The Effect of Reduced CP, Synthetic Amino Acid Supplemented Diets on Growth Performance and Nutrient Excretion in Wean To Finish Swine

Authors

Caitlin E Vonderohe
Kayla M Mills
Shule Liu
Matthew D Asmus
Emily R Otto-Tice
Brian T Richert
Ji-Qin Ni
John Scott Radcliffe

Publication Date

6-1-2022

Journal

Journal of Animal Science

DOI

10.1093/jas/skac075

PMID

35275195

PMCID

PMC9175295

PubMedCentral® Posted Date

3-11-2022

PubMedCentral® Full Text Version

Post-print

Published Open-Access

yes

Keywords

Amino Acids, Animal Feed, Animal Nutritional Physiological Phenomena, Animals, Diet, Diet, Protein-Restricted, Dietary Proteins, Dietary Supplements, Nitrogen, Nutrients, Swine, Weight Gain, amino acids, environmental footprint, protein, swine

Abstract

Mixed sex pigs (n = 720) were placed in 12 rooms (Purdue Swine Environmental Research Building) to measure the effect of reduced crude protein (CP), amino acid (AA)-supplemented diets on growth and the carcass. Pigs were blocked by body weight (BW) and gender and allotted to room and pen (10 mixed-sex pigs/pen). Pigs were fed a nine-phase, wean-finish program. Control pigs consumed corn-soybean meal-distiller’s dried grains with solubles (DDGS) diets containing no to minimal (Met) synthetic AA. The 2X diet was formulated to meet the seventh most-limiting AA, and balanced using synthetic AAs to meet all AA needs. The 1X diet was formulated to meet a CP value halfway between the control and 2X diet, and also balanced using synthetic AAs to meet all AA needs. Diets were formulated to identical net energy concentrations and balanced to meet standard ileal digestible NRC 2012 AA requirements. Pit vacuum samples were collected at the end of each growth phase for analyses of nitrogen, C and dry matter (DM). Pigs fed the Control and 1X diet grew faster (P < 0.005), had greater gain:feed (P < 0.001), and were heavier at market (P < 0.001) than animals fed the 2X diet. No consistent effects of diet were observed on average daily feed intake. Carcass data were analyzed for sex, diet and sex*diet effects. Reductions in dietary CP resulted in a linear reduction in ammonium nitrogen excretion per kg of BW gain in Nursery (P < 0.001) and Grow-Finish (P < 0.001) phases. Reductions in dietary CP, with synthetic AA supplementation resulted in a linear reduction in total nitrogen excreted per kg BW gain in the Grow-Finish phase (P < 0.001) and overall (P < 0.001). Total mineral excretion per kg gain was reduced in pigs fed 1X and 2X diets compared with control-fed pigs (P < 0.005). Reductions in dietary CP of ~3 and 5%-units from wean-finish result in reductions of total N excretion of 11.7 and 24.4%, respectively. Reduced performance and carcass characteristics observed in pigs fed the 2X diets indicates an inaccurate estimate of NRC 2012 AA requirements or ratios to lysine in a low CP diet.