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Panagrellus redivivusmass produced on solid media
as live food for Litopenaeus vannamei larvae
Ulfert Focken1, Christian Schlechtriem1,, Matthias von Wuthenau1, Armando Garc|a-Ortega2,
Ana Puello-Cruz2 & Klaus Becker1
1Aquaculture Systems and Animal Nutrition in the Tropics and Subtropics (480B), University of Hohenheim, Stuttgart,
Germany2CIAD (Research Centre for Food and Development), Aquaculture and Environmental Management, Mazatlan, Mexico
Correspondence: U Focken, Aquaculture Systems and Animal Nutrition in the Tropics and Subtropics (480B), University of Hohenheim
(480B), 70593 Stuttgart, Germany. E-mail: [email protected] address: Institute of Aquaculture, University of Stirling, Stirling, Scotland, UK.
Abstract
The free-living soil nematode Panagrellus redivivus is
well known to be an excellent food source for rst
feedi ng sh larvae. It represents an alternative to the
highly expensive Artemia, which is commonly used.
The lack of a proper method for mass production of
P. redivivus has prevented its wider use in commercial
hatcheries. A newcultivation method allows the pro-
duction of a sucient quantity of nematodes to deli-
ver a standardized and permanently available live
food of high quality, throughout the larval rearing
period. In two experiments ^ carried out at the Cen-tro de Investigacion en Alimentacion y Desarrollo,
Mexico ^ several feeding regimes were established to
prove the quality of the mass produced P. redivivus for
larvae of Litopenaeus vannamei, the Pacic white
shrimp. Two dierent nematode treatments were
compared with a no-feed group and a control group
that was fed withArtemia. All treatments had an ad-
ditional algal co-feed and were run in ve replicates.
Panagrellus redivivus was cultured on two dierent
media (wheat/corn our and oat our) to compare
these for their suitability as high-quality live food for
the larvae. Shrimp fed nematodes grown on wheat/
corn medium reached the postlarval stage earlier
than those from other treatments. The nematode
treatments showed promising results; however,
further research is needed on the development of im-
proved culture media or enrichment methods to
further increase the nutritional value ofP. redivivus.
Keywords: Litopenaeus vannamei, larviculture,
live food, nematodes
Introduction
The contribution of the crustacean to the world
aquaculture production values (excluding algae)
reached 22.6% in 2004. Shrimps ^ representing 83%
of crustacean production in tonnes and 85% in va-
lues ^ are the largest group of species in crustacean
farming. Most of these shrimp species derive from
the family Penaeidae. Litopenaeus vannamei contri-
butes to 47% of aquacultural shrimp production and
43% of production values (FAO 2006).
One of the major bottlenecks in aquaculture pro-
duction is the rearing of sh and crustacean larvae(Lavens & Sorgeloos 1996). This is due to the fact that
many of the species cultured depend on live
food during larval stages (Sorgeloos, Dhert & Candre-
va 2001). This live food s hould be easily available, re-
producible and economical (Watanabe & Kiron1994).
Problems occurring in supply with this live food may
prevent successful larval rearing, which limits the
whole production system (Guillaume, Kaushik, Ber-
got & Me tailler 2001).
The most frequently used live food organism is the
brine shrimp Artemiasp. This small crustacean has
the advantage that its culture can be started from
dried eggs (Sorgeloos & Persoone 1975; Liao 1992).
These dormant cysts can be stored for longer periods
in cans and, if needed, used as a convenient o-the-
shelf live food (Lavens & Sorgeloos 2000). All that is
needed for incubation is t he hydration of the cyst in
warm, aerated seawater and illumination.This is suf-
cient to start the embryonic development in the dor-
mant cysts and leads to the hatching of the nauplii
(Sorgeloos & Persoone 1975).
Aquaculture Research, 2006, 37, 1429^1436 doi: 10.1111/j.1365-2109.2006.01578.x
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Although Artemia is particularly convenient to use
in hatcheries (Wickins & Lee 2002), it also has some
prominent negative aspects. The most common ones
are: high costs, a highly variable hatching rate, quick
growth, the varying nutritional quality and the prop-
erty to consume algal feed and therefore to competewith the cultured species for food (Biedenbach,
Smith, Thomsen & Lawrence 1989; Lavens & Sorge-
loos 1996, 2000). The main drawback for future use
is that the cyst production in the Great Salt Lake
(Utah, USA) which is the major production site ofAr-
temia, is limited and does not satisfy the growing
world demand (Lavens & Sorgeloos 2000).
