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Equine Nutr > Lecture 7 - Anti nutritional factors in feeds > Flashcards

Lecture 7 - Anti nutritional factors in feeds Flashcards

(49 cards)

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1
Q

Example of global climate change

A

2012 North American drought

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2
Q

Drought, flooding and temp changes can

A

increase chance of mycotoxin contamination of feed grains

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3
Q

Increase chances of mycotoxin combinations in feed

A

global trading of feed grains

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4
Q

Most common found mycotoxins

A

aflatoxin

fusarium toxins

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5
Q

Fusarium toxins more difficult to analyze

A
  • large number of compounds

- widely varying chemical structures

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6
Q

What is necessary to analyze fusarium toxins

A

DON as a marker compound

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7
Q

Found in naturally contaminated corn and wheat from slovakia?

A

biologically active
non detectable
glucose conjugates of DON
- fraction of total DON represented by glucose conjugate is up to 30%

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8
Q

Chemical hydrolysis of feed samples before DON measurements resulted in

A

up to 88% increase in detectable DON in barely

- north dakota

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9
Q

Glucose conjugates of what compound have been reported?>

A 
zearalenone 
fumonisin
nivalenol
fusarenon-X
T-2 toxin
HT-2 toxin
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10
Q

Use what in lab to optimize hydrolysis conditions for corn and wheat

A

TFMSA

-trifluoromethanesulfonic acid

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11
Q

Avg increase in Canadian wheat with acid hydrolysis treatment

A

36.8%

7%-64%

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12
Q

Avg DON increase in corn with acid hydrolysis treatment

A

35.5%

17%-70%

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13
Q

2012 US corn crop (alfatoxin)

A

some alfatoxin but within legal limit

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14
Q

Fumomosin incidence

A

Significant amounts reported in 2012 in U.S corn

  • formed from strain of fusaium fungi
  • same strain forms fusaric acid
  • crops not typically analyzed for this
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15
Q

Most sensitive species to fusarium toxins

A

swine and horses

  • poultry more resistant but have altered metabolism and specific legions
  • ruminant animals most resistant, but effect reproduction and milk production
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16
Q

Fumonisins effects

A

inhibit synthesis of membrane lipids

  • result “equine leucoencephalomalacia”
  • ataxia and sudden death
  • massive atrophy of the brain
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17
Q

Fumonisins required to produce syndrome

A

3ppm

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18
Q

Major source of fumonisins

A

corn and corn screening

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19
Q

Trichothecenes

A

family of 100+ structurally related toxins

  • feed refusal toxins
  • most common deoxynivalenol (DON)
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20
Q

Trichothecenes effects

Study These Flashcards
A
  1. alter brain neurochemistry by increasing tryptophan and serotonin levels
  2. dermal necrotic agents and inhibit cellular protein synthesis
  3. cause hemorrhaging of intestinal tract, ulcers and nutrient malabsorption (bloody feces)
  4. immunosuppressive, make susceptible to 2nd mycotoxic disease (inhibit immunoglobulin synthesis)
21
Q

Zearalenone

Study These Flashcards
A

Estrogenic fusarium mycotoxin

22
Q

Zearalenone effects

Study These Flashcards
A

bind estrogen binding sites

- enlargement of uterus and rectal and vaginal prolapse

23
Q

Fusaric Acid

Study These Flashcards
A

inhibits enzyme dopamine-beta-hydroxylase

  • catalyzes dopamine to norepinephrine
  • causes lowering blood pressure

increases brain conc of tryptophan and seritonin

  • acts with vomitoxin (DON) synergistically
  • reduce feed consumption, muscle contraction and lethargy
24
Q

Fusaric acid content of cereal grains

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A 
whole foods - 35.8mg/kg
high moisture corn - 26.4
barely - 12.2
dry corn - 11.8
wheat - 11.6
25
Alfatoxins produced mainly by? | - what are they
aspergillus flavus aspergilus parasiticus - tropical / semitropical fungi - thrive in warm moist climates
26
Naturally occurring aflatoxins
Aflatoxins B1, B2, G1, G2
27
What are Alfatoxins
hepatotoxins - cause fatty infiltration and fibrosis of the liver - following acute exposure - due to inhibition of helpatic protein synthesis * one of the most carcinogenic compounds known chronic exposure causes liver cancer
28
Aflatoxicosis in ponies
increase serum enzyme activities of gamma glutamyl transferase (GGT) - confirms liver is key target - kidney secondary target
29
Aflatoxins exposure other than feed?
Inhalation from bedding material covered with mold and mycotoxins - respiratory disorders in horses and agricultural workers
30
Activation of aflatoxin B1 | - where is it highest
Converted to AFB1 epoxide - by cytochrome P-450 Activation higher in nasal olfactory mucosa than liver - predisposes equines to respiratory disease
31
Low level aflatoxin contamination
respiratory problems and immunosuppression
32
Fescue
important pasture forage crop in humid regions | - especially eastern US
33
Equine Fescue Toxicosis cause
Endophytic fungi grow symbiotically on tall fescue and ryegrass
34
Endophyte infected tallgrass contains
``` ergopeptide alkaloids (ergovaline) - tall fescue toxicosis ```
35
Endophyte infected ryegrass contains
``` lolitrem alkaloids (lolitrem B) - ryegrass staggers ```
36
Equine fescue toxicosis exist because
equines lack rumen detoxification of compounds | - protects grazing cattle
37
Equine fascue toxicosis signs / symptoms
characterized by reduced concentrations of IgC in milk - predispose foals to septicemia and death also prone to: - hypothyroidism - incoordination - poor suckle reflex - hypothermia - goitre Alkaloids are vasoconstrictive - predispose to laminitis from increased edema and vascular collapse
38
Endophyte infected fescue cardiorespiratory and thermoragulatory effects
exercising horses - slower recovery post exercise - recovery to pre-exercise levels was prolonged for heart rate and skin temp - increase water consumption and sweating
39
Equine fescue toxicosis effects on reproduction
vasconstriction of peripheral blood flow, leads to - increased gestation lengths - early embryonic mortality - agalactia - weak and immature foals
40
Equine Ergot Toxicosis initiation
fungus claviceps purpurea - produces alkaloid indolics (erotamine) - when invading wheat, rye and oats
41
Equine Ergot signs/symptoms
reduced udder development | weak foals lacking suckle reflex
42
Ergot contamination detection
visual examination for sclerotia (ergot bodies)
43
Equine Tremorgenic Mycotoxins (tremorgens)
Lolitrem B (neurotoxin) - produced by acremonium lolli - cause ryegrass staggers
44
Equine Tremorgenic Mycotoxins (tremorgens) common problem in
Australia New Zealand Western North America
45
Lolitrem B signs/symptoms
trembling hypersensitivity to stimuli abdominal muscle spasms disorientation of horse (Tremorgens)
46
Lolitrem B (tremorgens) proposed mechanism of action
inhibition of gamma-aminobutyric acid in the nervous system - inhibits chloride flux - prolongs nerve depolarization causing tremors
47
Equine Slaframine Toxicosis initiation
fungus 'rhizoctonia leguminicola - grows on red clover - others include soybeans, cow peas, alfalfa, white clover
48
Equine Slaframine Toxicosis signs/symptoms
Salivary syndrome or slobbers - due to slaframine - parasympathetic alkaloid - salivation - diarrhea - piloerection - respiratory failure - feed refusal
49
stratagies to prevent mycotoxicities
``` dilution with sound grain diversion to less susceptible species processing methods such as cleaning use of mold inhibitors (ex. propionic acid) use of enzymes mycotoxin adsorbents physical treatment (heat) ```

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