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Aflatoxin contamination in corn sold for wildlife feed in Texas

  • Anastasia Mosquito Control District

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Supplemental feeding with corn to attract and manage deer is a common practice throughout Texas. Other species, including northern bobwhites (Colinus virginianus), are commonly seen feeding around supplemental deer feeders. In many cases, supplemental feeding continues year-round so feed supply stores always have supplemental corn in stock. Fluctuating weather and improper storage of corn can lead to and/or amplify aflatoxin contamination. Due to the recent decline of bobwhites throughout the Rolling Plains ecoregion of Texas, there has been interest in finding factors such as toxins that could be linked to their decline. In this study, we purchased and sampled supplemental corn from 19 locations throughout this ecoregion to determine if aflatoxin contamination was present in individual bags prior to being dispersed to wildlife. Of the 57 bags sampled, 33 bags (approximately 58%) contained aflatoxin with a bag range between 0.0–19.91 parts per billion (ppb). Additionally, three metal and three polypropylene supplemental feeders were each filled with 45.4 kg of triple cleaned corn and placed in an open field to study long-term aflatoxin buildup. Feeders were sampled every 3 months from November 2013–November 2014. Average concentration of aflatoxin over the year was 4.08 ± 2.53 ppb (±SE) in metal feeders, and 1.43 ± 0.89 ppb (±SE) in polypropylene feeders. The concentration of aflatoxins is not affected by the type of feeder (metal vs polypropylene), the season corn was sampled, and the location in the feeder (top, middle, bottom) where corn is sampled. It is unlikely that corn used in supplemental feeders is contributing to the bobwhite decline due to the low levels of aflatoxin found in purchased corn and long-term storage of corn used in supplemental feeders.
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Ecotoxicology (2017) 26:516520
DOI 10.1007/s10646-017-1782-7
Aatoxin contamination in corn sold for wildlife feed in texas
Nicholas R. Dunham
Steven T. Peper
Carson D. Downing
Ronald J. Kendall
Accepted: 14 February 2017 / Published online: 27 February 2017
© Springer Science+Business Media New York 2017
Abstract Supplemental feeding with corn to attract and
manage deer is a common practice throughout Texas. Other
species, including northern bobwhites (Colinus virginia-
nus), are commonly seen feeding around supplemental deer
feeders. In many cases, supplemental feeding continues
year-round so feed supply stores always have supplemental
corn in stock. Fluctuating weather and improper storage of
corn can lead to and/or amplify aatoxin contamination.
Due to the recent decline of bobwhites throughout the
Rolling Plains ecoregion of Texas, there has been interest in
nding factors such as toxins that could be linked to their
decline. In this study, we purchased and sampled supple-
mental corn from 19 locations throughout this ecoregion to
determine if aatoxin contamination was present in indivi-
dual bags prior to being dispersed to wildlife. Of the 57
bags sampled, 33 bags (approximately 58%) contained
aatoxin with a bag range between 0.019.91 parts per
billion (ppb). Additionally, three metal and three poly-
propylene supplemental feeders were each lled with
45.4 kg of triple cleaned corn and placed in an open eld to
study long-term aatoxin buildup. Feeders were sampled
every 3 months from November 2013November 2014.
Average concentration of aatoxin over the year was
4.08 ±2.53 ppb (±SE) in metal feeders, and 1.43 ±0.89
ppb (±SE) in polypropylene feeders. The concentration of
aatoxins is not affected by the type of feeder (metal vs
polypropylene), the season corn was sampled, and the
location in the feeder (top, middle, bottom) where corn is
sampled. It is unlikely that corn used in supplemental fee-
ders is contributing to the bobwhite decline due to the low
levels of aatoxin found in purchased corn and long-term
storage of corn used in supplemental feeders.
Keywords Aatoxin Aspergillus spp. Corn Rolling
Plains Supplemental Feeder Texas
Supplemental feeding with corn to attract white-tailed
(Odocoileus virginianus) and mule deer (Odocoileus
hemionus) is a common practice throughout Texas.
Ranchers, landowners, and hunters often consider supple-
mental feeding a necessary and benecial management
technique (Perkins 1991). Some use supplemental feeding
to help inuence hunting while others use it for some type
of active game management (Hernández and Guthery
2012). Corn is the primary feed of choice, many people also
use a protein based feed to help provide adequate nutrition
as well as to increase the antler size of their deer. In many
cases, supplemental feeding continues year-round so feed
supply stores always have deer corn in stock. Besides deer,
other species including northern bobwhites (Colinus virgi-
nianus) and scaled quail (Callipepla squamata) are com-
monly seen feeding around supplemental deer feeders. Both
northern bobwhites and scaled quail have been steadily
declining throughout all of Texas for decades (Church et al.
