The aim of this plan is evaluating NNV inactivated vaccine to induce the broodstock to produce the neutralizing antibody. We wish to reduce or block the roe of NNV vertical infection. That vaccination can reduce the risk of vertical transmission of NNV of grouper broodfish. The nano- encapsulation of inactive vaccine can diluted with 500~1000 fold was sufficient to induce high protection (RPS=70). Then, the primers of real-time PCR with MX, CD8 and TNF-αwere established and that can both detected Epinephelus coioides and Epinephelus lanceolatus.
Encapsulated IgY (including 5%) and non-treated IgY (including 30% and 5%) were mixed individually with eel feed meals to fed grouper .For prevention experiments, TGIV challenge tests were carried out at 1 days after we finished feeding for 3 consecutive days. The relative survival rates were 50% in encapsulated IgY group, and 40% in non-treated high-dose group, respectively. No protection was found in both non-treated low-dose IgY group and blank egg powder group. For therapeutic experiments, fish in each groups were challenged first with TGIV .After 24 hours, the fish were fed for 3 consecutive days. The group of 24 hours feedings, the relative survival rates was 20% in encapsulated IgY group and 15% in non-treated high-dose group, respectively. No protection was found in both non-treated low-dose IgY group and blank egg powder group. As a conclusion, the passive protection effect of anti-TGIV IgY has been confirmed and an emulsified technique can improve the efficiency of IgY.
The new hybrid tilapia, bred by Freshwater Aquaculture Research Center, FRI, only need to be cultured for one year to marketable size, with high male ratio, are very suitable for the farmers. Previously, 300 thousand fry were produced this year, but total of 82 thousand had been already sold to 2 farmers. Additionally, fry of Nile tilapia (Oreochromis niloticus) and Blue tilapia (Oreochromis aurea), respectively, were cultured to be selected as broodstock next year.
This study aimed to improve factors affecting the growth and survival in early stages in the larval rearing of cobia (Rachycentron canadum) under a recirculating system. The initial trial (T1) of this study was conducted to examine the use of copepods, Apocyclops royi, as live prey for cobia larvae and compare the performance of copepod as live prey with that of the traditional live prey, Artemia nauplii. Subsequently in a second trial (T2) was designed to evaluate the influence of tank wall color on the growth and survival of cobia larvae. Fatty acid profile of live preys used throughout this study was analyzed. At the end of T1, means of standard length (14.40 ± 0.035mm) and survival rates (8.32 ± 0.32%) of larvae fed with copepods were significantly improved. In T2, brown tank wall color had the fastest mean growth (16.1 ± 0.49 mm) but the greatest survival rates were achieved in tanks with gray and red wallcolors. Results of these trials present evidence that factors such as type of live feed, larval culture systems and rearing techniques influence in the performance of cobia larvae in terms of growth and survival rates.