An approximation to the study of lmmunoneuroendocrine Phenotypes in Japanese quail

Abstract

Immunoneuroendocrinology studies the interaction among immune, nervous and endocrinesystems. Different communicational paths have been described for birds and mammals: theHypothalamus-Pituitary-Adrenal, for example, has an anti-inflammatory activity mediated byglucocorticoids and a pro-inflammatory activity dependent on dehidroepiandrosterone. Immunesystem provides each individual with rapid and efficient responses that involve activation andpolarization of the system, leading to either inflammatory or anti-inflammatory profiles. The conceptof Immunoneuroendocrine Phenotype has recently been proposed for mammals. This notion implies the categorization of a population in subgroups with different immunoneuroendocrine backgrounds. Lewis and Fisher rats expressing a Th1-proinflammatory and a Th2-antiinflammatory profile respectively are used to characterize these phenotypes in mammals. In poultry, up to where we know, these phenotypes have not been described yet. This study attempts to determine the existence and distribution of one or more phenotypes in a population of adult Japanese quail. Thus, we selected and evaluated general immunoneuroendocrine variables: plasma corticosterone, lymphoproliferative response to phytohemagglutinin-p, antibody response against sheep red blood cell and frequency of leukocyte subpopulations distribution. After hatch, quails were housed in home cages and at 30 days of age, 60 animals were sexed, wing-banded and housed in adult cages. The mentioned variables were studied at 42 days of age. Different factors (animal?s origin, location in the cages batteries and order of manipulation) were also statistically considered, showing no significant effects on the variables studied. Principal component analysis was then performed with all data from each animal. Results revealed that birds can be classified within two extreme groups that showed statistically significant differences in the 4 variables measured. These groups were termed "A" and "B" and corresponded to the 15% of the animals positioned on the tails of the population data distribution. "A" quail showed in comparison to "B" counterparts, lower plasma corticosterone, higher proliferation and antibody titters and elevated mononuclear and polymorphonuclear populations. Thus, two polarized groups with a naturally and opposite immune and endocrine response can be detected. This finding could be considered a first approximation to the concept of immunoneuroendocrine phenotype in avian species.