Document Type

Dissertation - Open Access

Award Date

2021

Degree Name

Doctor of Philosophy (PhD)

Department / School

Animal Science

First Advisor

Ryan Samuel

Keywords

Branched Chain Amino Acids, Corn Protein, Dried Distillers Grains with Solubles, Grow-Finish Pigs, High Protein Dried Distillers Grains, Tryptophan

Abstract

A total of four studies were conducted in an effort to determine the impact of Trp and the BCAA in swine diets containing DDGS or HPDDG on the growth performance and carcass characteristics of the growing and finishing pig. The first study utilized 1,170 pigs (PIC 800 x PIC, initial BW 38.6 kg) in a 98-d grow-finish study to determine the performance response of pigs fed increasing levels of SID Trp:Lys in swine diets containing 40% DDGS. Treatments consisted of diets containing 40% DDGS with a SID Trp:Lys ratios of 15, 18, 21, or 24% or a corn-SBM diet for a total of five dietary treatments. Dietary treatments were replicated nine times and each pen contained 26 pigs balanced for sex. Data was analyzed as a randomized complete block design with the blocking factor of previous treatment considered as random. Pair-wise comparisons were used to evaluate dietary treatment impact on performance and carcass characteristics. Single degree of freedom orthogonal polynomials were used to evaluate the dose response of increasing the SID Trp:Lys in diets containing 40% DDGS. Increasing the SID Trp:Lys ratio in 40% DDGS diets increased (Linear, P< 0.023) ADG, ADFI, final BW, HCW, carcass gain, and standardized fat free lean weight. However, pigs fed the corn-SBM diet had greater ADG (P< 0.008) and heavier (P< 0.002) final BW compared to pigs fed 40% DDGS. Supplying a SID Trp:Lys ratio in 40% DDGS diets resulted in similar (P=0.253) ADFI compared to pigs fed a corn-SBM diet. Corn-SBM fed pigs also had heavier HCW and standardized fat free lean weights, greater carcass yields and gains, and increased loin depths (P< 0.001) compared to pigs fed diets containing 40% DDGS. The SID Trp:Lys ratio did not impact (P >0.151) pigs with a lighter starting BW differently compared to average and heavy starting BW pigs. Data from this study would indicate that increasing the SID Trp:Lys ratio in diets containing 40% DDGS linearly improved ADG and ADFI until pigs reached approximately 115 kg, but feeding corn- SBM diets will still outperform pigs fed DDGS diets. In the second experiment, a total of 2,430 (DNA 600 x PIC PN70, initial BW 39.4 kg) were used in a 28-d study to determine the SID Val:Lys requirement of pigs fed diets containing 30% DDGS. Dietary treatments consisted of five diets containing 30% DDGS with a SID Val:Lys ratios of 60, 65, 70, 75, or 80% and a corn-SBM diet. Pens of pigs were randomly assigned to one of six dietary treatments in a randomized complete block design with initial weight as the random blocking factor and each treatment was replicated 15 times. Pair-wise comparisons were used to evaluate dietary treatment impact on growth performance of pigs and single degree of freedom orthogonal polynomials were used to evaluate the dose response of increasing the SID Val:Lys ratio in 30% DDGS diets. Increasing the SID Val:Lys ratio in diets containing 30% DDGS increased (Quadratic, P0.153). However, increasing the SID Ile:Lys ratio in 20% DDGS diets decreased back fat (Quadratic, P=0.014), increase loin depth (Quadratic, P=0.029), and tended to increase percent lean (Quadratic, P=0.076), with the optimal carcass parameters occurring when supplying a 65% SID Ile:Lys ratio in 20% DDGS diets. Pig fed the corn-SBM diet had similar final BW compared to pigs fed 20% DDGS diets containing 60 and 70% SID Ile:Lys ratios (P>0.060) and greater ADFI compared to pigs receiving diets with SID Ile:Lys ratios of 65 and 75% (P0.118) with the exception of the pigs fed the corn-SBM and HP50/50 dietary treatments having a greater (PP>0.065) final BW, carcass yield, and standardized fat free lean. Reduction of SBM inclusion in these diets also tended to reduce (Quadratic, P=0.075) back fat, but did not impact HCW (P=0.142). Data from this study indicates HPDDG is a suitable feedstuff for grow-finish swine diets at low dietary inclusion levels and that, when adjusting BCAA ratios to mitigate negative impacts of excess dietary Leu, utilizing SBM provides a benefit compared to crystalline AA. In overall conclusion, increasing the SID Trp:Lys ratio in 40% DDGS diets lead to an increase in ADG as a result of an increased ADFI and no difference in G:F. Providing diets with a SID Trp:Lys ratio of 24% lead to similar ADFI between pigs fed 40% DDGS diets and corn-SBM fed pigs. but ADG of pigs fed corn-SBM diets will be greater and lead to pigs with heavier final BW. When feeding 30% DDGS during the growing period, the SID Val:Lys requirement was determined to be 68%, but DDGS fed pigs still had worse performance compared to corn-SBM fed pigs. During the finishing period, supplying a SID Ile:Lys ratio of 65% would provide optimal carcass characteristics when feeding diet containing 20% DDGS. Finally, when adjusting the BCAA ratios in HPDDGS diets, it is better to utilize SBM compared to crystalline AA and low inclusion levels of HPDDG have minimal impact on growth performance and carcass characteristics of growing-finishing pigs.

Library of Congress Subject Headings

Swine -- Feeding and feeds.
Tryptophan.
Amino acids in animal nutrition.
Branched chain amino acids.
Distillers feeds.
Swine -- Growth.
Swine -- Carcasses.

Number of Pages

190

Publisher

South Dakota State University

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Rights Statement

In Copyright