1993; Hernández et al. 2013). One of the major issues
*Ronald J. Kendall
The Wildlife Toxicology Laboratory, The Institute of
Environmental and Human Health, Texas Tech University, Box
41163, Lubbock, Texas 79409-1162, USA
Vector-Borne Zoonoses Laboratory, The Institute of
Environmental and Human Health, Texas Tech University, Box
41163, Lubbock, Texas 79409-1162, USA
related to supplemental feeding is the potential for wildlife,
especially quail, to be exposed to aatoxin. Studies have
reported the incidence of aatoxin contamination in corn
that is being used as bait for deer (Fischer et al. 1995).
Corn is known to constitute an important part of the diet
of bobwhite quail. Corn provides quail with digestible
carbohydrates and Vitamin A that play a key role in the
survival of quail during winter season (Nestler 1949). A
study by Korschgen (1948) has revealed that corn makes up
to 16.8% of the total diet of bobwhite quail in Missouri
during the late-fall and early-winter seasons (Korschgen
1948). More importantly, the opportunistic feeding of corn
in deer feeders by quail has been documented in the lit-
erature (Dietz et al. 2009).
Aatoxin is a fungal metabolite that is produced by two
strains of mold (Aspergillus avus and Aspergillus para-
siticus) which grows on corn and most types of grain
vegetables. Major crops that are affected by aatoxin con-
tamination are peanuts (Arachis hypogaea), cotton (Gos-
sypium spp.), and corn (Zea mays) (Thompson and Henke
2000). Corn is especially vulnerable to contamination due to
cracked corn kernels that facilitate the invasion, germina-
tion, and growth of the fungus (Bingham et al. 2003).
Exposure to aatoxin can be harmful to both humans and
wildlife (Stoloff 1980) because it is a known carcinogen and
has been documented to cause excessive weight loss, liver
damage, impaired immune systems, and mortality to avian
species, including quail (Thaxton et al. 1973; Pier 1992;
Ruff et al. 1992; Quist et al. 2000). Some of these negative
effects have been documented in bobwhite quail with aa-
toxin levels as low as 100 parts per billion (ppb) (Moore
et al. 2013).
Many factors contribute to the production of aatoxin on
grain products, including moisture level of feed, tempera-
ture, pH, relative humidity, and a variety of plant stressors
such as damaged kernels and insect infestation (Jacques
1988). Aspergillus infection and aatoxin contamination of
corn kernels is predominantly observed during high tem-
perature (>90 °F with warm nights) and drought conditions
(Vincelli et al. 1995). Aatoxin can infect agricultural and
wild plants in the eld, or while in storage, regardless of
storage system, time of year, or environmental condition
(Thompson and Henke 2000). Aatoxin growth on stored
grains has contributed to most of the recorded animal
aatoxin poisoning incidents (Jacques 1988). Given the
duration of growth when conditions are optimal, and
the variety of plants that aatoxin can infect, quail have the
potential to be exposed to aatoxin through much of their
diets (Oberheu and Dabbert 2001a).
Because aatoxin contaminated grain has been docu-
mented to cause a variety of negative effects to humans and
domestic animals, the U.S Food and Drug Administration
(US FDA) has implemented a <20 ppb aatoxin level in
grains used for human consumption and strict regulations
for domestic animals (US FDA 1979). Supplemental feed
for wildlife species is not governed by these federal reg-
ulations, but some state governments have implemented
their own regulations. In Texas, corn sold for the sole
purpose of supplemental wildlife feeding activities is
required to have <50 ppb of aatoxin prior to being bagged
and sold to consumers (Texas Commercial Feed Control
Act 2011). Additionally, supplemental wildlife feed com-
panies have their corn tested and guarantee that the corn
Meets the Texas <50 ppb standard for wildlife feed;
however, most companies ensure that they meet the <20
ppb aatoxin standards to ensure they are safe for wildlife
Feeding aatoxin contaminated grain may increase their
risk of contamination and potentially diminish any realized
benet from supplemental feeding (Perez et al. 2001). With
stores having deer corn available year round there is a
concern of amplication of aatoxin production within each
bag. This is also alarming due to many of these feed/seed
stores storage practices. Many of these stores have grain
stored on the oor of an unventilated steel building or stored
outside of a store where they are constantly being exposed
to various weather conditions (Wildlife Toxicology
Laboratory, personal observation). Henke et al. (2001)
reported aatoxin in wild bird seed purchased throughout
Texas, of which 83% contained corn as an ingredient.
