Producer > Pig

Q.4. Strategies
(a) Avoiding mycotoxicosis in crops
Achieving total detoxification of crops is unrealistic but there are a number of ways to reduce the risk:

• Planting insect and disease-resistant varieties and practising crop rotation
• Avoiding or minimising the effects of plant stressors that predispose to mould infestation and mycotoxin production
• Cleaning bins prior to use
• Cleaning feed bins and fully discarding contaminated crops

(b) Storing your feed
The forages
Are conditions likely to lead to aerobic instability? If so, prevention starts with excluding air when filling the clamp through effective consolidation and sheeting. At feed out, good face management is essential but with some forages, especially maize and other whole crop cereal silages, all this might still be insufficient.

The wet feeds (e.g. brewers' grains)
If wet feeds are being fed 'fresh', do they develop moulds before the next delivery? Is the new load dropped on top of the old one? If they are clamped, are they sheeted properly?

The straights
Take a good look at the storage facilities. Are they really good enough? If not, the options are:

• Invest money to improve the facilities
• Recognise that you will need to use a mycotoxin adsorbent

The management of feed stores (including those for compound feeds)
Do you have an effective bunker, bin or loft hygiene programme in place?
When was the last time the store was emptied and cleaned out?
Is there a plan for stock rotation so that new feed is not put on top of old?

The feed trough
Keep trough clean and the feed fresh.

Feed Deliveries

• Check all feeds on arrival - including compound feeds - before delivery is accepted
• Do not accept delivery of any mouldy feed
• Reject any feed that is hot, especially compound feed that is going to be stored in a metal bin where condensation will occur
• If it is supposed to be a 'dry' feed, make sure it is

This is all common sense. Regardless of the risk of mycotoxin contamination, feeds and forages cost money and should be stored effectively.

(c) Mycotoxin Action Plan
If you are having problems that you suspect might be due to mycotoxin contamination:

1. Consult your vet and/or your feed adviser
2. Eliminate any other possible causes of the problems
3. Remove (or minimise the use of) any suspect or contaminated feeds.
4. Ensure the total diet is geared to a fully functional intestine and a healthy pig
5. Talk to your Alltech representative for advice

(d) Feed Strategies
Mycotoxin adsorbents and binders
Speciality feed additives, known as mycotoxin adsorbents or binding agents are the most common approach to prevent and treat mycotoxicosis in animals. It is believed that the agents bind to the mycotoxin preventing them from being absorbed. The mycotoxins and the binding agent are excreted in the manure.

An effective binder or sequestering agent is one that prevents or limits mycotoxin absorption from the gastro-intestinal tract of the animal. In addition, they should be free from impurities and odours. Be aware that not all are equally effective. Many can impair nutrient utilisation and are mainly marketed, based on in-vitro data only.

There are two types of mycotoxin adsorbent/binder:

• Inorganic binders
• Organic adsorbents

Inorganic binders
Inorganic mycotoxin binders include:

• zeolites
• bentonites
• bleaching clays from the refining of canola oil
• hydrated sodium calcium aluminosilicates (HSCAS)
• diatomaceous earth
• numerous clays

These materials are often inexpensive and easy to handle. These products are traditionally mixed with compound feed at a mill or mixed on farm for home mixers. Costs are cheap but require a high inclusion rate in animals taking up valuable space in the diet. Most either only adsorb specific mycotoxins, bind minerals and vitamins, cause other health complications or due to the high inclusion rate required, are too expensive for industrial applications. However they are also non-biodegradable and can present disposal problems when fed at high levels of dietary inclusion.

The amount of organic acids in clays is often very small. Does the small amount of organic acid(s) really work in inhibiting moulds? The answer is NO; and it can actually do more harm than good:

The small amount of acids quite often has no effect. Worst of all, if the acids do work, due to such small amounts, they are not enough to kill the mould. Instead, the acids change the pH of the environment and bring pH stress to the moulds. The pH stress can actually stimulate the moulds to produce MORE mycotoxins (REMEMBER, mycotoxins are the secondary metabolites from moulds produced due to stress from environmental factors, such as pH).

Organic Adsorbents
Organic mycotoxin adsorbents include:

• fibrous plant sources such as:
  • oat hulls
  • wheat bran
  • alfalfa fibre
  • extracts of yeast cell wall
  • cellulose
  • hemi-cellulose
  • pectin

Such materials are biodegradable but can, in some cases, also be sources of mycotoxin contamination. Benefits of yeast cell wall as an adsorbent are low inclusion levels in the diet, high surface area allowing for adsorption of a large number of mycotoxins and certainly no toxic contaminants.

The efficacy of glucomannan-containing yeast products as mycotoxin adsorbents in feeds has been investigated globally with several studies across all animal species [Click here to see in vivo research].

Mycotoxin adsorbents offer an attractive short-term solution to the challenge of mycotoxin-contaminated animal feeds. The only complete solution to the mycotoxin challenge will be the long-term goal of eliminating mycotoxins from the food and feed chains through improved quality control based on better analytical techniques coupled with genetic advances in plant resistance to fungal infestation.

If you are considering adding a mycotoxin adsorbent to your feed you need to look for the following:

• Proven efficacy in vivo (in the animal) as well as in vitro (in a test tube)
• Low effective inclusion rate
• Stable over a wide pH range (this is necessary so that the mycotoxin stays attached to the adsorbent throughout the gut and is excreted.)
• High affinity to adsorb low concentrations of mycotoxins
• High capacity to adsorb high concentrations of mycotoxins
• Ability to act rapidly before the mycotoxin can be absorbed into the bloodstream.

Above all when you are considering using a mycotoxin adsorbent you need to be confident that the product has been proven to work in the animal in a commercial situation. It is extremely important that any in vitro results be supported by in vivo experiments relevant to the species being fed.