Exam 2- Mycotoxin

Question 1

What are mycotoxins

Answer 1

Secondary metabolites of fungi

Economic cost of $0.5-5 Billion/year

Question 2

What are influences on mycotoxin production

Answer 2

plant varieties, climate and weather, crop monoculture, seed coat damage, insect damage, storage quality, milling practices

Question 3

How does fungi develop in grain bins?

Answer 3

Moisture migration and bin condensation

Question 4

What is the common source for Aflatoxin?

Answer 4

Aspergillus flavus
source; high energy grains -> use energy from kernel
Corn peanuts, milo, cottonseed

Question 5

Waht factors favor Aflatoxin

Answer 5

Temp 78-90
drought stress
insect damage
High humidity and moisture

Question 6

Mechanism of Action associated with Aflatoxin

Answer 6

AFB1 metabolized by eposide. Epoxide binds to nucleic acids (DNA and RNA), Inhibition of protein synthesis, cell processes are disrupted, cell death -> necrosis

Question 7

What are predisposing factors to Aflatoxin

Answer 7

low protein diet, low antioxidants, low vitamin A, low choline/methionine

Question 8

clinical signs associated with Aflatoxin

Answer 8

Acute: anorexia, depression, emesis, bloody diarrhea, hemorrhage, icterus

chronic: decreased weight gain/production, immune suppression, Teratogenic, Carcinogenic, hepatic damage

Question 9

Acute Lesions associated with Aflatoxin

Answer 9

Liver- tan to yellow, multi-organ hemorrhage

Microscopic: hepatocellular vacuolization, centrilobular congestion and necrosis, renal tubular necrosis

Question 10

Chronic lesions associated with Aflatoxin

Answer 10

Nutmeg liver

hepatocellular vacuolization, hepatic fibrosis, bile duct proliferation

Question 11

Human health concerns associated with Aflatoxin

Answer 11

Considered carcinogenic: FDA actino level is 0.5ppb

no treatment or antidote

Question 12

Tricothecene Mycotoxins favored conditions

Answer 12

Cool temperatures or alternatign cool and warm temps

high moisture

Question 13

Effects of Tricothecene

Answer 13

wide range of effects on the body- dependent on toxin

hematopoetic, dermal, lymphoid, GI

Question 14

T2 toxin effect

Answer 14

Dermal and mucosal necrosis

Affects rapidly dividing cells
Causes immunosuppression: Lymphoid depletion, thymic involution, pancytopenia

Question 15

Deoxynivalenol source, and conditions

Answer 15

corn

wet and cool conditions

Question 16

What is Deoxynivalenol produces with

Answer 16

Zearalenone

Called a “vomitoxin”

Question 17

Clinical effects in swine of Deoxynivalentol

Answer 17

Swine are the msot sensitive species -> younger pigs are more sensitive (feed averson, vomiting, feed refusal)

Neurochemical effect (increased serotonin): learning period of feed refusal

ruminants and horses are resistant!

Question 18

How is the presence of Deoxynivalenol diagnosed?

Answer 18

History and presence of vomitoxin in feed

Question 19

Source, conditions associated with Zearalenone

Answer 19

Corn is the main source
Optimal conditiosn: cool wet environments

Estrogenic conditions

** Zearalenone and vomitoxin are typically found together **

Question 20

MOA of Zearalenone

Answer 20

binds to estradiol receptor -> promotes signs of estrogenism: decreased folicular maturation, inhibtion of ovulation

Question 21

clinical effects of Zearalenone

Answer 21

Reproductive issues:
Females: hyperestrogenism, anestrus, embryonic losses, mammary gland development (NOT ABORTIVE!!!)

Males: decreased libido and semen quality

Question 22

Fumosin species susceptible

Answer 22

Equine and swine are the most affected species

Question 23

MOA of fumosin

Answer 23

inhibits sphingolipid synthesis

sphingolipids: components of cell membranes, and nervous tissues

Question 24

clinical effects of Fumosin

Answer 24

Swine: Respiratory- dyspnea, cyanosis, weakness, acute death
Equine: neurologic - blind, ataxia, depressed

Question 25

Lesion in swine associated with Fumosin

Answer 25

wet heavy edematous lungs
Pulmonary edema- expanded interlobular septa
Tan friable liver

Microscopic lesions: pulmoanry edema, centrilobular necrosis, portal fibrosis, fatty disposition

Question 26

Lesions associated with Equine and fumosin

Answer 26

Gross lesions are necrosis of the white matter
Leukoencephalomalacia
Brown-yellow liver
Microscopic lesions include: neuronal vacuolization: expansion and edema

Question 27

Clinical pathology associated

Answer 27

inidcators of hepatic insult

elevated liver values