Page 10 - IJA-Vol.3-No.22
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International Journal of Aquaculture, 2013, Vol.3, No.22, 126
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131
(7)
Starting on day four to the sixth day, 30 larvae
were randomly picked from each experimental basin
one hour after the first feeding (9.00am) for
measurement of total length (TL) as an indicator of
growth. Each of the 30 larvae was placed on filter
paper to allow absorption of excess water and for
create a situation of inactivity before taking length
measurements using a Vernier calliper.
(8)
On the Seventh day, 30 fish larvae were scooped
out of each experimental basin, excess water removed
using filter paper, weighed using a sensitive analytical
balance (nearest 0.0001g), packaged in aluminium foil
and stored under ice before transporting the samples to
the Department of Chemistry, Makerere University for
subsequent fatty acid analysis.
4.3
Determination of Fatty Acids Composition
Fatty acid profiles of freshly collected fish larval
samples were analysed following Joensen et al., (2000).
Once the methyl esters were obtained from the
samples, extracts were stored under refrigeration until
Gas Chromatography-Mass Spectrometry (GC-MS)
analysis using an Agilent 6890N GC-MS (USA
version). The fatty acids in the samples were
identified by means of the standard mixture GLC-68D
from Nu-Chek-Prep (Elysian, Minn., USA) containing
20
fatty acids and by mass spectrometry. Quantification
of the esters was achieved by integration of the peaks
using Chemstation software obtained from Thermo
LabSystems. The relative amount of each fatty acid
ester in each sample was expressed as a percentage of
all the esters in the sample.
4.4
Data Analysis
One-way ANOVA was used to compare growth
performance of larvae fed on different diets and
significant means compared using Tukey’s HSD test.
The results obtained from the chromatography
readings were presented as means±SD.
Acknowledgements
This research study was financed by the National Agricultural Research
Organization through the Competitive Research Grant Scheme. The
Department of Biological Sciences and Department of Chemistry of
Makerere University, and the National Fisheries Resources Research
Institute, Jinja, provided technical and logistical support. Special thanks go
to Mr. Paul Sekyewa of Ssenya fish farm for availing us his hatchery unit
and for his collaborative efforts. We also thank Ivan Abaho for his tireless
assistance on the project.
Authors’ Contributions
GB, PC, AAI, GM and LN participated in the design of the study, cultured
the Cyclopoid copepods, carried out the diet experiment on African catfish
larvae, and fully participated in writing of this manuscript. JK analyzed fatty
acid profiles and participated in the writing of the manuscript. PC and GB
also provided extra input by analyzing the data and in supervising and
coordinating the research activities.
References
Bell J. G., Castell J. D., Tocher D. R., MacDonald F. M., and Sargent J. R.,
1995,
Effects of different dietary arachidonic acid: docosahexaenoic
acid ratios on phospholipid fatty acid compositions and prostaglandin
production in juvenile turbot (
Scophthalmus maximus
),
Fish Physiology
and Biochemistry, 14(2): 139-151,
Bell J. G., McEvoy L. A., Estevez A., Shields R. J., and Sargent J. R., 2003,
Optimising lipid nutrition in first-feeding flatfish larvae, Aquaculture,
227: 211-220,
Brett M. T., and Muller-Navarra D. C., 1997, The role of fatty acids in
aquatic food web processes, Freshwater Biology, 38: 483-499,
Cahu C., and Infante J. Z., 2001, Substitution of live food by formulated
diets in marine fish larvae, Aquaculture, 200: 161-180,
Conceica L. E. C., Yufera M., Makridis P., Morais S., and Dinis M. T., 2010,
Live feeds for early stages of fish rearing, Aquaculture Research, 41(5):
613-640,
Desvilettes C., Bourdier G., and Breton J. C., 1997, On the occurrence of a
possible bioconversion of linolenic acid into docosahexaenoic acid by
the copepod Eucyclops serrulatus fed on microalgae, Journal of
Plankton Research, 19(2): 273–278,
Evjemo J. O., Reitan K. I. and Olsen Y., 2003, Copepods as live food
organisms in the larval rearing of halibut larvae (
Hippoglossus
hippoglossus L.
)
with special emphasis on the nutritional value,
Aquaculture, 227: 191-210,
)
00503-9
FAO, 2006, National Aquaculture Sector Overview, Uganda, National
Aquaculture Sector Overview Fact Sheets, Text by Mwanja W. W In:
FAO Fisheries and Aquaculture Department, Rome,
.
org/fishery/countrysector/naso_uganda/en
FAO, 2008, The state of world fisheries and aquaculture, Fisheries and
aquaculture department, United Nations, Rome,
/
docrep/011/i0250e/i0250e00.htm
Feller S. E., 2008, Acyl chain conformations in phospholipid bilayers: a
comparative study of docosahexaenoic acid and saturated fatty acids,
Chemistry and Physics of Lipids, 153: 76-80,
/
j.chemphyslip.2008.02.013
Infante J. L. Z., and Cahu C. L., 2001, Ontogeny of the gastrointestinal tract
of marine fish larvae, Comparative Biochemistry and Physiology, Part
C: Toxicology and Pharmacology, 130: 477-487,
1016/
S1532-0456(01)00274-5
Joensen H., Steingrund P., Fjallstein I., and Grahl-Nielsen O., 2000,
Discrimination between two reared stocks of cod (
Gadus morhua
)
from
the Faroe Islands by chemometry of the fatty acid composition in the
heart tissue, Marine Biology, 136: 573
–
580,
/
s002270050717
Lavens P., and Sorgeloos P., 2000, The history, present status and prospects
of the availability of
Artemia
cysts for aquaculture, Aquaculture,
181:
397–403,
Lubzens E., 1987, Raising rotifer for use in aquaculture, Hydrobiologia, 42:
245-255,
McKinnon A. D., Duggan S., Nichols P. D., Rimmer M. A., Semmens G.,
and Robino B., 2003, The potential of tropical paracalanid copepods as
live feeds in aquaculture, Aquaculture, 223: 89–106,
10.1016/
S0044-8486(03)00161-3
Nanton D. A., and Castell J. D., 1998, The effects of dietary fatty acids on
the fatty acid composition of the harpacticoid copepod,
Tisbe
sp., for
use as a live food for marine fish larvae, Aquaculture, 163: 251–261,
Molejon O. G., Alvarez-Lajonchere L. 2003, Culture experiments with
