Date post: | 27-Jul-2015 |
Category: |
Science |
Upload: | international-institute-of-tropical-agriculture |
View: | 34 times |
Download: | 0 times |
www.iita.org A member of CGIAR consortium
Development of biocontrol product (Aflasafe) for maize and groundnut in Rwanda
Joseph Atehnkeng, IITA
For the team
www.iita.org A member of CGIAR consortium
Occurrence of aflatoxin in crops Biocontrol technology Product development for Rwanda Experiences in Nigeria Conclusion
Outline
www.iita.org A member of CGIAR consortium
Joseph Atehnkeng, IITA
Research experience continues
Aspergillus in
maize Healthy maize cobs
Aspergillus in groundnut
Aflatoxin contamination in grains
Chronic exposure
Liver cancer
Immunosupression
Underweight
Stunting
Infants & young children
most affected
Acute exposure
Death (eg. Kenya in 2004)
Unreported cases,
UNKNOWN
Farm animals
Reduced feed consumption
Reduced reproductivity
Immune suppression
Decreased milk and egg
production
Retarded growth and
development
CONSEQUENCE?
Reduction in farmers’ incomes
Effects on human & animal health and Trade
Trade losses (US$ 450
million/annum) in Africa
due to aflatoxin contamination
Aflatoxin Contamination Occurs in Two Phases
Phase I: Before Crop Maturity
Developing crops become infected.
Associated with crop damage (insect, bird, stress).
Favored by high temperature (night) and dry conditions.
Phase II: After Crop Maturity
Aflatoxin increases in mature crop.
Seed is vulnerable until consumed.
Rain on the mature crop increases contamination.
Associated with high humidity in the field & store, insect
damage, and improper crop storage or transportation.
6
History of Acute Aflatoxicoses Outbreaks
Taiwan
1967
Uganda
1970
Western India
1974
Kenya
1982
2002
2004
2005
2006
2007
2008
Malaysia
1988
35°N
35°S
5 billion people
exposed --CDC
Aflatoxin Contamination: A Perennial Concern in
Warm Climates
Contamination is worse during dry
periods.
During droughts the zone containing
contaminated crops enlarges.
Management Strategies
Pre harvest
• Awareness
• Host plant resistance
• Insect control
• Irrigation
• Biological control
Post harvest
• Time of harvest
• Sorting and processing
• Grain drying method
• Storage structure
• Insect control
• Hygiene and sanitation
www.iita.org
AF36
Aflaguard
Biocontrol WORKS
In 100’S of thousands of acres in
the US!
IT WORKS In Africa
TOO!
Aflasafe
www.iita.org A member of CGIAR consortium Contract Review , 04 October , 2013
Naturally, some strains produce aflatoxins (toxigenic)
while others do not (atoxigenic)
Atoxigenic strains co-exist with toxigenic relatives and
present in soil and on crop
Increase the frequency of atoxigenic strains & shift the
population profile
Consequently, reducing aflatoxin contamination
Application of atoxigenic strains can be done without
increasing infection and without increasing the overall
quantity of A. flavus on the crop or the environment
Strains protect crop from field to store
Multiple year & multiple crop benefit
Only native strains used.
0
20
40
60
80
100
Natural BiocontrolF
req
ue
nc
y (
%)
AT
OX
IGE
NIC
TO
XIG
EN
IC
Biocontrol principle
www.iita.org
Farmers treating maize and groundnut fields with Aflasafe in Nigeria
MAIZE: Aflatoxin reduction (%)
Stage 2009 2010 2011 2012
Harvest 82 94 83 93
Storage 92 93 x x
PEANUT: Aflatoxin reduction (%)
Stage 2009 2010 2011
Harvest - 95 82
Storage 100 80 x
Results from 482
on-farm trials
71% and 52% carry-over of
inoculum 1 & 2 years after
application
www.iita.org A member of CGIAR consortium
Nsengiyumva et al., 2012 https://www.linkedin.com/pub/nsengiyumva-prosper/7b/887/a04.
Prevalence of aflatoxin in Rwanda
• Analysed eight samples of maize flour collected from four markets in
Kigali and were from two origins, industrial and non industrial.
• The average contents in industrial maize flour ranged from (0.9-3.1
ppb) while for traditional maize flour, aflatoxin level was very high with
91.2 ppb.
• Also collected peanuts from three different markets in Kigali.
• Highly variable aflatoxin contamination levels were found in three
markets samples 0.13, 22.58 and >35.95 ppb respectively for the
three markets.
• This study showed that the total aflatoxins in industrial maize flour is
much lower than the regulated maximum amount allowed in foodstuffs
in Rwanda
www.iita.org A member of CGIAR consortium
• Evaluated different crop samples for the prevalence of
mycotoxins in Rwanda.
• Data obtained reveal that peanuts and maize were the
most contaminated with mycotoxins at the incidence rate
of 85 and 80% respectively.
