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| Larviculture newsletter < Year 2005 < Issue 222 |
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| Larviculture newsletter < Year 2005 < Issue 222 |
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THE AMERICAN BRINE SHRIMP AS AN EXOTIC INVASIVE SPECIES IN
THE WESTERN MEDITERRANEAN
Francisco Amat, Francisco Hontoria, Olga Ruiz, Andy J. Green, Marta I. Sanchez,
Jordi Figuerola, Francisco Hortas-2005
Biological Invasions 7: 37-47
Abstract:
The hypersaline environments and salterns present in the western Mediterranean
region (including Italy, southern France, the Iberian Peninsula and Morocco)
contain autochthonous forms of the brine shrimp Artemia, with parthenogenetic
diploid and tetraploid strains coexisting with the bisexual species A. salina.
Introduced populations of the American brine shrimp A. franciscana have also
been recorded in these Mediterranean environments since the 1980s. Based on
brine shrimp cyst samples collected in these countries from 1980 until 2003,
we were able to establish the present distribution of autochthonous brine shrimps
and of A. franciscana, which is shown to be an expanding invasive species. The
results obtained show that A. franciscana is now the dominant Artemia species
in Portuguese salterns, along the French Mediterranean coast and in Cadiz bay
(Spain). Co-occurrence of autochthonous (parthenogenetic) and American brine
shrimp populations was observed in Morocco (Mar Chica) and France (Aigues Mortes),
whereas A. franciscana was not found in Italian cyst samples. The results suggest
these exotic A. franciscana populations originate as intentional or non-intentional
inoculations through aquacultural (hatchery effluents) or pet market activities,
and suggest that the native species can be rapidly replaced by the exotic species.
(Instituto de Acuicultura de Torre de la Sal (CSIC), 12595 Ribera de Cabanes
(Castellon), Spain; email of F. Amat: amat@ iats.csic.es)
DISPERSAL OF INVASIVE AND NATIVE BRINE SHRIMPS ARTEMIA (ANOSTRACA)
VIA WATERBIRDS
A.J. Green, M.I. Sánchez,, F. Amat, J. Figuerola, F. Hontoria, O. Ruiz, F. Hortas-2005
Limnal. Oceanogr. 50(2): 737-742
Abstract:
North American brine shrimp Artemia franciscana have been exported worldwide
since the 1950s for use in aquarium trade and fish farming. Aquaculture is expanding
along the Mediterranean coast, leading to the release of A. franciscana into
native Artemia populations. A. franciscana was first detected in 1981 in Portugal
and has since spread to saltworks along the East Atlantic flyway used by shorebirds.
Once A. franciscana becomes established in a locality, native Artemia tend to
disappear. To test whether migratory shorebirds can disperse invasive and native
Artemia between wetlands, we extracted Artemia cysts from feces and pellets
collected at Castro Marim (Portugal) and Cadiz Bay (Spain) during southward
migration. We found that large numbers of viable eggs of A. franciscana and
native Artemia parthenogenetica were dispersed by Redshank Tringa totanus, Blacktailed
Godwit Limosa limosa, and other shorebirds migrating through the Iberian Peninsula.
This is the most extensive field demonstration to date that invertebrates can
disperse readily via gut passage through birds.
