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June 14, 2013

United States

Texas—A Potential Cure for EMS


On June 13, 2013, I chatted with Maurice Kemp, Ph.D., chief technical officer of Mionix Corporation, a technology company with products that help reduce food contaminating pathogens and control bacterial diseases that may infect animals.  Mionix markets a product called “Vitoxal®”, a blend of sodium/calcium aluminosilicate mixed with acidified calcium sulfate (approved by the FDA and USDA) that has the potential for stopping early mortality syndrome (EMS).  Recent research in Malaysia has shown that high pH levels trigger EMS outbreaks in shrimp ponds.  Blended with feed and consumed by shrimp, Vitoxal lowers the pH in the gut of shrimp and prevents bacteria like Vibrio parahaemolyticus from replicating and spreading.



In general, acidification of the gastrointestinal tract facilitates growth of gram-positive bacteria, which competitively exclude and/or secrete products that suppress and/or inhibit development of gram-negative bacterial pathogens like Vibrio spp. and Pseudomonas spp.  Gram-negative bacteria are more sensitive to pH changes than gram-positive bacteria.


Shrimp News: Do you think Vitoxal will be effective against EMS?


Maurice Kemp: Yes, but it depends on when the bacteria enters the shrimp’s body.  If it enters prior to adding Vitoxal to the diet, it probably will not stop the disease, but if the bacteria enters the shrimp’s body after it has consumed Vitoxal, it is very likely that it will prevent Vibrio parahaemolyticus from infecting the shrimp.


EMS/AHPNS is caused by a bacteria (Vibrio parahaemolyticus) that’s infected with a virus (a phage) and transmitted orally.  Together, they colonize the shrimp’s gastrointestinal tract and cross the gut membrane thereby establishing a systemic infection.  Typically, a toxin is then produced by the phage coded gene that is secreted, causing tissue destruction and dysfunction of the hepatopancreas, a multi-function organ distinct from the gut.


Shrimp News: When the Vibrio populations are reduced does the phage also suffer?


Maurice Kemp: Yes, in fact the phage’s DNA becomes part of the Vibrio’s DNA, so they go down together.


Shrimp News: Have you tested the product on shrimp?


Maurice Kemp: Yes, but not to treat EMS.  Vitoxal has been used in Ecuador to control Vibrios in general early in the growout cycle and late in the growout cycle.  It eliminates the Vibrios early in the growth cycle and if stress causes them to reappear, Vitoxal will bring them under control again.  We’re not talking about wiping out the Vibrios like you would with an antibiotic, we’re talking about controlling them, so that the shrimp continue to grow normally.


Shrimp News: Is it the low pH that stops the growth of the Vibrio in the gut of the shrimp.


Maurice Kemp: Yes, It brings down the pH and stops the replication of the Vibrio.  Normally, the gut of a shrimp has a neutral pH (around 7).  Blended with feed, Vitoxal lowers the pH in the gut to 4–5.  When consumed it likewise lowers the pH to a level the Vibrios can’t tolerate.  In addition, research conducted at the Texas A&M Mariculture Research Center by Dr. Addison Lawrence indicates that Vitoxal changes the surface of the gut wall so that the Vibrios are no longer capable attaching themselves to it, further preventing a systemic infection.  Dr. Lawrence’s studies also clearly indicate that Vitoxal stimulates the shrimp’s primitive immune system, which adds even more protection.  So, in addition to creating an environment where Vibrios can’t reproduce, we’re changing the gut membranes and we’re stimulating the shrimp’s primitive immune system.  Together, these three factors should bring an end to the EMS epidemic.


Shrimp News: Are you making any arrangements to test your acidifier on animals that have been exposed to EMS.


Maurice Kemp: Yes, we are going to do challenge studies.


Shrimp News: How much will it cost to add your acidifier to shrimp feed?


Maurice Kemp: It will add less than three percent to the cost of the feed when added at a level of 1%!


Information: Maurice C. Kemp, Ph.D., Mionix Corporation, Suite B 206-343, 8127 Mesa Drive, Austin, Texas 78759, USA (phone, 1-877-464-6649 or 916-616-7037, fax 1-520-441-9871, email, webpage


Sources: 1. Maurice Kemp, Telephone Interview by Bob Rosenberry, Shrimp News International.  June 13, 2013.  2. Journal of the World Aquaculture Society.  Effect of Dietary Supplementation of Acidic Calcium Sulfate (Vitoxal) on Growth, Survival, Immune Response and Gut Microbiota of the Pacific White Shrimp, Litopenaeus vannamei. Effect of Dietary Supplementation of Acidic Calcium Sulfate (Vitoxal) on Growth, Survival, Immune Response and Gut Microbiota of the Pacific White Shrimp, Litopenaeus vannamei.  J. Davies Anuta (Agrilife Research Mariculture Laboratory, Texas A&M System, Port Aransas, Texas 78343, USA), Alejandro Buentello, Susmita Patnaik, Addison Lawrence (Texas AgriLife Research Mariculture Laboratory, Texas A&M University System, Port Aransas, Texas 78373, USA (phone (phone 1-361-749-4625, extension 223, email, Ahmed Mustafa, Michael E. Hume, Delbert M. Gatlin III and Maurice Kemp.  Volume 42, Number 6, December 2011.


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