The immune response of tilapia Oreochromis mossambicus and its susceptibility to Streptococcus iniae under stress in low and high temperatures

• Published in: Fish & Shellfish Immunology Vol. 22; no. 6; pp. 686 - 694
• Main Authors: Ndong, Diegane, Chen, Yu-Yuan, Lin, Yu-Hung, Vaseeharan, Baskaralingam, Chen, Jiann-Chu
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-06-2007
• Subjects: Animals; Challenge; Disease Susceptibility - veterinary; Fish Diseases - immunology; Fish Diseases - microbiology; Freshwater; Leukocyte Count; Leukocytes - immunology; Mozambique tilapia; Muramidase - analysis; Muramidase - metabolism; Non-specific cellular response; Non-specific humoral response; Oreochromis mossambicus; Phagocytosis - immunology; Respiratory Burst - immunology; Streptococcal Infections - immunology; Streptococcal Infections - veterinary; Streptococcus - immunology; Streptococcus iniae; Stress, Physiological - veterinary; Temperature; Tilapia - immunology; Time Factors; Mozambique; Temperature; Oreochromis mossambicus; Streptococcus iniae; Non-specific cellular response; Non-specific humoral response; Mozambique tilapia; Challenge
• ISSN: 1050-4648; 1095-9947; 1365-2567
• DOI: 10.1016/j.fsi.2006.08.015

Mozambique tilapia
Oreochromis mossambicus acclimated to 27
°C were then held at 19, 23, 27 (control), 31 and 35
°C, and were examined for non-specific cellular and humoral responses after 12–96
h. Total leucocyte count decreased significantly when fish were transferred to 19 and 23
°C after 48 and 96
h, and when transferred to 35
°C over 12–96
h, respectively. Respiratory burst decreased significantly when fish were transferred to 19, 31 and 35
°C over 24–96
h, whereas phagocytic activity and phagocytic index decreased significantly when fish were transferred to low temperatures (19 and 23
°C) and high temperatures (31 and 35
°C) over 12–96
h. Lysozyme activity decreased significantly when fish were transferred to 19
°C after 12–96
h, but increased significantly when transferred to 31 and 35
°C over 48–96
h. Alternative complement pathway (ACH
50) also decreased significantly when transferred to 19 and 23
°C after 12
h, but increased significantly when transferred to 31 and 35
°C after 24
h. In another experiment, tilapia reared at 27
°C were injected intraperitoneally with
Streptococcus iniae at a dose of 1
×
10
7
colony-forming units (cfu)
fish
−1, and then reared onward at water temperatures of 19, 23, 27 (control), 31 and 35
°C. Over 48–168
h, the cumulative mortality of
S. iniae-injected fish held in 19 and 35
°C was significantly higher than that of injected-fish held in 23, 27 and 31
°C. It is concluded that transfer of tilapia
O. mossambicus from 27
°C to low temperatures (19 and 23
°C) after 12
h, and transfer of fish from 27
°C to high temperatures (31 and 35
°C) reduced their immune capability. Moreover, tilapia under temperature stress at 19 and 35
°C from 27
°C decreased its resistance against
S. iniae.