International Journal of Aquaculture, 2015, Vol.5, No.3, 1
-
13
1
Research Article Open Access
Effects of stocking density and water exchange rates on growth performances,
production traits, feed utilization and body composition of mono-sex male Nile
tilapia,
Oreochromis niloticus
(L.) cultured in concrete tanks
Deyab M. S. D. El-Saidy , Ebtehal El-Sayed Hussein
Department of Poultry Production, Faculty of Agriculture, Minufiya University, Shebin El-Kom, P.O.Box 32516, Egypt
Corresponding author Email
International Journal of Aquaculture, 2015, Vol.5, No.3 doi: 10.5376/ija.2015.05.0003
Received: 10 Feb., 2015
Accepted: 26 Mar., 2015
Published: 27 Apr., 2015
Copyright © 2015 El-Saidy and Hussein, This is an open access article published under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
El-Saidy and Hussein, 2015,
Effects of stocking density and water exchange rates on growth performances, production traits, feed utilization and body
composition of mono-sex male Nile tilapia,
Oreochromis niloticus
(L.) cultured in concrete tanks, International Journal of Aquaculture, Vol.5, No.3: 1-13 (doi:
Abstract
A 44-week randomized factorial design 2 x 3 x 2 ( two water exchange rates, three stocking density and two replicates)
rearing trial was conducted in concrete tanks with average initial weight and length of 7.5
1.2 g/fish and of 8.9
0.5 cm/fish of
mono-sex male Nile tilapia,
Oreochromis niloticus
, to examine the effects of two water exchange rates and three stocking density on
growth performances, production traits, feed utilization and body composition. Twelve concrete tanks 4 m
3
each were stocked with
either 200, 300 and 400 fish for each tank to give a stocking rate of 50, 75 and 100 fish /m
3
, respectively and mentioned at 8L/min. or
12 L/min. water exchange rates. The results revealed that, growth performance and feed utilization parameters were significantly (P
0.01) the best at the lowest stocking density. No significant differences (P
0.05) were found between water exchange rates in terms
of growth performance, feed utilization and all production traits. The lowest stocking density (50fish/m
3
) had significantly the best
feed utilization parameters. There were no significant differences between it and the stocking density of 75fish/m
3
. Whole fish body
composition % of protein, fat and ash contents were significantly (P
0.05) influenced by stocking density but did not influenced by
water exchange rates. From the above results it can be concluded that, stocking density of 75 fish /m
3
of mono-sex male Nile tilapia
reared at either 8L/min or 12L/min. water exchange rates exhibited the highest net profit and would seem to be the most desirable
density under this system conditions.
Keywords
Nile tilapia; Stocking density; Water exchange rates; Growth performances
Introduction
Tilapias can become the worlds most important
warm water cultured fishes (FAO, 1980). Among all
cultured tilapia species, Nile tilapia,
Oreochromis
niloticus
has emerged as the single most important
species. The attributes, which make Nile tilapia so
suitable for fish farming, are its general hardiness,
ease of breeding, rapid growth rate, ability to
efficiently convert organic and domestic wastes into
high quality protein, and good taste. (Yi et al.
1996). For optimizing production from a system, a
number of factors which are directly related to the
stocking density must be considered. These factors
are the physio-chemical condition of water, the
production system, the types and the size of rearing
tanks, the water exchange rate, the size of the fish
and the quantity of the ration have been particularly
emphasized (Trzebiatoowski et al. 1981).
Studies on the relation between stocking density and
growth of tilapia have been numerous (Youssif (2002).
The optimal stocking density of certain species for
obtaining the highest possible yield depends on the
amount and the quality of food available (Zonneveld
and Fadholi, 1991). The increases in stocking density
become possible by the introduction of oxygen
depletion (El-Saidy and Gaber 2002b). High-density
culture of tilapia has been successful (Youssif 2002),
but comparing results is difficult because individual
studies do not address the full complex of parameters.
Honer et al. (1987, a & b) , indicated that high density
fostered faster growth but, with slightly greater
variance than low-density culture in juvenile and adult
tilapia. Wallace et al
.
(1988) found that rearing
fingerling salmonids at very high densities reduced the
phenotype variance while Bagley et al. (1994)
observed more rapid growth, increased genetic
variance and reduced environmental variance.
