Researchers at the University of Illinois tested the effects of pelleting and in-feeder storage on lysine bioavailability in nursery pig diets.

Ioannis Mavromichalis and David Baker found pelleting of a complex phase 1 diet (28% lactose, 1.4% lysine) did not reduce the lysine bioavailability.

The pellets tested were 5 mm, larger than most commercial pellets which commonly are 2-4 mm. The researchers are currently testing smaller pellet sizes for lysine damage.

While pelleting did not have an impact on lysine bioavailability, storage did. The researchers found that placing the diet in metallic feeders in an occupied nursery facility for one week reduced bioavailability of lysine by an average of 12%. The lysine loss was observed in both meal feed and pelleted feed (Table 1).

The Maillard or non-enzymatic browning reaction that renders lysine unavailable is favored by high temperatures, humidity, time and presence of trace minerals. The nursery diets are susceptible to lysine destruction during pelleting and during prolonged storage in warm and humid conditions. In addition, producers fill feeders with enough feed for four to 10 days to reduce labor and storage space, thus exposing costly diets to the warm and humid nursery environment for prolonged periods of time.

In order to avoid losses of lysine and ensure maximum performance, the researchers suggest more frequent feeding intervals, especially in the critical two weeks postweaning. Prolonged storage of starter diets during summer months is also discouraged. Fresh nursery diets should be prepared and fed immediately.

Researchers: Ioannis Mavromichalis and David Baker, University of Illinois. Phone Mavromichalis at (217) 333-4366 or e-mail mavromic@uiuc.edu.