Owing to the obvious limitations ofArtemia, other
live organisms have been examined for their use in
penaeid shrimp larviculture; copepods, rotifers,
Daphnia,Moinaand nematodes have been suggested
by various authors (Wilkenfeld, Lawrence & Kuban
1984; Lavens & Sorgeloos 1996; Guillaume et al .
2001; Lee, OBryen & Marcus 2005).
Samocha and Lewinsohn (1977) reported on the
successful use of the free-living soil nematodePana-
grellusredivivus in rearingpostlarvae ofPenaeusse mi-
sculcatus and Metapenaeus stebbingi. The authors gave
nematodes in a ground mixture withSepia,Artemia,
Tubifex and Enchytraeus. Kahan, Bar-El, Brandstein,
Rigbi and Oland (1980) suggested nematodes as a po-
tential candidate for a live food organism in rearing
sh fry. Their suitable size, high nutritional values
and an easy cultivation promised nematodes to be a
valuable feed. Wilkenfeldet al. (1984) stated that thenematodes were able to substituteArtemiain penaeid
larval rearing diets. Their experiments showed the
capability ofFarfantepenaeus aztecus,Litopenaeus seti-
ferus and L. vannamei to consume and survive on
P. redivivus as the only food source from the Proto-
zoea 1 (PZ-1) stage. Experiments of Biedenbachet al.
(1989) withP. redivivusin the larval rearing ofL. van-
nameiconrmed these results.
Hitherto, nematodes are most commonly cultured
on a variety of solid and liquid media. In these pro-
duction systems, only small amounts of nematodes
could be produced.The lackof a proper mass produc-
tion technology for nematodes is the most limiting
factor to commercial application (Fisher & Fletcher
1995) and further investigation on such techniques
is recommended (Biedenbachetal . 1989).
Fisher and Fletcher (1995) produced nematodes
by the means of a biological fermenter lled with
culture medium, inoculated with Escherichia coli
and P. redivivus. Although designed for the produc-
tion of large quantities of nematodes, it seems that
this system has not yet been commercially
established.
Bedding (1981) and Bedding, Staneld and Cromp-
ton (1991) developed a solid-medium technique for
the production of entomopathogenic nematodes like
Neoplectana spp. and Heterorhabditis spp. With thenovelty of the exploitation of the third dimension,
this system enlarges the usable surface inside the
growing system by using crumbled polyether poly-
urethane sponges to create an interstitial space. This
space allowed optimal reproduction conditions and
served as a living habitat for the nematodes. It also
guaranteed sucient aeration. From the solid-med-
ium system of Bedding (1981) and Bedding et al.
(1991), Ricc i, Fi, Ragni, Schlechtriem and Focken
(2003) developed a system for the mass production
ofP. redivivus. It consisted of autoclavable plastic bags
lled with sponges soaked with medium. The bags
were inoculated with Saccharomyces cerevisiae to
guarantee a monoxenic culture. The system was
aerated and kept humid during the 11^13 days of
incubation. Several media, medium quantities and
inoculation densities have been investigated. Com-
pared withthe biological fermenter proposed by Fish-
er and Fletcher (1995), the bag system by Ricci et al.
(2003) delivers higher multiplication factors and is
less complicated to apply (Schlechtriem, Ricci, Fock-
en & Becker 2004a).
Rouse, Webster and Radwin (1992) have shown
that the nutritional character ofP. redivivus depends
on the nutritional qualities of the culture medium itis grownon.Wilkenfeld etal. (1984) used soft dough of
corn our and deionized water; Biedenbach et al.
(1989) worked with a mixture (50/50) of non-
bleached wheat our, corn meal and deionized water
to produce soft dough. Kumlu, Fletcher and Fisher
(1998) used baed 250 mL asks and a medium of
animal protein, corn oil and yeast inoculated with
E. coli. Riccietal . (2003) used an oatmeal-based med-
ium and a soluble medium made up of puried ingre-
dients, resembling the proximate composition of oat.
Additional investigations concerning the eect of an
added oil source (sh oil or sunower oil) on body
composition, average yields and multiplication fac-
tors of the nematodes were conducted by Schlech-
triem, Ricci, Focken and Becker (2004a, b). The
enrichment of culture media with further lipid
sources (capelin oil, cod liver oil and marilla oil) was
tested by Kumluetal . (1998).
