Comparative study on the non-specific immune response and hsp70 gene expression among three strains of koi (Cyprinus carpio) under acute heat stress

• Main Authors: Huanhuan Yu, Chongying Zhang, Wei Xing, Tieliang Li, Guanling Xu, Zhihong Ma, Na Jiang, Lin Luo
• Format: Article
• Language: English
• Published: Elsevier 2020-11-01
• Series: Aquaculture Reports
• Subjects: Koi (Cyprinus carpio); Strains; Heat stress; Non-specific immunity; hsp70
• Online Access: http://www.sciencedirect.com/science/article/pii/S2352513420305512

A comparative study was performed to examine the effects of acute heat stress on non-specific immune response and heat shock protein 70 (hsp70) gene expression in three strains of koi (Cyprinus carpio), Showa Sanshoku, Kohaku, Ogon. Fish were exposed to increasing water temperature from 25 to 32 °C. Samples were collected at 0, 2, 6, 10, 14, 18, 22, 26 h after heat stress. Data were analysed by two-way ANOVA with strains of koi and time after heat-stressed as fixed factors. The results indicated that different strains had significant effects on whole blood respiratory burst (RB) and plasma superoxide dismutase (SOD) activity (P < 0.01). Different strains, time after heat-stressed and interaction of both factors affected plasma malonaldehyde (MDA), myeloperoxidase (MPO), complement 3 (C3), and heart hsp70 gene expression significantly (P <  0.01). After heat stress, Showa Sanshoku showed increased MDA, MPO, and suppressed C3 (P <  0.05). In Kohaku, MDA firstly raised (P <  0.05) and then fell to the basal level, while MPO, C3 significantly enhanced (P <  0.05). Continuously declined MDA and increased C3 were observed in Ogon (P <  0.05). The expression of hsp70 in the heart of koi was remarkably induced by heat stress and peaked at 2 h. After a sharp increase, the mRNA level of hsp70 recovered to the basal level (P >  0.05) but was induced again by continuous heat stress (P <  0.05). In summary, MPO, C3, and hsp70 played important roles in coping with heat stress. Hsp70 was a sensitive biomarker of heat stress in koi. The three strains of koi responded differently to heat stress. Ogon seemed to have the best ability to cope with heat stress, followed by Kohaku, while the Showa Sanshoku showed continuous oxidative stress and immunosuppression under acute heat stress.