• The highest aflatoxin contamination was in the Western
province with a mean of 829.3 ng/g and range of 1.3 –
3219.6 ng/g followed by
• peanut from the same region with a mean of 401.5 and
range of 3.2 – 1755.8 ng/g.
Felicie Nyinawabali (2013),
Prevalence of aflatoxin in Rwanda
www.iita.org A member of CGIAR consortium Date: 02 – May - 2013
Atoxigenic Strain Identification
Collection/characterization Toxin assay
Field
efficacy
test
Lab
competition
assay
VCG/DNA characterization
cnx nia-D
Unknown 2
+
www.iita.org A member of CGIAR consortium
GOAL: To develop aflatoxin bio-control product for the mitigation of aflatoxins in maize & groundnuts in Rwanda, using native atoxigenic strains of Aspergillus flavus
Specific objectives:
Determine the prevalence of aflatoxin contamination in maize and groundnuts in Rwanda
Determine the distribution and aflatoxin-producing profiles of the etiologic agents
Identify and select atoxigenic strains of Aspergillus flavus native to target regions for large scale aflatoxin mitigation in maize and groundnuts in Ghana.
Evaluate the efficacy of the atoxigenic strains in reducing aflatoxin contamination in- vitro, and under field conditions on farmers’ fields in aflatoxin-prone regions in Ghana.
Research objectives
Data on aflatoxin prevalence grouped into four categories based on their
aflatoxin content as recognized by different regulatory bodies: samples with no
detectable aflatoxins (Limit of detection = 0.1 μg/kg),
Sample processing Developed TLC plate
Extraction
Densitometry
Aflatoxin analysis
www.iita.org A member of CGIAR consortium
Province Districts Number of samples Mean Aflatoxin
(ng/g)
Range
Eastern
Bugesera 5 6.2 4.1-18.9
Gatsibo 15 5.7 0.0 -15.4
Kirehe 15 5.3 0.0 -14.2
Nyagatare 15 6.2 2.3 -9.4
Northern
Burera 15 9.6 4.6 -18.9
Gakenke 5 5.6 4.2 - 8.3
Musanze 15 9.6 0.0 -15.0
Rurindo 5 11.4 4.5 -15.3
Southern
Gisagara 5 6.9 2.9 -12.2
Kamonyi 5 4.4 2.6 -7.8
Mahunga 5 9.4 4.2-2
Ruhango 5 6.9 1.7-12.6
Western
Karongi 15 4.1 0.0 -7.1
Nyabihu 15 5.2 0.0 -8.5
Nyamasheke 5 6.4 1.5 -12.6
Rusizi 15 5.0 0.0-9.8
Rutsiro 15 8.5 2.7-15.2
Aflatoxin concentration (ng/g) in maize in
each province
www.iita.org A member of CGIAR consortium
Region Crop <4 <10 <20
Eastern
Maize
24.0 94.0 100.0
Northern 2.5 62.5 100.0
Southern 25.0 85.0 100.0
Western 32.3 93.8 100.0
Proportion (%) of samples that met each
cut off
<4 = EU/Nestle acceptable limit, <10 = World Food Program acceptable
limit, <20 = US regulation limit, >20 = unacceptable level of aflatoxin.
www.iita.org A member of CGIAR consortium
Isolation & identification of Aspergillus sect. Flavi
L - strain S - morphotype
A. tamarii A. parasiticus
31 oC
3 days
31 oC
5 – 7 days
++++ +/-
- ++++
Silica save
H2O save
www.iita.org A member of CGIAR consortium
Laboratory selection for atoxigenics
Extraction TLC
Positiv
e
Extraction
TLC Negative
Single spore twice
Atoxigenic L
strain on silica
H2O save Healthy maize
Colonized grains
31 oC
7 days
≈ 1.0 x 106 spores
Genetic &
molecular
analysis
Densitometry
www.iita.org A member of CGIAR consortium
Crop Provinces Number of
samples
Aspergillus species/strain distribution
(%)
L % S % P % T %
Groundnut Eastern 16 9.3b 26.1a 60.5a 4.1a
Southern 19 26.3a 11.4a 52.2a 10.0a
Maize
Eastern 55 63.7a 12.3a 17.3a 6.9a
Southern 35 73.0a 10.5a 13.8a 2.8a
Western 20 69.5a 14.4a 12.9a 3.2a
Northern 65 79.3a 8.9a 11.3a 0.5a
Strain distribution in maize and groundnut
samples
We examined 1261 isolates
www.iita.org A member of CGIAR consortium
Proportion of Toxigenic and Atoxigenic
strains obtained in each District
www.iita.org A member of CGIAR consortium
Proportion of Toxigenic and Atoxigenic
strains obtained in each province
www.iita.org A member of CGIAR consortium Contract Review , 04 October , 2013
A total of 379 atoxigenic strains was obtained
after strain characterization and are further
undergoing molecular characterization at
Cotty laboratory, University of Arizona to
select the best 8-12 isolates for field
evaluation.