Additionally aatoxin was not detected in bags of supple-
mental feed prior to them being used to ll feeders but
aatoxin production in the feeders increased overtime ran-
ging from 0.57 to 15.47 ppb (Oberheu and Dabbert 2001b).
While aatoxin is not be the sole contributor to the decline
of quail in Texas, it may inuence and/or be a confounding
Since aatoxin can grow fast given the right environ-
mental conditions, the goals of this study were to: (1)
Follow-up on two of Oberheau and Dabbert (2001a, 2001b)
studies that documented aatoxin production in supple-
mental feed bags and aatoxin production in metal sup-
plemental feeders to understand if storage practices and
overall cleanliness has reduced contamination and (2)
Examine if aatoxin production varied between two com-
mon supplemental wildlife feeders types used throughout
the Rolling Plains of Texas.
Materials and methods
Supplemental corn collection
Bags of deer corn (n=57) were purchased from opportu-
nistically selected stores throughout the Rolling Plains of
Texas from OctoberDecember 2013. At the time of
Aatoxin contamination in corn sold for wildlife feed in texas 517
purchase, the clerk was asked to sell us the most popular
selling brands of deer corn. Three 18.14 to 22.68-kg bags of
deer corn were purchased from each location based on the
recommendations of the store clerk. All corn was labelled
recleanedor triple cleanedmeaning that the husk, debris,
and other organic products are removed, leaving only dry
corn. Additionally, all bags were labeled as tested to ensure
<20 ppb of aatoxin contamination prior to being pack-
aged. Corn was returned to Texas Tech University and
approximately 250 g of corn was sampled from the top,
middle, and bottom of each individual bag. Aatoxin con-
tamination is usually localized in nature and does not occur
uniformly throughout a given bag. Hence, composite sam-
pling of the bag is recommended (Aatoxins in Corn,
2017). To simulate composite sampling, corn was sampled
from the top, middle, and bottom portions of each bag. All
corn was sampled within 2 days of purchase. Subsamples
from each bag (n=3) were later pooled together to get an
average aatoxin concentration in a bag. Individual sub-
samples were placed into a plastic freezer bag and stored at
80 °C until analysis.
Supplemental feeder collection
From November 2013November 2014, three 97.72-kg
capacity metal (Moultrie Pro-Hunter Tripod Feeder; Calera,
Al, USA) and three 136.1-kg capacity polypropylene/PP
(Wildgame Innovations Poly Barrel Feeder; Grand Prairie,
TX, USA) supplemental feeders were each lled with
45.36-kg of triple cleaned deer corn, certied at <20 ppb,
purchased from the local feed store. Feeders were placed in
an open eld in Lubbock County, TX (33°3514.2N, 102°
0152.6W) for the duration of the experiment. Bottom feed
ports of each feeder were left open but modied with a
screen so corn would not dispense but allow for normal
exposure conditions. Three 250 g samples from each feeder
(top, middle, bottom) were collected every 3 months i.e.
November 2013, February 2014 (Spring), May 2014
(Summer), August 2014 (Fall), and November 2015
(Winter). Sampling at these time periods would give us a
good chance to investigate the seasonal variations in aa-
toxin contamination. Samples were collected on the same
day every 3 months over the duration of the study. Indivi-
dual subsamples were placed into a plastic freezer bag and
stored at 80 °C until analysis.
Sample analysis
Each subsample was analyzed for aatoxin contamination
using the FluoroQuant® Aa Test kit (Romer Labs Inc.,
Union, MO 63084, USA), which could detect aatoxins in
the range of 0 to1000 ppb. We followed the Romer Labs
Inc. instructions which included grinding corn enough to
pass through a #20 size mesh sieve, and then combining
ground corn with 100 ml methanol/water (80:20) in an
extraction container. Contents were blended for 1 min and
then ltered into a polypropylene container. Next, 1 ml of
extract was pipetted into a column (SolSep® 2001 Aa-
toxin column) and mixed with 1 ml of diluent. The extract
was slowly pushed through the column and a total of 500 µl
of sample extract was then pipetted and transferred into a
clean, scratch-free 12 ×75 mm cuvette. One ml of prepared
developer was then added to purify the extract. The cuvette
was capped and vortexed for 5 sec then wiped clean and
inserted into the calibrated uorometer (Romer Series III,
Model RL100) to determine level of aatoxin contamina-
tion. Fluorometer was recalibrated daily using the calibra-
tion standards provided by Romer Labs Inc.
Data analysis
One-way ANOVA was performed using MINITAB 17
(2010) to detect any signicant differences in ataoxin
concentrations from the top, middle and bottom sub-
samples of all 57 bags. This was conducted to check if
the aatoxin concentrations varied among the sampling
locations (top, middle and bottom) of each bag.
