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Relative toxicity of gossypol enantiomers in broilers
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Orientador(es)
Resumo(s)
Use of cottonseed meal in poultry diets has
been avoided in large part because of fear of gossypol
toxicity. Gossypol exists naturally as a mixture of 2 enantiomers
that exhibit different biological activities. Two experiments
were conducted to determine the relative toxicity
of gossypol enantiomers on broilers. In the first experiment,
3-d-old broilers were fed a standard diet containing
0, 100, 200, 300, or 400 mg of gossypol from gossypol
acetic acid per kilogram of diet from 3 to 42 d of age.
This form of gossypol contains both enantiomers in an
equimolar ratio. Each dietary treatment consisted of 6
replicate pens of 4 birds. In the second experiment, 3-dold
broilers were divided into 15 pens of 4 birds each
and fed a standard diet supplemented with either no
gossypol or one of the gossypol enantiomers at 200 or
400 mg/kg of diet from 3 to 21 d of age. In both experiments,
feed intake and BW gain were measured. In addi-
(Key words: cottonseed meal, gossypol, gossypol enantiomer, broiler)
2005 Poultry Science 84:1376–1382
INTRODUCTION
Cottonseed meal (CSM) could be an attractive alternative
protein source for poultry diets, but concern over
the presence of the potentially toxic agent, gossypol, has
limited its use. Gossypol [1,1′,6,6′,7,7′-hexahydroxy-5,5′-
diisopropyl-3, 3′-dimethyl-(2, 2′- binaphthalene)-8, 8′-dicarboxaldehyde]
is a polyphenolic compound located in
pigment glands that are distributed throughout the cotton
plant. Gossypol is composed of 2 naphthalene rings with
restricted rotation around the bond connecting the rings.
As a result of this restricted rotation, gossypol occurs
naturally as a mixture of 2 enantiomers [(+)- and (−)-
2005 Poultry Science Association, Inc.
Received for publication February 7, 2005.
Accepted for publication May 5, 2005.
1This research was supported in part by grant 2631RE683-118 from
the Georgia Cotton Commission, Perry, GA.
2Mention of trade names or commercial products in this article is
solely for the purpose of providing specific information and does not
imply recommendation or endorsement by the US Department of Agriculture.
3To whom correspondence should be addressed: ajdavis@uga.edu.
1376
tion, several organ and tissue samples were collected at
21 d (experiments 1 and 2) and 42 d (experiment 1) of
age and analyzed for gossypol. In experiment 1, feed
consumption and BW gain were reduced (P < 0.05) at 21
and 42 d for the birds fed the highest level of gossypol.
The concentration of gossypol in the heart, kidney, and
plasma were equivalent at 21 and 42 d of age. In experiment
2, total feed consumption was reduced only in birds
consuming (−)-gossypol, but BW gains were lower for
birds fed either enantiomer. However, (−)-gossypol was
more detrimental to growth than (+)-gossypol. The liver
had the highest tissue concentration of both enantiomers,
and accumulation of (+)-gossypol was higher than (−)-
gossypol in all tissues examined. No racemization of the
enantiomers was apparent in the tissues analyzed. Our
results indicated that both gossypol enantiomers were
toxic to broilers but that (−)-gossypol was more harmful
to efficient broiler production than (+)-gossypol.
Descrição
Palavras-chave
cottonseed meal gossypol gossypol enantiomer broiler
Contexto Educativo
Citação
"Poultry Science". ISSN 0032-5791. 84 (2005) 1376-1382