A chemically defined diet for maximal growth of pigs

Three growth assays and one balance experiment were conducted to determine the optimal mixture of dietary amino acids for 10-kg pigs fed a chemically defined diet. Pigs were meal fed at 0700 and 1700 h in all experiments. Increasing all indispensable amino acids by 20% from their original levels improved weight gain and gain:feed ratio to levels equivalent to those of pigs fed a 20% protein corn-soybean meal-dried whey positive control diet. Replacing the glutamate-glycine-proline dispensable amino acid mixture with a complete mixture of dispensable amino acids (i.e., glutamate, glycine, proline, glutamine, serine, alanine, aspartate and asparagine) did not improve growth rate. A balance study showed that retention of nitrogen and energy (percentage of intake) from the final purified diet was superior to that of pigs fed the corn-soybean meal-dried whey diet. Metabolizable energy and metabolizable energy corrected for nitrogen retention of the final purified amino acid diet were determined to be 14.43 and 13.96 MJ/kg diet, respectively. The chemically defined diet developed here for young pigs provides a means of studying nutrient utilization in the pig under conditions in which all nutrients are essentially 100% bioavailable.