YOUNG ANIMAL FEED ▶▶▶


Countdown to 2022: achieving swine production goals without zinc oxide


From January 2022, new regulations will ban the use of pharmaceutical levels of zinc in the EU. What challenges do these restrictions pose for pig producers striving to support herd health and productivity?


BY NIENKE DE GROOT, GLOBAL PROGRAMME MANAGER SWINE GUT HEALTH AND RUBEN DECALUWE – GLOBAL TECHNICAL MANAGER MILKIWEAN, TROUW NUTRITION


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his article presents a perspective on the forthcom- ing regulations. In it we consider why farms have historically relied on zinc oxide (ZnO), and look at innovations that could support and even improve


swine production without ZnO or in-feed antimicrobials.


Environmental concerns drive restrictions Environmental concerns are a key factor driving the EU’s ZnO restrictions. Compared to other zinc sources such as zinc sul- phate or zinc methionine, ZnO has a high zinc content, is in- soluble in water and has lower bioavailability. This ensures that minimum inhibitory concentrations (MIC) are reached in the intestinal lumen, thus achieving an antimicrobial effect on undesirable bacteria. However, low bioavailability also results in high levels of zinc excretion in the environment, increasing the risk of contamination of groundwater and oth- er water supplies. Another concern is that high levels of ZnO


Figure 1 - Cumulative percentage of herd treatments (pens) during the experimental period in each of the six groups. Vertical lines indicate changes in diet.


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increase multi-drug resistance in bacteria such as Escherichia coli and Salmonella.


Relevance of using ZnO in piglet feed Pharmaceutical doses of zinc are used in nursery pigs to reduce post-weaning diarrhoea (PWD) and improve perfor- mance. PWD is characterised by diarrhoea, dehydration and slower growth. This condition can increase mortality rates by up to 30%. Stress associated with weaning is known to increase piglets’ susceptibility to PWD. Low feed intake post-weaning leads to negative consequences such as lower performance and increased intestinal inflammation, which is seen in poor villus and crypt development. Intestinal inflam- mation creates an ideal environment for the proliferation of bacteria, including E. coli, and the production of toxins, which may reach sub-epithelial tissues due to the increased intestinal permeability caused by ‘leaky gut’ syndrome. Exac- erbating the challenge, piglets’ intestinal barrier function and immune system are not fully developed at this age. ZnO mainly affects the lower part of the gastro-intestinal tract (GIT). In recent years, nutritionists have developed a greater understanding of a pig’s GIT, particularly with regards to the microbiome. The microbiome’s influence on health and performance is reflected in a question posed by Dr John Cryan in a TED talk: “What if you are not just what you eat, but also what your microbes eat?” This certainly holds true for piglets – we not only feed the piglets, but also feed and influence their microbiome. Certain microbes, such as Lach- nospira and Lactobacilli, produce beneficial metabolites as a by-product of their growth on complex carbohydrate sub- strates. These metabolites can be absorbed by the intestine of the pig and may cuase several responses such as immuno- modulatory effects. Research by Trouw Nutrition R&D has shown that ZnO increased the beneficial microbes Lach- nospira and Lactobacilli in the faeces of pigs 14 days post-weaning. Indeed, research suggests that what the mi- crobes eat and the metabolites produced inside the GIT cer- tainly affect the phenotypic pig that farmers feed. Regula- tions restricting pharmaceutical levels of ZnO in piglets’ diets and new insights into the importance of a balanced intesti- nal microbiota make it clear that the industry needs an effective alternative to control PWD.


Herd treatments, %


PHOTO: PETER J.E.ROEK


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