Document Type

Dissertation - Open Access

Award Date

2021

Degree Name

Doctor of Philosophy (PhD)

Department

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, P<0.001) final BW, ADG, ADFI, and G:F of pigs. However, pigs fed the corn-SBM diet had heavier final BW and improved (P<0.032) ADG, G:F, and ADFI compared to pigs fed the 30% DDGS diets with the exception of ADFI of pigs supplied a SID Val:Lys ratio of 75% (P=0.167). The SID Val:Lys requirement for the ADG response was estimated at 66.6% (95% CI: [65.9, 67.4]) from the SBL analysis and 69.9% (95% CI: [68.2, 71.5]) from the QBL analysis. Optimal SID Val:Lys ratio for the G:F response was estimated at 68.4% (95% CI: [66.0, 70.8]) and 72.8% (95% CI: [69.8, 75.8]) from the SBL and QBL methods. Data from this study would indicate that feeding a SID Val:Lys ratio of 68% in 30% DDGS diets will yield more than 99% and 98.5% of the maximum ADG and G:F response but a corn-SBM diet will still outperform DDGS diets for the 39 to 68 kg pig. In the third experiment, 2,268 (DNA 600 x PIC PN70, initial BW 82.3 kg) pig were used in a 56-d study to quantify the SID Ile:Lys requirement in finishing swine diets containing 20% DDGS. A total of six dietary treatments were fed and consisted of five diets containing 20% DDGS with a SID Ile:Lys ratios of 55, 60, 65, 70, or 75% or a corn- SBM diet. Pens were assigned to dietary treatments within block, balancing for previous treatment, and each treatment was replicated 14 times. Pair-wise comparisons were used to evaluate dietary treatment impact on performance and carcass traits. Single degree of freedom orthogonal polynomials were used to evaluate the dose response of increasing the SID Ile:Lys ratio in 20% DDGS diets. Increasing the SID Ile:Lys ratio in 20% DDGS diets did not impact growth performance in a quadratic or linear fashion (P>0.153). 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% (P<0.001). This data would indicate that the optimal SID Ile:Lys requirement to maximize carcass parameters would be 65%, while the optimal Ile requirement for growth performance is less clear. In the fourth experiment, a total of 1,170 pigs (PIC 359 x PIC, initial BW 59.5 kg) were utilized in a 79-d grow-finish study to evaluate the impact of HPDDG (NexPro® protein ingredient, Flint Hills Resources, Wichita, KS) and SBM inclusion level on the performance and carcass traits of growing-finishing pigs when BCAA ratios were adjusted. Pen of pigs were allotted to one of five dietary treatments which included: 1) corn-SBM diet, 2) diet containing HPDDG with an SID Ile:Lys ratio of 56%, or diets containing HPDDG with a SID Val:Lys and Ile:Lys ratios of 75 and 65% met through the inclusion of 3) SBM (HPSBM), 4) 50% SBM and 50% crystalline AA blend (HP50/50), or 5) crystalline AA (HPAA). The inclusion of HPDDG in diets was 15% for phase one and 10% for phases two and three. Data was analyzed as a randomized complete block design with previous treatment considered as the random blocking factor. Pair-wise comparisons were used to evaluate dietary treatments impact on performance and carcass traits. Single degree of freedom orthogonal polynomials were used to evaluate dose response of SBM in HPDDG diets where SID Val:Lys and Ile:Lys ratios were held at 75 and 65%. Dietary treatment did not impact final BW, cumulative ADG, ADFI, G:F, or carcass traits (P>0.118) with the exception of the pigs fed the corn-SBM and HP50/50 dietary treatments having a greater (P<0.043) carcass yield compared to the HPSBM treatment. The reduction of SBM in HPDDG diets when SID Val and Ile were held constant relative to Lys resulted in a decrease (Linear, P<0.046) in ADG and G:F and tended to reduce (Linear, 0.094>P>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.

Number of Pages

190

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

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