Highlights of the David Baker Symposium: Beyond Ideal Protein
By: Luke Zimmerman
Dr. Martin Nyachoti, University of Manitoba, began the symposium with his presentation “Opportunities for using low-protein diets for weanling pigs to improve intestinal health.” Dr. Nyachoti explained that while low crude protein amino acid supplemented diets may help maintain gut integrity during infection, diets must be formulated carefully. He concluded by reviewing the compensatory growth phenomenon and explaining that we should expect performance losses in the nursery when using low-protein diets.
Dr. Sai Zhang, University of Maryland, continued the symposium with a presentation on the “Impact of a near ideal amino acid profile on the efficiency of nitrogen and energy utilization in lactating sows.” Dr. Zhang found that feeding lactating sows reduced crude protein and improved amino acid balance 1) Increased milk yield, 2) Increased nitrogen and amino acid efficiency, 3) Increased energy efficiency, and 4) Decreased heat production.
Dr. John Htoo, Evonik, presented on “Challenges and opportunities for formulating low-protein diets for maintaining growth and N-retention of weanling and growing-finishing pigs.” Dr. Htoo covered several reasons for the inconsistent results the industry has seen when feeding low CP-AA diets. He also emphasized that in order to maintain optimal feed intake, growth, and carcass characteristics, low crude protein diets must be balanced for adequate levels of both essential and non-essential amino acids.
Dr. Pengcheng Xue, Provimi, presented on how “An adjusted SID-Thr:Lys ratio offsets growth performance depressions in finishing pigs fed moderately high distillers dried grains with solubles (DDGS).” Dr. Xue shared two grow-finish trials demonstrating that a greater SID Thr:Lys ratio may help offset the negative impact of DDGS on body weight gain and feed efficiency in grow-finish pigs.
Dr. Anoosh Rakhshandeh, Texas Tech University, presented on “Sulfur amino acid (SAA, Met + Cys) utilization during immune system stimulation (ISS) in pigs.” Dr. Rakhshandeh’s research investigated the impact of ISS on various aspects of SAA utilization, including ileal digestibility, plasma kinetics, the glutathione (GSH) synthesis rate, the irreversible loss of cystine, and dietary total SAA requirements. He found that disease alters SAA metabolism, utilization, and, consequently, the SAA requirements of growing pigs.
Dr. Maroua Zouaoui, Laval University, presented on a “Meta-analysis of the response of piglets to dietary valine: impact of other branch chain amino acids (BCAA).” Dr. Zouaoui found that leucine was the strongest regulator of BCAA metabolism and that isoleucine had little effect on the metabolism of the other BCAAs.
Dr. Mike Tokach, Kansas State University, concluded the symposium with an overview of the “Challenges and implications of feeding diets with excess concentrations of leucine to growing-finishing pigs.” Dr. Tokach reviewed the three proposed modes of action of how excess leucine leads to a reduction in feed intake. He also covered how the use of corn-byproducts can result in diets with excess leucine and presented research showing that higher levels of valine, isoleucine, and tryptophan show potential as a way to reduce the negative effect of a high leucine diet.