Food values of Artemia and rotifer

[kareen]

Biochemical composition of Rotifers

The biochemical composition of rotifers and therefore their nutritional value to larval fish is determined by diet. An extensive analysis of the biochemical composition of B. plicatilis was completed by Watanabe, et al (1983a). Nannochloropsis fed rotifers were composed of 75% protein, 22% lipid and 3% ash by dry weight, whereas the same values for yeast fed rotifers were 71%, 17% and 12% respectively.

Food values of artemia

New hatched Artemia (<0.6mm in length) are high in fats with a range of 12-32% of the dry weight (Dutrieu, 1960). In the metanauplius stage (2.5mm) the fat levels decrease to 16.5% and by the time the nauplii reach a pre-adult stage fat levels decrease to 7%. The protein content increases from 42.5% in new hatched nauplii to 62.8% in adult stages (Helfrich, 1973). Based on this knowledge, culturists should determine at what age brine shrimp should be harvested and fed to obtain the best food values. For example, young fish larvae need higher fat levels while older juveniles need more protein. Letting Artemia grow to adults before utilizing them as food may not be advantageous and is more costly.

Like rotifers, the food value of Artemia can be improved by enrichment with highly unsaturated fatty acids………..

[kareen]

Food value of Copperpods (might as well put this in.... same source)

Due to their overall larger size, copepods could be an important transitionals food and/or a direct substitute for Artemia. Newly hatched copepod nauplii, range from 30 to 80um, and can be selectively sieved to feed small early stage larvae. There is little question abut their food value since they are rich in waxy esters and marine oils. Food reserveds are stored as oils in some copepods often giving the body a brilliant red color, as in Diaptomus (Barnes, 1963).

Stomach analysis of adult and sub-adult marine clownfish, Amphiprion chrysopterus, A.melanopus, and A. tricinctus revealed that copepods constitute 38% of their diet (Allen, 1972) Based on this, there is no doubt about the food value of copepods in the culture of clownfish and many other marine tropicals........

[Gouldian]

Like to share what I have found too.

For example, newly hatched brine shrimp (Artemia) are a simple and easily cultured food for the larvae (juveniles) of many marine organisms, but because these shrimp typically lack sufficient quantities of EPA & DHA, most marine fish fed exclusively on baby brine begin to die off within a week or so after hatching (reviewed by Holt 2003). The widespread success of culturing and breeding many marine animals has come only since the discovery of the importance of including these essential fatty acids in the diet. DHA has been shown to be important in the normal growth and development of the central nervous system, and in particular the brain, eyes and reproductive organs, while EPA is important to cardiovascular health and plays an essential role in certain immune responses. Among the common symptoms of EPA/DHA deficiency in marine animals are1) Sudden fright syndrome - shock, convulsion or even death when the animals are frightened; 2) poor vision, and reduced ability to locate prey; 3) worn or mysteriously eroding fins; 4) poor growth rates or sudden massive die offs during early development; 5) low egg viability or infertility; 6) high mortality and disease rates, particularly when under stress (e.g., shipping or acclimation), and 7) inability to properly heal after being wounded (reviewed by Rainuzzo et al. 1997; Masuda et al. 1998; Fredalina et al. 1999; Furuita et al. 1999; Sargent et al. 1999; Ishizaki et al. 2001; Holt 2003). By "enriching" food items such as Artemia with phytoplankton prior to feeding them to the marine animals being raised, the amount of EPA & DHA is often increased to the point that die-offs and developmental problems previously encountered are completely avoided (reviewed by Rainuzzo et al. 1997; Sargent et al. 1999; Holt 2003).

Source: AQUARIUM INVERTEBRATES by ROB TOONEN, Ph.D.

http://www.advancedaquarist.com/issues/dec...nvert%20(2).htm

[Gouldian]

And a little on Rotifers as well.

Although rotifers and ciliate protozoans are a small and generally uninteresting group to almost everyone else, they are quite well known among marine aquarists as the food of choice for breeding most saltwater fishes and many invertebrates. These nearly microscopic to microscopic little critters make a living in a wide variety of ways, ranging from filter-feeders to predatory species that feed on other rotifers and/or ciliates. Many of the most popular reef fishes (including most of the butterflies, angels and wrasses, to name a few) spawn tiny pelagic eggs that hatch into small larvae with mouths too small to eat anything larger than a ciliate. Studies on the natural diets of fish larvae reveal that they are composed largely of micro-zooplankton including protozoans (primarily tintinids, ciliates & foraminiferans), dinoflagellates, larvae of barnacles and molluscs, and copepod eggs and nauplii (Holt 2003). Planktonic diatoms are also eaten, and usually account for about 5% of the total content of larval fish guts (Holt 2003). The guts of wild-collected fish larvae contain a variety of these micro-plankton, with prey items ranging between 3 and 100 μm in length, with the vast majority of the gut contents being less than 60 μm (Holt 2003). Thus, the larvae of tropical marine fishes are simply too small to eat even tiny newly hatched brine shrimp (~5 times bigger than the largest prey found in the guts of wild-collected fish larvae), and smaller sources of food (such as rotifers and ciliates) are necessary if you hope to feed the early stages of most marine ornamental fish species.

Overall, rotifers enriched with phytoplankton and HUFA appear to provide a suitable food for the juveniles of a number of marine fish species, and a number of species were first cultured successfully when fed on enriched plankton such as rotifers (reviewed by Watanabe et al. 1983).

Source: AQUARIUM INVERTEBRATES by ROB TOONEN, Ph.D.

http://www.advancedaquarist.com/issues/dec...nvert%20(2).htm

[Gouldian]

Oh some more info, hope you guys don't mind me sharing.

CONCLUSIONS

For any given width, rotifers have a higher caloric

content than Tigriopus nauplii. First-feeding fish eat-

ing the smallest rotifers get twice as many calories per

bite as they do eating Tigriopus nauplii of the same

width (Table 2). Many first-feeding fish larvae select

prey from the smallest size classes, yet older larvae eat

prey belonging to all size classes. As a result, varia-

tion in estimated daily consumption by larval fish may

be caysed in part by the differences between the

weight estimate for the average prey item and the

actual weight of the item eaten. Clearly, an error in

estimating food consumption can also result from

ignoring specific differences in caloric content among

prey organisms.

Regressions of the width-weight measurements can

be used to predict the dry weight of rotifers and nauplii

of known width. The copepod width-weight model

probably cannot be used for weights of calanoid life

stages because calanoid nauplii are shaped more like

an ellipsoid and thus would weigh more than dor-

soventrally compressed harpacticoid nauplii of corre-

sponding width. The copepod volume-weight model

may be applicable to calanoid life stages.

Source: GAIL H. THEILACKER AND AMY S. KIMBALL

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Southwest Fisheries Center

La Jolla, California 92038

http://www.calcofi.org/newhome/publication...r___Kimball.pdf