Author ORCID Identifier
Semester
Fall
Date of Graduation
2024
Document Type
Thesis
Degree Type
MS
College
Davis College of Agriculture, Natural Resources and Design
Department
Animal and Nutritional Sciences
Committee Chair
Joseph Moritz
Committee Member
Janet Tou
Committee Member
Marie Krause
Abstract
In Chapter 2, a study was designed to evaluate the effects of varying dietary branched-chain amino acids (BCAA) ratio in corn and soybean meal-based turkey starter diets. The BCAA leucine, isoleucine, and valine are considered indispensable amino acids needed for energy and stimulation of muscle protein synthesis via the mammalian target of rapamycin (mTOR) pathway. Imbalanced BCAA ratios can lead to antagonism and degradation of limiting BCAA, particularly in diets with excess leucine. Concentrated corn proteins contain high levels of leucine and can alter BCAA requirements; however, crystalline BCAA may be added to correct these ratios. This study aimed to determine the effects of varying dietary BCAA ratio using corn gluten meal (CG), L-isoleucine, and L-valine on performance, mTOR activation, and apparent ileal AA digestibility (AIAAD) in commercial turkey hens from 0-21days of age. A 38.4% corn and 49.8% soybean meal diet served as the Control, and CG was serially increased to create an uncorrected low- and high-leucine diet. The high-leucine diet was then used to create partially or fully corrected diets by inclusion of L-isoleucine and/or L-valine. In uncorrected high-leucine treatments, feed intake, bird weight, and live weight gain decreased (P < 0.05), and feed conversion ratio (FCR) increased relative to the Control at day 14 (P < 0.05). Performance equivalent to the Control was induced by adding both L-isoleucine and L-valine at day 14 (P > 0.05), and FCR decreased relative to the Control at day 21 (P < 0.05). Relative mTOR activation numerically increased in high-leucine diets compared to the Control (P = 0.13). BCAA digestibility was maximized in high-leucine diets with additional L-isoleucine and L-valine (P < 0.05). These results demonstrate that diets containing excess leucine from concentrated corn proteins can decrease poult hen performance, but concomitant additions of crystalline isoleucine and valine may restore performance. In production settings, nutritionists should assess the costs associated with BCAA supplementation at practical levels versus corn and soybean meal-based diets.
In Chapter 3, a follow-up study was designed to investigate the influence of dietary branched chain amino acid (BCAA) and tryptophan ratio in turkeys. Larger inclusions of concentrated corn proteins in corn and soybean meal-based diets can increase leucine levels above requirement, leading to potential deficiency of limiting isoleucine and valine. Excess leucine may also inhibit tryptophan absorption and transport, influencing serotonin synthesis. Hence, high-leucine diets corrected with supplementary isoleucine, valine, and tryptophan could prevent performance reductions associated with imbalanced BCAA and tryptophan ratios. This study evaluated the effects of varying dietary BCAA and tryptophan ratios using corn gluten meal (CG), L-isoleucine, L-valine, and L-tryptophan on performance, plasma serotonin concentration, immune organ weight, and tibia mineralization in commercial turkey hens from 0-28 days of age. A 34.8% corn and 54.0% soybean meal diet served as the Control. An uncorrected high-leucine diet was formulated with a high inclusion of CG and the subsequent high-leucine diets contained partial or total correction with L-isoleucine, L-valine, and L-tryptophan. Diets were fed to 15 replicate cages of 6 poults using a randomized complete block design. Uncorrected high-Leu diets (1.6 Leu:Lys) reduced feed intake (FI), body weight (BW), and live weight gain (LWG) relative to the Control at day 14 (P
Recommended Citation
Estanich, Emily Blair, "Performance and physiological impacts of branched-chain amino acid and tryptophan ratio variations in turkey starter diets utilizing concentrated corn proteins" (2024). Graduate Theses, Dissertations, and Problem Reports. 12646.
https://researchrepository.wvu.edu/etd/12646