A model was employed to determine if the aatoxin
concentrations in supplemental feeders are inuenced by the
type of feeder (metal vs PP) and the season/time during
which corn was sampled. The model consisted of two xed
factors, container type (metal vs PP) and the season. A
random factor, i.e. container number (1, 2, and 3) is nested
within the type of container. An ANOVA was run on
MINITAB 17 on the aatoxin concentrations that were
determined to be positive.
Binary logistic regression on SAS (Version 9.3) was
used to account for the samples with no aatoxins (zero
aatoxin concentrations). The response was considered to
be zero if the concentration of aatoxin in the sample is 0.
The response is considered to be 1 if the concentration of
aatoxin in the sample is greater that zero. SAS (version
9.3) was employed to perform the binary logistic regression,
as MINITAB does not allow nested or random factors in
logistic regression.
Signicance was inferred at a p-value 0.05. The aa-
toxin concentrations are reported a mean ±standard error
Of the 57 bags of supplemental corn purchased from feed
stores throughout the Rolling Plains, aatoxins were found
in 33 (58%) of the bags. The average aatoxin concentra-
tion in the 57 bags ranged from 0.0019.71 ppb. Of the
518 N. R. Dunham et al.
171 sub-samples, only three sub-samples had an aatoxin
concentration greater than 20 ppb (59.13, 47.84, 21.65 ppb,
respectively), conrming that aatoxin contamination, if
any, is localized within a given region in the bags. No
signicant difference in the concentration of aatoxins
between the top, middle and bottom locations of the bag
was observed (One-way ANOVA, p=0.328). The low
levels of aatoxins in the corn bought from the stores are
expected because it is recleanedor triple cleanedand is
sampled within 2 days of purchase.
Many feed stores throughout the Rolling Plains store
their grain products in a variety of storage areas that often
do not have a consistent temperature or proper ventilation
(Wildlife Toxicology Laboratory, personal observation).
These storage locations would range from the oor of a
warehouse, stacked up in a steel building, or simply placed
outside of a store for a costumer to purchase. Due to these
inconsistencies, we expected to see higher aatoxin levels
within corn bags purchased throughout the region; however,
aatoxin was found to be extremely low and nowhere near
the 50 ppb wildlife feed standard or even the 20 ppb bag
guaranteelisted on the label. Reducing the amount of
organic matter and drying the corn kernels prior to bagging
is likely helping reduce the amount of aatoxin production
within each supplemental corn bags. It is possible that
aatoxin may not have been found within each bag because
this corn may have been newly packaged. Unfortunately,
the date of packaging was not recorded for each of these
bags sampled.
Aatoxin contamination was observed in the feeders
(both metal and PP) during every season the corn was
sampled, in agreement with the results of Oberheau and
Dabbert (2001b). The average level of aatoxins in the
supplementary feeders during a given season is summarized
in Fig. 1. Over the time frame of November 2013 through
November 2014, the level of aatoxins in the metal feeders
ranged from 0.00114.44 ppb with an average aatoxin
concentration of 4.08 ±2.53 ppb. During the same time
frame, the level of aatoxins in the PP feeders ranged from
0.0040.68 ppb with an average aatoxin concentration of
1.43 ±0.89 ppb. Neither the xed factors (type of container
and the season during which corn was sampled) nor the
random factor (container number nested within the type of
container) affected the concentration of aatoxins in the
feeders (ANOVA, p>0.05). Results from the binary logistic
regression analysis also suggested that the aatoxin con-
centrations in the feeders is not affected/inuenced by the
type of container, the season during which corn was sam-
pled, and the location of corn in the feeder (top, middle, and
Fluctuating weather and long-term storage of corn was
expected to increase the amount of aatoxin contamination
within the feeders. Over the course of our study, the loca-
tion of these supplemental feeders experiences more than
25.4 cm higher precipitation than each of the 3 years prior
(NOAA 2016). Optimal aatoxin production happens when
relative humidity is between 7090% and temperature range
between 3638 °C, but it can grow at temperatures as low as
6 °C (Salunkhe et al. 1987). The conditions in which this
fungus can grow are commonly experienced throughout
Texas, including Lubbock County and throughout the
Rolling Plains ecoregion.
While aatoxin may not have been found at alarming
levels during the long-term storage of triple cleaned sup-
plemental deer corn, many landowners and hunters will
often supplement with a mixed grain (corn, milo, soybeans,
sunowers, etc.) feed. These mixed grain feeds contain
many forms of organic products that are not triple cleaned
which may increase in its susceptibility to aatoxin pro-
duction. Much like supplemental corn, these mixed grain
feeders are also used to supplement for wildlife all year long
but monitoring production in mixed grains were out of the
scope of the present study. Future research is needed to
investigate the difference in corn versus mix grain supple-
mental feed aatoxin production.
