HAS THE UPPER LIMIT OF UREASE ACTIVITY BEEN REVISED?

Now the issue of reducing the upper limit of the urease activity to 0.050 pH units is under discussion.

What is the reason for this change in the requirements for the quality of soybean processing?

In 2005, two American scientists, Ruiz and Belalcázar, examined six rapid feed passage outbreaks in broilers that occurred between 1998 and 2005 in South America.

They came to the following conclusions:

• the dysbacteriosis in broiler chickens is directly related to high content of trypsin inhibitors in their diet

• exceeding 1.95...2.85 mg of trypsin inhibitors in 1 g of feed (corresponds to a urease activity of 0.050 pH units) leads to a dysbacteriosis in broiler chickens aged 40- 42 days.

In practice this means the following:

1) The activity of urease in the feed for chickens should not exceed 0.050 pH units.

2) The input of components with a content of inhibitors of trypsin above 2.85 mg units is limited based on the final activity of urease in the feed mix

3) 0.050 pH units IS THE LIMITATION FOR THE FEED but not for its components

FOR EXAMPLE:

For feed mixes, it is planned to use soybean oil cake resulted in extrusion and mechanical oil pressing.

Temperature, time and other modes of soy processing are selected so as to maximize the nutritional properties of the protein in soybean oil cake.

We keep the protein, but we get the oil cake with a content of up to 5.0...6.5 mg of trypsin inhibitors per gram that corresponds to the urease activity 0.20 pH units).

If 25% of the soybean meal is introduced into the chicken broiler feed recipe, the feed mix will contain 1.25...1.63 mg of trypsin inhibitors per 1 g of feed (corresponding to the urease activity to 0.050 pH units).

AS A RESULT:

• 25% of soybean meal with high-quality protein and urease activity of 0,20 pH units added into the feed.
• the urease activity of feed does not exceed 0,050 pH units
• feed doesn’t cause dysbacteriosis

Urease activity and trypsin inhibitors in SBM from six rapid feed passage outbreaks (adapted from Ruiz,2012)

The source of information:

"NEW INSIGHTS ON THE UREASE ACTIVITY RANGE FOR SOYBEAN MEAL". Nelson Ruiz, PhD. Nelson Ruiz Nutrition, LLC USA