PSXIV-20 - Potassium Carbonate Rescues Growth and Bone Attenuation Responses to Ammonium Chloride in Feed for Growing Pigs, Supporting the Importance of the K:cl Ratio in Diet Formulations

Wednesday, June 29, 2022

12:00 PM – 1:00 PM CT

Location: Exhibit Hall A

Author(s)

JH

Johanna Hutchinson, n/a

Department of Animal and Dairy Sciences, University of Wisconsin-Madison
Madison, Wisconsin, United States
BK

Brittney P. Kokinos, n/a

Department of Animal and Dairy Sciences, University of Wisconsin-Madison
Madison, WI, United States
MG

Mariola Grez Capdeville, PhD

Graduate student
Department of Animal and Dairy Sciences, University of Wisconsin-Madison
Madison, WI, United States
LA

Laura A. Amundson, PhD

Department of Animal and Dairy Sciences, University of Wisconsin-Madison
Madison, Wisconsin, United States

Presenting Author(s)

TC

Thomas D. Crenshaw, n/a

Professor
Department of Animal and Dairy Sciences, University of Wisconsin-Madison
Madison, Wisconsin, United States

Abstract: Addition of 2% NH₄Cl to feed effectively attenuated growth of pigs fed a diet specifically formulated with reduced lysine, phosphorus, and potassium (HG). The reduction in K was intended to minimize the amount of NH₄Cl required to attenuate growth, as the K:Cl ratio affects growth. The objective was to validate the importance of the K:Cl ratio in HG diets supplemented with 2.0% NH₄Cl. The K:Cl ratio hypothesis assumes that excess Cl from NH₄Cl supplements interacts with K to create an apparent K deficiency, as renal K excretion must increase to counterbalance excess Cl under restraints imposed by HG diets. Additions of K should rescue growth of pigs fed diets with 2% NH₄Cl. After adjustment to individual pens, 18 F₂barrows (12-15 kg) were randomly assigned to 1 of 4 diets: Control standard diet (Ctl, n=4); basal HG, low K diet, no added NH₄Cl (HG, n=4); HG+2% NH₄Cl for growth-attenuation (2%NH₄Cl, n=5); and HG+2%NH₄Cl+K₂CO₃ to counter-balance excess Cl from NH₄Cl (2%NH₄Cl+K, n=5). Pigs were allowed free access to fresh water and assigned diets for 14 days. Daily pig weights and feed consumption, end of treatment urine electrolytes, and whole-body DXA scans were used to calculate gain, intake, body composition, and efficiency of Ca and P retention. Gain (74%); lean (72%); bone ash (58%); Ca (27%); and P (32%) efficiency traits were reduced (P < 0.05) in pigs fed 2%NH₄Cl vs. Ctl. Addition of K to NH₄Cl diets partly rescued responses of these traits, restoring responses to that of pigs fed the HG diet. Inferences from urine electrolyte concentrations were consistent with K allowing an increase clearance of excess Cl. In conclusion, NH₄Cl attenuation of growth and bone ash responses were mediated by K X Cl interactions. Future experiments will focus on diet modifications to enhance body composition during recovery.