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

Lecture 7 - Anti nutritional factors in feeds Flashcards

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

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

A

Estrogenic fusarium mycotoxin

22
Q

Zearalenone effects

A

bind estrogen binding sites

- enlargement of uterus and rectal and vaginal prolapse

23
Q

Fusaric Acid

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

A 
whole foods - 35.8mg/kg
high moisture corn - 26.4
barely - 12.2
dry corn - 11.8
wheat - 11.6
25
Q

Alfatoxins produced mainly by?

- what are they

A

aspergillus flavus
aspergilus parasiticus
- tropical / semitropical fungi
- thrive in warm moist climates

26
Q

Naturally occurring aflatoxins

A

Aflatoxins B1, B2, G1, G2

27
Q

What are Alfatoxins

A

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
Q

Aflatoxicosis in ponies

A

increase serum enzyme activities of gamma glutamyl transferase (GGT)

  • confirms liver is key target
  • kidney secondary target
29
Q

Aflatoxins exposure other than feed?

A

Inhalation from bedding material covered with mold and mycotoxins
- respiratory disorders in horses and agricultural workers

30
Q

Activation of aflatoxin B1

- where is it highest

A

Converted to AFB1 epoxide
- by cytochrome P-450

Activation higher in nasal olfactory mucosa than liver
- predisposes equines to respiratory disease

31
Q

Low level aflatoxin contamination

A

respiratory problems and immunosuppression

32
Q

Fescue

A

important pasture forage crop in humid regions

- especially eastern US

33
Q

Equine Fescue Toxicosis cause

A

Endophytic fungi grow symbiotically on tall fescue and ryegrass

34
Q

Endophyte infected tallgrass contains

A 
ergopeptide alkaloids (ergovaline)
- tall fescue toxicosis
35
Q

Endophyte infected ryegrass contains

A 
lolitrem alkaloids (lolitrem B)
- ryegrass staggers
36
Q

Equine fescue toxicosis exist because

A

equines lack rumen detoxification of compounds

- protects grazing cattle

37
Q

Equine fascue toxicosis signs / symptoms

A

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
Q

Endophyte infected fescue cardiorespiratory and thermoragulatory effects

A

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
Q

Equine fescue toxicosis effects on reproduction

A

vasconstriction of peripheral blood flow, leads to

  • increased gestation lengths
  • early embryonic mortality
  • agalactia
  • weak and immature foals
40
Q

Equine Ergot Toxicosis initiation

A

fungus claviceps purpurea

  • produces alkaloid indolics (erotamine)
  • when invading wheat, rye and oats
41
Q

Equine Ergot signs/symptoms

A

reduced udder development

weak foals lacking suckle reflex

42
Q

Ergot contamination detection

A

visual examination for sclerotia (ergot bodies)

43
Q

Equine Tremorgenic Mycotoxins (tremorgens)

A

Lolitrem B (neurotoxin)

  • produced by acremonium lolli
  • cause ryegrass staggers
44
Q

Equine Tremorgenic Mycotoxins (tremorgens) common problem in

A

Australia
New Zealand
Western North America

45
Q

Lolitrem B signs/symptoms

A

trembling
hypersensitivity to stimuli
abdominal muscle spasms
disorientation of horse

(Tremorgens)

46
Q

Lolitrem B (tremorgens) proposed mechanism of action

A

inhibition of gamma-aminobutyric acid in the nervous system

  • inhibits chloride flux
  • prolongs nerve depolarization causing tremors
47
Q

Equine Slaframine Toxicosis initiation

A

fungus ‘rhizoctonia leguminicola

  • grows on red clover
  • others include soybeans, cow peas, alfalfa, white clover
48
Q

Equine Slaframine Toxicosis signs/symptoms

A

Salivary syndrome or slobbers

  • due to slaframine - parasympathetic alkaloid
  • salivation
  • diarrhea
  • piloerection
  • respiratory failure
  • feed refusal
49
Q

stratagies to prevent mycotoxicities

A 
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)

Equine Nutr (5 decks)

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