Modulating offspring responses: concerted effects of stress and immunogenic challenge in the parental generation

Abstract

The perception, processing and response to environmental challenges involves the activation of the immuno-neuroendocrine (INE) interplay. Concerted environmental challenges might induce trade-off when resource allocation to one trait occurs at the expense of another, also producing potential transgenerational effects in the offspring. We evaluated whether concerted challenges, in the form of an immune inoculum against inactivated Salmonella Enteritidis (immune challenge, ICH) and a chronic heat stress (CHS) exposure on adult Japanese quail, modulates the INE responses of the parental generation and their offspring. Adults were inoculated and later exposed to a CHS along 9 consecutive days. The last 5 days of CHS, eggs were collected for incubation. Chicks were identified according to their parental treatments and remained undisturbed. Induced inflammatory response, Heterophil/Lymphocyte (H/L) ratio and specific humoral response against sheep red blood cells (SRBC) were evaluated in both generations. Regardless of the ICH, stressed adults showed a reduced inflammatory response (p<0.001) and an elevated H/L ratio (p=0.02) compared to controls. In offspring, the inflammatory response was elevated (p=0.03) and the specific SRBC antibody titers were diminished (p=0.02) in those chicks prenatally exposed to CHS, regardless of the ICH. No differences were found in the H/L ratio of the offspring. Together, our results suggest that CHS exposure influences the INE interplay of adult quail, establishing trade-offs within their immune system. Moreover, CHS not only affected parental INE responses but also modulated their offspring, probably affecting their potential to respond to future challenges. The adaptability of offspring's programming would depend on the environment encountered.