Neil Jaworski, global nutritionist with Trouw Nutrition, speaks to The Pig Site about zinc oxide – why it’s used and how producers can manage without it. Jaworski is based in the Netherlands and has worked for Trouw Nutrition for five years focusing on feed ingredient evaluation.
Wherever you are in the world, zinc oxide use in piglets is likely to be removed from piglet diets in the coming months or a few years, or it has already been eliminated. We’ll have a look at how it is being used now and how to raise piglets without it.
“Zinc oxide is used in pharmacological levels for nursery pigs. Right after piglets are weaned, we feed a high level of zinc oxide to reduce post-weaning diarrhea, especially in the Americas, but in Europe, we're getting away from its use,” said Jaworski. “Most likely it's used because the pig is transitioning from sow’s milk to solid feed. We hypothesize that this is a transition of the microflora, and zinc oxide helps mask our inability to properly help this nutritional transition.”
Researchers are still studying what piglet’s bodies need to smooth this transition and even further what gut microbes need during the transition. The microbes aren't being fed when the pig is drinking milk because most of the milk is digested by the piglet. Thus, there's not a lot left for the microbes. When piglets switch to solid food, there is a lot of protein and fiber being fed to replace the milk. All of the sudden, the microbes must shift to figure out how to eat. Use of zinc oxide has helped control the microbes in the correct way to make a smoother transition from milk to feed.
“There are many other ingredients being provided to piglets in their diet that aren't very digestible,” he said. “These undigested portions are going to be food for the microbiota. If you feed the microbiota the wrong things, it can lead to differences in populations, so you have proteolytic fermentation occurring which causes post-weaning diarrhea.”
Is this a management opportunity?
“This provides a huge opportunity to try to understand how best to transition this pig and the microbes from milk to solid feed. Some nutritional strategies to use are to look at lactose levels in the first diet,” he said. “Zinc oxide destroys or eliminates Lactobacillus in the intestinal tract. Why is that? I don't know, but this transition and the supply of lactose probably has something to do with it.”
Another management strategy is to reduce protein so there’s less undigested protein ending up in the hind gut that will be fermented again, causing post-weaning diarrhea. Lastly, it’s time for the industry to better understand dietary fiber and the fiber fermentation by weaned pigs, which will help to decipher the microbiota response.
“In the end, we want the opportunity to use feed ingredients in the right way while decreasing our reliance on this zinc oxide, but still controlling post-weaning diarrhea,” he said. “It's going to require a complete management package to make it work, including focusing on things like biosecurity, crowding, and temperature control.”
The more stressful events that the pig must experience, the higher the risk for post-weaning diarrhea. Without zinc oxide, it will require a higher level of management, but the opportunities are available to create a more comprehensive feed-farm-health approach, he said.