There are several studies on the use of mass-pro-
ducedP. redivivus in the rearing of rst feeding sh
larvae (Santiago, Ricci & Reyes-Lampa 2004;
Nematodes as live food for shrimp larvae U Focken et al. Aquaculture Research, 2006, 37, 1429^1436
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Schlechtriem et al. 2004a, b; Schlechtriem, Focken &
Becker 2005). The authors concluded that the bag
system is suitable for the mass production of nema-
todes as live food for rst feeding larvae of sh and
crustacean species, and Ricciet al. (2003) stated that
it should be applicable for small-scale live feed produ-cers in developing countries dueto its simple technol-
ogy. Although there are several studies of the new
mass production system and it is known thatP. redi-
vivusis a suitable food for rst feeding shrimp larvae,
no trials have been conducted to evaluate the use of
mass-produced P. redivivusin the rearing ofL. vanna-
meilarvae.
In this study, P. redivivus was mass produced
according to the method of Ricci et al. (2003) on two
types of cereal-based media that are commonly used
for the cultivation of nematodes. The suitability of
both kinds of nematodes was compared with Artemia
intheiruse as live food forrearing L. vannamei larvae.
Materials and methods
Nematode production
The nematodes were mass produced on a monoxenic
solid culture (single microorganism: Saccharomyces
cerevisiae) accordingto Ricci etal. (2003).Two dierent
culture media were used. One consisted of a mix of
wheat and corn our (50/50) (Biedenbach et al. 1989)
and the other exclusively of oatmeal (Riccietal. 2003).
The ours were mixed with a 0.8% marine salt solu-tion (Tetra Marin), and crumbled polyether polyur-
ethane sponges (75 g) were added. The mixture of
sponges and culture media was inserted into autocla-
vable bags (50 30 cm) and then autoclaved for
55 min at 121 1C. Each bag was inoculated with ap-
proximately 5.5 105 organisms ofP. redivivus. The
bags were aerated via plastic tubes; the incoming air
passed an air lter (0.2 mm) and a bottle lled with
water, resulting in a constant humidity of air. The ne-
matode culture was incubated for12 days in a climati-
callycontrolled room at an average of 22 1C.
For harvest, culture media with nematodes were
placed in a sieve clad out with a milk lter
(+200 mm, Hygia Favorit by Paul Hartmann AG,Heidenheim, Germany). This sieve was placed on a
plate half lled with water. Nematodes crawling
through the milk lter dropped into the water. This
water was ltered several times with a 112 mm plank-
ton net until most of the nematodes were removed.
The mass of nematodes was washed with distilled
water to clean them from adhering culture media or
yeast. Nematodes were harvested daily and stored
until feeding in a Petri dish in a fridge at ca.4 1C.
Feeding trials
The experimental set-up for shrimp larval rearing
was adapted from Puello-Cruz, Sangha, Jones and Le
Vay (2002). Twenty bottles with a round body and a
long neck were placed in a water bath at 28 1C in an
air-conditioned chamber at 22 1C with a 12 h dark/
light cycle. Each bottle contained 1.5 L of fresh s ea-
water at 35 1ppt. The water was aerated by the
means of plastic tubes (+0.5 cm) ending in a glass
tube, reaching down to the bottom. The current of
the air stream was regulated, so that one air bubble
per second was emitted, which guaranteed sucient
aeration and food distribution in the water column.Bottles were stocked with batches of 150 nauplii of
L. vannamei. In the rst trial, stocking was performed
using a volumetric method. Even though nauplii at
this stage still deplete internal reserves and do not
feed on algae, a mixture of 20 algalcells mL1 (70%
Chaetoceros muelleri, 30% Isochrisis galbana) was
added to guarantee feed supply once the animals
reached the protozoea stage.
Table 1 Treatments and feeds for each successive stage of larval development ofLitopenaeus vannamei
Stage Wheat/corn-nematodes Oat-nematodes Artemia Algae-only
Nauplius 5 Mixed algae: 20 cellsmL1 Mixed algae: 20 cellsmL1 Mixed algae: 20 cellsmL1 Mixed algae: 20 cellsmL1
Protozoea 1 Mixed algae: 50 cellsmL1 Mixed algae: 50 cellsmL1 Mixed algae: 50 cellsmL1 Mixed algae: 50 cellsmL1
Protozoea 2 Mixed algae: 50 cellsmL1
P. redivivus: 75mL1 (100mL1)
Mixed algae: 50 cellsmL1
P. redivivus: 75mL1 (100mL1)
Mixed algae: 50 cellsmL1 Mixed algae: 50 cellsmL1
Protozoea 3
to Mysis 3
P. redivivus: 75mL1 (150mL1) P. redivivus: 75mL1 (150mL1) Artemia: 210mL1 Mixed algae 50 cellsmL1
Number of nematodes fed in the second experiment are given in parenthesis.
