Shrimp production intensification is one of the government’s strategic to achieve national goals production up to 2 million tons in 2024. The rapid development and intensification of cultural practices have been associated with several problems inside, one of them is disease outbreaks. Diseases outbreaks can caused by bacteria, viral disease, and microscopdia parasites and it decrease shrimp production up to 20%. AHPND (Acute Hepatopancreatic Necrosis Disease) and EHP (Enterocytozoon hepatopenaei) plague the industry because impactfull in growth shrimp and heterogenous shrimp size.
In terms of that problem, FUI (Indonesian Shrimp Forum) held webinar on January 27th 2022, which was supported by BPBAP Takalar, KKP, and UNIDO. Discern enthusiasm audience during webinar be held we can say that AHPND and EHP are being big concern among servant government or shrimp farmer.
First speaker was delivered by Mr. Supito S.Pi, M.Si, head of BPBAP Takalar. He said that disease is second effect from environmental changes (fluctuation water quality) in ponds. It will cause disease outbreak in shrimp farming because pathogen infect shrimp while shrimp in stress condition. Range fluctuative in pH parameter should not more than 0.5 but it should to around <0.3. Mr. Supito said that the keys how to success minimize shrimp disease risk in intensive shrimp farming are we have to complete understanding of shrimp culture technology, disciplined and has experienced technical employee, consistently applying technology, using guaranteed quality at input production (feed, shrimp fry, etc.), and improved surveillance.
The second speaker, Mr. Guno Gumilar, presented basic concepts and more detailed about preventive way in AHPND/EHP disease. He shared his experience about AHPND. First, we have to know the phase of AHPND. Based on the bacterial density and hispathology of AHPND, there are 3 phases: initial (initial), middle (acute), and final (terminal) which can seen different each phase from size and colour at intestine and hepatopancreas. AHPND outbreak come on DOC 35 in BPBAP Takalar.
Control and management of AHPND treatment can divided into conventional which is disinfection and antibiotics, but both can be resistance. The other one is control potential includes probiotics treatment, phage therapy, and environmental manipulation. BPBAP Takalar uses mitigation strategy to prevent AHPND with microbial community management (MCM) by enrichment feed and stabilizing C/N in pond culture.
Feed enrichment with probiotics was choosen because it can improve growth, enhached immune gene expression, and maintain microbial balance. The probiotics used are combination of Bacillus sp. (heterotrophic bacteria), Lactobacillus sp. (breaks down protein into peptides and amino acids), and Rhodobacter sp.. Enrichment treatment begins by activate probiotics for 6 hours then blend into feed with binder. Enrichment probiotics into the feed begins in DOC 25. Quorum sensing process in enrichment probiotic can decrease pathogenic bacteria that causes AHPND (Vibrio parahaemolyticus).
Balancing between heterotrophs bacteria, nitrifying bacteria, and denitrifying bacteria must be stable from early shrimp culture. BPBAP Takalar during a period shrimpculture, they don’t use siphone method because they found out in 2016, after siphoning WFD disease comes. He assumpt that WFD outbreak because the C/N in the water become unstable condition due to nitrogen sources (organic matter) decreased. An alternative treatment to make organic matter not excessive in the water is water change after DOC 35 which 5% in the first month with 2 times and 10% after DOC 90.
In first month of period shrimp culture, nitrite is low but nitrate was certainly lower because there was no nitrification process. After first month culture, nitrification process began, nitrate increased rapidly until at 10-12th week but denitrification conditions was running which caused nitrite to decrease. Therefore, the calculation of C/N in the culture pond must be right and very crucial for the mixotropic system to work even though algae blooms are a limiting factor due to the high nitrate in the water. The control of water quality, via the control of nitrogen accumulation and the use of high quality probiotics and immune-stimulants, greatly reduces the environmental stress on the animals
The discussion session also discussed about Enterocytozoon hepatoenaei (EHP). This microsporidiosis can live hidden in soil so remains possibility of shrimp being attacked by EHP. These spores have a characteristic, thick cell wall, so strong oxidizing such as hydrogen peroxide are needed. Giving H2O2 a dose of 5% in lining ponds can minimize these spores.