NUTRIENT REQUIREMENTS FOR CANADIAN YORKSHIRE SWINE: IV. A STUDY OF THE LYSINE, TRYPTOPHAN, RIBOFLAVIN, AND PANTOTHENIC ACID REQUIREMENTS OF PIGS WEIGHING 50 TO 100 POUNDS

Abstract

Eight basic rations were linear programmed electronically with 13 nutrients controlled. The rations differed as follows: (1) based on the minimum requirements, (2) 15% increase in levels of 12 nutrients, (3) 15% increase in lysine, (4) 15% increase in tryptophan, (5) 15% increase in both lysine and tryptophan, (6) riboflavin at 75% of minimum requirement, (7) pantothenic acid at 75% of the minimum requirement, and (8) 15% increase in lysine and tryptophan; riboflavin and pantothenic acid at 75%. A corresponding series of rations was supplemented with 10 p.p.m. oxytetracycline + 2 p.p.m. oleandomycin.Forty-eight barrows and forty-eight gilts were employed in combined growth, feed utilization, and digestibility trials over the weight interval 50–100 lb.The results confirmed the nutritional inadequacy of grower rations based on the minimum standards and provided evidence that an increase in lysine level from 0.65 to 0.75% was as effective as increasing the levels of 12 nutrients. Increasing tryptophan level and reducing the riboflavin level did not affect growth or feed utilization. Decreasing the level of pantothenic acid was associated with improved growth and feed efficiency but further work is being undertaken to determine whether the response was due to this vitamin per se.