(Estación Biológica de Dońana, Avda. María Luisa s/n, 41013 Sevilla, Spain;
email of A. Green: ajgreen@ebd.csic.es)
DISSOLVED INORGANIC CARBON UPTAKE BY RHODOMONAS SP. AND ISOCHRYSIS
AFF. GALBANA DETERMINED BY A POTENTIOMETRIC TECHNIQUE
Tania K. Camiro-Vargasa, J. Martín Hernández-Ayóna, Enrique Valenzuela-Espinoza,
Francisco Delgadillo-Hinojosa, Ramón Cajal-Medrano-2005
Aquacultural Engineering 33 (2): 83-95
Abstract:
Dissolved inorganic carbon uptake (DIC) was determined in batch culture of the
marine microalgae Rhodomonas sp. and Isochrysis aff. galbana (Clone T-ISO) for
seven days using a simple potentiometric technique. The system used allowed
the determination of small variations of the three independent parameters: pH,
dissolved inorganic carbon and total alkalinity (At). The aerated cultures began
with 13 µmol kg-1 of CO2 (calculated using Ct-pH), but after the third day,
the concentration was almost zero. Cultures of Rhodomonas sp. continued growing
in the absence of CO2 with a total DIC depletion of 1330.5 µmol kg-1 and a final
pH of 10. Since HCO3- is the predominant form of inorganic carbon at alkaline
pH, Rhodomonas sp. shows potential for direct HCO3- uptake. On the other hand,
the cultures of I. aff. galbana only removed DIC during the first three days
while CO2 was available, and also when the pH from culture was below 9. Nutrients
(PO43-, NO3-, NO2- and NH4+) uptakes were also analyzed for the two cultures.
The nutrient uptake in both microalgae did not show dependency on any specific
DIC form. An extra addition of CO2 during cultivation is recommended for enhanced
growth mainly in I. galbana.
(Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California,
Km. 103, Carr. Tijuana-Ensenada, Baja California, México; email of J. Martín
Hernández-Ayóna: jmartin@uabc.mx)
HATCHERY PERFORMANCE OF EARLY BENTHIC JUVENILE AMERICAN LOBSTERS
(HOMARUS AMERICANUS) FED ENRICHED FROZEN ADULT ARTEMIA DIETS
Michael F. Tlusty, Jason S. Goldstein, Denise R. Fiore-2005
Aquaculture Nutrition 11(3): 191-198
Abstract :
One of the main factors hindering aquaculture production of American lobsters
(Homarus americanus) is the need for a cost-effective and nutritionally sound
diet. Live Artemia results in good growth, but is expensive and is a constant
source of contamination. Frozen Artemia, although lower in cost, generally results
in decreased survivorship and growth relative to live Artemia. The recent advent
and mass production of enriched frozen Artemia products may provide for a cost-effective
and nutritionally complete food source for culturing American lobsters. Here,
commercially available frozen adult Artemia enriched with either n-3 fatty acids,
or Spirulina was fed to juvenile American lobsters, and their growth and survivorship
for three months was compared with that of animals fed unenriched frozen adult
Artemia. Both enriched Artemia products produced survivorship superior to that
for animals fed unenriched Artemia. Results for growth were equivocal although
animals fed the Spirulina-enriched Artemia had the greatest condition factor.
Although more costly by the end of the experiment, enriched diets were more
economically efficient than unenriched Artemia. This research demonstrates that
enriched feedstuffs are cost-effective over longer time intervals, and benefits
may continue beyond the hatchery-rearing phase. Enriched diets may also yield
animals with a better condition factor, which may further influence their survivorship
when released to the wild in enhancement programmes.
(New England Aquarium, Research Department, 1 Central Wharf, Boston, MA 02110,
USA; email of Michael Tlusty: mtlusty@neaq.org)
EFFECT OF DIFFERENT FEED FORMULATIONS ON FEED EFFICIENCY, GONAD
YIELD AND GONAD QUALITY IN THE PURPLE SEA URCHIN HELIOCIDARIS ERYTHROGRAMMA
M. Senaratna, L.H. Evans, L. Southam, E. Tsvetnenko-2005
Aquaculture Nutrition 11(3): 199-208
Abstract:
The nutritive values of three pelleted prepared diets, based on animal (AP),
vegetable (VP) and yeast protein (YP) were studied for the sea urchin Heliocidaris
erythrogramma (Val.). Fresh macroalga Ulva australis was used as a natural control
diet. Triplicate groups of five animals were fed one of the four diets ad libitum
every second day for 85 days. Sea urchins fed pelleted feeds had significantly
higher food consumption rates (dry basis) and significantly lower total and
protein absorption efficiencies compared with the algal diet. The gonad yield
and gonad production efficiency in sea urchins fed the natural diet were significantly
higher compared with initial group (gonad yield only) and urchins fed animal
and vegetable diets, but did not differ significantly from those of the animals
fed the yeast diet. Percent protein and lipid in the gonads were not affected
by the dietary source. The taste and smell of gonads were generally better in
sea urchins collected from the wild or fed yeast and natural diets than in sea
urchins fed animal and vegetable diets. The animal protein diet was the most
stable in seawater while the yeast protein diet had the poorest water stability.
