Effects of Short‐ and Long‐term Ultraviolet B Irradiation on the Immune System of the Common Carp (Cyprinus carpio)^¶

Abstract

Carp (Cyprinus carpio) were repeatedly exposed to 0, 60, 120 and 240 mJ/cm2 ultraviolet B (UVB) radiation three times in 1 week (short‐term exposure) or 12 times in 4 weeks (long‐term exposure). The effect of UVB on the functioning of the carp immune system was studied on day 2 after the final irradiation. After short‐term UVB exposure, the whole‐blood respiratory burst and cytotoxic activity were markedly enhanced, with parallel responses in both the number of circulating granulocytes and in the plasma cortisol concentration of the fish. These changes were not detectable after long‐term exposure. The respiratory burst by head kidney granulocytes was suppressed dose dependently after both exposures, but cytotoxic activity was not affected. Exposure to UVB also modulated lymphocyte functions: nonstimulated and PHA‐stimulated proliferation of head kidney lymphocytes in vitro was enhanced by both short‐term and long‐term exposure. LPS‐stimulated proliferation was not affected by exposure nor was the number of immunoglobulin‐secreting cells in the head kidney. In long‐term exposure, the highest dose reduced the level of plasma IgM. This study indicates that UVB irradiation induces immunomodulation in the blood and head kidney of the carp and that the effects of short‐ and long‐term exposure differ from each other. The results emphasize the potentially harmful impact of increased solar UVB radiation on fish immune functions.

Different sensitivity of carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss) to the immunomodulatory effects of UVB irradiation

“…In Experiment II, carp head kidney leucocytes were collected from the interface between densities 1.040 and 1.090 g ml ÿ1 , and for separation of rainbow trout head kidney leucocytes a one-step Percoll gradient (1.090 g ml ÿ1 ) was used. Cells were then washed twice, re-suspended into incubation or culture medium (RPMI-1640, supplemented with 3% Ultroser G, 0.5 mg ml ÿ1 sodium pyruvate, 2 mM L-glutamine, 100 IU ml ÿ1 penicillin, 100 mg ml ÿ1 streptomycin, and 10 mM HEPES, pH 7.4 [5]), and counted with trypan blue exclusion in a haemocytometer (viability >95%). The cell suspension was then adjusted to the desired concentration.…”

“…The concentration of IgM in carp plasma was measured by enzyme-linked immunosorbent assay (ELISA) [5]. Monoclonal mouse anti-roach IgM antibody (R1a4) was used as the trapping and detection agent after strong cross reactivity with carp IgM was established.…”

“…Effects of a single, moderate level UVB dose on roach (Rutilus rutilus) have been thoroughly examined, and markedly changed immune functions were noted [1e4]. Sub-chronic UVB exposure caused profound effects on the immune system of carp (C. carpio), revealing lack of adaptability of fish to treatment during 4 weeks irradiation [5]. Cyprinids are bottom-feeding species able to tolerate poor water quality, and also exploit turbid waters, sheltered from solar UVB radiation.…”

Immune deficiency causes annual late summer brown trout (Salmo trutta) mortality in Austrian prealpine river systems

“…Environmental pollutants such as, e.g., polychlorinated biphenyls (PCBs) (Ouabius et al 2005) or municipal sewage effluent (Hoeger et al 2004) are immunotoxic and impair the ability of fish to respond to additional stressors (Köllner et al 2002). Prolonged changes in natural photoperiod (Leonardi and Klempau 2003), diet, temperature (Bly and Clem 1992;Le Morvan et al 1998), artificial or natural solar UV radiation (Markkula et al 2005a(Markkula et al , 2005bSalo et al 2000), and bacterial or viral diseases affect the immune system of teleost fish and Salmonidae in particular.…”

Carotenoids in Aquatic Ecosystems and Aquaculture: A Colorful Business with Implications for Human Health

“…Although the direct effects of exposure to UV radiation are likely minimal within the context of all the other environmental factors that cause very high levels of egg and larval mortality in marine organisms, studies have shown that UV-induced egg mortality could be as high as 32.5% for the planktonic copepod Calanus finmarchicus and considerably less (1.2%) for the Atlantic cod Gadus morhua in the waters of the estuary and Gulf of St. Lawrence, Canada (Browman et al, 2000). Other direct effects of UV exposure on fish eggs or larvae include malformation (Dong et al, 2007), retarded growth (Jokinen et al, 2008), lesion of skin, eyes, and brain (Blazer et al, 1997;McFadzen et al, 2000), and weakened immune system (Markkula et al, 2005, 2006). These pernicious effects may be higher for fish larvae that are often present in surface waters since UV-B (λ = 280-320 nm) exposure induces DNA damage in a variety of fish larvae such as Atlantic cod, northern anchovy Englausis mordax, icefish Cephalus aceratus and Japanese medaka Oryzias latipes (see Fukunishi et al, 2012 for references).…”