Peptides and Nitrogen-Free Analogs as Substitutes for Dietary Amino Acids: Significance in the Nutriture of Chicks and Rats

Chick and rat bioassays were conducted to establish quantitative efficacy values (slope-ratio procedure) for the D-isomer, the (alpha)-keto analog and the D- and L-(alpha)-hydroxy analogs of phenylalanine (Phe), leucine (Leu), isoleucine (Ile) and valine (Val). D-Phe was well utilized by both chicks (75%) and rats (68%). L-phenyllactic acid (L-PLA) had an efficacy value of 67% for chicks and 46% for rats. D-PLA had no growth-promoting activity for either chicks or rats. KMV, (alpha)-keto-(beta)-L-methylvaleric acid (60%, chicks; 38%, rats) was markedly inferior to L-(alpha)-hydroxymethylvaleric acid, L-HMV (84%, chicks; 65%, rats), as a source of dietary Ile for both chicks and rats. D-HMV had no growth-promoting activity for either chicks or rats. D-Val was well utilized by chicks (72%) but had only marginal Val bioactivity for rats (16%). Efficacy values of the isomers of (alpha)-hydroxyisovaleric acid (HIV) for the chick were: L-HIV, 82% and D-HIV, 66%. KIV, 49%; L-HIV, 54%; and D-HIV, 46%, had comparable efficacy values for the rat. Efficacy values of the isomers of Leu and (alpha)-hydroxyisocaproic acid (HIC) and (alpha)-ketoisocaproic acid (KIC) for the rat were: D-Leu, 48%; KIC, 56%; L-HIC, 58%; and D-HIC, 41%.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Animal Science

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Boebel, Katherine Pigg

• Health Sciences, Nutrition

Identifier

(UMI)AAI8218433

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/69993