International Journal of Aquaculture 2015, Vol.5, No. 41, 1-20
1
Dietary Phytase Improves Growth and Water Quality Parameters for Juvenile
Clarias gariepinus
Fed Soyabean Meal-based Diets
Akpoilih B.U.
1
, Ajani E.K.
2
, Omitoyin B.O.
2
1 Department of Fisheries, University of Port Harcourt, Nigeria
2 Department of Aquaculture and Fisheries Management, University of Ibadan, Nigeria
Corresponding author email:
International Journal of Aquaculture, 2015, Vol.5, No.41 doi:
Received: 26 Oct., 2015
Accepted: 10 Dec., 2015
Published: 29 Feb., 2016
Copyright © 2015
Akpoilih et al., 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:
Akpoilih B.U., Ajani E.K. and Omitoyin B.O., 2015, Dietary Phytase Improves Growth and Water Quality Parameters for Juvenile
Clarias gariepinus
Fed
Soyabean Meal-based Diets, International Journal of Aquaculture, 5(41): 1-20 (doi:
Abstract
The effect of phytase on growth, nutrient utilization of juvenile
Clarias gariepinus
fed soya bean using a 4x5
experimental design was investigated. 15.13% (S1), 34.16% (S2), 58.85% (S3) and 92.15% (S4) soyabean were formulated to
substitute fish meal at 25 %, 50 %, 75 % and 100 %, respectively as basal controls with no phytase (P0). Another four diets were
formulated with the same composition as the basal diet, but were supplemented with 250 FTU/g (P1), 500 FTU/g (P2), 750 FTU/g
(P3) and 1000 FTU/g (P4), respectively. A fish meal diet, S0 (100%) and commercial diet (comm. diet), which served as controls,
were included in the experiment to compare growth performance with experiment diet. A total of 1638 fish of average weight 11.55+
0.20g were randomly allocated to experimental diets and fed at 3% body weight to replicate group of fish stocked at 26 fish per tank
for 84 days. Growth performance was significant with phytase addition to diet (ANOVA, P<0.05). Mean weight gain declined with
increasing substitution of fish meal by soya bean (Duncan, P<0.05), and irrespective of phytase levels (Tukey, P<0.05). However,
significant improvement in weight gain of fish was observed with phytase addition to diets compared to diets without phytase (Tukey,
P<0.05). Mean weight gain and feed conversion ratio (FCR) for fish fed S3P1 and S0P0 did not differ significantly (Duncan, P>0.05).
Significant interaction for survival of fish showed a decline with increasing phytase, regardless of soya bean levels (Tukey, P<0.05).
However, survival of fish fed fish meal diet was less than soya bean substitution up to 75%, regardless of phytase level (Turkey,
P>0.05). Improvement in growth by phytase resulted in reduction of phytate (r= -0.231, P>0.05) and oxalate (r= -0.328, P<0.05) and
improvement in water quality (Tukey, P<0.05) for oxygen (r= 0.262, P>0.05) and ammonia (r= -0.105, P>0.05). In conclusion, the
study has demonstrated that phytase at low level of supplementation in soyabean diet of
Clarias gariepinus
can effectively utilize
phosphorus from phytate, cut and manage pollution in aquaculture environments, and improve overall growth of fish compared to
commercial diet.
Keywords
Soya bean; Phytase; Growth; Water quality;
Clarias gariepinus
1 Introduction
Statistics have confirmed that world aquaculture
production has been rising, with a reported increase of
aquaculture food production from 66 million tonnes in
2012 to 70.5 million tonnes in 2013 (FAO, 2014).
Consequently, the sustainability of feed based
production systems may be threatened by shortages
and price rises of fish meal and fish oil, and thus step
must be taken to reduce their inclusion levels in
aqua-feeds by use of alternative protein source
(Lunger et al., 2007; Pham et al., 2008; Lim et al.,
2011). There has been a decline in the use of pelagic
fish meal used in aquaculture feed production due to
the limited amount available, which has resulted in
massive research to identify alternative protein
sources (Olsen and Hasan, 2012). Among the many
alternatives that have been examined, plant meals
appear to have the most potential with extensive
research conducted to evaluate the feasibility of plants
(El-Saidy and Gaber, 2003; Abdelgamy, 2004;
Catacutan and Pagador, 2004). The major protein
concentrates used animal feed formulation are the oil
seeds meals such as soya bean meal (Adeniji, 2009).
Soybeans are the most plentiful of oilseed crops, and
one of the cheapest plant sources of protein (Hussain
et al., 2011), with a worldwide production of 253.1
million metric tonnes in 2012 (FAO, 2013). It is
widely grown in Nigeria, with a yield of soybean of
Research Article
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