Progress so far
• Criteria
• Atoxigenic
• Well distributed
• Highly competitive in lab and field
• Must not be related to and toxin producing family.
• Stability in the field
VCG/DNA characterization
cnx nia-D
Unknown 2
+
www.iita.org A member of CGIAR consortium
„Experience with conducting agricultural research
• 2003-06: Strain collection and characterization, atoxigenic strain identification (BMZ)
• 2007-08: on-station efficacy testing (IITA)
• 2009-10: provisional registration, partnerships, on-farm efficacy testing (Mycored, AATF)
• 2010-11: Advocacy, training, awareness campaign, market linkages (Mycored, AATF)
• 2011 / 2012: Large scales testing (BMGF)
• 2012/2017: AgResults (G20)
Nigeria Aflatoxin Biocontrol: Genesis and Time Line
www.iita.org A member of CGIAR consortium R4D week, 25 – 30 Nov. 2013
Integrated approach to manage aflatoxins in crops
www.iita.org www.iita.org A member of CGIAR consortium Contract Review , 04
October , 2013
Training materials
Aflatoxin
management
Video
www.iita.org www.iita.org A member of CGIAR consortium 38
•Target Group
• Farmers
• Extension agents
• Media houses
• National bodies eg NAERLS, ADP,
NAFDAC
• Community leaders
•National policy /decision makers •Agriculture •Trade •Health
www.iita.org A member of CGIAR consortium Contract Review , 04 October , 2013
Babban Gona Pilot
www.iita.org A member of CGIAR consortium Mycored Europe, 28 May, 2013
Willingness to Pay
www.iita.org Mycored Europe, 28 May, 2013 A member of CGIAR consortium Mycored Europe, 28 May, 2013
100% 99%
83%
60%
25%
19%
34% 31%
18%
12%
5% 4% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Farmers who have used Aflasafe (n=246) Farmers who have not used Aflasafe (n=119)
Target Farm Gate Price
Range
Poultry Feeding Study
$3,200 net
profit from
10,000 birds
in 8 weeks
www.iita.org Mycored Europe, 28 May, 2013 A member of CGIAR consortium
Aflasafe maize feed Toxic maize feed
G-20 AgResults Aflasafe
www.iita.org A member of CGIAR consortium
• Pull mechanism – Aflasafe is one of the first three pilots
• Provides incentives after demonstrating adoption
• Private sector driven, but focused on smallholder groups
• Implementers provide credit, inputs and technical services to increase yield
• Aflasafe purchased at cost to improve quality
• Maize tested for aflasafe strains; if present in large frequency, the implementers incentivized with $18.75/ton maize
• Implementers negotiate maize sale at premium
• Project provides aflatoxin awareness, training of implementers, and identifies potential market linkages
• Target: 200,000 ha in 4 years
www.iita.org A member of CGIAR consortium
Implementer Participating Farmers (No.)
Samples Submitted
(No.)
Aflatoxin Concentration (ng/g)
Mean Range Samples above 20 ng/g (No.)
Samples above 20 ng/g (%)
Babban Gona
621 521 0.3 ND – 21.6 1 0.2
Kaduna CADP
190 108 1.4 ND – 69.6 2 1.8
Kano CADP 182 20 2.1 ND – 27.1 1 5.3
Maslaha 22 11 0.4 ND – 0.7 0 0
Total 1015 660 1.1 ND – 29.8 4 0.7
Samples exhibited consistently low levels of Aflatoxin
42
The introduction of Aflasafe caused reduced Aflatoxin levels during Pilot Year 0. Nevertheless, extreme outliers leave some questions (e.g. a Kaduna CADP sample at 69.6ng/g and a Kano CADP sample at 27.1ng/g). These results could extend from mistimed application, or heavy rainfall right after application.
www.iita.org www.iita.org A member of CGIAR consortium
Conclusion • Awareness and training are key to understanding the dangers
posed by aflatoxin.
• The aflatoxin concentration in maize samples collected during the
survey were within the US acceptable limits for human
consumption.
• The L-strains of Aspergillus flavus were the most occurring of the
Aspergillus species obtained during isolation.
• The presence of high aflatoxin producers like S-morphotypes and
A. parasiticus was higher in groundnut than maizet samples.
• The proportion of aflatoxin producers was higher in 16 of the 18
districts. However a total of 379 atoxigenic strains was obtained
after strain characterization and are further undergoing molecular
characterization at Cotty laboratory, University of Arizona to
select the best 8-12 isolates for field evaluation.
Ibadan IITA
Tucson
USDA/ARS IITA, USDA & Doreo have Teamed up to Bring
Aflatoxin Prevention to Africa
Made Possible by Many National Partners in Ministries, Industry, and on the Farm
Nigeria
For more information about aflatoxin biocontrol for Africa, check out: www.aflasafe.com