The results of this study suggest that development of a more stable, single-cell,
protein-based diet has a potential to promote gonad production of H. erythrogramma.
(Aquatic Science Research Unit, Curtin University of Technology, PO Box U1987,
Perth, WA 6845, Australia; email of Elena Tsvetnenko: e.tsvetnenko@curtin.edu.au)
EXAMINATION OF LARVAL MALFORMATIONS IN AFRICAN CATFISH CLARIAS
GARIEPINUS FOLLOWING FERTILIZATION WITH CRYOPRESERVED SPERM
Edit Miskolczi, Szilvia Mihálffy, Eszter Patakiné Várkonyi, Béla Urbányi? Ákos
Horváth-2005
Aquaculture 247 (1-4): 119-125
Abstract:
In our earlier experiments on the cryopreservation of African catfish (Clarias
gariepinus) sperm a high number of malformed individuals were found among the
larvae hatched from eggs fertilized with frozenthawed sperm. In our present
study we explored one of the possible reasons of this malformation by examining
the ploidy of the larvae. Sperm was frozen in a 6% fructose extender containing
10% methanol and 10% DMSO as cryoprotectant. Sperm was drawn to straw of different
volumes (0.25, 0.5 and 1.2 ml). Freezing was carried out in liquid nitrogen
vapor. Fifteen grams or thirty grams of eggs were used for fertilization. Chromosome
preparations were made of non-feeding larvae. Fifty to one hundred larvae were
incubated in 0.05% colchicine for 3 h then in a hypotonic 0.075M KCl solution
for 25 min. Larvae were fixed in a 3:1 solution of methanol and acetic acid,
then cell suspensions were made in 50% acetic acid. The suspensions were spread
on slides and stained in 4% Giemsa for 8 min. Chromosome counting and evaluation
was done at 1200× magnification on well spread metaphases. A majority of the
hatched larvae were diploid, with 56 chromosomes. Surprisingly some of the malformed
larvae hatched from eggs fertilized with cryopreserved sperm were haploids.
Haploids occurred only when 0.25 or 0.5 ml straws were used for freezing. One
possible explanation of haploidy is that the genome of the fertilizing spermatozoon
is damaged during the process of freezing thus it can still move and fertilize
the egg but its genome does not take part in the development of the embryo.
This hypothesis is supported by the fact that no haploids were found among the
malformed larvae of the control group which was fertilized with fresh sperm.
(Department of Fish Culture, Szent István University, H-2103 Gödöllo, Páter
K. u. 1., Hungary; email of Edit Miskolczi: miskolczi.edit@mkk.szie.hu)
RELATIONS BETWEEN EGG SIZE, REPRODUCTIVE SUCCESS AND GROWTH
PERFORMANCE OF PROGENY IN ISOGENIC OREOCHROMIS NILOTICUS LINES
Andreas Müller-Belecke-2005
Aquaculture 247 (1-4): 127-134
Abstract:
The present study followed the reproductive performance within four genetic
groups of Oreochromis niloticus females belonging to two homozygous isogenic
lines (C1, C2) developed by induced gynogenesis, a heterozygous isogenic line
(C1 × C2) resulting from crossbreeding C1 and C2, and a heterogenic control
group. Each genetic group consisted of 12 females and observations continued
for 60 days. Digital photographs were taken of the egg batches and hatching
larvae. With the help of image analysing software, the two-dimensional surface
of individual eggs was measured to ascertain egg size. Larval size was also
recorded. To follow their particular growth progresses, isogenic larvae belonging
to C1 and C2 were reared individually from day 6 until day 80 of life under
standardised environmental conditions. Their homozygous isogenic status was
later proven by gene marker studies. In comparison to the heterogenic controls,
the coefficient of variation of egg size was similarly higher both in C1 and
C2, and lower in C1 × C2. Egg size variation observed within the egg batches
from the homozygous isogenic females indicated the influence of environmental
and/or epigenetic effects during the earliest developmental phases. Compared
to the control, high variation in egg size and hatching rates as well as low
mean egg numbers and developmental rates was observed within the two homozygous
isogenic groups. The significant differences in mean egg size between C1 (5.7
mm2) and C2 (4.4 mm2) were not reflected in the measurements taken during the
later growth phase. In both the homozygous isogenic lines the coefficient of
variation for body length increased from day 6 (mean: 11.7%) until day 80 of
life (mean: 19.0%). As shown by comparably low coefficients of correlation between
measurements the size ranking of individual larvae and fingerlings within C1
and C2 changed during growth.
