title: Decreasing salinity of seawater moderates immune response and increases survival rate of giant groupers post betanodavirus infection.
abstract: Giant groupers (Epinephelus lanceolatus), an important aquaculture fish in Asia, are attacked by nervous necrosis virus (NNV), belonging to betanodavirus. Environmental salinity can affect fish immunity and physiology. We examined whether decreasing salinity from 30 to 15 ppt during acclimation of groupers could affect survival with NNV infection and the associated factors. Although NNV infection decreased muscle moisture, up-regulated the gene expression of Na(+)-K(+)-2Cl(-) cotransporter isoform 2, and elevated plasma cortisol level in groupers, these factors were not related to the higher mortality of groupers reared at 30-ppt salinity (S30-groupers), compared to 15-ppt reared groupers (S15-groupers). Infected S30-groupers exhibited high leukocyte count and innate immune gene expression level. Moreover, NNV-infected dead S30-groupers showed high IL-1β gene expression level but low NNV load in the brain. The high or excess IL-1β gene expression levels in the brain of NNV-infected S30-groupers may be the factor in high mortality.
authors: Department of Life Science, National Taiwan University, Taipei 10617, Taiwan.
authors: Tz-Shiang
authors: TS
authors: Chen
authors: Department of Life Science, National Taiwan University, Taipei 10617, Taiwan; Institute of Molecular Medicine, National Taiwan University, Taipei 10002, Taiwan. Electronic address: yuchiwu@ntu.edu.tw.
authors: Yu-Chi
authors: YC
authors: Wu
authors: Department of Life Science, National Taiwan University, Taipei 10617, Taiwan. Electronic address: shauchi@ntu.edu.tw.
authors: Shau-Chi
authors: SC
authors: Chi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001492:Bass; D001774:Blood Chemical Analysis / Q000662:veterinary; D005393:Fish Diseases / Q000235:genetics / Q000276:immunology* / Q000821:virology; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D007113:Immunity, Innate; D008136:Longevity; D009132:Muscles / Q000737:chemistry; D030381:Nodaviridae / Q000502:physiology; D009928:Organ Specificity; D010802:Phylogeny; D012327:RNA Virus Infections / Q000235:genetics / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D054712:Salinity; D012623:Seawater / Q000737:chemistry; D016415:Sequence Alignment / Q000662:veterinary
chemical_list: D029941:Fish Proteins
keywords: Betanodavirus; Grouper; Interleukin-1β; Na(+)-K(+)-2Cl(−) cotransporter 2; Salinity