Aatoxin can grow on nearly all agricultural and wild
foods (Salunkhe et al. 1987; Oberheau and Dabbert 2001a)
but contamination was not found at alarming levels
throughout this entire study. Given the results of the study,
aatoxin contamination is likely not impacting northern
bobwhites and or other wildlife species throughout the
Rolling Plains of Texas. Additional research is needed to
determine if aatoxin poses a risk in mixed grain supple-
mental feed and if aatoxin is problematic in other regions
of the United States.
Acknowledgements Funding for this research was provided by Park
Cities Quail and the Rolling Plains Quail Research Foundation. We
would like to sincerely thank Professor James Surles at the Texas Tech
University Department of Mathematics and Statistics for his help with
the data analysis. We thank members of the Wildlife Toxicology
Laboratory for all of their help sampling and processing the
Fig. 1 Mean aatoxin production (±SE) in metal and polypropylene
supplemental wildlife feeders from November 2013November 2014
Aatoxin contamination in corn sold for wildlife feed in texas 519
supplemental feed during this experiment. We also would like to thank
the reviewers for their time and valuable input regarding this
Compliance with ethical standards
Conict of interest The authors declare that they have no competing
Ethical approval This article does not contain any studies with
human participants or animals performed by any of the authors.
Informed consent Informed consent was obtained from all indivi-
dual participants included in the study.
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... comm.). Aflatoxins have been reported in wildlife feeders in Texas and Oklahoma (Oberheu and Dabbert 2001) and in bags of corn sold for wildlife feeding in the US areas of Georgia (Schweitzer et al. 2001), the Carolinas (Fischer et al. 1995), and Texas (Dunham et al. 2017). ...
... Despite the popularity of feeding and the risk of aflatoxin contamination, there are still unknowns, including how risk differs by feed type and season. Past studies tended to focus on corn (Dunham et al. 2017), despite the variety of feeds used by hunters, most notably protein pellets (Bartoskewitz et al. 2003). Past studies also tended to sample during hunting season (October-February; Oberheu and Dabbert 2001), when feeding is more common but the climate is less hospitable to fungal growth (Sanchis and Magan 2004). ...
... We collected 100-g samples from bagged and bulk feed from six states, deer feeders in year-round use on 17 properties in Mississippi, and corn piles over time during May-January 2019 and 2020 ( Fig. 1). Because aflatoxins are not uniformly distributed in feed (Dunham et al. 2017) or feeders (Newman et al. 2019), all samples consisted of multiple subsamples from throughout the feeder, feed bag, or feed pile. We kept all samples refrigerated until submission to the Mississippi State Chemical Laboratory, which used an enzyme-linked immunosorbent assay with a 5 ppb detection limit to detect aflatoxins. ...
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This review is a systematic scientific work on medicinal and traditional use, on the chemical composition of specialized metabolites, volatile and non-volatile, on aspects related to toxicology and phytotherapy of Nigella damascena L. The genus Nigella (Ranunculaceae) is distributed throughout the Mediterranean basin, extending to northern India, and has been divided into three sections. Nigella damanscena L. is traditionally used as an ingredient in food, for example, as flavouring agents in bread and cheese, but is also known in folk medicine, used to regulate menstruation; for catarrhal affections and amenorrhea; as a diuretic and sternutatory; as an analgesic, anti-oedematous, and antipyretic; and for vermifuge and its disinfectant effects. This paper reviews the most dated to the latest scientific research on this species, highlighting the single isolated metabolites and exploring their biological activity. Fifty-seven natural compounds have been isolated and characterised from the seeds, roots, and aerial parts of the plant. Among these constituents, alkaloids, flavonoids, diterpenes, triterpenes, and aromatic compounds are the main constituents. The isolated compounds and the various extracts obtained with solvents of different polarities presented a diverse spectrum of biological activities such as antibacterial, antifungal, antitumour, antioxidant, anti-inflammatory, antipyretic, anti-oedema, and antiviral activities. Various in vitro and in vivo tests have demonstrated the pharmacological potential of β-elemene and alkaloid damascenin. Unfortunately, the largest number of biological studies on this species and its metabolites have been conducted in vitro; therefore, further investigation is necessary to evaluate the toxicological aspects and real mechanisms of action of crude extracts to confirm the therapeutic potential of N. damascena.
... Maize can be a suitable substrate for the growth of A. flavus and production of AFT. Therefore, grain from all over the world can suffer from AFT contamination (Daniel et al., 2011;Dunham et al., 2017;Gao et al., 2011;Mitchell et al., 2016), and the economic loss caused by AFT contamination was reported to be more than $200 million (Shi et al., 2017a). ...
