HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lee, C. Articles by Wynn, P. C. Search for Related Content PubMed PubMed Citation Articles by Lee, C. Articles by Wynn, P. C.

The effect of active immunization against adrenocorticotropic hormone on cortisol, ß-endorphin, vocalization, and growth in pigs¹

C. Lee^*,2, L. R. Giles, W. L. Bryden, J. A. Downing^*, D. C. Collins and P. C. Wynn^*

^* Faculty of Veterinary Science, The University of Sydney, Camden, NSW 2570, Australia; and Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Camden NSW 2570, Australia; and and School of Animal Studies, The University of Queensland, Gatton Qld 4343, Australia

² Correspondence: CSIRO Livestock Industries, Locked Bag 1, Armidale, NSW 2350, Australia (phone: 61-2-6776-1459; fax: 61-2-6776-1333; e-mail: Caroline.Lee{at}csiro.au).

Because the poor growth performance of intensively housed pigs is associated with increased circulating glucocorticoid concentrations, we investigated the effects of glucocorticoid suppression by inducing a humoral immune response to ACTH on physiological and production variables in growing pigs. Grower pigs (28.6 ± 0.9 kg) were immunized with amino acids 1 through 24 of ACTH conjugated to ovalbumin and suspended in diethylaminoethyl (DEAE) dextran-adjuvant or adjuvant alone (control) on d 1, 28, and 56. The ACTH-specific antibody titers generated suppressed increases in cortisol concentrations on d 63 in response to an acute stressor (P = 0.002; control = 71 ± 8.2 ng/mL; ACTH-immune = 43 ± 4.9 ng/mL) without altering basal concentrations. Plasma ß-endorphin concentrations were also increased (P < 0.001) on d 63 (control = 18 ± 2.1 ng/mL; ACTH-immune = 63 ± 7.3 ng/mL), presumably because of a release from negative feedback on the expression of proopiomelanocortin in pituitary corticotropes. Immunization against ACTH did not alter ADG (P = 0.120; control = 1,077 ± 25; ACTH-immune = 1,143 ± 25 g) or ADFI (P = 0.64; control = 2,719 ± 42; ACTH-immune = 2,749 ± 42 g) and did not modify behavior (P = 0.681) assessed by measuring vocalization in response to acute restraint. In summary, suppression of stress-induced cortisol responses through ACTH immunization increased ß-endorphin concentrations, but it did not modify ADG, ADFI, or restraint vocalization score in growing pigs.

Key Words: Adrenocorticotropic Hormone Immunization • ß-Endorphin • Cortisol • Growth • Pig • Vocalization