Effects of a Dissostichus mawsoni-CaM recombinant proteins feed additive on the juvenile orange-spotted grouper (Epinephelus coioides) under the acute low temperature challenge.

The effects of Dissostichus mawsoni-Calmodulin (Dm-CaM) on growth performance, enzyme activities, respiratory burst, MDA level and immune-related gene expressions of the orange-spotted grouper (Epinephelus coioides) exposed to the acute low temperature stress were evaluated. The commercial diet supplemented with Dm-CaM protein was fed to the groupers for 6 weeks. No significant difference was observed in the specific growth rates, weight gains and survivals. After the feeding trial, the groupers were exposed to acute low temperature challenge. The groupers fed with Dm-CaM additive diet showed a significant decrease in the respiratory burst activity, while the blood cell number increased significantly at 25 °C by comparing with the control and additive control group. The enzymatic activity of SOD, ACP and ALP increased significantly in Dm-CaM additive group, while MDA level maintained stable with the lowest value. qRT-PCR analysis indicated that the up-regulated transcript expressions of CaM, C3, SOD2, LysC and HSPA4 were observed in Dm-CaM additive group. These results indicated that Dm-CaM additive diet may regulate the grouper immune response to the acute low temperature challenge.

Effects of a recombinant complement component C3b functional fragment α2MR (α2-macroglobulin receptor) additive on the immune response of juvenile orange-spotted grouper (Epinephelus coioides) after the exposure to cold shock challenge.

The effects of Ec-α2MR (Epinephelus coiodes-α2-macroglobulin receptor) on growth performance, enzymatic activity, respiratory burst, MDA level, total antioxidant capacity, DPPH radical scavenging percentage and immune-related gene expressions of the juvenile orange-spotted grouper were evaluated. The commercial diet supplemented with α2MR additive was used to feed the orange-spotted grouper for six weeks. Although a slight increase was observed in the specific growth rate, survival rate and weight gain, no significance was observed among different group. After the feeding trial, the groupers were exposed to cold stress. Respiratory burst activity and MDA level decreased significantly in α2MR additive group by comparing with the control and additive control group, while a sharp increase of ACP activity, ALP activity, total antioxidant capacity and DPPH radial scavenging percentage was observed in α2MR additive group. qRT-PCR analyses confirmed that the up-regulated mRNA expressions of C3, TNF1, TNF2, IL-6, CTL, LysC, SOD1 and SOD2 were observed in α2MR additive group at 20 °C. These results showed that α2MR additive may moderate the immune response in grouper following cold shock challenge.

Functional analysis of a dietary recombinant fatty acid binding protein 10 (FABP10) on the Epinephelus coioides in response to acute low temperature challenge.

The effect of Ec-FABP10 (Epinephelus coiodes-FABP10) on growth performance, enzyme activity, respiratory burst, MDA level, ATP content, immune-related gene expression of juvenile orange-spotted grouper (E. coioides). The commercial diet supplemented with FABP10 protein was feed to orange-spotted grouper for six weeks. No significant difference was observed in the specific growth rates, while the survival rate in the FABP10 additive group was significantly higher. After the feeding trial, the groupers were exposed to acute low temperature challenge. The decreased level of respiratory burst activity was observed in the FABP10 additive group after the exposure to the acute low temperature stress, while the blood cell count increased significantly at 15 °C and a significant increase of ATP content was observed at 10 °C. Higher enzymatic activities of CAT and SOD were observed at 20 °C and 15 °C, respectively. Meanwhile, the lower level of MDA was observed after the exposure to acute low temperature challenge by comparing with the controls. Further transcript expression analyses of FABP10, SOD2, GPX4, HSPA4 and LIPC in liver by quantitative real-time PCR demonstrated that the up-regulated transcript expression of FABP10, SOD2, HSPA4 and LIPC was observed in FABP10 additive group at 15 °C, while the transcript expression of GPX4 increased significantly at 20 °C. Western blotting analysis confirmed that FABP10 protein expression strongly increased at 15 ± 0.5 °C in FABP10 additive group. These results showed that FABP10 additive diet could moderate the metabolic and immune abilities mainly via ROS pathway in the orange-spotted grouper.