Biosecurity In charge of farm infrastructure and marketing, Hearty has gone all out to ensure that the farm biosecurity is maintained at all times. At the farm entrance is a shower area, specifically for the part-time harvesting team of seven to shower before entering the ponds for the partial harvesting process. Usually, there will be three partial harvests for each pond. Hearty has also set up a harvest station close to the entrance. Buyers’ lorries are not permitted to enter the farm at all. Within the farm, groups of ponds are fenced off and only pond aides for the particular area are allowed to enter the area. Ong described the steps in the mitigation and PCR diagnosis of the white spot virus after stocking. “In the first 15 days after stocking, we will add the immunostimulant with anti-viral properties, Beta Defense Plus to the feed. After 15 days, we test the shrimp. This is to determine if there has been a transfer of the virus from the hatchery. Throughout the farming cycle, every 15 days, we send shrimp samples for PCR test for the virus. We also use the Pockit PCR system (GeneReach, Taiwan) for quick results but confirm with PCR tests at the NPPC laboratory. If the virus is detected, we immediately use Beta Defense Plus and mitigation protocol to counter the white spot virus. We then send another sample for testing after a week. Otherwise, we just continue with Beta Defense. “When we look back at how we have been challenged by white spot virus since 2010, we are glad that we now have a solution. We have managed to reverse the positive results to negative ones. The regularity of PCR test may cost money but we only needed to do four tests if the cycle is 90 days. Imagine the consequence of not testing and faced with an outbreak.”
Improving shrimp resistance to diseases through early detection and immuno-response enhancement During the conference, Simon Ong, representing GS Biotech, Malaysia and HPML looked back at some experiences in handling diseases at Hoc Po farms as well as at other farms. He discussed some trials with disease mitigation of the white spot virus syndrome, occurring singly or coinfection with white faeces disease in farms, using Beta Defense Plus. Ong said that white spot is a major threat while the emerging ones are Enterocytozoon hepatopenaei (EHP), which also occurs together with WSSV. “White spot virus can cause the primary infection followed by Vibrio or vice versa. Contrary to our experiences, where yellow colonies are not toxic like the green colonies, we consider both as harmful. This came about from our experiences in dealing with luminous shrimp disease during the days of farming the monodon shrimp. Filipino farmers understand and know how to control Vibrio harveyi, the causative pathogen for the luminous disease. Thus today, they continue to apply the same protocols in combating other Vibrio sp including V. parahaemolyticus, the cause of EMS/AHPND.” Ong showed PCR test results demonstrating the efficacy of Beta Defense and Beta Defense Plus in mitigating several disease situations. “I have used these facilities to detect suspected pathogens as well as confirm negative results after we have implemented some strategies. PCR test results are negative for the virus. Shrimp survival was 100%.
Key performance indicators for Calumangan farm • ADG: 0.25g • Harvest size: ~15g <DOC70 • Survival rate: 80% from PL 12 to 15g • Number of cycles/year: 2 • Feed cost/kg of shrimp: PHP56/kg of shrimp at FCR 1.3 and 15 g shrimp over DOC90
“For the Negros Occidental farmers the cooperative NPPC provides testing services and in Iloilo, there is SEAFDEC-AQD which also offers its services. In 2016, BFAR offered free tests as they wanted farmers to schedule testing every 15 days. Today, almost all farms follow a strict protocol of testing every 15 days.” What is clear, continued Ong is that, “We must not let the immune system be interrupted. The white spot virus will block the immune system. What Beta Defense does is to induce the prophenoloxidase (PPO), the immune protein and Beta Defense plus is to block the virus entering the host. There is actually no killing of the virus.”
January/February 2018 AQUA Culture Asia Pacific Magazine