Seasonal variations in some hematological traits of Tilapia zillii (Gervais, 1848) in a southern Mediterranean Sea brackish lagoon

Citation: Ayman A. S. Abduljalil,  Ramadan A. S. Ali, Yousef K. A. Abdalhafid, Sayed Mohamed Ali (2022)  Seasonal variations in some hematological traits of Tilapia zillii (Gervais, 1848) in a southern Mediterranean Sea brackish lagoon, International Research Journal of Natural Sciences, Vol.10, No.1, pp.22-38

Abstract: The aim of this study was to determine seasonal variations in CBC, and liver and kidney functions of Tilapia zillii of Ras Al-Tin brackish lagoon, eastern Libya, Southern Mediterranean Sea, during 2019/2020. During this period, the seawater temperature averaged 23⁰C; the minimum was in winter and the maximum in summer. Salinity was 4.67 to 23⁰/₀₀, the lowest was in winter, and the highest in summer. Conductivity was 11 to 27mS/cm. Dissolved oxygen was minimal in summer (9.5mg/L) and maximal in autumn and spring (11.9 and 11.4mg/L consecutively). In summer and autumn, the minimum and maximum WBC and RBC counts were 153.6 and 211.9 (103/L), respectively, and 0.798 and 1.7 (106/L). Hb was highest in winter, while HCT was highest in autumn. The effect of season on MCV, and PLT was insignificant. MCH and MCHC were highest in winter. Strong correlations occurred between Hb/RBC, HCT/RBC, HCT/Hb and MCHC/MCH. Minimum and maximum GOT activities were 90.6 in winter and 160.3U/L in autumn, for GPT, the activities were 12.0 in spring and 25.6U/L in autumn. ALP levels were lowest in the winter (83.8mg/L) and highest in the summer (112.4mg/L). LDH activity was lowest in autumn (291.3 mg/L) and highest in spring (1331.0 mg/L). Urea was high in spring, while uric acid was highest in autumn (4.33mg/dL). The effect of season on creatinine was insignificant. Strong correlations occurred between LDH/Urea and LDH/GPT. All the above hematological variations were attributed to seasonal changes in the habitat conditions. However, these conditions were within the range favorable for the thriving and flourishing of T. zillii.

Keywords: Tilapia zillii, brackish lagoon, hematological traits, seasonal variations, southern Mediterranean Sea