Altering the essential amino acid-nitrogen:total nitrogen ratio with ammonium phosphate impacts nitrogen retention, lysine requirement and body composition of growing pigs
Date
2023-07-11
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Thesis
Degree Level
Masters
Abstract
Low protein (LP) diets have improved nitrogen (N) utilization while maintaining the performance of growing pigs. Regardless, LP diets may be limiting in N content to meet non-essential amino acid (NEAA) requirements, which may alter essential amino acid (EAA) utilization and requirements, as well as animal growth. Inclusion of a source of non-protein N (NPN) may be beneficial for improving utilization of EAA for lean gain in LP diets. Therefore, this thesis evaluated the effects of providing no NPN supplementation (NAP) or 1.7% NPN inclusion (AP) in an N-deficient diet, as indicated by a high EAA-N:total N ratio (EAA-N:TN) on the lysine (Lys) requirement for N retention (NR) and growth performance in pigs. An N balance study estimated 1.09% SID Lys requirement to maximize NR in NAP-fed pigs (EAA-N:TN of 0.36), while a 1.00% standardized ileal digestible (SID) Lys requirement was determined in AP-fed pigs (EAA-N:TN of 0.33). This result indicates that N is limiting in LP diets, and that Lys requirement and NR are greater with NPN supplementation. A subsequent growth performance study was conducted using the same dietary factor of NPN inclusion. Lysine content was based on NRC (2012) requirement and breakpoint values from the N-balance study and formulated for 20-40kg pigs. Average daily gain (ADG), average daily feed intake (ADFI), gain:feed (G:F), N output and carcass characteristics were assessed. Overall ADG and d 28 BW were improved with increasing Lys content, while G:F and lean depth were greater with NPN inclusion. Fecal N output was increased with NPN supplementation. Overall, N may be limiting in LP diets and ammonium phosphate is a suitable source of N for growing pigs, improving NR and maintaining growth in pigs fed diets deficient in NEAA-N. By improving the efficiency of N utilization and our knowledge of the importance of N to growing pigs, nutritionists will further improve diet formulation to reduce N excretion, diet costs and improve overall swine production.
Description
Keywords
protein, swine nutrition, nitrogen-limiting, non-protein nitrogen
Citation
Degree
Master of Science (M.Sc.)
Department
Animal and Poultry Science
Program
Animal Science