Survival Rate and Immunological Responses of Mirror Carp Selective Breeding Generations to CyHV‐3

Abstract

To explore the effect of three selective generations of mirror carp, Cyprinus carpio L., resistant to Cyprinid herpesvirus 3 (CyHV‐3), the mirror carp were infected with the virus, and differences of survival rate and immunity among generations were evaluated. These results demonstrated that there were significant survival rate differences between G1 and the other two generations, which implied that G2 has similar genetic resistance ability with G3. Acid phosphatase (ACP) in the spleen, glutathione (GSH) and total antioxidation capacity (T‐AOC) in the kidney, lysozyme (LZM) and immunoglobulin M (IgM) in the serum, and alkaline phosphatase (AKP) in the spleen and kidney also showed significant differences between G1 and G3 or G1 and G2/G3, while complement 3 (C3), C4, and superoxide dismutase showed no significant difference between G1 and G3. These results indicated that ACP, AKP, GSH, T‐AOC, LZM, and IgM were activated in response to infection of CyHV‐3 and helped to protect fish from virus damage. The increasing trends were concordant with the survival rate among the three generations except for the decline in the ACP activity. Therefore, these could be indicators for resistance of common carp to CyHV‐3, especially for AKP. The agreement of the significance between survival rate and immunity illustrates that G3 possesses strong resistance ability to CyHV‐3 virus and has little or no potency for further selective breeding.

Seroconversion and Skin Mucosal Parameters during Koi Herpesvirus Shedding in Common Carp, Cyprinus carpio

“…However, the strong positive correlation of lysG up-regulation with the viral shedding observed in the present study could also suggest a specific antiviral role of lysozyme in the KHV infection. Increased up-regulation of lysozyme in the serum of mirror carp was measured during KHV infections [ 48 ], and in rohu ( Labeo rohita ) after induction with poly I:C, a dsRNA viral analogue [ 49 ]. Lysozyme plays an important role in the non-specific immune system; its antiviral function has been described in higher vertebrates, yet further studies are required to understand its role during viral infections in teleost fish [ 26 ].…”

Local immune depression in Baltic cod (Gadus morhua) liver infected with Contracaecum osculatum

“…In addition, the loss of effector molecule production upon nematode infection is noteworthy. Lysozyme is produced by neutrophils/phagocytes and is a central molecule in the innate fish defence system (Jia et al ., 2018), and the downregulation of genes encoding lysozyme G1 and G2 in infected cod liver may contribute to increased pathogen survival.…”

Progress in Aquaculture Genetics and Breeding in China

“…Besides growth performance, disease resistance is another most targeted trait for selective breeding. Jia et al () evaluated resistance to Cyprinid herpesvirus 3 (CyHV‐3) of three selected generations of mirror carp, Cyprinus carpio L. They found that the survival rate of generations G1, G2, and G3 was 3.7, 31.2, and 35.1%, respectively, higher than the control. G2 and G3 had significantly larger survival rates than G1 ( P = 0.000), but there was no significant difference between G2 and G3.…”

“…G2 and G3 had significantly larger survival rates than G1 ( P = 0.000), but there was no significant difference between G2 and G3. Thus, G3 possesses strong resistance ability to CyHV‐3 virus but has little potency for further selection for CyHV‐3 virus resistance (Jia et al ).…”