P. redivivus, Panagrellus redivivus.
Aquaculture Research, 2006, 37, 1429 ^1436 Nematod es a s live fo od for s hr imp l ar vae U Focken et al.
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Four dierent treatments with ve replicates each
were teste d (Table 1): one Artemiatreatment, two ne-
matode treatments (oat and wheat/corn) and one
treatment of algae only. In the rst stages ^ from Nau-
plii 5 to Protozoea 3 (PZ3) ^ all treatments were fed
with an algae mixture of 70% C. muelleri and 30%I. galbana. From stage PZ2 on, nematodes were given.
Owingto its size, Artemia couldonlybe fed from stage
PZ3 on. This kind of feeding had been used as Arte-
mia treatment in former experi ments in CIAD. To the
remaining ve replicates, no further food but algae
was added.
The mixture of algae was prepared from algae
(C. muelleriand I. galbana) strains regularly used in
CIAD. Algae were cultivated in aerated seawater
(35 1ppt) at a temperature of 22 1 1C.The num-
bers of cells were evaluated under the microscope,
the mixture was prepared and the appropriate
amount of algal solution (Table 1) was injected into
the bottles by means of a syringe.
Artemiacysts (Premium Brine Shrimp eggs, Prime
Artemia, Midvale, UT, USA) were incubated for 24 h at
28 1C, an average salinity of 35 ppt and constant illu-
mination.The hatched Artemia nauplii were separated
from the remaining cysts, whether unhatched or bro-
ken, and inserted into the bottles after counting.
Nematodes were constantly extracted and counted
daily. The number of nematodes per millilitre in the
resulting solution was calculated and the appropriate
amount of animals was injected into the bottles. The
numberof nematodes and Artemia andthe amount ofalgae fed were adapted towards the growing de-
mands of the growing larvae (see Table 1). In the rst
experiment, 75 nematodes mL1were given for each
developmental stage. In the second experiment,
100 nematodes mL1 were given for PZ3 and
150 nematodes mL1 for the subsequent stages. In
this experiment, the nauplii of L. vannamei were
counted individually. Apart from these changes, the
set-up of both experiments was identical. Represen-
tative samples of nematodes andArtemia were freeze
dried for later chemical analysis.
The experiments were terminated when 90% of
the shrimps in one replicate of onetreatment reached
the rst postlarval stage. The larvae and postlarvae
were counted for survival, development stages were
evaluated and the length of the animals was mea-
sured. The accumulated average dry weight of the
larvae was measured after freeze-drying.
Statistical analysis was performred with the pro-
gramme GRAPHPAD PRISM 4.03 and INSTAT 3.05. Data
were analysed using a one-way analysis of variance
(ANOVA) and the Tukeys test after testing for devia-
tions from normal distribution by the using Kolmo-
gorov^Smirnovs test. The dierences were reported
as statistically signicant whenPo0.05.
Results
In the two experiments conducted, the most striking
dierence was observed in the rates of development
and survival. In the rst experiment, all animals of
theArtemiatreatment were found in the postlarval
stage at day 11. A n average of 16% of the shrimp fed
oat-nematodes transformed into postlarval stages.
No further postlarvae were found in any other treat-
ment. (Fig.1).
In the rst experiment, the highest average survi-
val was found in the oat-nematode treatment (85.8%),followed by shrimps from algae-only treatment
(72.6%), the Artemia treatment (70.0%) and the
wheat/corn-nematode treatment (69.6%). No signi-
cant dierence in survival could be observed be-
tween the treatments from the rst trial (Table 2).
The average dry weight of the shrimps from the Arte-
mia treatment (90.9mg) was signicantlyhigher than
that of shrimps from the other treatments (Table 2).
The weight of shrimps fed oat nematodes (45.5 mg),
wheat/corn nematodes (37.9 mg) or algae-only
(30.3 mg) did not dier signicantly from each other.
Shrimps fed Artemia (5.7 mm) were signicantly
longer than the animals from other treatments.
Shrimp from the wheat/corn-nematode treatment
Artemia Oat Nem WC Nem Algae0
25
50
75
100
Mysis 3Postlarvae Mysis 2
Diet
%
Figure 1 Average number of shrimps found in the dier-
ent developmental stages in the dierent treatments from
the rst experiment (Day 11). Oat Nem, nematodes reared
on oat medium; WC Nem, nematodes reared on wheat/
corn medium.
