Effect of mycotoxins in the nutrition of
farm animals
• secondary metabolites of fungi
• fungi start to produce them under stress conditions
• some of them are produced on the field (fusarium toxins), others
during the storage (ochratoxin)
• not only mycotoxins are harmful, but also their metabolites,
produced in their digestion and metabolism in the animals
• They have an influence :
• on the health and immune system of the animals
• on the cell metabolism,
• the reproduction processes,
• the function of liver and kidney,
• the production traits.
• They also mean a potential food safety risk
Aflatoxin
Producing:
– Aspergillus flavus, A. parasiticus
Effects:
– binds to the DNA and protein of the cells,
– cause mutation, cancer, cell toxicity
– the liver is damaged first time
The most important metabolite is aflatoxin B1
(AFB1).
The most dangerous toxin for both human and
animals (excreted also in the milk)
Produced mostly under warm temperature
conditions
Potential sources groundnut, soybean, corn
Ochratoxin
Producing:
– Aspergillus alutaceus, Penicillium verrucosum
Effects:
– inhibits the protein synthesis (PHE - tRNS)
– increase the lipid peroxidation
– decrease the cell respiration, gluconeogenezis, the ATP
level of the cells
– damages mostly the kidney
The more frequently produced metabolite is ochratoxin A
(OTA).
Produced in the storage period
Can be found also in animal products (egg, meat, liver),
potential food safety risk factor
Zearalenon (ZON), F-2 toxin
Producing:
– fusarium species (F. graminearum, F. culmorum, F.
avenaceum, F. poae, F. moniliforme)
Effects:
– oestrogenic effect
– increase the plasma oestrogen level, causing
dysfunction in reproduction
– increase the lipid peroxidation
– bleedings in the liver
Poultry species are resistant to ZON, but causing
serious reproduction problems in pigs, beef and
horse.
Deoxynivalenol (DON, vomitoxin)
Producing:
– Fusarium species
Effects:
–
–
–
–
inhibiting the protein synthesis and cell proliferation
damages the liver fat metabolism
decrease the success of vaccination
stimulates the synthesis of B-limphocytes.
Pigs refuse to eat DON contaminated diets,
In horses it decreasing the plasma immunoglobulin
level
In cows decrease the milk production and milk fat.
Poultry species are not so sensitive for DON
T-2 toxin
Producing:
– Fusarium species
One of the most harmful toxins
Effects:
– decrease protein synthesis and cell proliferation
– producing lesions around the mouth
– animals refusing food intake
– poor feather production
– worse egg shell strength
– increase the lipidperoxidation in the liver
– increase the death rate after infections
– decrease milk fat
Fumonisins
Producing:
– Fusarium species (Fusarium moliniformin)
Effects:
– increase the weight, but decrease the fat content of liver
– impaired function of the immune system
The most common form is fumonisin B1 (FB1),
Can be found mostly in corn
Decreasing milk production in ruminants, damages
the liver
Horses are especially sensitive for this toxin
(softening of the brain, giddiness, lameness).
Interaction among different
toxins
Mostly more mycotoxins can be found at
the same time.
Their interaction depends:
– on the type of toxin
– on their concentration
– on the investigated parameter
The interaction of OTA, FB1 and DON are
additive on the weight gain, but it is
synergetic on the plasma asparatic
acid aminotransferase enzyme.
Food safety aspects
• According to the investigations of Institute of
International Cancer Research:
–
–
–
–
carcinogenic: AFB1
potential carcinogenic: OTA
probably not carcinogenic: ZON, FB1, T-2
not enough information: DON, NIV
• Some of them are metabolised already in the
enterocytes of the intestine.
• Therefore their metabolites are also important
(ZON
α-ZOL, β-ZOL , AFB1
AFM1)
• Absorbed quickly, after 6 hours reach their
highest concentration in the blood.
Food safety aspects
• The half-life time of ZON is the longest (12-28
hours), therefore it can be found in the egg and
liver)
• 4-5 mg/kg of DON was not detectable from the
tissues
• 30 mg/kg of FB1 detectable also from the kidney,
liver and egg.
• Small concentration of OTA and T-2 toxins were
found in eggs and other animal tissues
Chances to feed toxin contaminated
feedstuffs
Possibilities:
– dilution with toxin free feedstuffs
– feeding with not so sensitive animal species and adults
(beef cattle – milking cow; pig – poultry)
– using toxin binders
Toxin binders:
– a bentonit, a zeolit, sodium-kalcium-aluminiumhydrosilicates, glukomannans, binders containing
enzymes can be used efficiently (60-90%) against AFB1
– Their affinity for fusarium toxins (ZON, DON, T-2) is
however, poor (10-60%)
– They also bind some other bioactive substances
(vitamins, amino acids, minerals etc.)
Effects of feeding mycotoxin contaminated diets and different toxin
binders on the weight gain of broiler chicks
3
2,53
2,55
2,44
2,47
2,5
2,10
2,09
c bc
b
c
a
a
a
a
POZK
SAFE
MYCOAZ
1
0,5
2,12
NEGK
2
1,5
2,12
Kakas
cockerel
pullet
Jérce
The weight of bursa fabricii (g)
2,49
2,5
1,93 1,91
2
1,59
1,5
a
b
ab
1
0,5
1,88
ab
1,27
1,38
ab
a
Kakas
cockerel
Jérce
pullet
a
1,26
a
NEGK
POZK
SAFE
MYCOAZ