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.com
Volume 6, Issue 4 (Suppl)
Agrotechnology, an open access journal
ISSN: 2168-9881
Agri 2017
October 02-04, 2017
allied
academies
10
th
International Conference on
AGRICULTURE & HORTICULTURE
October 02-04, 2017 London, UK
Genetic diversity of
Aspergillus flavus
and occurrence of aflatoxin contamination in stored maize
across three agro-ecological zones in Kenya
Grace W Gachara
1
, Anthony K Nyamache
1
, Jagger Harvey
2
, Gbemenou Joselin Benoit Gnonlonfin
2
and
James Wainaina
2
1
Kenyatta University, Kenya
2
Biosciences Eastern and Central Africa-International Livestock Research Institute, Kenya
A
flatoxin contamination at post-harvest poses a serious challenge in achieving millennium development goals on food
security especially in the developing world. In Kenya, major outbreaks of aflatoxicoses have been attributed to poor post
harvest storage practices. In this study, we conducted a cross-sectional survey within three Agro-ecological zones in Kenya,
to determine occurrence and distribution of total aflatoxin in stored maize and the aflatoxigenicity potential of
Aspergillus
flavus
in stored maize. The counties selected were; Kitui, Nakuru and Kitale (in Trans-Nzoia County). Sampling sites were
selected based on previous aflatoxicoses outbreaks (Kitui) and major maize production areas (Nakuru and Kitale) where little
information exists on the occurrence of aflatoxin contamination. A total of one hundred and thirty (130) kernel maize samples
were random collected during the period between June and August 2012. Moisture content was determined using the standard
oven method and
Aspergillus flavus
was isolated by direct plating technique. Genetic diversity of the isolates was determined
by PCR and Single Sequence Repeats (SSR) micro satellites analysis. Positive strains were induced to produce B1 aflatoxins on
Yeast Extract Sucrose Agar (YESA) and quantified using competitive ELISA technique. The results indicated mean moisture
content of maize ranged between 6% and 34%, although this was found not to be significantly different (p=0.23>0.05).
However, total aflatoxin contamination of postharvest stored maize samples between sites was significantly different (p=0.000,
<0.05); with the highest contamination in Kitale at a mean of (9.68 µg/kg).
A. flavus
was isolated in 70% (N= 91) of the maize
samples collected at postharvest.
A. flavus
isolates with the highest aflatoxigenicity potential were from Nakuru County with
mean aflatoxin level at 239.7 µg/kg. Genetic distance based on Neighbor Joining (NJ) clustered the
A. flavus
isolates into five
main clusters. Principal coordinate Analysis (PCA) analysis showed five distinct clusters with both axes explaining 60.17% of
the variance. This study showed widespread distribution of aflatoxin contamination and a highly toxigenic
A. flavus
in stored
maize in three major agro ecological zones in Kenya. These results suggest a potential health risk of aflatoxin outbreaks within
these areas, thus call for more investigations.
kikogash@gmail.comAgrotechnology 2017, 6:4(Suppl)
DOI: 10.4172/2168-9881-C1-028