Maize is susceptible to contamination with aflatoxins (AFs). Consumption of AFs contaminated maize can cause poisoning and even death. The goals of this study were to determine the detoxification efficacy of sulfurous acid (H2SO3) on aflatoxin B1 (AFB1) within the range of soaking parameters used in industrial maize production, to identify the transformation product of AFB1 and analyze the cytotoxicity of transformation product. AFB1 contaminated maize was soaked in different concentrations of H2SO3 and the results indicated that soaking time and temperature could significantly influence the detoxification efficiency; 25–31 μg/kg of AFB1 in maize could be detoxified by 0.2–0.3 % of H2SO3. The transformation product was obtained using mass spectrometry and molecular formula analysis. It was identified as C17H14O9S, named as AFB1-HSO3. The toxicity of AFB1-HSO3 was evaluated. Cell morphology showed that the damage caused by AFB1 was significantly greater than that caused by AFB1-HSO3. It also found that the effects of AFB1-HSO3 on the activity, ATP and DNA content of Hep G2 cells were significantly less than that of AFB1. It was concluded that AFB1-HSO3 was less toxic than AFB1 in this system. These results suggest that H2SO3 can be used as a potential detoxification agent in industrial maize production.
... This may cause an array of metabolic, physiological and immunological problems for livestock. Research on poultry and other livestock and wild species has shown marked interspecific variation in the effects of mycotoxins (Perez et al., 2001;Dunham et al., 2017;Wang et al., 2018a;Paoloni et al., 2018). An example is a study by Murray et al. (2016), which found that piles of compost visited by coyotes in urban areas were contaminated by at least one mycotoxin (OTA, T2 and ZEN). ...
The antioxidant and mutagenic/antimutagenic activities of the fixed oils from Nigella sativa (NSO) and Nigella damascena (NDO) seeds, obtained by cold press-extraction from the cultivar samples, were comparatively investigated for the first time. The antimutagenicity test was carried out using classical and modified Ames tests. The fatty acid composition of the fixed oils was characterized by gas chromatography–mass spectrometry (GC-MS) while the quantification of thymoquinone in the fixed oils was determined by UPC². The main components of the NSO and NDO were found to be linoleic acid, oleic acid, and palmitic acid. The results of the Ames test confirmed the safety of NSO and NDO from the viewpoint of mutagenicity. The results of the three antioxidant test methods were correlated with each other, indicating NDO as having a superior antioxidant activity, when compared to the NSO. Both NSO and NDO exhibited a significant protective effect against the mutagenicity induced by aflatoxin B1 in Salmonella typhimurium TA98 and TA100 strains. When microsomal metabolism was terminated after metabolic activation of the mycotoxin, a significant increase in antimutagenic activity was observed, suggesting that the degradation of aflatoxin B1 epoxides by these oils may be a possible antimutagenic mechanism. It is worthy to note that this is the first study to assess the mutagenicity of NSO and NDO according to the OECD 471 guideline and to investigate antimutagenicity of NDO in comparison to NSO against aflatoxin.
Provision of supplementary food for garden birds is practiced on a large scale in multiple countries. While this resource has benefits for wild bird populations, concern has been expressed regarding the potential for contamination of foodstuffs by mycotoxins, and the implications this might have for wildlife health. We investigated whether aflatoxin (AF) and ochratoxin A (OA) residues are present in foodstuffs sold for wild bird consumption at point of sale in Great Britain using high pressure liquid chromatography analyses. The hypothesis that production of these mycotoxins occurs in British climatic conditions, or under storage conditions after the point of sale, was tested under experimental conditions but was not proved by our study. While the majority of peanut samples were negative for AF residues, 10% (10/98) of samples at point of sale and 11% (13/119) of those across the storage and climate exposure treatment replicates contained AFB1 that exceeded the maximum permitted limit of 20 μg/kg. No significant difference was found in the detection of either mycotoxin between branded and non-branded products. The clinical significance, if any, of exposure of wild birds to mycotoxins requires further investigation. Nevertheless, the precautionary principle should be adopted and best practice steps to reduce the likelihood of wild bird exposure to mycotoxins are recommended.
