Submitted to: Journal Of Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/1998
Publication Date: N/A
Interpretive Summary: The neuroendocrine system plays a critical role in homeostatic regulation of host immune response. In mammals as well as in chickens, both neuroendocrine and immune systems help an organism to cope with changing environmental demands including infection. To understand the role of the pineal gland in regulating the immune response and the role of photoperiod in influencing immune response in chickens, the ARS scientist and scientists at the Pennsylvania State University conducted various studies in chickens. The results indicated that chickens grown under different photoperiod regimens show different immune responses. Furthermore, melatonin can enhance host lymphocyte response. In summary these results suggest that the immune system of chickens can be enhanced by controlling photoperiods or by supplementing their diet with melatonin. This information will help poultry industry scientists to develop new management strategy for poultry production.
Technical Abstract: Understanding the role of the pineal gland in regulating the immune response and the role of photoperiod in influencing pineal gland secretions are becoming increasingly important. The purpose of this study was to investigate the effects of different photoperiod regimens and melatonin on T- and B-cell activities and on lymphocyte subpopulations. Splenic lymphocytes from 6-week-old chickens grown in intermittent lighting had higher T- and B-cell activities than those from chickens grown in constant lighting. Melatonin enhanced mitogenic responses of peripheral blood lymphocytes and splenic cells from 6-week-old chickens Finally, intermittent lighting versus other photoperiod regimens increased the percentages of splenic CD4+, CD8+, and CD3+ cells, but not B cell subpopulation at 6 weeks of age presumably due to increased levels of melatonin in chickens receiving intermittent lighting. These results indicate that melatonin can influence host immune system.