Nematodes as live food for shrimp larvae U Focken et al. Aquaculture Research, 2006, 37, 1429^1436
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(4.8 mm) were signicantly longer than shrimp algae
only (4.4 mm); shrimps fed oat nematodes (4.6 mm)
were intermediate anddid notdier from wheat/corn
nematode or algae treatment.
In the second experiment, in which the feeding
intensity for the nematode treatments had been
increased, the development in the wheat/corn nema-
tode treatment was faster. On day 9, in some repli-
cates of this treatment, all animals had reached
postlarval stage, the average was 74%, followed by
the oat-nematode treatment with 70%. Only 4% of
the shrimp from the Artemia treatment had trans-
formed to the postlarval stage at that day (Fig. 2).
Survival rates, dry weight and length at the end of
the second experiment are given in Table 3. Shrimps
fed algae-only, Artemia and wheat/corn-nematodes
had a survival rate of 90.4%,85.1% and 74.8% respec-
tively.The lowest survival rate was observed in the
oat-nematode treatment (37.1%). The survival of
shrimps fed oat-nematodes was signicantly lower
than the survival rate of shrimps fedArtemiaand al-
gae-only. The survival rate of animals fe d wheat/
corn-nematodes was not statistically dierent from
those of any other treatment. In dry weight, no sig-
nicant dierences occurred between shrimps fed
with Artemia(82.1 mg) or nematodes, whether these
were grown on oat (82.8 mg) or wheat/corn (80.2 mg)
medium.The weights of the shrimps from thesethree
treatments was signicantly higher than that of
shrimp from the algae-only treatment (26.8 mg). In
the second experiment, the average length of
shrimps fed oat nematodes or wheat/corn nematodes
was identical (5.2 mm). The dierence f rom shrimps
fed Artemia (4.8 mm) was not signicant. All three
treatments showed a s ignicant dierence in length
compared with the shrimps from the algae-only
treatment (3.7 mm).
Discussion
The experiments ended when 90% of the shrimps of
one replicate of a treatment had transformed into the
rst postlarval stage. Shrimps in the other treatments
found in larval stages ^ for example mysis ^ were
judged to show a slower development compared with
those already in the postlarval stage. During the two
experiments, it was observed that if shrimps of one
treatment performed well in terms of fastness of de-
velopment, the survival rate of the same treatment
was lowered. This may be due to the higher number
of moults that postlarvae have already performed
during their development compared with the lower
stages. Generally, the mortality in this experiment
was similar to that observed by Puello-Cruz et al.
(2002) in the same set-up (47.6^70.0%), but some-
what lower than the values observed by Wilkenfeld
et al. (1984) and Biedenbach et al. (1989), who report
survival rates between 73% and 90%.The large stan-
dard deviation indicates that survival may have also
been aected by factors not related to the feeding
Table 2 Survival rate, nal dry weight and length ofLitopenaeus vannameifrom Experiment1
Diet
Artemia Oat nematodes Wheat/corn nematodes Algae
Survival (%) 70.0 34.6 85.8 9.8 69.6 18.6 72.6 17.9
Dry weight (mg) 90.9a 15.6 45.5b 18.3 37.9b 8.2 30.3b 4.0
Length (mm) 5.7a 0.1 4.6bc 0.2 4.8b 0.2 4.4c 0.1
Mean SD, ve replicates per treatment.
Means not sharing a common superscript are statistically dierent at Po0.05.
Artemia Oat Nem WC Nem Algae0
25
50
75
100
Mysis 3
Postlarvae
Mysis 1
Mysis 2
Diet
%
Figure 2 Average number of shrimps found in the dier-
ent developmental stages in the dierent treatments from
the second experiment (Day 9). Oat Nem, Nematodes
reared on oat medium; WC Nem, Nematodes reared on
wheat/corn medium.
Aquaculture Research, 2006, 37, 1429 ^1436 Nematod es a s live fo od for s hr imp l ar vae U Focken et al.
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treatments, oering scope to improve survival in all
treatments. To reach postlarval stages faster means
to have shorter intermoult periods in that the animal
can replace energy losses during moults. Moulting
animals are also especially vulnerable to cannibal-
ism (Wickins & Lee 2002) and weak in the end of
moulting (Hartnoll 1982). The whole progress of
moulting and emerging from the old exosceleton is
an energy-consuming activity (Hartnoll 1982) and
all of this may weaken and stress the shrimp larvae
and could lead to a lower survival rate.