(Institute of Animal Husbandry and Genetics, University of Göttingen, Albrecht-Thaer-Weg
3, 37075 Göttingen, Germanys; email of A. Müller: amuelle5@gwdg.de)
THE RELATIONSHIP OF THE CRYOPROTECTANTS METHANOL AND DIMETHYL
SULFOXIDE AND HYPEROSMOTIC EXTENDERS ON SPERM CRYOPRESERVATION OF TWO NORTH-AMERICAN
STURGEON SPECIES
Ákos Horváth, William R. Wayman, Béla Urbányi, Kent M. Ware, Jan C. Dean, Terrence
R. Tiersch-2005
Aquaculture 247 (1-4): 243-251
Abstract:
Successful sperm cryopreservation techniques have been developed for Eurasian
sturgeon species; however, there is little information available on these techniques
for North-American species. In this study, two sets of sperm cryopreservation
experiments were carried out on the endangered shortnose sturgeon (Acipenser
brevirostrum). In the first set, the cryoprotectants methanol (MeOH) and dimethyl
sulfoxide (DMSO) were investigated using three concentrations (5%, 10% and 15%).
The highest post-thaw motility was found using 5% DMSO (26±13%) while the use
of 5% MeOH resulted in the highest rates for fertilization at the 4-cell stage
(40±15%), neurulation (38±13%) and hatching (32±12%). In the second set, the
Original Tsvetkova's extender (OT), Modified Tsvetkova's extender (MT) and modified
Hanks' balanced salt solution (mHBSS) were investigated in combination with
three MeOH concentrations. The highest post-thaw motility (18±10%), fertilization
(18±11%) and hatching rates (17±12%) were observed with MT extender used in
combination with 5% MeOH. In another set of experiments, the effects of two
extenders (MT and mHBSS) and two concentrations of MeOH were investigated for
sperm cryopreservation of pallid sturgeon (Scaphyrinchus albus). The highest
post-thaw motility (70±10%) was observed using MT and 10% MeOH while MT and
5% MeOH yielded the highest rates of fertilization (88±6%) and hatching (73±14%).
In general we conclude that although hyperosmotic conditions of extenders and
cryoprotectants result in higher post-thaw motility, they seem to reduce the
fertilizing ability of the sperm.
(Aquaculture Research Station, Louisiana Agricultural Experiment Station, Louisiana
State University Agricultural Center, Baton Rouge, 2410 Ben Hur Road, LA 70820,
USA; email of A. Horváth: Horvath.Akos@mkk.szie.hu)
COMMUNAL LARVAL REARING OF EUROPEAN LOBSTER (HOMARUS GAMMARUS):
FAMILY IDENTIFICATION BY MICROSATELLITE DNA PROFILING AND OFFSPRING FITNESS
COMPARISONS
Knut E. Jřrstad, Paulo A. Prodöhl, Tore S. Kristiansen, Maria Hughes, Eva Farestveit,
John B. Taggart, Ann-L. Agnalt, Andy Ferguson-2005
Aquaculture 247 (1-4): 275-285
Abstract:
Stock enhancement experiments of European lobster (Homarus gammarus) have been
carried out around the Kvitsřy Islands in south-western Norway since 1990. In
addition to releases of coded wire tagged lobster juveniles (cultured) and subsequent
monitoring of commercial fishery, a lobster hatchery was established in 1997.
