Roles of Amino Acid Chelates in Animal Nutrition - UNIMUS

502 Pages·2004·5.4 MB·English

THE ROLES OF AMINO ACID CHELATES
IN ANIMAL NUTRITION

THE ROLES OF
AMINO ACID CHELATES
IN ANIMAL NUTRITION
Edited by
H. DeWayne Ashmead
Albion Laboratories, Inc.
Clearfield, Utah
Reprint Edition
NOYES PUBUCATIONS
Westwood, NewJersey,U.S.A.
Copyright © 1993 by Noyes Publications
No partofthis book may be reproduced or utilizedin
any form or by any means, electronicormechanical,
including photocopying, recording or by any informa
tionstorage and retrieval system, without permission
in writingfrom the Publisher.
Library ofCongress Catalog Card Number: 92-25242
ISBN: 0-8155-1312-7
Printed in the United States
Published in the United States ofAmerica by
Noyes Publications
Fairview Avenue, Westwood, NewJersey 07675
10987 65432
Library ofCongress Cataloging-in-Publication Data
The Roles ofamino acid chelates in animal nutrition / edited by H.
DeWayne Ashmead.
p. em.
Includes bibliographical references (p. )and indexes.
ISBN0-8155-1312-7
1.Amino acid chelates in animalnutrition. 1.Ashmead, H.
DeWayne.
SF98.A38R64 1992
636.08'52--dc20 92-25242
CIP
INTRODUCTION
This book wi11 be of great interest to anyone
concerned with animal feeds and feeding programs whether
one is studying bovine, porcine, equine, avian or lower
vertebrate (fish and eel) nutrition. This information
is critical to the success of an animal feeding program.
Sometimes the difference between a successful and a
failing program can be traced to mineral deficiencies
which cause either abnormal growth, reduced milk
production, interrupted fertility and breeding,
compromised immune system integrity and/or decrement in
normal hemoglobin concentration. Increased
morbidity/mortality rates can make a profitable animal
feeding program into a financial failure overnight when
the replacement costs for a prize animal are considered.
These abnormalities, and others, are addressed in the
pages that follow.
From 25 controlled studies by 42 different authors
in five different countries a diverse array of data is
presented. These data val idate the effectiveness of
mineral nutrients presented as amino acid chelates when
compared with the ionic forms derived from the inorganic
salts. These studies further support the resul ts of
numerous laboratory experiments showing increased
absorption, assimilation and reduced toxicity of the
forms of minerals chelated to amino acids. With little
cost and effort animals can be supplemented with amino
acid chelates which will promote, with little risk of
overdose, a fuller genetic potential achievement as far
as mineral requirements are concerned. Results of this
supplementation are reflected in increased growth,
immunological integrity, and more consistent
reproduction (increased ovulation and conception after
first service) as a result of increased bioavailability
of these chelated forms.
v
VI Introduction
Of novel interest are the reports showing a
protein sparing as a result of amino acid chelate
supp1ementation. In the face of dwindl ing protein
sources for animal feeds, this effect of chelated
minerals needs further scrutiny in feeding programs in
other species.
Darrell J. Graff, Ph.D.
Weber State University
Ogden, Utah, U.S.A.
A NOTE TO THE READER
In the late 1800's, many of the fundamental
concepts of che1ation chemistry were evo1ving. Chemists
began to recognize that certain atoms could exist in
more than one valence state, but could not comprehend
how atoms with more than one valence could form a highly
stable compound.
Alfred Werner, a German chemist, was the first to
break with traditional thinking and propose an entirely
new molecular structure to describe these highly stable
molecules. He noted that certain structural entities,
which he called "complexes", remained intact through a
series of chemical transformations. In 1893, Werner
wrote, "If we think of the metal ion as the center of
the whole system, then we can most simply place the
mo1ecules bound to it at the corners of an
octahedron."(1) For the first time a chelate had been
described.
Werner further refined this revolutionary concept
in the succeeding years. He concluded that a metal ion
was characterized by two valences. The first, which he
called the "principal valency", is now termed the
oxidation state, or oxidation number, of the metal. The
second valency, which he called the "auxiliary valency",
represents the number of ligand atoms associated with
the central metal atom. This is the same as the
coordination number of the metal. Werner's concepts
(2-7)
were fundamental to the comprehension of chelates.
The term, "chelate", was finally used by Morgan
and Drew, in 1920, to describe the molecular structure
discovered by Werner. As noted above, the fi rst
chelating molecules that had been discovered were those
VII
VIII A Note to the Reader
with two points of attachment. It was this caliper-like
mode of attaching the ligand (the chelating molecule) to
the metal atom that led Morgan and Drew to suggest the
word "chelate" to describe the molecule.(8) The word is
derived from the Greek word "chele", meaning lobster's
claw. The word, IIchelatell was originally used as an
,
adjective. It later became a more versatile word and
today is used as an adjective, adverb, or noun. The
ligands are chelating agents, and the complexes they
form are metal chelates.
Because the claw, or ligand, held the cation, the
metal was no longer free to enter into other chemical
reactions. Thus it quickly became evident that when a
metal was che1ated, the chemical and physical
characteristics of the constituent metal ion and ligands
were changed. This had far reaching consequences in the
realms of chemistry and general biology. In spite of
the knowledge of what chelation could do to and for a
metal ion, it was not until the early 1960's that anyone
thought seriously about using this molecule for
nutritional purposes.
At that period, a handful of investigators,
independent of each other, each conceived the idea that
if a metal ion could be chelated before feeding it to
animals, the ligand would sequester the cation and
prevent it from entering into various absorption
inhibiting chemical reactions in the gut. The
theoretical consequence was greater nutritional uptake
of the ions.
Two schools of thought quickly developed. One,
led by the pioneering research of Albion Laboratories,
Inc., proposed that amino acid chelates were the proper
chelates to enhance mineral absorption. As attested by
a large number of research reports, lectures, and
publications based on the research efforts both
A Note to the Reader IX
coordinated and conducted by this organization, the use
of amino acid chelates in animal nutrition were both
positive and highly encouraging. At that point in time
these amino acids were called "metal proteinates"
instead of chelates.
Concurrently, with the development of the amino
acid chelates, a second school of thought approached
animal nutrition with synthetic chelates based on
ethylenediaminetetraacetic acid (EOTA). The theory was
the same as before. The EOTA ligand would chelate the
cation and protect it from chemical reactions in the
gut. While it successfully accomplished its mission in
terms of protection, it genera11y fai1ed to enhance
mineral nutrition because it formed chelates that were
too stable. The biological ligands in the animals'
bodies were incapable of extracting the cations from the
EOTA chelates, even after they were absorbed into the
blood. Thus, the EOTA chelates were returned to the
lower bowels or excreted into the urine still protecting
the cations that the animals were supposed to have
utilized. As Bates, et li., concluded, even though
chelation plays a dominant role in mineral absorption,
"chelation does not, in itself, insure efficient uptake
because the absorption of the ferric chelates of EOTA,
NTA, and gluconate were not significantly different than
that of ferrous sulfate.
,,(9)
These synthetic chelates were heavily promoted in
the decade of the 60's and the early part of the 70's.
When they could not deliver the enhanced mineral
nutrition promised by the chelation concept, all
nutritional products using the word "chelation" lost
favor with most animal nutritionists. The "c" word
became a word to avoid if one wished to amicably discuss
animal nutrition.