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Aflatoxin contamination in corn sold for wildlife feed in Texas

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Abstract and Figures

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
1
Steven T. Peper
2
Carson D. Downing
1
Ronald J. Kendall
1
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
Introduction
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
ron.kendall@ttu.edu
1
The Wildlife Toxicology Laboratory, The Institute of
Environmental and Human Health, Texas Tech University, Box
41163, Lubbock, Texas 79409-1162, USA
2
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
consumption.
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
factor.
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
(SE).
Results/Discussion
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
bottom).
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
manuscript.
Compliance with ethical standards
Conict of interest The authors declare that they have no competing
interests.
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.
References
Aatoxins in Corn: Iowa State University Extension and Outreach
(2017). https://store.extension.iastate.edu/Product/pm1800-pdf.
Accessed 11 Jan 2017
Bingham AK, Phillips TD, Bauer JE (2003) Potential for dietary
protection against the effects of aatoxins in animals. J Amer Vet
Med Assoc 222:591596
Church KE, Sauer JR, Droege S (1993) Population trends of quails in
North America. Nat Quail Symp 3:4454
Dietz DR, Whiting RM, Koerth NE (2009) Winter food habits and
preferences of northern bobwhites in east Texas. In: Cederbaum
SB, Faircloth BC, Terhune TM, Thompson JJ, Carroll JP (eds)
Gamebird 2006: Quail VI and Perdix XII. Warnell School of
Forestry and Natural Resources, University of Georgia, Athens,
GA, pp 160171
Fischer JR, Jain AV, Shipes DA, Osborne JS (1995) Aatoxin con-
tamination of corn used as bait for deer in the Southeastern
United States. J Wildl Dis 31:570572
Henke SE, Gallardo VC, Martinez B, Bailey R (2001) Survey of
aatoxin concentrations in wild bird seed purchased in Texas. J
Wildl Dis 37:831835
Hernández F, Brennan LA, DeMaso SJ, Sands JP, Wester DB (2013)
On reversing the northern bobwhite population decline: 20 years
later. Wildl Soc Bull 37:177188
Hernández F, Guthery FS (2012) Beef, brush, and bobwhites: quail
management in cattle country. Texas A&M University Press,
Kingsville, p 85
Korschgen LJ (1948) Late-Fall and early-Winter Food Habits of
Bobwhite Quail in Missouri. J Wildl Manage 12:4657
MINITAB 17 Statistical Software (2010). [Computer software]. State
College, PA: Minitab, Inc. www.minitab.com
Moore DL, Henke SE, Fedynich AM, Laurenz JC, Morgan R (2013)
Acute effects of aatoxin on Northern Bobwhites (Colinus vir-
ginianus). J Wildl Dis 49:568578
National Oceanic and Atmospheric Administration (NOAA) (2016)
National weather service forecast ofce: Lubbock, TX. http://
www.srh.noaa.gov/lub/?n=climate-klbb-pcpn. Assessed Feb
2016
Nestler RB (1949) Nutrition of Bobwhite Quail. J Wildl Manage 13
(4):342358
Oberheu DG, Dabbert CB (2001a) Aatoxin contamination in sup-
plemental and wild foods of northern bobwhite. Ecotox
10:125129
Oberheu DG, Dabbert CB (2001b) Aatoxin production in supple-
mental feeders provided for Northern Bobwhite in Texas and
Oklahoma. J Wildl Dis 37:475480
Perez M, Henke SE, Fedynich AM (2001) Detection of aatoxin-
contaminated grain by three granivorous bird species. J Wildl Dis
37:358361
Perkins JR (1991) Supplemental feeding. Texas parks and wildlife
department: sheries and wildlife division. Contribution of Fed-
eral Aid Project W-129-M, Austin, Texas, p 14
Pier AC (1992) Major biological consequences of aatoxicosis in
animal production. J Anim Sci 70:39643967
Quist CF, Bounous DI, Kilburn JV, Nettles VF, Wyatt RD (2000) The
effect of dietary aatoxin on wild turkey poult. J Wildl Dis
36:436444
Ruff MD, Huff WE, Wilkins GC (1992) Characterization of the
toxicity of the mycotoxins aatoxin, ochratoxin, and T-2 toxin in
game birds.III. Bobwhite and Japanese quail. Avian Dis 36:3439
Salunkhe DK, Adsule RN, Padule DN (1987) Aatoxins in foods and
feeds. Metropolitan BookCo., New Delhi, p 510
Stoloff L (1980) Aatoxin control: Past and present. J Assoc Off Anal
Chem 63:10671073
Texas Commercial Feed Control Act. (2011). Texas administrative
code commercial feed rules 61:148. http://otscweb.tamu.edu/
Laws/PDF/FeedRules.pdf. Accessed Oct 2014
Thaxton JP, Tung HT, Hamilton PB (1973) Immunosuppression in
chickens by aatoxin. Poultry Sci 53:721725
Thompson C, Henke SE (2000) Effect of climate and type of storage
container on aatoxin production in corn and its associated risks
to wildlife species. J Wildl Dis 36:172179
United State Food and Drug Administration (US FDA) (1979) CPG
SEC. 683.100. Action levels for aatoxin in animal feeds. http://
www.fda.gov/ICECI/ComplianceManuals/CompliancePolicy
GuidanceManual/ucm074703.htm#. Accessed July 2014
Vincelli P, Parker G, McNeill S, Smith RA, Woloshuk C, Coffey R,
Overhults DG (1995) Atatoxins in corn. University of Kentucky
Cooperative Extension Service: Lexington, KY, USA
520 N. R. Dunham et al.
... 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 states 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). ...
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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). ...
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... 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). ...
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Aflatoxins, toxic metabolites of Aspergillus flavus or Aspergillus parasiticus, cause poor feed utilization, decreased weight gains, depressed immune function, liver dysfunction, coagulation abnormalities, and death in a wide variety of species including humans. Conservationists have become concerned that increasingly popular wildlife feeding or baiting practices could expose wildlife to toxic amounts of aflatoxin-contaminated grains. In particular, the effects of aflatoxins on the wild turkey (Meleagris gallopova silvestris) are of concern because the conspecific domestic turkey is highly susceptible to aflatoxins. To evaluate the effect of dietary aflatoxin on wild turkeys, four groups of 4-mo-old wild turkeys were fed diets containing either 0, 100, 200, or 400 micrograms aflatoxin/kg feed for 2 wk in September and October 1996. Aflatoxin-fed poults had decreased feed consumption and weight gains as compared with control poults. Decreased liver-to-body weight ratios, liver enzyme alterations, slightly altered blood coagulation patterns, and mild histologic changes indicated low-level liver damage. Compromise of cell-mediated immunity was indicated by decreased lymphoblast transformation. The effects were apparent in all treatment groups to variable levels, but significant differences most often were found at 400 micrograms aflatoxin/kg feed. This study shows that short-term aflatoxin ingestion by wild turkeys can induce undesirable physiologic changes; therefore, exposure of wild turkeys to feeds containing aflatoxin levels of 100 micrograms aflatoxin/kg feed or more should be avoided.