Hartnoll (1982) described the growth of crusta-
cean species as a discontinuous process with succes-
sive moults and intermoults. During the moults, the
animals shed their old integument and gain body
length and mass until the new integument has har-
dened (Wickins & Lee 2002). No major growth in
fresh weight occurs in the intermoult, which is the
time between two moults. Owing to the hard exoske-
leton, the growth is restricted and may be ignored formost purposes (Hartnoll 1982). The discontinuous
growth pattern may also explain the lack of a signi-
cant dierence in the average dry weight as observed
between shrimps from the dierent treatments of the
second trial. Shrimps fed oat-nematodes were signi-
cantly longer than shrimp from the Artemia treat-
ment and therefore a higher dry weight should be
expected. However, the growth occurring during
moulting is mainly due to the absorption of water; la-
ter, this water will be replaced gradually by proteins
(Wickins & Lee 2002). Just having passed into the
postlarval stage, this water has not been replaced by
proteins and dry weight of the freshly moulted
shrimps may be lower than that of those still in the
last larval stage.
The gradual increase in nematodes injected into
the bottles during the second experiment induced a
similar performance of larvae fed nematodes com-
pared with shrimps fed Artemia. Shrimps from both
nematode treatments outperformed those from the
algae-only treatment in all relevant criteria except
survival rate. The signicantly (Po0.05) lower survi-
val rate in the oat-nematode treatment during the
second experiment may be due to the faster develop-
ment of the shrimp larvae or to lower water quality, a
topic that is most critical during larvae culture
(Wickins & Lee 2002). In the experiment conducted
no water exchange was performed to guarantee an
undisturbed larval development. However, for feed-
ing high numbers of nematodes, a water exchange
seems crucial, due to nematodes dying and decaying
after 72 h in salt water (Biedenbachet al. 1989). The
introduction of residues of nematode culture med-
ium into the experimental system may also have a
detrimental eect on the water quality. The problem
of a lower water quality using nematodes as live feed
was described by other authors (Wilkenfeld et al.
1984; Biedenbach et al. 1989; Santiago et al. 2004).
However, washing nematodes even more thoroughly
before being fed to shrimp larvae may reduce the risk
of introducing micro-organisms or residues of cul-ture medium. A regular water exchange or adding
water during larval culture ^ as practiced in com-
mercial hatcheries ^ should further enhance water
quality. In future experiments, higher survival rates
may be accomplished if these points are taken into
consideration.
Litopenaeus vannamei has a dietary protein re-
quirement of about 20^30% (New 1980); however,
their larvae, that are more carnivorous, may have a
higher requirement (Lee, Smith & Lawrence 1984).
The body compositions of nematodes produced on
oatmeal and wheat/corn medium were described in
detail by Schlechtriemet al. (2004a) and Biedenbach
etal. (1989). Nematodesgrown on oat and wheat/corn
mediumhada crude proteincontent of 62% and 48%
in the dry matter respectively. The amino acid c om-
position of both types of nematodes was similar to
that of plankton and Artemia and can thus be consid-
ered to be appropriate to cover the essential amino
acid requirement of shrimp larvae. The lipid require-
ments of penaeid larvae are not fully understood but
Table 3 Survival rate, nal dry weight and length ofLitopenaeus vannameifrom Experiment 2
Diet
Artemia Oat nematodes Wheat/corn nematodes Algae
Survival % 85.1a 8.6 37.1b 33.8 70.8ab 30.3 90.4a 3.0
Dry weight (mg) 82.1a 8.8 82.8a 17.4 80.2a 11.9 26.8b 1.2
Length (mm) 4.8a 0.3 5.2a 0.3 5.2a 0.3 3.7b 0.2
Mean SD, ve replicates per treatment.
Means not sharing a common superscript are statistically dierent at Po0.05.
Nematodes as live food for shrimp larvae U Focken et al. Aquaculture Research, 2006, 37, 1429^1436
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a crucial role of polyunsaturated fatty acids, choles-
terol and phospholipids became apparent during the
last years (Jones,Yule & Holland1997; Guillaume etal.