Several experiments were made on the communal-rearing approach where the performance
of mixed larval groups (families) was evaluated under identical conditions.
Berried females of wild and cultured origin and their respective fertilised
eggs were screened by using microsatellite DNA profiling involving a multiplex
set of six lobster specific primers, thereby allowing determination of both
parental genotypes. Each female were kept separately during hatching, and the
offspring were later mixed and raised in a communal rearing system. The early-larval
survival was estimated at stage IV (bottom stage), and the survivors were identified
to family and group by microsatellite profiling. Five different communal experiments
were conducted, representing offspring from 65 berried females. Of the surviving
larvae, 6.3% could not be assigned to family due to degraded DNA and no PCR
amplification. Significant differences in early survival between offspring of
wild and cultured origin were found in the experiments. No differences between
the groups were found in stage IV larval size. Based on the pooled data on survival
(as a measure of early larvae fitness) offspring of cultured females displayed
a relative fitness of 60% in comparison to offspring from wild females. Large
variation in survival was also observed among families within the "wild" and
"cultured" groups, suggesting a genetic component for these traits and a potential
for selective breeding.
(Department of Aquaculture, Institute of Marine Research, P.O. Box 1870 Nordnes,
5024 Bergen, Norway; email of K. Jřrstad: knut.joerstad@im.no)
SPERM MOTILITY AND FERTILIZING ABILITY IN THE PERSIAN STURGEON
ACIPENSER PERSICUS
Sayyed Mohammad Hadi Alavi, Jacky Cosson-2005
Aquaculture Research 36 (9): 841 -850
Abstract:
The motility and fertilizing ability of the Persian sturgeon, Acipenser persicus,
spermatozoa were investigated. Optimum ionic content (Na+, K+, Ca2+ and Mg2+)
and pH of activation solution as well as the optimum dilution rate were determined.
The results show optimum motility characteristics of spermatozoa in buffered
solutions containing 25, 0.2, 3 and 10 mM L1 Na+, K+, Ca2+ and Mg2+, respectively,
at dilution rate 1:50 and pH 8.0. To test the fertilizing ability of sperm,
two buffered saline solutions were used as activation solution of sperm motility.
The present study indicated (1) spermatozoa motility is one of key factors that
influence on fertilizing ability of sperm, (2) a high fertilizing ability of
sperm is obtained after dilution in saline solutions rather than in freshwater
and (3) a maximum fertilization rate occurs in buffered saline solution containing
0.2 mM L1 K+. There is also a good correlation between biochemical characteristics
of seminal plasma and fertilizing ability of sperm.
(Department of Fisheries and Environmental Sciences, Faculty of Natural Resources,
University of Tehran, PO Box: 31585-4314, Karaj, Iran; email of S. Mohammad
Hadi Alavi: smhadi_alavi@yahoo.com)
INCUBATION OF EUROPEAN SQUID (LOLIGO VULGARIS LAMARCK, 1798)
EGGS AT DIFFERENT SALINITIES
Halil Sen-2005
Aquaculture Research 36 (9): 876-881
Abstract :
Loligo vulgaris is a commercially important squid throughout the Mediterranean
region and is a candidate species in biomedical and aquaculture research. Some
loligo species (L. opalescens, L. forbesi, Sepiteuthis lessoniana) have now
been cultured through some successive generations in closed, recirculating seawater
systems. The effects of salinity on hatching European Squid (L. vulgaris Lamarck,
1798) eggs were investigated during November 2004. The egg capsules were incubated
directly in salinity of 32, 34, 36, 38, 40, 42 and 37 g L1 (control group) at
19.8°C (SD 1.2°C), and a photoperiodicity of 12 h light:12 h dark for 1623 days
before hatching. In all treatments, the eggs were developed and hatched normally
after 1622 days at 32 g L1, 1722 days at 34, 1821 days at 42 g L1, 1822 days
at 36 and 40 g L1, 1922 days at 37 g L1 and 1923 h at 38 g L1. In the experiments,
the highest hatching rate and hatching success (HS) of the eggs were obtained
at 38 g L1 (hatching rate: 100% (SD 0%) and HS: 96.7% (SD 3.5%)) and the lowest
hatching rate at 42 g L1 (hatching rate: 3% (SD 6%) and HS: 0%). Dorsal mantle
lengths (DML) of new hatchlings ranged from 2.08 to 2.80 mm. The present study
showed that salinity affects the hatching rate and HS of eggs and first hatching
time and DML of paralarvae in L. vulgaris. The squid eggs at stage 11 (I) can
tolerate 5 g L1 reduction and 3 g L1 increase in salinity.
