Effect of Tryptophan Deficiency on the Pig

Tryptophan has been proven indispensable for growing Duroc weanling pigs by the use of a purified diet which was deficient in this amino acid. Lack of tryptophan decreases the feed efficiency and feed consumption, and causes a loss in weight in young pigs. Although the minimum level of tryptophan needed for optimum growth and feed efficiency is not known, a level of 0.4% of DL-tryptophan seems to be adequate to meet the normal requirement in pigs weighing 50 to 100 lbs. A purified diet has been formulated which supports a rate of growth equal to that obtained on a good natural grain ration.