Amino acid digestibility of a yeast-derived protein source and gut endogenous losses in newly weaned pigs

The objective of this experiment was to determine the ileal digestibility of amino acids (AA) in a yeast-derived protein source (YP) in 4-week old piglets. Thirty piglets, weaned at 18–19 days of age, were allocated to 5 diets: a control diet based on wheat, soybean meal, casein and whey powder; the control diet with inclusion of 3%, 6% or 9% YP, and a protein-free (PF) diet. Piglets were fed the diets for 9 days. Pigs were euthanized on day 10 and the contents of terminal ileum collected. Body weight, weight gain and feed intake before and after allocation to dietary treatments did not differ (P > 0.1) among groups. Inclusion of YP did not affect (P > 0.1) the apparent and standardized ileal digestibilities of AA compared to the control containing high-quality protein. Mean apparent and standardized ileal digestibilities of AA were 75.7% and 84.5%, respectively, and similar to that reported for pigs 6 to 8-week old. YP provides highly digestible AA for newly weaned pigs. These standardized and apparent ileal digestibility values for YP may be used in diet formulation for pigs between 20 and 56 days old.