To toast or not to toast – Grass peas for weaned piglets

Summary

In organic pig production, supply with high-quality protein-rich feeds is tense. As part of the EU Core Organic II research project ICOPP (Improved contribution of local feed to support 100% organic feed supply to pigs and poultry), in 2012 a feeding trial with grass peas fed to weaned piglets was conducted. The grass pea (Lathyrus sativus) is a hardy grain legume that produces seeds with crude protein contents between 200 and 300 g kg-1. Unfortunately it contains the neurotoxin ODAP, which causes nerve damage in farm animals as well as humans. Since ODAP is water-soluble and susceptible to heat, hydrothermal treatment (=toasting) greatly reduces toxicity. In the feeding trial, four experimental diets were fed to a total of 144 piglets: One control diet, one diet containing 20% raw grass peas and two diets with toasted grass peas (20 and 30%, respectively). Data were analysed using proc glm (feed intake) and proc mixed (body weight) of SAS 9.1.
Feed intake did not differ (on average 731 g day-1), but feeding 20% raw grass peas had significant negative effects on body weight gain: While the diets containing toasted grass peas resulted in body weight gain similar to the control diet (on average 395 g day-1), piglets fed raw grass peas grew much slower (292 g day-1) and consequently feed conversion ratio was significantly higher (2.28 versus 1.96 kg feed kg-1 weight gain in the control group). Therefore toasting of grass peas prior to feeding to weaned piglets is recommended.