Saponins are secondary metabolites of plants. They are found in most vegetables, beans, and herbs. There are different types of saponins. Some saponins are harmless in the levels found in plants. Others can cause problems when included in poultry diets. Alfalfa contains a low level of saponins in the spring and fall and high levels in midsummer. Low saponin alfalfa has been developed. The seeds and leaves of chickpeas, soybeans, and other beans contain saponins.
Saponins form a soapy lather when mixed and shaken with water. They are included in some detergents, foaming agents, and emulsifiers. Saponins from yucca and quillaja plants are used in some beers to produce a stable foam. They are included in shampoos, facial cleansers, and cosmetic creams. Digitalis is a saponin and is important in heart health. Saponins have other health benefits. They bind with bile salt and cholesterol in the digestive tract. Bile is important in absorption of cholesterol and other fatty substances from the digestive tract. The inhibited cholesterol absorption results in a reduction of blood cholesterol levels.
Saponins are bitter and reduce feed intake of livestock, including poultry. High levels of saponins in poultry diets result in decreased performance and growth rate.