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A Discussion from the Shrimp List
This discussion took place on the Shrimp List June 2005.
Julio Estrada (firstname.lastname@example.org): I know we’ve talked about Vibrio several times, but I still have a bunch of questions about it:
Have any (legally permitted) treatments been found?
Have any peer reviewed studies appeared on the use of probiotics to prevent vibriosis?
How often are Vibrios the primary pathogens, how often the secondary, opportunistic pathogens?
Is it generally accepted that some strains of B. subtilis excrete (manufacture) flavomycin? Not sure where I picked that one up!
Is Flavomycin/Flavophospholipol a universally accepted antibiotic, or are there restrictions on its use in some countries?
Is it true that Vibrio populations do better in ponds that have been pretreated with chlorine or other biocides?
Jose Narvaez (email@example.com): What is your standard protocol for handling Vibrio? At what stage in the growout cycle does it usually hit you?
Larry Drazba (firstname.lastname@example.org): Vibrio control is easiest or most effective when you have little or no water exchange. Water exchange affects the pond stability and makes any control measures a hit or miss proposition. There are probiotics that give results under zero or little water exchange. We have proven that they colonize the hepatopancreas and gut, and empirical evidence shows that we have less Vibrio-related disease problems. Probiotics also seem to lessen problems with NHP, although we do not know why yet. Some strains of Vibrio can be primary pathogens, but most are usually secondary, especially in the presence of viral pathogens like whitespot.
Julio Estrada (email@example.com): Like most whitespot victims, we had more or less set aside the Vibrio issue, and now we are taking a fresh look at it. We’re just beginning to collect data and haven’t set up a proper way to record and collate it yet. In fact the pathology lab is just now getting reactivated. So we have nothing but questions, certainly nothing that we could call a “protocol”, standard or otherwise, sorry! Once we are ready to put together some sort of plan, I’ll push for close collaboration with your group and others.
Jose Narvaez (firstname.lastname@example.org): On my farm, Vibrio usually shows up around day 25 to 30. It’s been like that for years, so what we do is start monitoring early, and from day 16, depending on the Vibrio counts, we treat the ponds with either calcium hydroxide at 20 kg/ha or Riboflox at 2.5kg/ton of feed for 8 days. In the future, we plan to switch to just Riboflox because we have consistently been able to reduce our mortality rates during the first 35 days of growout, and we get better performance from the animals until around day 55. By treating the ponds early in the cycle, the cost is rather low.
Chong KK (email@example.com): Please tell us more about your program to control vibriosis. What is the chemical content of Riboflox? Is it available in Asia?
Julio Estrada (firstname.lastname@example.org): When you use calcium hydroxide, does the pond salinity affect the results? There seem to be differing opinions on this. Riboflox is new to me, and I couldn’t Google up anything on it. Do you have contact data for a supplier?
Rommel E. Hernandez R. (email@example.com): Riboflox is an antibiotic (enrofloxacyn).
Jose Narvaez (firstname.lastname@example.org): Does pond salinity affect any of my treatments for Vibrio? My first response would be to say “No”, but I’ll check with my production staff and get back to you on that one. Our salinities move in a range of 20 to 45 parts per million from January to June and from 11 to 40 ppm from July to November. We usually let the ponds lie idle from early December to late January. Regarding Ribolox, I’ll have the manufacturer’s name for you in a couple of days. We start checking bacterial levels 15 days into growout. If they rise, we start calcium hydroxide treatments immediately and send water samples to the lab. If the samples test positive for Vibrio, we start treating with Riboflox.
Julio Estrada (email@example.com): Very preliminary data seems to show that we, too, get the Vibrio problems around day 35, but it may prove to be more dependent on shrimp size than time in the pond. Significant mortalities seem to last for several days, then disappear even if untreated. Higher temperatures seem to make mortalities more severe. Salinities are in the midrange (say 12-30 ppt) for most of the time in our main production areas, but a strong rainy season will bring that down below 3 ppt in a hurry.
Ribolox turns out to be an antibiotic and that is something we don’t want. We will certainly try calcium hydroxide at several dosages. We will probably try to correlate environmental factors with the Vibrio mortalities, working on the theory that Vibrio is omnipresent and becomes a problem only when the shrimp are stressed. We have lots of tedious analysis to do, but we may get lucky and pinpoint something significant.
Alistair Dick (firstname.lastname@example.org): It occurs to me that Vibrios may be identified grossly in ponds through a range of symptoms and responses. I feel that “red-head syndrome”, a chronic condition affecting the hepatopancreas that does not cause major mortalities, may be one such response. Can anyone verify this or add further to the discussion?
Andrew Normoyle (email@example.com): Can anyone tell me who manufactures the Riboflox product?
Attilio Castano (firstname.lastname@example.org): Dose anybody have experience with Vibrio vaccines? How effective are they? How difficult to apply?
M. Chandrasekar (email@example.com): You can probably use Schering Plough’s new Vibrio fish vaccine on shrimp. Contact Mr. Nakano Satoru at Sheering Plough for details (firstname.lastname@example.org). The product needs to be tested on shrimp. The company is working on it. Information: M. Chandrasekar, Aquaculture Manager, Oman Fisheries Company (SAOG), P.O. Box 2900, PC 112, Ruwi, Sultanate of Oman (phone 968-24509544, fax 968-24597804, mobile phone 968-99523620, email email@example.com, webpage www.omanfisheries.com).
Carlos Lara (firstname.lastname@example.org): Mario Aquire is the Latin America representative for the Aquaculture Division of Schering-Plough. Mario was recently in Costa Rica and showed me some impressive results with shrimp—at the hatchery and pond levels. You can contact Mario at email@example.com.
Alistair Dick (firstname.lastname@example.org): Apparently, Riboflox is an antibiotic and cannot be legally used in Australia.
David Leong (email@example.com): For an equivalent antibiotic you can contact Avimex, it has enroblend, or enrofloxacin. Contact Jorge Cardenas, firstname.lastname@example.org.
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