2001). As other animals, crustaceans are incapable of
producing linoleic acid (LIN, 18:2n6) and a-linolenic
acid (ALA, 18:3n3), but they can use these as precur-sors to synthesize the corresponding higher polyun-
saturates. However, the ability for bioconversion of
ALA and LIN to highly unsaturated fatty acids
(HUFA) as eicosapentaenoic (EPA; 20:5n3) and deco-
sahexaenoic (DHA; 20:6n3) is limited (Teshima, Ka-
nazawa & Koshio 1992) and therefore requirements
for these compounds must be satised by the diet.
Phospholipids, which play an important role in cellu-
lar membranes as well as sterols that cannot be
synthesized by crustaceans, are further essential
dietary compounds.The chemical composition of ne-
matodes can be signicantly inuenced by the com-
position of the culture medium, that is at least partly
ingested by the nematodes. The lipid class composi-
tion ofP. redivivusmass produced on dierent media
was described in detail by Schlechtriem,Tocher, Dick
and Becker (2004c). Nematodes produced on cereal-
based medium are poor in EPA and contain no DHA;
however, Schlechtriem et al. (2004b) described that
the addition of sh oil to culture media can increase
the HUFA content of the nematodes signi cantly.
The results of this study show that mass-produced
P. redivivus seems to be a potentialreplacement forAr-
temia in the larval rearing ofL. vannamei. However,
further studies are required to test whether tailoringthe body composition ofP. redivivustowards the spe-
cic need of crustacean species can further improve
the nutritional value and thus the suitability of ne-
matodes in larval rearing of shrimps.
Acknowledgment
This work was partly funded by a grant of the Eiselen
Foundation Ulm to MvW.
References
Bedding R.A. (1981) Low cost in vitro mass production of
Neoplectana and Heterorhabditis species (Nematoda) for
eld control of insect pests.Nematologica 27, 109^114.
Bedd ing R.A., Staneld M.A. & Crompton G.V. (1991)Appara-
tus and methods for rearing nematodes, fungi, tissue cultures
and the like, and for harvesting nematodes. Patent, Interna-
tional application nu mber, PCT/AU91/00136.
Biedenbach J.M., Smith L.L.,Thomsen T.K. & Lawrence A.L.
(1989) Use of the nematodePanagrellus redivivusas anAr-
temiareplacement in a larval penaeid diet. Journal of the
World Aquaculture Society 20, 61^71.
FAO (2006)FISHSTAT Plus: Universal softwarefor shery sta-
tistical timeseries.Version 2.3.2000 Fisheries Department,
Fishery Information Data and Statistic Unit Data sets
released March 2006.
Fisher C.M.L. & Fletcher D.J. (1995): Novel feeds for use in
aquaculture. Patent, International application number,
A01K67/033, A23K1/18.
Guillaume J., Kaushik S., Bergot P. & Metailler R. (2001)
Nutrition and Feeding of Fish and Crustaceans. Springer
Praxis, Chichester, Great Britain, 408pp.
Hartnoll R.G. (1982) Growth. In: The Biology of Crustacea,
Vol. 2: Embryology, Morphology, and Genetics(ed. by L.G.
Abele), pp.111^185. Academic Press, NewYork, USA.
Jones D.A.,Yule A.B. & Holland D.L. (1997) Larval nutrition.
In:Advances inWorld Aquaculture,Vol.6: Crustacean Nutri-
tion(ed. by L.R. DAbramo, D.E. Conklin & D.M. Akiyama),pp. 353^389. The World Aquaculture Society, Louisiana,
USA.
Kahan D., Bar-El T., BrandsteinY., RigbiM. & OlandB. (1980)
Free livingnematodes as a dietarysupplementin therear-
ing of sh fry and hatcheries. General Fisheries Council
for the Mediterranean.Studies and Reviews 57, 67^78.
Kumlu M., Fletcher D.J. & Fisher C.M.L. (1998) Larval pig-
mentation, survival and growth ofPenaeus indicusfed ne-
matode Panagrellus redivivus enriched with astaxanthin
and various lipids.Aquaculture Nutrition 4, 193^200.
Lavens P. & Sorgeloos P. (1996)Manual in the Production and
Use of Live Food forAquaculture.FAO, FisheriesTechnical Pa-
per (361). FAO, Rome, Italy.
Lavens P. & Sorgeloos P. (2000) The history, present status
andprospects of theavailabilityofArtemia cysts forAqua-
culture.Aquaculture 181, 397^403.
Lee C.S., OBryen P.J. & Marcus N.H., (eds) (2005) Copepods in
Aquaculture. Blackwell Publishing, Ames, IA, USA.
Lee P.G., Smith L.L. & Lawrence A.L. (1984) Digestive pro-
teases of Penaeus vannamei: relationship between enzyme
activity, size and diet.Aquaculture 42, 225^239.
