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Bioscience Methods 2014, Vol.5, No.2, 1-8
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Research Article Open Access
Anti-nutritional factors in cowpea cultivars and their effects on susceptibility to
Callosobruchus maculatus
(Fab.) [Coleoptera: Bruchidae] infestation
Kayode David Ileke
Department of Environmental Biology and Fisheries, Faculty of Science, Adekunle Ajasin University, PMB 001, Akungba Akoko, Ondo State, Nigeria
Corresponding author email
Bioscience Methods, 2014, Vol.5, No.2 doi: 10.5376/bm.2014.05.0002
Received: 30 Mar., 2014
Accepted: 08 Sep., 2014
Published: 20 Nov., 2014
Copyright
©
2014 Ileke, 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:
Ileke, 2014, Anti-nutritional factors in cowpea cultivars and their effects on susceptibility to
Callosobruchus maculatus
(Fab.) [Coleoptera: Bruchidae]
infestation, Bioscience Methods, Vol.5, No.2 1
-
8 (doi
Abstract
Thirty-one cowpea cultivars from IITA in Nigeria were investigated for their antinutritional factors to determine their
susceptibility to cowpea bruchid,
Callosobruchus maculatus
(Fab.) [Coleoptera: Chrysomelidae] infestation. Percentage seed damage
and pest tolerance, Phytate, tannins and oxalate contents were determined using standard methods. The result showed significant
variations in both % seed damage and pest tolerance among the cowpea cultivars tested. Cultivars MIT04K-399-1, MIT07K-299-92,
IT96-610, MIT06K-281-1, MIT07K-187-24, MIT06K-121, MIT07K-304-9 and EIT07K-291-69 were the least susceptible to
C.
maculatus
with 100% pest tolerance. The result of anti-nutritional factors clearly showed that cowpea seeds contain more phytate
than oxalate and tannin. The mean phytate content in seeds was (3.10 mg/g) which was about three times higher than that of oxalate
(0.78 mg/g) and five times higher than tannins (0.31 mg/g). Cultivar MIT04K-339-1 recorded the highest amount of phytate while
cultivar MIT03K-337-6 recorded the lowest. The amount of oxalate ranges from 0.42 mg/g to 0.92 mg/g. Cultivar IT96-610 recorded
the highest amount of tannin while cultivar MIT03K-337-6 recorded the lowest amount of tannin. This study revealed variations in
the anti-nutrients composition among the cowpea cultivars. These variations contribute to the susceptibility of cowpea to
C.
maculatus
infestation.
Keywords
Callosobruchus maculatus
; Cowpea seeds; Pest tolerance; Phytate; tannins; Oxalate; Susceptibility indices
Introduction
Cowpea,
Vigna unguiculata
(L) Walp is one of the
most important food legume crops widely grown in
semi-arid tropics as an inexpensive source of protein
in both human diet and animal feed (Mahe et al
.
, 1994;
Ofuya, 2001). The cowpea bruchid,
Callosobruchus
maculatus
(Fab.) has been recognized for decades as
the major post harvest insect pest of cowpea seeds. It
is a cosmopolitan species and a field-to-store insect
pest of cowpea (Ofuya, 2001; Gbaye and Holloway,
2011). The huge post-harvest losses and quality
deterioration caused by this insect is a major obstacle
to achieving food security in developing countries
such as Nigeria (Ileke et al., 2013).
Anti-nutritional factors are plant’s secondary
metabolites which act to reduce food nutrient
utilization (Soetan, 2008). Anti-nutritional factors
affect susceptibility of grains to insect attack
(Harborne, 1989). However, the presence of
anti-nutritional factors commonly found in legumes is
a major factor limiting the wider food use of these
essential tropical plants (Liener, 1980). For instance,
phytic acid and Oxalic acid reduce mineral
bioavailability that leads to various mineral deficiency
diseases e.g. anaemia (Gluthrie and Picciano, 1996),
or form deleterious complexes with metal ions e.g.
calcium-oxalate that leads to renal damage (Shukkur
et al
.,
2006). Plants contain thousands of compounds
which, depending upon the situations, can have
beneficial or deleterious effects on organisms
consuming them. These compounds, with the
exception of nutrients, are referred to as
‘allelochemicals’ (Conn, 1979).
Anti-nutrients have been shown to possess
pharmacological values. Tannins for examples,
possess anticancer and cytotoxic properties (Koratkar
and Rao, 1997; Das and Mahato, 1983; Schopke and
Hiller, 1990; Wakabayashi et al., 1997). Tannins are
complex polyphenol found widely in the plant
kingdom (Haregman and Buther, 1978). Phytic acid's