The new method uses proteins from mushrooms. The proteins are called lectins. The lectins cause an animal's own defense system to release chemicals that fight the parasites. Mushroom lectin is injected into chicken embryos. The lectin is also added to drinking water for chickens.
Source: tatoeba (12268346)
The result proved less about the safety of genetic engineering than it did about the safety of lectins – known animal poisons.
Source: wiktionary
Soybeans are another excellent source of plant proteins but they are also on the list of high lectin foods. They are very important to vegans and vegetarians as they make it easy for them to get adequate proteins in their diet.
Source: wiktionary