Liao I-C. (1992) Penaeid larvicultu re: taiwanese method. In:
MarineShrimpCulture:Principles and Practices(ed. byA.W.
Fast & L.J. Lester),pp.193^215. Elsevier SciencePublishers
B.V., Am sterdam, the Netherlands.
New M.B. (1980) Bibliography of shrimp and prawn nutri-
tion.Aquaculture 21,101^128.Puello-Cru z A.C., Sangha R.S., Jones D.A. & Le Vay L. (2002)
Trypsin enzym activity during larval development ofLito-
penaeus vannamei (Boone) fed on live feeds. Aquaculture
Research 33, 333^338.
Ricci M., Fi A.P., Ragni A., Schlechtriem C. & Focken U.
(2003) Development of a low-cost technology for mass
production of the free-living nematodePanagrellus redivi-
vus as an alternative live food for rst feeding sh larvae.
Applied Microbiologyand Biotechnology 60, 556^559.
Aquaculture Research, 2006, 37, 1429 ^1436 Nematod es a s live fo od for s hr imp l ar vae U Focken et al.
r 2006 The Authors
Journal Compilationr 2006 Blackwell Publishing Ltd, Aquaculture Research, 37, 1429^1436 1435
8/10/2019 9fcfd50d20ed062197
8/8
Rouse D.B.,Webster C.D. & Radwin I.A. (1992) Enhancement
of the fattyacid composition of the nematodes Panagrellus
redivivususing three dierent media. Journal of theWorld
Aquaculture Society 23, 89^95.
Santiago C.B., Ricci M. & Reyes-Lampa A. (2004) Eect of
nematodePanagrellus redivivusdensity on growth, survi-
val, feed consumption and carcass composition of big-
head carp Aristichtys nobilis (Richardson) larvae.Journal
of Applied Ichthyology 20, 22^27.
Samocha T. & Lewinsohn C. (1977) A preliminary report on
rearing penaeid shrimps in Israel. Aquaculture10, 291^292.
Schlechtriem C., Ricci M., FockenU. & Becker K.(2004a) The
suitability of the free living nematode Panagrellus redivi-
vus as live food for rst-feeding sh larvae. Journal of
Applied Ichthyology 20,161^168.
Schlechtriem C., Ricci M., Focken U. & Becker K. (2004b)
Mass produced nematodes Panagrellus redivivus as live
foodfor rearingcarp larvae. Preliminary results. Aquacul-
ture Research 35, 547^551.
Schlechtriem C., Tocher D.R., D ick J.R. & Becker K. (2004c)Incorporation and metabolism of fatty acids by desatura-
tion andelongationin the nematode Panagrellus redivivus.
Nematology 6,783^795.
Schlechtriem C., Focken U. & Becker K. (2005) Digestion and
assimilation of the free-living nematode Panagrellus redi-
vivus fed to rst feeding coregonid larvae: evidence from
histologicaland isotopic studies.Journal of theWorld Aqua-
culture Society 36, 24^31.
Sorgeloos P. & Persoone G. (1975) Technological improve-
ments for thecultivationof invertebrates as foodfor shes
and crustaceans. II. Hatching and culturing of the brine
shrimp,Artemia salinaL.Aquaculture 6, 303^317.
Sorgeloos P., Dhert P. & Candreva P. (2001) Use of the brine
shrimp, Artemia spp., in marine sh larviculture. Aqua-
culture 200, 147^149.
Teshima S., Kanazawa A. & Koshio S. (1992) Ability for
bioconversion of n-3 fatty acids in sh and crustaceans.
Oceanis 18, 67^75.
Watanabe T. & Kiron V. (1994) Review ^ prospects in larval
nutrition.Aquaculture 124, 223^251.
Wickins J.F. & Lee D.OC. (2002) Crustacean Farming Ranching
and Culture, 2nd edn. Blackwell Science, Oxford,446pp.
Wilkenf eld J.S., Lawrence A.L. & Kuban F.D. (1984) Survival,metamorphosis and growth of penaeid shrimp larvae
reared on a variety of algal and animal foods. Journal of
theWorld Maricultural Society 15, 31^49.
Nematodes as live food for shrimp larvae U Focken et al. Aquaculture Research, 2006, 37, 1429^1436
r 2006 The Authors
1436 Journal Compilationr 2006 Blackwell Publishing Ltd, Aquaculture Research, 37, 1429^1436