Degree Type

Dissertation

Date of Award

1986

Degree Name

Doctor of Philosophy

Department

Animal Science

Abstract

Two trials were conducted to determine the total aromatic amino acids (TAAA) and phenylalanine (L-PHE) requirement for pregnant swine. In trial one, twelve Yorkshire x Landrace (Y x L) gravid gilts and in trial two six Y x L gravid gilts were assigned to 6 x 6 Latin-square experiments from d 40 to d 100 of gestation. A basal 12% protein diet of dextrose, corn starch, dried whey, L-glutamic acid, solka floc, soybean oil, amino acids, minerals and vitamins was fed at a rate of 1.82 kg/d. In trial one, the basal diet (.13% L-PHE plus L-TYR) was supplemented with L-PHE to provide 2.37 (basal), 4.19, 6.00, 7.83, 9.65, and 11.47 grams/day (g/d) TAAA. In trial two, the basal diet was supplemented with 6.00 g/d L-TYR and 1.46 (basal), 2.27, 3.27, 4.20, 5.10, and 6.00 g/d L-PHE. Each treatment diet was fed within each of six 10-d periods. In trial one, urine nitrogen (N) excretion decreased, while daily (N) retention increased (lin. P < .01, quad. P < .05) with increasing levels of TAAA intake to a breakpoint of .43% and .42% or 7.38 and 7.64 g/d TAAA, respectively. Fasting and postfed plasma urine N concentrations decreased (lin. and quad. P < .01) to a breakpoint of .37% and .34% or 6.73 and 6.19 g/d, respectively. Urine urea decreased (lin. P < .01) with increasing dietary TAAA to 9.65 g/d or .53% intake. Plasma L-PHE and L-TYR increased (lin. P < .01) as dietary total TAAA intake increased. In trial two, maximum N retention and minimum urine N excretion (lin. P < .05) occurred when 5.10 g/d L-PHE (.28% of diet) were consumed. Plasma urea N did not change significantly, however, the lowest level occurred at an intake of 2.73 g/d L-PHE (.15% of diet). Urine N responded (quartic, P < .05) to increasing levels of L-PHE with minimum excretion occurring when 4.2 g/d L-PHE (.23% of diet) were consumed. As L-PHE intake increased plasma L-PHE concentrations postfed increased (lin. P < .01) and 3.27 g/d L-PHE (.18% of diet) increased postfed concentrations equal to fasted concentrations. Fasting levels of L-TYR increased (lin. P < .05; cubic, P < .01) with increasing levels of L-PHE intake while postfed concentration did not change. Considering the criteria evaluated in trial 1 and adjusting for diets containing natural feedstuffs, .41% or 7.44 g/d TAAA seems to meet the dietary requirement for pregnancy. Response criteria in trial 2 suggest a minimal L-PHE intake of .24% or 4.35 g/d.

DOI

https://doi.org/10.31274/rtd-180813-6802

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

James Curtis Trew

Language

en

Proquest ID

AAI8627155

File Format

application/pdf

File Size

42 pages

Share

COinS