The Effect of Supplementing Low Crude Protein Diets with Crystalline Amino Acids on Growth Performance and Skin Collagen Abundance of Nursery Pigs

Abstract

Low-crude protein (CP) diets supplemented with crystalline amino acids (CAA) in swine production reduces nitrogen (N) excretion into the environment, and reduces the concentration of non-essential amino acids (NEAA) and N, potentially limiting growth and important metabolic processes. Therefore, this thesis investigates whether supplementing NEAA glycine (Gly) and serine (Ser) to a low-CP diet will improve growth performance, and skin collagen abundance, and to determine if additional threonine (Thr) supplementation will spare Gly and Ser. Glycine and Ser supplemented diets had similar skin collagen abundance to CON while glutamate (Glu) diets resulted in lower collagen abundance and growth performance. Pigs fed low-CP diets supplemented with Thr had lower performance, but supplementation with 2.8 x Thr rescued collagen abundance in experiment two. Skin collagen abundance and processes beyond protein retention, have unknown implications for long-term productivity of pigs, therefore when feeding low CP diets supplementation with specific NEAA may be warranted.