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Post-harvest aflatoxin contamination is a challenging issue that affects peanut quality. Aflatoxin is produced by fungi belonging to the Aspergilli group, and is known as an acutely toxic, carcinogenic and immune-suppressing class of mycotoxins. Evidence for several host genetic factors that may impact aflatoxin contamination has been reported,e.g., genes for lipoxygenase (PnLOX1 and PnLOX2/PnLOX3 that showed either positive or negative regulation withAspergillusinfection), ROS, and WRKY (highly associated with or differentially expressed upon infection of maize withA. flavus); however, their roles remain unclear. Therefore, we conducted an RNA-seq experiment to differentiate gene response to the infection byAspergillus flavusbetween resistant (ICG 1471) and susceptible (Florida-07) cultivated peanut genotypes. The gene expression profiling analysis was designed to reveal differentially expressed genes in response to the infection (infected vs mock-treated seeds). In addition, the differential expression of the fungal genes was profiled. The study revealed the complexity of the interaction between the fungus and peanut seeds as expression of a large number of genes was altered including some in the process of plant defense to aflatoxin accumulation. Analysis of the experimental data with 'keggseq', a novel designed tool for KEGG enrichment analysis, showed the importance of alpha-linolenic acid metabolism, protein processing in endoplasmic reticulum, spliceosome, and carbon fixation and metabolism pathways in conditioning resistance to aflatoxin accumulation. In addition, co-expression network analysis was carried out to reveal the correlation of gene expression among peanut and fungal genes. The results showed the importance of WRKY, TIR-NBS-LRR, ethylene, and heat shock proteins in the resistance mechanism.
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The northern bobwhite (Colinus virginianus) decline has become a cause célébre of wildlife conservation during the past 2 decades. With few exceptions, current broad-scale population trends show ongoing erosion in bobwhite numbers across most of the species' range. The causes of these declines are ultimate factors exacerbated by certain proximate factors. Ultimate factors are centered on the loss and fragmentation of habitat. Proximate factors such as predation and disease also may be present. The impacts of some factors, such as climate change, remain unknown but may influence bobwhite population trajectories over the long term. Progress has occurred in bobwhite conservation efforts since 1990 and has culminated in the formation of the National Bobwhite Technical Committee and the publication of the Northern Bobwhite Conservation Initiative. The vast majority of prevailing agricultural, forestry, and to some extent rangeland land uses in the United States continue as threats to bobwhite population persistence in the foreseeable future. Land-use patterns that once sustained widespread abundance of northern bobwhite during the early 20th century clearly are past and likely never to return. Landscape features that sustain and elevate northern bobwhite populations will only be maintained as a function of purposeful management actions directed at saving and creating usable space. © The Wildlife Society, 2012
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Aflatoxin, a potent natural contaminant in feedstuffs, suppressed hemagglutinin formation in chickens. The primary immune response was reduced in a dose-related fashion when aflatoxin was incorporated into the diet at levels as low as 0.625 μg. per gram. The relative sizes of the bursa of Fabricius and the thymus, the primary initiators of immunity in the chicken, were reduced by 30% and 55%, respectively, when chickens ate a diet containing 10 μg. of aflatoxin per gram of feed. The state of immunosuppression can account for the carcinogenecity of aflatoxin as well as the enhanced susceptibility to some infectious agents found during aflatoxicosis.
Aflatoxin is a widely occurring and harmful mycotoxin produced by strains of Aspergillus spp. growing on vegetable matter. We investigated the concentration of aflatoxin needed to impair normal physiologic responses and induce acute morbidity and mortality in Northern Bobwhites (Colinus virginianus). Ten wild-caught adult bobwhites (five males and five females) from southern Texas were randomly assigned to each treatment group (0, 100, 500, 1,000, and 2,000 parts per billion (ppb) aflatoxin; n=50). We orally administered 100 μL of aflatoxin, derived from Aspergillus flavus, once per week for 4 wk and monitored bird mass, daily feed consumption, liver histology, and blood chemistries. An in vitro white blood cell proliferation test was conducted using spleen tissue to determine the effect of aflatoxin on the immune system. There was no mortality in the control groups, whereas mortalities occurred in all treatment groups except in the 100 ppb aflatoxin treatment. Immunosuppression, reduction in gamma-globulin, glucose, and gamma-glutamyltransferase blood levels, and abnormal liver histology were observed in aflatoxin-exposed quail. Blood chemistry indicated cellular damage to the liver and kidneys. We concluded that short-term, acute doses of aflatoxin as low as 100 ppb can be detrimental to the health of Northern Bobwhites.
