Reduced stress and increased immune responses in Nile tilapia kept under self-feeding conditions |
| |
| Authors: | MAKOTO ENDO CHIKAKO KUMAHARA TERUTOYO YOSHIDA AND MITSUO TABATA |
| |
| Institution: | Laboratory of Fisheries Sciences, Faculty of Agriculture, Miyazaki University, Miyazaki, Miyazaki 889-2192 and; Department of Biosciences, Teikyo University of Science &Technology, 2525 Uenohara, Yamanashi 409-0193, Japan |
| |
| Abstract: | ABSTRACT: Stress and immune responses were studied in Nile tilapia Oreochromis niloticus under both conditions of self-feeding and scheduled feeding. Self-feeding fish had a significantly lower cortisol level in their blood plasma than that of scheduled feeding fish. Furthermore, skin color was found to be paler in the self-feeding fish compared with that of the scheduled feeding fish. Thus, the self-feeding fish had a less stressful physiological status than the other experimental fish. Immunological analyses revealed that the self-feeding fish significantly exceeded the scheduled feeding fish in the phagocytic activity of their macrophages, antibody production, and the number of blood-circulating lymphocytes. The higher immune responses of self-feeding fish seem to be attained through a less stressful environment. This self-feeding behavior could be exploited to create reduced stress for disease control in fish farming. |
| |
| Keywords: | antibody production cortisol immunity phagocytosis self-feeding stress |
|
|