(Aquaculture Department, Fisheries Faculty, Ege University, 35440 Iskele-Urla,
Izmir, Turkey; email of H. Sen: sen@sufak.ege.edu.tr)
LARVAL QUALITY IN RELATION TO CONSECUTIVE SPAWNINGS IN WHITE
SHRIMP LITOPENAEUS VANNAMEI BOONE
Fabiola G. Arcos, Elena Palacios, Ana M. Ibarra, Ilie S. Racotta-2005
Aquaculture Research 36 (9): 890-897
Abstract:
In this study, we determined the influence of the time broodstock spend in reproduction,
and the effect of consecutive spawnings (spawning order) on larval quality of
Litopenaeus vannamei. Spawns were sampled at days 14, 1820 and 3840 after unilateral
eyestalk ablation and ordered according to the number of spawns or spawning
order (111) of each female. Larvae were reared individually to 2-day-old postlarvae
(PL2); spawn and larval quality was determined in terms of fecundity, fertilization,
hatching, morphometric traits, ammonium stress resistance applied at zoea, salinity
stress resistance applied at postlarval stages, and survival during culture.
Fecundity was not affected by consecutive spawns, whereas it increased with
time spent in production. Nauplii length and survival to zoea and mysis stages
decreased with time spent in production, whereas no consistent influence of
consecutive spawning was observed. Survival to PL2, and to the ammonia and salinity
stress tests did not decrease with increasing time in production or spawning
order. This study separated the specific influence of time spent in production
(which negatively affects larval quality) and consecutive spawns (which had
no effect or had an inconsistent effect), and reinforced previous suggestions
that selection of females with multiple spawn capacity would be desirable for
production purposes.
(Programa de Acuicultura, Centro de Investigaciones Biológicas del Noroeste
(CIBNOR), Mar Bermejo 195, La Paz, B.C.S. 23090, México; email of I. S. Racotta:
iracotta@cibnor.mx)
SHORT COMMUNICATION: ACCLIMATION OF MOZAMBIQUE TILAPIA (OREOCHROMIS
MOSSAMBICUS) TO SALINITY CHANGES ALTERS PROTEIN CONTENT OF THE LARVAE AND THEIR
LIVER AND KIDNEY
An-Chin Lee, Chwen-Ru Lin, Su-Mei Chen-2005
Aquaculture Research 36 (9: 936 -
(Department of Aquatic Biosciences, National Chiayi University, 300 University
Road, Chiayi 600, Taiwan; email of An-Chin Lee: aclee@mail.ncyu.edu.tw)
SHORT REPORT ON THE EFFECT OF A PARASITIC ISOPOD ON THE REPRODUCTIVE
PERFORMANCE OF A SHRIMP
Ricardo Calado, Cátia Bartilotti, Luís Narciso-2005
Journal of Experimental Marine Biology and Ecology 321 (1): 13-18
Abstract:
The present work studied the degree of inhibition caused by the bopyrid isopod
Eophryxus lysmatae (Caroli, 1930 [Caroli, E., 1930. Notizia di tre specie nuove
ed una poco nota di Bopiridi addominali, parassiti di Caridei del golfo di Napoli.
