Aflatoxin B1 to Aflatoxin M1, what happens?

Its main toxic and carcinogenic effects are:

• Hepatotoxicity, hepatocarcinogenic
• Neurotoxicity, nephrotoxicity
• Hemotoxicity
• Enterotoxicity
• Osteotoxicity
• Inmunosuppresant

The main clinical signs that occur are:

• Anorexia
• ↓ body weight
• ↓ productivity (eggs or milk)
• Bleeding
• Embryotoxicity
• ↓ reproductive performance
• ↑ disease susceptibility

WHAT IS KNOWN ABOUT AFLATOXICOSIS IN DAIRY COWS?

The following points must be considered in order to assess present knowledge and what still remains undetermined.

• It is necessary to work with data.
• Scientific literature based on high levels of contamination (far from field reality) Nonlinear dose-effect response.
• The presence of other mycotoxins that have not been investigated.
• Is there a clear answer? NO!
• Uncertainty around Aflatoxin leads to “debatable” decisions.
• Feed contamination also causes a delay in heifer puberty.

Mechanisms of Aflatoxin Excretion in ruminants:

• Feces: 55-80%
• Urine: 10-20%
• Meat: <1%
• Milk: 1-3%

Carry over  = Percentage of AFB1 excreted in milk as the metabolite AFM1.

This rate varies between 1-3% (min. 0.1% and max. 10%) and depends on:

• Species: dairy cattle, sheep or milk goats (dott. Battacone)
• Production level and days in milk
• Somatic cells, due to membrane permeability. Masoero et al. (2017).

These authors showed that cows with high somatic cell counts excrete more AFM1 in milk than cows with similar production levels but with lower somatic cell counts.

WHAT IS AN ADSORBENT AND WHAT FUNCTIONS SHOULD IT FULFILL?

EUROPEAN COMMISSION REGULATION (EC) No 386/2009, defines these additives as “reducers of feed contamination with mycotoxins: substances which may suppress or reduce absorption, promote excretion or modify  mycotoxins’ action mechanism”.

An adsorbent must:

• Prevent or limit the absorption of mycotoxins in the gastrointestinal tract
• Be free of impurities and be odorless
• Not modify nutrient availability
• Have been evaluated both in laboratory conditions and in animal trials.

European regulation

This additive category is 1m558, specified in Implementing Regulation (EU) No 1060/2013.

The only mechanism recognised by the EU is the 1m558 group”category of technological additives. Functional group: reducers of feed contamination by mycotoxins: aflatoxin B1″.

This category specifies that Bentonite is the ONLY authorised adsorbent (EU). This bentonite must meet very specific and restrictive characteristics (other bentonites that do not meet the criteria are classified as additives 1m558i).

POSITIVE ASPECTS

• Reduced cost
• Rapid sequestering mechanism
• Relatively easy assessment of sequestering activity
• Easy farm use or inclusion in feed
• They have “little” or “no” impact on animal health status
• Various mechanisms of action to increase effectiveness(must be verified)

NEGATIVE ASPECTS

• They represent an extra cost (1-4% ration cost)
• Very little time to intervene
• Titration requires in vitro screening tests (low cost) or in vivo confirmatory tests (high cost) or EXPERIENCE
• The type of use improves or worsens the effectiveness of the sequestering action
• Possible side effects due to prolonged use and with high doses
• Interfere with analytical determinations of Aflatoxins

WHAT SHOULD BE DONE WHEN AFM1 IS DETECTED IN MILK?

Remove feed from milking cows and recycle it with heifers, in case it is not highly contaminated…

Carry out reliable SAMPLING with a quick response (ANALYSIS) in order to rapidly identify contaminated ingredient(s).

Quickly test corn and other suspicious ingredients with rapid tests (“immediate” response) and then confirm with HPLC (acetone).

Contaminated corn?  Encourage contact between corn and adsorbing agent.

Screen, ventilate or clean the grain and/or reduce its inclusion with alternative ingredients (wheat, barley and sorghum).

Analyze cotton, soybeans and corn mix and silo (acetone+HPLC)

Contaminated cotton?  Eliminate.

Contaminated corn silo or mix?  Promote contact between adsorbent and feed and / or reduce its use with other alternatives (Grass silo, cereal silo, etc.)

Add 100-150g (or as indicated by technicians) of a guaranteed adsorbent(well chosen). Avoid overdosing.

If possible, put the contaminated feed in contact with the adsorbing agent.

Wait for 1-4 milkings (this will depend on the initial contamination levels).