Zinc oxide is a component added to piglet feed that will be banned from 2022 in Europe.

Feed is one of the most important parameters in animal production as it is considered the most expensive input. Therefore, providing adequate and balanced feed to pigs increases production performance and avoids cost overruns.

In the diet, it is essential to consider macro and micro minerals since these elements have multiple physiological functions. Zinc is one of the most important microminerals for the correct cellular functioning of growing pigs. Therefore, inorganic feed additives such as zinc oxide are added to provide it.

However, recently, animal health control entities in Europe have considered its ban gradually since 2017. As a result, the use of this component in pig diets will be banned from 2022.

What is zinc oxide?

Zinc oxide is a compound that has been used since the 1990s in pig farming. This ingredient is added to piglet feed to prevent diarrhea after weaning. This substance can be used at doses of 200-3000ppm which represents a therapeutic effect. At lower doses, it is considered a permitted feed additive. Another dosage formula is 100mg/kg body weight per animal for 14 consecutive days.

There are other inorganic forms of supplying zinc to animals, as it is an essential element for them. However, they have shown adverse effects and only zinc oxide has been used until this year. The advantage of zinc oxide is that it is absorbed at the intestinal level in very low quantities.

On the other hand, zinc oxide has shown good results as a growth promoter. This function has allowed it to be widely used in many European countries to accelerate piglet growth. The mechanism of this is associated with an increase in ghrelin, which is a gastrointestinal hormone produced to regulate feed intake. Zinc oxide favors the increase of ghrelin, which goes to the hypothalamic level and stimulates appetite. For this reason, animals consume more feed and increase their body growth.

What are the risks of using zinc oxide?

The use of zinc oxide is controversial. On the one hand, it has been associated that diets that include this additive may decrease the effectiveness of antibiotics and contribute to bacterial resistance. For example, methicillin-resistant Staphylococcus aureus (MRSA) can develop zinc-resistant genes. On the other hand, the environmental impact caused by zinc oxide is considerable due to its residual in pig urine. These residues have increased the amount of zinc deposited in soils and waters.

When was it banned?

The organizations on the use of veterinary medicinal products in Europe discussed on the use of zinc oxide in 2016. At this meeting they determined that the risk-benefit did not justify its continued use and thus that it was necessary to change the regulation on this inorganic additive. To this end, these organizations recommended two mechanisms to discourage the use of zinc oxide. First, they rejected marketing authorizations for the product thereafter. Second, it promoted the withdrawal of marketing authorizations for existing products.

Thus, in Europe, it was established a deadline in 2017. Specifically, it was a five-year transition period for member countries to stop using it. Hence, from 2022, alternatives to zinc oxide in pig farming must be introduced.

In Canada, government have taken some steps to avoid the use of zinc oxide. Meanwhile, in the United States, it is proposed to continue using it more strictly and moderately while new solutions appear. In Colombia, zinc oxide is still being promoted in a protected presentation that seeks to reduce the environmental impact and bacterial resistance. However, pig-producing countries in Latin America have begun to consider the possibility of searching for alternatives and contributing to the global “ZnO Free” or “Zero ZnO” initiative.

Finally, China established 2018 the maximum dose of ZnO at 1600ppm in the first two weeks post-weaning.

Alternatives to zinc oxide

Zinc oxide is an inorganic compound that has demonstrated efficacy in the prevention and management of post-weaning diarrhea in piglets. This stage is critical in pig production as the animals are exposed to many pathogens such as bacteria. Therefore, because of the ban on zinc oxide in Europe, alternatives must be put in place.

On the one hand, it is advisable to improve on-farm biosecurity. For this, a review and update of the biosecurity protocols within the farm should be carried out to reduce the number of environmental pathogens to a minimum. This preventive control avoids the appearance of infectious diseases in the pig farm.

On the other hand, reviewing vaccination schedules is appropriate to establish one according to the needs of the farm. That would help to prevent disease outbreaks. Many bacterial diseases are the result of a previous viral disease that immunosuppresses the animals.

You might also be interested in Use of intestinal conditioner pronutrients in newborn piglets

Finally, diet management can contribute positively as feed can play a key role in the prevention of infectious diseases. Increasing fiber in the diet improves intestinal transit and decreasing the amount of protein prevents the occurrence of diarrhea in piglets.

Intestinal conditioner pronutrients

Diarrhea in piglets has several predisposing factors that should be considered to prevent the occurrence of this problem.

• Social and environmental changes
• Nutritional changes
• Changes in the intestinal microbiota

You might also be interested in post-weaning diarrhea: control using Intestinal conditioner pronutrients.

Intestinal conditioner pronutrients are currently available and have shown excellent results. These are active molecules of plant origin that improve the quality of the intestinal epithelium and optimize digestive physiology. When these pronutrients are added to the diet of pigs, they improve enterocyte activity and promote their regeneration. These qualities provide animals with increased resistance to infections and improve nutrient absorption.

Intestinal conditioner pronutrients, on the other hand, are not considered drugs. For this reason, they do not generate resistance or leave residues in animals or the environment and are an alternative to zinc oxide.

The efficacy of Intestinal conditioner pronutrients has been compared with zinc oxide in the control of post-weaning diarrhea in piglets. For this purpose, a study was conducted with 66 piglets divided into two batches. One of the batch received 0.5 kg/ton of pronutrients, and the other lot received 2 kg/ton of zinc oxide, in both cases added to the feed. In this study they found that the animals with intestinal conditioner pronutrients had 42% less occurrence of diarrhea, compared to the group that used zinc oxide (4.18% and 7.21% respectively). On the other hand, in the intestinal conditioner pronutrient group, pigs had milder diarrhea compared to the other group. Thus, these products are found to be an outstanding alternative for the replacement of zinc oxide in swine.

Conclusions

Zinc oxide is an inorganic compound used in swine farming for the prevention of diarrhea in piglets, especially during weaning.

However, since 2017, its prohibition began to be regulated in Europe as a therapeutic compound administered in the diet of pigs. By 2022, it will be banned, and alternatives are needed.

Investigations by regulatory agencies have found negative effects concerning the environment and bacterial resistance. Especially when zinc oxide is added to the diet at therapeutic amounts.

There are alternatives to replace zinc oxide related to the sanitary and diet management of pigs during weaning. In addition, intestinal conditioner pronutrients are now available. These active molecules of vegetable origin and without residual effect are an efficient and clean alternative.