many marine larvae, rotifers are also enriched in iodine in order to obtain iodine levels similar to those of copepods (Srivastava et al, 2006). 

Selenium is important in the development of the thyroid and is only present in low amounts (around 0.08 mg/kg DW) in cultured rotifers compared to 2-5 mg/kg DW in wild copepods (Hamre et al., 2008). Through enrichment during 3 h with selenized yeast, Ribeiro et al. (2011) were able to obtain Se levels of 35.9-104.0 mg/kg DW in rotifers. As this is much higher than the levels of wild copepods, lower amounts of selenized yeast could be used. 

The microbial community of the rotifers can also be shifted through a microbial enrichment (Makridis et al, 2000). This enrichment takes place after the rotifers have been harvested and prior to feeding them to the predator larvae. Makridis et al (2000) harvested and rinsed rotifers and exposed them to 5 x 10 CFU/mL of four probiotic species for 20-60 min. The probiotics remained associated with the rotifers for 4-24 h when placed in tanks with Tetraselmis sp. mimicking the conditions in turbot larvae tanks. 

FERNANDEZ-REntiz u, LABARTA u and FERREIRO M J (1993) Effects of commercial enrichment diets on the nutritional alue of the rotifer (Brachionus plicatilis). Aquaculture 112 195-206. 

FERREIRA M, couTiNHO p, SEDCAS p, FABREGAS J and OTERO A (2009) Enriching rotifers with Premium microalgae Nannochloropsis gaditana. Marine Biotechnology 11 585-595. 

HACHfi R and PLANTE s (2011) The relationship between enrichment, fatty acid profiles and bacterial load in cultnre rotifers Brachionus plicatilis L-strain) and Artemia Artemia salina strain Franciscana). Aquaculture 311 201-208. 

KOTANIT, GENKA T, FUSHIMI H, HAYASHI M, DIERCKENS K and SORGELOOS P (2009) Effect of cultivation methods on nutritional enrichment of euryhaline rotifer Brachionus plicatilis. Fish Science 75 975-984. 

RIBEIRO A R A, RIBEIRO L, DIMS M T and MOREN M (2011) Protocol to enrich rotifers Brachionus plicatilis) with iodine and selenium. Aquaculture Research 42 1737-1740. 

SRIVASTAVA A, STOSS J and HAMRE K (2011) A Study on enrichment of the rotifer Brachionus Cayman with iodine and selected vitamins. Aquaculture 319 430-438. 

RIBIERO A R A, RIBIERO L, S.ELE 0, HAMRE K, DINIS M T and MOREN M (2009) lodiue-enriched rotifers and Artemia prevent goitre in Senegalese sole (Solea senegalen-sis) larvae reared in a recirculation system. Aquaculture Nutrition, 17,248-257. 

The bacterial community associated with rotifers has been studied extensively by culture-based approaches (Nicolas et ai, 1989 Skjermo and Vadstein, 1993 Blanch et al, 1997). These studies indicate that bacteria isolated from rotifers depend on the protocols used for rotifer cultivation and enrichment as well as the non-selective uptake of bacteria present in the culture water (Skjermo and Vadstein, 1993). A recent molecular study suggested that the bacterial communities of rotifers are more stable than communities associated with Artemia, with a stable core microbiota being present in most rotifer samples (McIntosh et ai, 2008). Both culture-based and molecular studies have shown that Vibrio spp. are significant components of the bacterial community associated with rotifers (Blanch et al., 1997 Nicolas et al, 1989 Brunvold et al, 2007). 

Crustacean zoeae, Artemia Enriched Artemia Rotifers (5 ind mL ) Artemia metanauplii... 

RAiNUZZO J R, REiTAN K I and OLSEN Y (1994) Effect of short- and long-term lipid enrichment on total lipids, lipid class and fatty acid composition in rotifers. Aquaculture International, 2,19-32. 

Feeding protocols are essentially the same as those described for other temperate marine fish larvae including mulloway (Argyrosomus japonicus) (Fielder and Heasman, 2011). Hatchery-reared YTK larvae are initially fed small or large strain rotifers Brachionus spp.) enriched with commercial products at 5-20 rotifers mL . Enriched Anemia meta-nauplii are subsequently added to the diet 10-14 days after hatch. Metamorphosis occurs approximately 20 days after hatching and 10 mm SL, is coincident with weaning onto inert formulated foods and is usually completed 40-50 days after hatching. 

In this method, the antimicrobial extracts are incorporated into live feed organisms such as Anemia or rotifers either directly or indirectly to ensure the complete acceptability of the incorporated compounds. This is the simplest and most effective method of delivering antimicrobial extracts to the early fish and shrimp post-larvae of PL 1-20. The herbal extracts are emulsified by mixing herbal extracts, egg yolk and cod liver oil in a ratio of 1 1 1. The enrichment schedule is 200 mg of emulsified diet mixed with 100 ml water and the nauplii density is 100/ml. After enrichment at several intervals they will be ready to use for feeding. 

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