International Journal of Aquaculture, 2013, Vol.3, No.23, 133
-
137
http://ija.sophiapublisher.com
133
Research Report Open Access
Preliminary Investigation of
Tribulus terrestris
(
Linn., 1753) Extracts as Natural
Sex Reversal Agent in
Oreochromis niloticus
(
Linn., 1758) Larvae
B. O Omitoyin , E. K Ajani , H. O Sadiq
Department of Aquaculture and Fisheries Management, University of Ibadan, Nigeria
Corresponding author email:
sadiqhauwa@gmail.com
;
Authors
International Journal of Aquaculture, 2013, Vol.3, No.23 doi: 10.5376/ija.2013.03.0023
Received: 8 Jun., 2013
Accepted: 22 Jul., 2013
Published: 23 Aug., 2013
Copyright © 2013
Omitoyin. 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
:
Omitoyin, 2013, Preliminary Investigation of
Tribulus terrestris
(
Linn., 1753) Extracts as Natural Sex Reversal Agent in
Oreochromis niloticus
(
Linn., 1758)
Larvae, International Journal of Aquaculture, Vol.3, No.23 133-137 (doi: 10.5376/ija.2013. 03.0023)
Abstract
Synthetic sex reversal hormone used in controlling Tilapia population under culture condition has a perceived public
health risk. This study therefore examined the prospect of utilization
Tribulus terrestris
as sex reversal agent in
Oreochromis niloticus
.
Five pairs of
Oreochromis niloticus
(350
±25.8) g in a ratio of 1:1 male to female were used for fry production. Four hundred and fifty
day-old fry were randomly distributed into 18 experimental tanks (30 L capacity) and fed 50% crude protein diets containing 0.0 g,
1.0
g, 1.5 g, 2.0 g, and 2.5 g per 1 kg of basal feed of
T. terrestris
extract. Diet six contained 50 mg/kg of basal feed of
17-
α-methyltestosterone served as control. Data collected includes, water quality (Temperature, pH and Dissolved oxygen), Growth
performance (Mean Weight Gain (MWG), Food Conversion Ratio (FCR) and Specific Growth Rate (SGR)), survival rates at the fry
and fingerlings stage and sex ratio. Data collected were subjected to 2-way analysis of variance. Temperature and pH ranged between
26
℃
to 28
℃
and 7.7 to 8.2 respectively. Dissolved oxygen varied from 5.13 mg/L to 9.12 mg/L. The mean weight gain of fry
ranged from (0.73±0.08) g to (0.92±0.1) g and fingerlings from (14.35±1.26) g to (18.29±1.59) g which was significantly different
across the treatments (p<0.05). FCR recorded for fry ranged from 1.53±0.17 to 2.12±0.14 and SGR, from 14.477±0.15 to
15.257
±0.25. There was no significant difference in FCR and SGR across the treatments for fingerlings. Survival rates ranged from
80%
to 89.3%. Percentage of males in treated fish increased as concentration of
T. terrestris
increased with T
5
-2.5
g (85.7±1.3) %.
Keywords
Sex reversal; Population control;
Tribulus terrestris
;
Oreochromis niloticus
Introduction
Tilapias constitute one of the most productive and
internationally traded food fish in the world
(
Modadugu and Belen 2004; Lim and Webster, 2006)
and one of the major sources of protein to most
developing countries. Characteristics that make Tilapia
the best choice for farmers include; resistance to
disease, tolerance to a wide range of environmental
conditions, ability to convert efficiently organic,
domestic and agricultural wastes, into high quality
protein, good growth rates and ease of growth in
intensive culture (Penna-Mendoza et al., 2005;
Altun et al., 2006). Despite having many good
characteristics, one of the major drawbacks in
commercial tilapia production is its precocious
maturity and the following uncontrolled reproduction,
resulting in increasing competition for feed followed
by stunted growth and low commercial value (Jegede
and Fagbenro, 2007; Wassermann and Afonso, 2003).
Fast growth rate at high density, acceptability to
artificial feed and controlled reproduction are some of
the most important characteristics in a successful fish
culture.
In populations of tilapia, males grow faster and are
more uniform in size than females (Tariq-Ezaz et al., 2004).
For this reason, the farming of monosex populations
of tilapias, which is achieved either by manual sexing,
direct hormonal sex reversal, hybridization or genetic
manipulation, has been reported as a solution to the
problem of early sexual maturation and unwanted
reproduction (Gupta and Acosta, 2004). The production
of monosex populations has been successfully
achieved by oral administration of natural or synthetic
steroidal hormone to masculinize or feminize sexually
undifferentiated fry (Pandian and Sheela, 1995). This
technique has been widely used. However, increasing
consumer rejection to the use of hormone in food
production has limited this application.
Tilapia can be masculinized by direct synthetic
hormonal treatment that is efficient and straightforward
(
Gale et al., 1995). However, synthetic hormones are