Abstract:
This study assessed the physiological responses of proactive and reactive Nile tilapia
(Oreochromis niloticus L.) during exposure to different salinity levels (SL). Physiological
responses were determined using glucose, plasma cortisol, hemoglobin, hematocrit, WBC, RBC,
and differential WBC. Glucose, plasma cortisol, WBC, RBC, monocytes, neutrophils,
eosinophils, and basophils were not affected among SL, between stress response group (SRG)
and by the interaction of SL and SRG. Hemoglobin and hematocrit were not affected by the
interaction of SL and SRG but values were significantly different between SRG. Hemoglobin of
proactive was significantly higher (3.86 g/dL) than the reactive individual (3.2 g/dL). Hematocrit
of proactive obtained 16.52% in which value seemed to be higher than reactive (20.03%).
Lymphocytes were not affected by the interaction of SL and SRG but were significantly different
between SL. The fish exposed at 10 ppt gained the highest value of lymphocytes among SL
which was 79.14%. Hemoglobin, hematocrit, and lymphocytes were indicators of stress. Nile
tilapia can be raised in environments with moderate levels of water salinity up to 15 ppt since the
values were in the range which was not stressful to them. Reactive individuals possessed lower
hemoglobin and higher hematocrit compared to proactive one.
|
