Innate‐immune responses of tilapia (Oreochromis mossambicus) exposure to acute cold stress

Abstract

In this present study, Oreochromis mossambicus tilapia were transferred to cold water at 12°C for various time intervals (1, 4, 8, 24, and 48 hr) and its innate immune response was analyzed by studying cellular and humoral parameters. In vivo, alternative complement pathway activity in blood plasma was rapidly increased at 1 hr of cold water (12°C) exposure. Lysozyme activity and cortisol levels of plasma were increased at 4 and 1 hr, respectively. Surprisingly, only plasma cortisol levels remained unchanged through 24 hr of cold water transfer. Phagocytic ability, phagocytic capacity, and respiratory burst (RB) activity of head kidney (HK) leukocytes and splenocytes showed no any significant changes. In peripheral blood leukocytes, phagocytic capacity, and RB activity were increased at 24 hr of cold water exposure. The expressions of genes involved innate immunity in splenocytes and HK leukocytes of tilapia cold water exposure were analyzed, messenger RNA (mRNA) expressions of HSP70, HSP90, and immunoglobulin M failed to change upon exposure to cold stress. Major histocompatibility complex‐I and II mRNAs were significantly increased in tilapia splenocytes at 1 hr of cold water transferred. Whereas myxovirus (Mx) expression was increased in splenocytes and HK leukocytes of tilapia after 1 hr of cold water exposed. Our result reveals that the exposure of tilapia to acute cold stress condition significantly enhances plasma acid phosphatase activity and both phagocytic capacity and RB activity. Furthermore, cold stress significantly stimulates Mx gene expression in splenocytes and HK leukocytes.

Effect of Low-Temperature Stress On Na+/K+-ATPase and Transcriptome Changes in Oreochromis Niloticus Gill Tissues

“…Water temperature is the main environmental factor that changes the immune response of sh (Xu et al 2012). A change in the water temperature could affect sh immunity by decreasing the disease resistance capability (Velmurugan et al 2019). In our experiment, many genes related to immune response were downregulated in the DEGs analysis, including tlr5, toll-like receptor 8 (tlr8), toll-like receptor 9 (tlr9), toll-like receptor 22 (tlr22), and fkbp5.…”

An updated review of cold shock and cold stress in fish

“…and phagocytic activity exhibited similar trends, whereas alternative complement pathway (ACP; an innate component of the immune system's protective complement system) and lysozyme activity remained depressed over the 96 h period (Cheng et al, 2009). ACP activity was elevated in Mozambique tilapia (Oreochromis mossambicus Peters 1852) over 4-24 h following cold stress (c. 24-28 to 12 C for up to 48 h), whereas lysozyme activity was also slightly elevated at 4 and 8 h post-exposure (Velmurugan et al, 2019).…”

“…ACP activity was elevated in Mozambique tilapia ( Oreochromis mossambicus Peters 1852) over 4–24 h following cold stress ( c . 24–28 to 12°C for up to 48 h), whereas lysozyme activity was also slightly elevated at 4 and 8 h post‐exposure (Velmurugan et al ., 2019).…”

Are fish immunocompetent enough to face climate change?

“…Moreover, the gene expression of antioxidant enzymes ( sod , cat ), hsp90 and complement c3 was increased by decreased temperatures and molecular markers for apoptosis were induced [51]. Tilapia ( Oreochromis mossambicus ) exposed to 12°C for up to 48 h (control 24 to 28°C) showed increased lysozyme, phagocytosis, respiratory burst and alternative complement pathway activities in blood plasma suggesting a potential role of humoral innate immune response during cold stress exposure [52]. The discussed studies provide compelling evidence on the interconnection of the stress and immune response upon acute temperature shifts in diverse fish species and highlight the importance of the complement system.…”