Questions raised over feed ingredient link to PEDV

Questions raised over feed ingredient link to PEDV

FOLLOWING the first discovery of porcine epidemic diarrhea virus (PEDV) in Canada, Ontario-based feed producer Grand Valley Fortifiers announced Feb. 9 that it has "moved exclusively" to produce and sell nursery pig feeds that do not contain animal byproducts.

Grand Valley Fortifiers said it made its decision based on a statement from Dr. Steve Dritz of Kansas State University that said, "The magnitude of risk that swine feed can be a potential vector for (PEDV) transmission is currently unknown. However, the Kansas State University Swine Nutrition team believes at this time it is prudent for pig producers be knowledgeable of feed ingredients that are in their swine rations. Also, the K-State team has provided example nursery diet options without porcine origin ingredients. These options range from removal of all porcine origin feed ingredients to removal of specific protein-based ingredients from nursery diets."

Dritz subsequently provided Feedstuffs with a link to Kansas State's information on reducing risks of PEDV from feed sources:

The Kansas State Swine Nutrition team is encouraging swine producers to be knowledgeable about their feed ingredients and to work with veterinarians and nutrition advisers in determining the best decisions for individual operations.

They suggested that some steps to reduce PEDV risk include:

* Testing porcine products for PEDV before using them in diets and only after the products have been verified as negative for PEDV by polymerase chain reaction testing;

* Replacing porcine-based products in diets with bovine products (e.g., bovine plasma to replace porcine plasma), or

* Removing all animal proteins except milk products from the diet.

In response, member companies of the North American Spray Dried Blood & Plasma Producers (NASDBPP) reiterated that they are "committed to producing safe, high-quality blood products for use in feeds for commercial livestock and companion animals."

In 1994, NASDBPP said its member companies developed good manufacturing practices (GMPs) to assure the proper sourcing, collection and processing of animal blood and blood products to maintain safety. These GMPs provide multiple safeguards for the safety and quality of spray-dried blood and plasma products.

NASDBPP said its members actively support continued research into the causes and control of PEDV and other diseases.

NASDBPP further reported that based on current scientific evidence, it has concluded that properly sourced, collected and processed porcine blood and porcine blood products are safe and do not contribute to the spread of PEDV.

"Envelope viruses, like PEDV, are inactivated by heat treatment and do not survive in dry environments," NASDBPP explained.

NASDBPP also pointed out that the presence of viral genome in spray-dried blood product does not mean that feeding the ingredient will transmit PEDV.

The National Renderers Assn. (NRA) pointed to research that shows that heating feed ingredients at temperatures of 140 degrees F for 30 minutes, 160 degrees F for 10 minutes or even 68 degrees F for seven days results in no detectable live virus.

The rendering process significantly exceeds that threshold (at a minimum of 240 degrees F for 40 minutes) and is designed to kill pathogenic organisms such as PEDV, NRA said. For assurance, most of the rendering industry follows a hazard analysis and critical control points-like code of practice that includes critical time and temperature control points as well as post-processing re-contamination prevention.

In addition, current scientific evidence indicates that collection and manufacturing processes ensure that spray-dried bovine or porcine blood and bovine or porcine plasma products are safe feed ingredients, NRA emphasized.


Surveillance test

The University of Minnesota College of Veterinary Medicine announced that it has developed a second PEDV diagnostic test to help stem the spread of the virus that is currently threatening North American swine populations.

The test is the first announced U.S. PEDV swine herd surveillance test and brings PEDV diagnostic testing up to swine industry disease monitoring standards.

This past summer, the University of Minnesota's College of Veterinary Medicine developed a PEDV diagnostic test that detected the presence of the virus. The second test can detect evidence of the virus and is a very precise tool to detect a history of exposure to the virus, the announcement said.

If one pig has been exposed to PEDV, all animals around it are at risk. The new test will allow the swine industry to identify which pigs have been exposed to PEDV and act accordingly, even if animals have not shown symptoms of the disease, the university said when it announced the test in late January.

Efforts to develop this test began in July 2013 — shortly after the first test was developed — as part of a dual-pronged approach to controlling the spread of PEDV.

To help combat the economic and animal welfare losses caused by PEDV diagnosis and spread, the University of Minnesota is making the newly developed diagnostic enzyme-linked immunosorbent assay herd surveillance test available to the swine industry. The fully validated test is available through the University of Minnesota Veterinary Diagnostic Laboratory.

"We understand that PEDV can result in significant health and financial blows, even putting farmers at risk of bankruptcy," said Michael Murtaugh, an expert in swine disease eradication at the University of Minnesota College of Veterinary Medicine. "We're committed to providing the industry with ongoing, science-driven solutions to this major problem. The swine industry has asked for our help, and we will continue putting in additional hours until the problem is solved."

When coupled with the University of Minnesota's rapid detection test, which can detect actively infected animals within 24 hours of sample submission, both immediate and long-term herd health can now be monitored in a comparable manner to monitoring for the well-established porcine reproductive and respiratory syndrome virus.

"The disease has already affected several-hundred farms in Minnesota," said David Preisler, executive director of the Minnesota Pork Board. "This test is very important because accurate, fast diagnostics are the best starting point to give veterinarians the best information to work with their farmer clients. This new test is a great next step in helping farmers manage this disease."


Genetic sequencing

The Ohio Department of Agriculture (ODA) recently made a scientific breakthrough that will help pork producers nationwide in the fight against PEDV.

Genetic sequencing of a new PEDV strain conducted by ODA's Animal Disease Diagnostic Laboratory (ADDL) may lead to a marketable vaccine for swine in the near future, according to a Feb. 11 announcement.

Scientists at ODA, led by ADDL virologist Dr. Yan Zhang, worked to complete genetic sequencing of a new PEDV that differs in a fragment of one gene (1,170 nucleic acids in the S1 domain of the Spike gene) that encodes a surface protein. The rest of the genome sequence is identical to the PEDV strain currently circulating in the U.S.

Most important, this new virus is associated with reduced mortality in piglets, based on the field observation, which may enhance its use as a potential vaccine.

ODA said this discovery will lay the groundwork for producing a vaccine to immunize swine against PEDV.

In a swine herd, the vaccine would be orally given to a sow, which would then pass on the immunization to its piglets through nursing. This may work to significantly reduce piglet death as a result of PEDV and have a positive impact on overall swine health.

Several animal health companies are currently involved in the vaccine development process with research universities (Feedstuffs, Feb. 17).

Meanwhile, PEDV continues to spread, with farms in Montana, Prince Edward Island and Manitoba recently confirming outbreaks.

Volume:86 Issue:08

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