Immune-neuroendocrine phenotypes and their social stress modulation in laying hens

NAZAR FRANCO NICOLÁS; ESTEVEZ INMA; CORREA SILVIA GRACIELA; MARÍN RAÚL HÉCTOR

Louisville, Kentucky.

Congreso; 2015 Poutry Science Association Annual Meeting; 2015

Immune, nervous and endocrine system studies in superior vertebrates have led to the description of immune-neuroendocrine phenotypes (INP), implying subgroups within a population differing on immune-neuroendocrine (INE) interactions. In mammals INPs are well represented by the Fisher/Lewis paradigm in rats. Moreover, the phenotypes have been associated with differences in the physiology of stress response. We proposed for the first time the existence of INPs in an avian species studying a Japanese quail population. In order to evaluate whether this biological phenomenon generalizes to other avian, we assessed the existence of INPs in Hy-line Brown laying hens. Two hen subsets with opposite profiles were found showing consistent results with previous studies in quail and mammals as follows: Lewis-like hens (16% of the hens studied) showed lower corticosterone basal levels associated with higher lymphoproliferative response, plasma interferon-γ and interleukin-4 levels and lower antibody titter against SRBC and innate/acquired leukocytes ratio than their Fischer-like hen counterparts (also 16% of the birds). Thus, the already observed INP phenomenon in mammals and quail appear to generalize to a new avian species that has a much greater productive relevance, and more interestingly, that has been intensely manipulated through a long history of selective breeding. Findings suggest that at a population level, hens are prepared to deal with a wide spectrum of INE challenges. This study also evaluated whether a social chronic stress disturbance modulates the individuals´ INE interplay affecting the proportions and distribution of the proposed INP. After stress, same individuals showing either Lewis- or Fischer-like INP retained their previous INE interplay. Nevertheless, an increase of about 13 % in those divergent INP frequencies (polarized effect) was found at the expense of a reduction in the number of hens showing intermediate INE responses. The increased frequency in polarized INP induced by chronic stress could represent an underlying population strategy to maximize survival.