Stocking density induced stress on plasma cortisol and whole blood glucose concentration in Nile Tilapia fish (Oreochromis niloticus) of Lake Victoria, Kenya
Publication Date
2020Author
Elija Odhiambo, Paul O Angienda, Patrick Okoth, David Onyango
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Show full item recordAbstract/ Overview
Effects of high stocking densities (HSDs) were evaluated for Nile tilapia fish (Oreochromis niloticus) under culture to determine its
influence on plasma cortisol and whole blood glucose concentration. Plasma cortisol levels (ng/ml) were assayed by EnzymeLinked Immunosorbent Assay (ELISA). Whole blood glucose levels were determined using a hand-held one touch ultraglucose
meter (MD-300) and test strips. Plasma cortisol and whole blood glucose level determinations were replicated three times for O.
niloticus reared under both low stocking densities (LSD) and HSD. One way Analysis of Variance (ANOVA) was performed on
the data collected, and comparison of significant differences in means was carried out between LSD and HSD at 0.01%. Plasma
cortisol levels revealed statistically (P ≤ 0.01) significant values of HSD at 6.32 ± 1.06 ng/ml than in LSD at 4.62 ± 1.58 ng/ml for
the O. niloticus groups studied. Whole blood glucose analysis revealed a statistical (P < 0.05) difference in the means in HSD and
LSD O. niloticus groups (F(df,1; 8) � 7.946 > Fcrit � 4.414; P � 0.01). Mean plasma glucose concentration was statistically (P ≤ 0.01)
higher for HSD than LSD O. niloticus groups at mean ± SD, 96.84 ± 5.28 and 76.82 ± 5.92, respectively. (e findings of this study
demonstrate that high stocking densities increase both cortisol and whole blood glucose concentration in tilapia fish, indicating a
marked increase in stress levels. Elevated plasma cortisol and whole blood glucose concentration can be used as biomarkers for
acute stress in O. niloticus produced under aquaculture systems. (e findings of this study can help inform policy on the
management of stress caused by overstocking of O. niloticus and other related Cichlids under industrial aquaculture production.
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- Department of Zoology [160]