Denmark sees progress in R&D on zinc alternatives in pig feed

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Sow diets, digestible protein, fiber and feed additives are all being considered as elements in the effort to end the use of zinc oxide in piglet feed in Denmark, says expert.

We caught up with Torben Skov Ancker, product manager at Hornsyld Købmandsgaard in Denmark at One 18, the Alltech’s ideas conference last week to hear more about his presentation and the ongoing work with piglet and sow diets as part of the preparations for the EU's impending ban on the use zinc oxide in swine diets.  

The EU issued in a 5-year transitional period last year for the zinc oxide phase out. Denmark is known for considerable use of ZnO in weaned piglet diets, with zinc oxide said to be a very effective way to tackle post-weaning diarrhea. Within that time frame, EU states have to work on alternative methods to tackle this problem in piglets. The Danish Pig Research Center has ongoing research trials examining a series of alternative feed ingredients.

“We already know that some feed additives have an effect on diarrhea and E. coli and all that, so they started up testing some commercial products like seaweed, probiotics, and some yeast products which were commercial and that companies are using to reduce diarrhea and then they tested it against zinc oxide at 2,500ppm,” ​he said. “They conducted that trial and they didn’t see any effect at all by using these products compared to zinc oxide.”​

However, that project was only one stage of the ongoing effort, he added.

“The Danish research center has [set] three themes and then [outlined] 12 concrete things they will do – the first [theme] was to see what was on the market and try that."​

Replacing zinc oxide​

In addition to trials on commercially available products, the Danish Research Center asked companies throughout Europe to suggest ideas of feed ingredients that might work, said Ancker. The project received 23 applications and is now examining the use of four combinations.

The alternative product combinations are being examined against the use of 2,500ppm zinc, and about 22 of the 60 intended replications have been completed, he said. Elements being considered in the combinations include using limited protein, adding more threonine and lysine, organic acids, probiotics, fiber, additional enzymes, organic mineral use and monoglycerides.

The results of the studies have yet to be completely published, he said. However, reviewing the information released it is apparent that two of the combinations are seeing a reduced need for piglets to be treated for diarrhea when compared to the group getting the zinc oxide additive.

"We know that [limited protein] works at reducing diarrhea and the fiber sources can do good things and organic acids as well, but I don’t think we’ll find one single product that will replace [the zinc],”​ he added.

Ancker said he has been trying diets with highly digestible protein and a novel soy protein concentrate that has low pH and potassium. “I think we have found something that can help us [go] in the right direction, but I think we still need to combine it with the low protein, and hopefully we’ll get more synthetic amino acids because then we can lower the amount of protein,”​ he added.

There is also interest in examining further the role of the sow’s diet in piglet production, he said. “If you can get a higher milk yield and wean more uniform pigs – it’s much easier to wean a pig which is 7-8 kilos than 4-5 kilo pigs and that will also help us get rid of the zinc oxide,”​ he added.

Phasing out zinc and antibiotics ​

Several factors were involved in the EU's decision to ban zinc oxide in swine feed. There are concerns about the levels of the feed additive collecting in soil and what that concentration will mean in the long term.

There also have been health concerns regarding the use of zinc oxide and MRSA in swine and bacteria that are resistant to antibiotics, said Ancker.

Zinc tends to be added to feed during the first two weeks after piglets are weaned to reduce instances of diarrhea, but it is also used at lower levels in the feed of older pigs.

“About 20-25% of farmers could already take out the zinc because their farms are so well managed,” ​he said. “They have a high health status with nice new stables for the pigs and they could actually take out the zinc today. We already have farmers using no zinc oxide at all, but as it is now they have a safe line, they can use a little more antibiotic, and they can still use zinc if it becomes a problem."​

Additionally, regulations do not allow producers to increase the use of antibiotics as the feed additive is cut, said Ancker.

“We’re not allowed to use more antibiotics even though we have the lowest use of antibiotic when you compare us to the other important pig industries in Europe like Spain and Germany and the Netherlands,” ​he said. “We have the lowest and now we’re getting the [ZnO] ban – we need to have a solution which can help us without negatively affecting welfare.”​

Potential positives​

There is a concern that the reformulated feeds will be more expensive, said Ancker.

However, feed intake can be limited when zinc is included in the diet, he said. Removing it may improve that side of things, he said.

Use of zinc oxide also presents challenges for veterinarians and feedmills stemming from the paperwork involved and the need to flush a feedmill after zinc is used, he said. “We have to have a big cleaning so we don’t have any carryover because we still have to follow the feed legislation by how much zinc oxide as an additive we can have in the feed, so I’m looking forward to having a solution,”​ he added.