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Alternatives to zinc and copper as reductions look likely

When it comes to gut health in weaners, the role of nutrition cannot be underestimated in ensuring young pigs are given the best opportunity to meet target growth rates, with limited risk of succumbing to disease.

But, with talk in the industry about imminent copper and zinc dietary restrictions, ABN Pig Nutritionist, Dr Steve Jagger, looks at how recent research into nutritional alternatives, such as benzoic acid, offers a light at the end of the tunnel for producers.

What’s next for zinc oxide?

Post weaning, zinc oxide and copper have been extensively used in recent years, to help to promote gut health and growth. The use of zinc oxide has led to reduced antibiotic usage for enteric diseases.

As zinc oxide is currently contained in the vast majority of starter diets at therapeutic levels, it’s important for producers to be prepared to consider alternatives following the opinion of the Committee for Medicinal Products for Veterinary Use (CVMP) to ban all products containing zinc oxide.

A final decision will be made on the future of the use of zinc oxide by the Veterinary Medicinal Products Standing Committee of the European Commission on June 19th.

Zinc oxide products are being considered for prohibition due to environmental concerns over levels of zinc excreted through manure and accumulating in soil and surface water, particularly in France, Denmark and the Netherlands. 

There are also concerns over the development of bacterial resistance, but evidence of a link with the use of zinc oxide is under dispute.

This is all in despite of the UK pig industry outlining the huge benefits to weaner gut health and the campaign for a reversal of the planned reductions.

“Zinc oxide when administered at 1,000 to 3,000 mg/kg in the first two weeks of a piglet’s life, is proven to help reduce the risk of post weaning diarrhoea (PWD) by 65%. This is in part a direct result of the improved function of the intestinal barrier and gut immune system,” explains Dr Jagger.

Recent research has outlined that PWD could be responsible for up to 25% of piglet mortality rates, costing up to £250 per sow.

“This reiterates the importance of keeping on top of the disease, and highlights the fact that the removal of this beneficial additive from diets could cause a damaging effect to the industry, pig performance and growth rates.

“There is also the risk that it will increase antibiotic usage which is the opposite of what we are trying to achieve as an industry,” he adds.

Will copper be safe?

Copper is currently added to feed at a level of 15 mg/kg to meet nutritional requirements. This level can be increased within the first 12 weeks of age to a level of 160 mg/kg, which is proven to have beneficial effects on growth and gut health.

Although copper has not yet been restricted, talks over decreasing this higher level of copper are ongoing in Europe.

“When copper is fed at the higher level in young piglets, it can help to reduce PWD, improve growth rates and reduce the need for antibiotic use. Without its use, producers could see a 40g reduction in growth rate, up to 12 weeks of age, and impaired gut health,” he adds.

“It’s all about timing now really, we are just waiting to hear when the use of the ingredient will be tightened up. The debate is now by how much and when, rather than if it will happen, despite the efforts of the industry to campaign against this.”

Research into alternatives

ABN, alongside other companies has been proactively considering nutritional alternatives to prepare for these imminent changes, and ensure that producers can continue to raise healthy pigs within a profitable margin.

“Since the copper issue has arisen, we have initiated a trial at the University of Leeds, which is using weaned pigs to try to establish the benefits of acidification in low copper diets on gut health and performance,” explains Dr Jagger.

“Secondly, we have been running a trial with our customers looking at the effect of probiotics on growth performance and health of pigs, from weaning to 55 days of age, compared with diets containing zinc oxide.

“The results of these studies will give us valuable insight which will allow us to advise and support customers through these potential changes.

“In addition, published work has looked at the effect of benzoic acid in pig diets and has found that it’s able to deliver a similar level of performance as diets containing higher copper levels.

“The research demonstrated that it’s possible to lower the content of copper in feed for weaned pigs to between 20 and 30 mg/kg, with the same beneficial effect to gut health as diets containing copper at 160 mg/kg, provided that benzoic acid is added to the feed,” he explains.

Considering this, ABN has increased the acid level of their weaner ration to offer customers protection from the uncertainty ahead, alongside offering high performance feed with specialist diet design.

“Although trials have demonstrated the potential for some acids to replace the role of copper, it is unlikely that acid will be able to replace high levels of copper in all circumstances.

“Acid cannot substitute the direct effects of copper or indeed zinc oxide on the metabolism of the animal, as it’s a different mode of action. It can however, protect the gut to reduce infection,” he explains.

Antibiotics

Antibiotics were the first port of call to help overcome PWD in the weaner stage to improve the welfare of the pig and also maintain performance. However, with environmental and human health concerns, continuous work into alternative nutritional additives is required.

“At ABN, we have been actively involved in the evaluation of alternatives to antibiotics since the ban on antibiotic growth promoters at the end of 2005, which has taken place at universities, research institutes and directly with our customers.

“Some of our customers have simply removed antibiotics altogether from their herd to establish the effects, and others have altered their management practices, such as increasing weaning age, to ensure a stronger pig at weaning.

“However, one of the main concerns when antibiotics are removed from a herd is that a ‘honeymoon period’ will occur. In this period, no negative effects will be visible, but after a few months the disease level may build-up again, causing problems, which is something that needs to be monitored and managed.

“To help reduce the need for antibiotics and improve health, we are not going to find a single solution, nothing will just replace copper, zinc or antibiotics. We need to be proactive and continue industry research in order to improve gut health and performance, through nutrition,” says Dr Jagger.

“We’re heading in the right direction, but there is still much more to be done to continue to find effective alternatives. This is why it’s important that companies such as ABN, continue to work with producers and scientists in order to offer stability to the industry, in light of future reductions.

“It’s therefore important that we’re open to change, and committed to making continual improvements to our diets for the industry,” he adds.