Cottonseed meal contains gossypol, which is toxic to swine. Gossypol binds both lysine and iron, making them unavailable to swine. Peanut meal contains more protein than soybean meal, but less lysine. Cottonseed meal and peanut meal should replace no more than half the lysine from soybean meal in swine diets. Soybeans can provide an excellent source of both energy and lysine, but they contain several compounds that reduce pig performance.
Cooked soybeans contain more energy than soybean meal because of their higher fat content.
Properly heated soybeans can be an excellent alternative to soybean meal if the price is right. Animal protein products were once the primary protein source for swine. Meat and bone meal is still used in many swine diets because of its high phosphorus content. Unlike phosphorus from plant sources, the phosphorus in meat and bone meal is readily used by swine. The main problem with animal by-products is product variation.