(Contributo alla conoscenza del genere Phrixus Rathke). Boll. Soc. Nat. Napoli
41, 258-269]), an abdominal parasite, on the reproductive performance of its
host, the protandric simultaneous hermaphrodite shrimp Lysmata seticaudata (Risso,
1816). Parasitized shrimp (PS) was not able to produce embryos, although they
could successfully fertilise the eggs of unparasitized shrimp (US). All US paired
with PS were able to fertilise eggs when paired with other US. The average number
of larvae (±S.D.) produced by US shrimp paired with US and PS (344±27 and 346±23,
respectively) was not significantly different (p=0.73). The average intermolt
period duration (±S.D.) for US and PS (10±1.2 and 11±0.8 days, respectively)
was not significantly different (p=0.82), with bopyrid parasites molting synchronously
with their host. No PS lost its parasite during ecdysis. Although only three
parasitized shrimp were used in the present work, parasitic castration induced
by E. lysmatae seems to only affect the female sexual system of the simultaneous
hermaphrodite L. seticaudata, and therefore parasite-induced "reproductive death"
does not occur in this species as in other gonochoric and sequencial hermaphroditic
caridean shrimp. Nutritional drain and disruption of endocrine mechanisms possibly
caused by the bopyrid parasite are discussed.
(Laboratório Marítimo da Guia, Departamento de Biologia Animal, Faculdade de
Cięncias da Universidade de Lisboa, Estrada do Guincho, 2750-642 Cascais, Portugal;
email of R. Calado: rjcalado@hotmail.com)
PRE-HYDROLYSIS IMPROVES UTILISATION OF DIETARY PROTEIN IN THE
LARVAL TELEOST ATLANTIC HALIBUT (HIPPOGLOSSUS HIPPOGLOSSUS L.)
Sigurd K. Tonheim, Marit Espe, Kristin Hamre, Ivar Rřnnestad-2005
Journal of Experimental Marine Biology and Ecology 321 (1): 19-34
Abstract:
A protein preparation labelled by incorporation of [U]14C-AA was hydrolysed
to various degrees and administered to a teleost fish larva (Atlantic halibut,
Hippoglossus hippoglossus L.) by tube-feeding, and its post-administration utilisation
was studied. Three treatments were prepared: IntP-intact protein, PHP-pepsin-hydrolysed
protein, and HHP-highly hydrolysed protein (using pepsin, trypsin, endoproteinase
Glu-C, Asp-N, and Pro-C). At small doses (11.4±1.5 µg larvae-1), the intact
protein (IntP) was digested and absorbed to 36±5.5%. However, the relative absorption
efficiency of the intact protein was reduced as the dose increased. Absorption
efficiency was higher when the protein was hydrolysed prior to feeding the larvae
and was constant at 63% (R2=98) independent of degree of proteolysis and dose
(ranging from 3.5 to 35 µg larvae-1). The initial absorption rate increased
with the degree of hydrolysis. Calculations based on data collected during the
first 30-120 min show that the absorption of PHP and HHP into extra-intestinal
body tissues was 2.2 and 3 times as fast, respectively, as that of intact protein.
However, the rates of absorption did not influence the distribution of absorbed
AA into either catabolism or anabolism, as all larvae, independent of which
protein solution they were given, catabolised 42±7% of the absorbed AA, and
accumulated 49±6% into the body tissue, during the 20 h post-feeding incubation
period.
Larval age and size did not influence the absorption and utilisation of the
hydrolysed protein preparations. This was different from the intact protein,
as significantly higher fractions of the intact protein were absorbed by the
larvae at 31 days past first feeding (dpff) than by larvae at 25 dpff. Analysis
of the faecal evacuation suggested that the poor protein utilisation in the
younger larvae was due to enhanced faecal evacuation, which in some larvae was
more than 50% only 4 h post diet administration, at a time when the process
of digestion and absorption was far from complete. This indicated that faecal
evacuation is a critical factor in the utilisation of slowly digested and absorbed
feed components, such as intact proteins, by fish larvae.
(National Institute of Nutrition and Seafood Research (NIFES), PO Box 2029 Nordnes,
Bergen N-5817, Norway; email of S. Tonheim: sigurd.tonheim@nifes.no)
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