Aflatoxins, a family of closely related, biologically active mycotoxins, have been known as a prominent cause of animal disease for 30 yr. The toxins occur naturally on several key animal feeds, including corn, cottonseed, and peanuts. Occurrence of aflatoxin on some field crops tends to spike in years when drought and insect damage facilitate invasion by the causative organisms, Aspergillus flavus and A. parasiticus, which abound in the crop's environment. Acute aflatoxicosis causes a distinct overt clinical disease marked by hepatitis, icterus, hemorrhage, and death. More chronic aflatoxin poisoning produces very protean signs that may not be clinically obvious; reduced rate of gain in young animals is a sensitive clinical register of chronic aflatoxicosis. The immune system is also sensitive to aflatoxin, and suppression of cell-mediated immune responsiveness, reduced phagocytosis, and depressed complement and interferon production are produced. Acquired immunity from vaccination programs may be substantially suppressed in some disease models. In such cases the signs of disease observed are those of the infectious process rather than those of the aflatoxin that predisposed the animal to infection. Mixtures of aflatoxin with other mycotoxins can result in greatly augmented biological responses in terms of rate of gain, lethality, and immune reactivity. Because of its great biological activity, its wide-spread potential presence in areas where critical feed crops are grown, and its propensity to spike in problem years, aflatoxin promises to be a continuing problem in animal production.
Bobwhite and Japanese quail were fed diets containing 1.25, 2.50, or 5.00 ppm aflatoxin; 1, 2, or 4 ppm ochratoxin A (OA); or 4, 8, or 16 ppm T-2 toxin. Aflatoxin induced mortality in bobwhites during the second and third week with 1.25 ppm (10%), 2.50 ppm (30%), and 5.00 ppm (40%), and during the same period with T-2 toxin at 8 ppm (20%) and 16 ppm (22.5%). Body weights of bobwhite quail were significantly decreased by the two higher levels of aflatoxin by 2 weeks of age, and by the two higher levels of T-2 toxin by 1 week of age. In Japanese quail, only the highest level of aflatoxin and T-2 toxin reduced body weight (by 3 weeks and by 1 week of age, respectively), and even then to a much lesser extent than in bobwhites (less than 10%). Aflatoxin did not affect feed-conversion ratio (FCR) in bobwhite quail, but the two higher levels of T-2 toxin increased FCR. None of the toxins induced mortality or increased the FCR in Japanese quail. Aflatoxin increased liver weight in both bobwhite and Japanese quail. OA increased kidney weight in 3-week-old Japanese quail but had no effect on the kidney weight of bobwhite quail. Mouth lesions were progressively more severe in bobwhite quail fed increasing levels of T-2 toxin, but lesions were far less severe in Japanese quail.
Domestic commodities most susceptible to aflatoxin contamination are peanuts, corn, cottonseed, and tree nuts (almond, pecans, walnuts); the most susceptible imported commodities are Brazil nuts and pistachio nuts. The development, effectiveness, and shortcomings of the strategies used to limit consumer exposure to aflatoxin from these commodities are reviewed.
Samples of shelled corn used for wildlife feed were taken from bait piles and storage bins in North Carolina and South Carolina (USA) from 29 September through 28 November 1993, and were analyzed for aflatoxin. Twenty (51%) of 39 samples were positive, with aflatoxin levels ranging from a trace to 750 parts per billion. Based on the high prevalence of aflatoxin-contaminated corn, exposure of wild-life to aflatoxin undoubtedly occurs, although the effects of such exposure are largely unknown.
The effects of grain storage containers on aflatoxin production, and the relationship between the level of aflatoxin and the number and weight of fluorescing kernels were determined in corn (Zea maize) stored in controlled climate regimes. Two hundred and forty 100-g samples were held up to 3 mos using four types of storage containers placed in four climates. Storage containers included corn placed in metal cans, paper bags, plastic bags, and paper bags placed in plastic bags. Climates were constant during the duration of the project and included a combination of temperatures and humidities. Temperatures were 29-32 C and 14-18 C; relative humidities were 85-88% and 35-40%. In addition, corn was exposed to environmental conditions conductive for aflatoxin production and 100 g samples were randomly collected, examined under ultraviolet light for fluorescence, and then quantified for aflatoxin levels. Corn samples tested negative for aflatoxin at the beginning of the project. Main (i.e., container, climate, and month) and interactive effects were not observed. Mean levels of aflatoxin ranged from 0 to 151 microg/kg. Aflatoxin was produced regardless of type of storage container, time of storage, and climatic conditions; however, only 8% of the samples produced aflatoxin levels that exceeded 50 microg/kg. Fluorescing corn ranged from 0 to 19 kernels per sample, while aflatoxin levels ranged from 0 to 1,375 microg/kg for the same samples. No relationships were found between the number and weight of fluorescing kernels of corn and aflatoxin levels. The black light test yielded a false negative rate of 23% when in fact the aflatoxin concentrations exceeded 50 microg/kg. Therefore, quantifying fluorescing grain under UV light should not be considered a feasible alternative for aflatoxin testing of grain intended for wildlife.