Immuno-modulation of hormones controlling growth

Abstract

Consumer discrimination against meat products from animals treated with hormones has provided the impetus to investigate alternative ways of boosting feed conversion efficiency and growth rates of animals and to manipulate the reproductive capacity of animals. In view of the longevity of the immune response to specific antigens and the realization that antibodies are capable of neutralizing or mimicking the actions of hormones, vaccination techniques have been explored as alternatives to hormone administration to boost animal productivity. To date, only two commercial vaccines are available to improve the efficiency of production, although neither is related to the stimulation of growth efficiency: Fecundin (registered product, Glaxo Pty Ltd) is designed to improve lambing percentages, and Vaxstrate (registered product, Arthur Webster & Co.) to prevent reproductive activity. In this review, recent advances in vaccine development are explored together with some of the problems encountered in research in this field.

Vascularization of the adrenal cortex: its possible involvement in the regulation of steroid hormone release

“…Studies using immuno-modulation of rat and ovine ACTH (Sillance et al, 1992;Wynn et al, 1994) have explored HPA axis activity in the absence of normal ACTH stimulation. These studies indicated that while ACTH is certainly the primary regulator of glucocorticoid output, adrenocortical cells are also affected by other modulators.…”

Active immunization against adrenocorticotrophic hormone (ACTH) in grazing lambs suppresses the immune response to a GnRH antigen but does not alter growth

“…Alternatively an elevation in other peptide hormones derived from increased pro-opiomelanocortin (POMC) expression due to ACTH immunization (Wynn et al 1994) may have maintained in part testicular steroidogenic activity. Such a response is most likely due to a reduction in the central negative feedback of either ACTH or glucocorticoids.…”

“…Since glucocorticoid hypersecretion appears to suppress growth performance and immune function, the long-term suppresion of secretory peaks of these hormones provides a potential target to boost growth efficiency and animal health. Our previous studies (Wynn et al 1994) have shown that the induction of autoimmunity to adrenocorticotrophic hormone (ACTH) using an ACTH (1-24):human serum albumin (HSA) conjugate in Freund's adjuvant in grazing sheep can decrease carcase fatness and increase muscle yield.…”

Antibodies as molecular mimics of biomolecules: roles in understanding physiological functions and mechanisms

“…A number of strategies have been attempted to invoke antibodies against adrenocorticotrophic hormone or cortisol. The underlying theory of this strategy is that antibodies could be used to neutralize these elements and reduce the effects of stress in animal models (115)(116)(117).…”