The threonine requirement of the weanling pig

Abstract

The L-threonine requirement of the weanling pig is 0·45% of the air-dry food. This level supports as good growth and economy of food conversion and promotes as good retention of nitrogen as higher amounts.It is unlikely, when pigs are fed normal rations, that L-threonine will be the limiting essential amino acid.A comparison in the period 120–180 lb. live weight between diets supplying 0·47 and 0·87% L-lysine, respectively, showed no benefit from feeding the higher amount. It seems uneconomic to feed animal-protein to supply lysine after 1201b. live weight. The requirement can be met at less cost from vegetable sources.In conclusion, the author desires to express his indebtedness to Messrs V. Thurlbourn and R. D. Willis for taking charge of the experimental animals during the N-balance trial. Also to Mr E. A. Porter for his care of the pigs during the growth trial.