17 / 25
Page 60
Notes:
Mycology 2017
September 25-26, 2017
conferenceseries
.com
September 25-26, 2017 Chicago, USA
2
nd
International Conference on
Mycology & Mushrooms
Volume 3, Issue 2 (Suppl)
Med Mycol Open Access
ISSN: 2471-8521
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 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.comMed Mycol Open Access, 3:2, 2017
DOI: 10.21767/2471-8521-C1-003