Soybean meal is a high quality source of protein for swine diets. Due to the growth in global production of pigs and poultry, demand for soybeans is increasing rapidly, outpacing production. Therefore, other sources of plant protein are sometimes used in diets to supply indispensable amino acids to the animals.
The most abundant oilseeds produced in the world, aside from soybeans, are cottonseed, canola seed (rapeseed), and sunflower seed. These oilseeds may be fed as de-oiled meals, or the full fat seeds can be fed to increase the energy concentration of the diet.

Oilseeds and oilseed meals also provide phosphorus to the diet. However, most of the phosphorus in these sources is bound to phytate, and is not available to pigs. An experiment was performed to determine the standardized total tract digestibility (STTD) of phosphorus in canola, cottonseed, and sunflower products, and to discover how the addition of phytase influences the STTD of phosphorus. The apparent total tract digestibility (ATTD) of calcium and the effect of adding phytase on ATTD of calcium were also measured.

González, J. C. and H. H. Stein. 2011. Digestibility of AA in canola-, cotton-, and sunflower-products fed to finishing pigs. J. Anim. Sci. 89(E-Suppl. 2):100 (Abstr.) Link to abstract (.pdf)