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Novel adjuvant may allow for DNA vaccinesNovel adjuvant may allow for DNA vaccines

Tim Lundeen 1

October 2, 2015

7 Min Read
Novel adjuvant may allow for DNA vaccines

AT the 2015 Animal Health Research Symposium, experts described four expectations that new vaccine adjuvants should meet and presented data about a next-generation vaccine under development that could be the first to use DNA technology to immunize poultry against avian influenza virus (AIV).

"Disease-causing organisms are constantly evolving to gain a competitive edge, and many endanger both human and animal health," VaxLiant co-founder Dr. Tim Miller said. "That's why it is so important to focus research on preventive solutions that are agile and flexible enough to match this evolution, especially that of rapidly changing viruses causing zoonotic diseases."

In his presentation, Miller highlighted the importance of developing new adjuvants -- ingredients added to vaccines to improve the resulting immune response -- that are versatile enough to create next-generation vaccines.

According to Miller, the ideal adjuvant should: (1) be flexible enough to enable vaccine developers to create a specific immune response (immunomodulation), (2) minimize cell destruction to allow in vitro development, (3) provide extended stability when the vaccine is stored or administered to the animal and (4) contain no animal-origin materials that could compromise safety or restrict the import or export of animals and animal products.

Miller showed research on a novel adjuvant (ENABL) that meets these four expectations and is now being used not only in conventional vaccines but also to develop a production platform for next-generation vaccines.

In a separate presentation, Dr. Mary Ann Pfannenstiel explained how the novel adjuvant is making it possible to create what could be the first practical DNA vaccine to fight AIV.

"For years, scientists have been looking for a way to overcome one of the key obstacles for DNA vaccines: large doses needed to create immunity, making them extremely expensive," Pfannenstiel said. "ENABL's unique design allows DNA vaccines to consistently deliver effectiveness using lower doses and with fewer inoculations. This means we can now tap into DNA technology to develop vaccines with distinct benefits for researchers, veterinarians and animals."

Pfannenstiel presented studies showing how her research team combined ENABL with gene-sequenced DNA (specifically, the AIV hemagglutinin gene) to create a vaccine that produced superior results when administered to chickens.

She explained that they developed this vaccine using DNA technology to select and encode a specific antigen of the virus, rather than using all of the viral antigens. This allows for differentiation among infected and vaccinated animals. Combining DNA technology and a novel adjuvant also makes it possible to more quickly adjust vaccines to reflect circulating strains of AIV and other disease pathogens.

"Adjuvants that can be formulated and customized to increase effectiveness truly are a valuable tool for advancing vaccine technology," Pfannenstiel concluded.

Although an AIV vaccine with ENABL is not yet available, research is continuing as the vaccine enters the commercial licensing process, according to VaxLiant.


Eggshell quality

Eggshell quality remains a key aspect of successful egg production for any layer operation. Broken and cracked eggs represent a significant loss to both the industry and to individual producers. As hens age, these losses grow more significant.

The most effective way to achieve the highest production possible is by boosting flock performance through optimal nutrition, according to an announcement from Novus International Inc.

Zinc, copper and manganese are vital to realizing optimal performance, particularly in layers, as these trace minerals play specific roles in metabolic activities directly related to eggshell formation. In a recent study, Novus investigated the impact of long-term use of chelated trace minerals (MINTREX brand) compared to inorganic trace minerals on layer performance, eggshell quality, tibia breaking strength and immune response.

Laying hens were allocated to six treatments with supplemental zinc, copper and manganese.

The results indicated that hens fed either no supplemental trace minerals or lower levels of supplemental inorganic trace minerals had reduced shell thickness compared to the eggs of hens fed high levels of sulfates. Further analysis showed improvements in shell breaking strength, shell thickness, tibia breaking strength and immune response in hens fed chelated trace minerals compared to inorganic trace minerals, Novus said.

The full research study was published in The Journal of Applied Poultry Research and is available for download.


Zinc chelate

Zinc plays a cross-functional role in animals, affecting gene expression, DNA and protein synthesis, cell signaling, cell division, animal growth, immune development and function, synthesis of structural proteins such as collagen and keratin, bone and tissue development, reproduction and defense against oxidative stress.

Because of its vital role, zinc is typically supplemented in all animal diets either as inorganic trace mineral salts -- such as sulfates, chlorides and oxides -- and/or as organic trace minerals.

"While inorganic trace minerals are relatively cheap, they suffer from poor bioavailability, or the degree to which an ingested nutrient is absorbed in a form that can be utilized in metabolism by the animal, as compared with some organic trace minerals," Karen Wedekind, Novus senior research scientist in comparative nutrition, said. "Poor uptake of inorganic trace minerals is mostly due to antagonisms and interactions in the animal system. An example of zinc antagonism occurs when there is an excess of calcium and/or phosphorus."

In a recent study, "Greater Bioavailability of Chelated Compared with Inorganic Zinc in Broiler Chicks in the Presence or Absence of Elevated Calcium & Phosphorus," Novus researchers compared chelated zinc with zinc sulfate in Cobb 500 broiler chicks. The chicks were fed a zinc-deficient corn/soybean meal diet either alone or one also containing elevated calcium and phosphorus as antagonists.

The results showed significantly greater zinc bioavailability for the chelated zinc treatment relative to zinc sulfate, as judged by total tibia zinc, the tibia zinc concentration and small intestinal metallothionein mRNA expression, Novus said.

"Feeding chelated zinc can offer advantages over inorganic zinc, especially in diets containing high levels of calcium and phosphorus, which is a common occurrence in livestock diets," Wedekind said.

The research study was published in Open Access Animal Physiology, an international, peer-reviewed, open-access, online journal that publishes original research, reports, reviews and commentaries on all areas of animal physiology.



DSM announced that the Food & Drug Administration has published a letter accepting DSM's conclusion that canthaxanthin is generally recognized as safe (GRAS) as a nutritive antioxidant to support the development of chicken embryos at levels of 6 parts per million of complete feed.

The GRAS notification was pursued in the context of DSM's MaxiChick project for increasing productivity in poultry production. It consists of a combination of Hy-D (the active form of vitamin D3) and CAROPHYLL Red 10% (canthaxanthin), which helps improve the number and quality of chicks produced, DSM explained. Claims are supported by solid scientific data from numerous experimental and customer trials in several countries, the company added.

Fernando Cisneros, global carotenoid manager for DSM Nutritional Products, said, "We are pleased that the FDA has accepted our conclusion that canthaxanthin is GRAS as a nutritive antioxidant for poultry breeders. DSM's CAROPHYLL Red, mainly used for pigmentation of table eggs and skin in chickens, is the first carotenoid product thoroughly evaluated as a nutritive antioxidant for poultry breeders and is patent protected."

Separately, DSM confirmed the authorization of its CRINAPoultry Plus (a preparation of benzoic acid, thymol, eugenol and piperine) as a zootechnical additive in the European Union.

Following the recent European Food Safety Authority's assessment in 2014, this announcement concludes the registration process with legal approval.

Based on the confirmed safety and performance enhancement benefits of CRINA Poultry Plus -- specifically for the target species that include chickens for fattening chickens reared for laying and minor poultry species for fattening and reared for laying -- the product is now listed as an approved feed additive in the EU.

Volume:87 Issue:38

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