18 Feb Moldy feed, consequences beyond mycotoxins
Spring is coming in the Northern Hemisphere and soon the weather will be warm and humid. Spring and Summer are the times at which farmers are more concerned by the presence of molds and their best known metabolites: mycotoxins. But, as we shall see later, neither mycotoxin contamination is particularly linked to the warm and humid climates, nor mycotoxicosis is the only important consequence of presence of molds.
Moldy feed won’t always contain mycotoxins, because only certain species of fungi are able to synthesize them, but the presence of considerable mold in itself may adversely affect production and health.
There are three main negative consequences of molds in feeds and raw materials:
Feed losses its nutritional value and palatability
Molds grow using carbohydrates as a source of energy and produce changes in the composition of fat, proteins, carbohydrates and vitamins.If we suspect that mold contamination is higher than normal, feed should be sent to laboratory for microbiological analysis. If mold count is more than 1 000 000 spores per gram, it is best to discount energy values by multiplying them by 0.95. If mold count is higher than 3 000 000 spores, it is advisable to mix the feed with clean feed or even to discard it.Additional vitamin supplementation is also recommended in case of high contamination, to compensate the vitamin loss caused by fungi.
Fungal growth also changes organoleptic properties, producing irritating odors, abnormal colors and viscous consistency, so feed intake should be monitored.
Molds spread and lead to infections
When molds are present in large numbers in feed, they are able to colonize animal tissues and cause diseases:
- Infection of poultry’s upper digestive system, specially mouth and gizzard, causing to mouth and gizzard pain, poor digestion, decreased feed intake and growth.
- Poultry aspergillosis.
- Digestive ulcers in pigs and ruminants.
- Mycotic abortion in ruminants.
Fungal toxins produce mycotoxicosis and impact productivity
Fusarium sp, Aspergillus sp, Penicillium sp, are the most relevant fungal genus that produce mycotoxins.There are more than 300 different mycotoxins described. Aflatoxins, trichothecenes, ochratoxins, fumonisins and zearalenone are the most important and well known groups.Their toxic effect increases with contamination level. Animals fed with low contaminated feed show no signs of disease, but their productive parameters worsen. Medium contamination leads to immune deficiency and vaccination failure. Higher levels cause visible and recognizable signs in organs such as digestive system, kidney, muscles, skin etc.The consequences of mycotoxin contamination in the animals will be different depending on mycotoxin group, animal specie, age, reproductive stage, level of immunity and nutritional status.
HOW TO PREVENT FUNGAL CONTAMINATION AND ITS CONSEQUENCES
Raw materials can be contaminated by molds in any stage of the production chain (pre-harvest, harvest, storage, feed production, feed storage, in-farm).
Fungal growth is not restricted to hot and humid climates. Even in cold climates, at temperatures as low as 4ºC, some mycotoxin-producing species of Fusarium and Penicillium are able to grow.
During feed manufacturing, high temperature treatments eliminate most of the microbiological contamination but do not completely kill fungal spores. Feed can also be re-contaminated after heat treatment, especially during cooling and subsequent handling, transportation and storage of feed or in the farm.
Regarding mycotoxins, once they enter the feed production chain, it is technically very difficult to remove or eliminate them.
For all the reasons exposed, prevention is the smartest strategy to fight molds.
Prevent mold contamination
Controlling moisture and temperature during all the steps of the feed chain is essential to prevent mold growth. Grains should be dried to below 18% moisture content and kept under 15ºC immediately after harvesting. Moisture content in long term storage should be below 15%, and ideal temperature under 5ºC.Stores and silos should be routinely cleaned and disinfected, and maintained with good ventilation and air flow. Insects, mites, rodents and birds should be controlled.
Use a mycotoxin binder
Choose the right mycotoxin binder paying attention to these key properties:
- The binder shows a high binding rate for all groups of mycotoxins at a low dose.
- The bond between mycotoxins and binder is strong and stable through all the pH conditions of the digestive system, thus mycotoxins do not detach neither in acids not in basic pH.
- It can be quickly and uniformly mixed with feed and it is stable in high temperatures.
- It does not adsorb nutrients at the recommended doses.
Include a mold growth inhibitor in your feed
PigletPlus and GrowthPlus are unique products that combine mycotoxin binding activity with plant ingredients that help preventing digestive diseases produced by bacteria and fungi.Both products contain cinnamon, rich in phenylpropanoids，with fungicide and bactericide activity. Cinnamon also promotes the optimal development of intestinal villi，improving nutrient absorption. Garlic and calcium propionate are also fungicides. (pigs) and (poultry, aquaculture, rabbits) are indicated in all moments of animal’s life, but they are specially useful in young animals or in critical periods such as weaning, during illness, or when we suspect that feed is highly contaminated.
Ms. Chen Yaqin, Product Development
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Certain health statements may not be applicable in your region.