How to maintain bioactive substances in feeds

The pilot plant

Since 2014, the independent foundation, Feed Design Lab, has been operating as a practical research and education centre for innovation and sustainability in the feed sector, together with 108 partners.

Its pilot plant is used for all types of experiments, mostly with raw materials for livestock feeds, fish or pet food. Training sessions combine theory with explaining and demonstrating the machinery. Specific projects tackle topics like the development of new raw materials in animal diets, such as algae, insects, high fibre products and wet waste streams.

Maintain properties

The knowledge about bioactive substances in raw materials is extensive and can help suppliers with making claims about their feed additives. A key opportunity for the future is to develop this knowledge further, to better understand the best way to maintain the properties of ingredients by optimal technology and optimal bio security of feed.

One challenge that the pilot plant can help with, is to make sure that the bioactive substances and the nutritional value in the raw materials are still available after the processing. This availability is affected by temperature, moisture content, time and friction during different parts of the processing.

In the conditioner, the quality of the used steam is essential, and in some feed plants an expander, extruder or Long Time Conditioner is used: these are all influencing the important parameters. During the pelleting process, friction heat is an important factor. Bioactivity can also be lost during cooling and drying.

Guarantee activity

How to guarantee the activity of thermolabile products in the final product? One way is to overdose additives in the mash, in the hope of ending up with just the right amount of activity in the final product. However, this is not sustainable and not cost effective.

Another option is to protect the bioactive substances against temperature by coating. This is tricky as it is very important that the active product is released at the right moment in the upper part of the gut of the animal. Some enzymes have natural thermo resistance, and so careful selection is essential for the development of new products.

Alternatively, it is possible to add the product after the heat treatment: post pelleting addition can be performed in a (vacuum) coater. Liquid products can be sprayed on the pellet or kibble.

Salmonella reduction

Yet another challenge is balancing the need for heat treatment to reduce salmonella in the feed production process, with the need to be as gentle as possible to maintain the bioactive substances. The variation in these parameters between feed plants also makes this a challenge in practice.