This was the conclusion from Copenhagen University when they published the results from a large scale-trial with no less than 1.240 piglets. The reason for the positive results is found in the many health benefits that come with feeding solid-state fermentation of rapeseed, which led to the conclusion, that; “Fermented rapeseed is at least as effective as zinc oxide to promote piglet growth, gut development and gut health”.


On a mission to find alternatives to ZnO

The trial purpose was to investigate whether fermented rapeseed could improve growth, gut development and gut health in comparison to non-health promoting protein, namely soyprotein- concentrate (SPC) and soyprotein-concentrate added 2.500 ppm zinc oxide (SPC+2.500 ppm). The feeding regimes started at 28 days of weaning up to 85 days.

Download the scientific paper here.

Growth without ZnO

A widely known concern within pig production is an expected loss in growth when zinc oxide is banned in 2022 by the EU, but the trial shows, that pig producers need not worry. The trial demonstrated that growth could be maintained and for some even increased when zinc oxide is removed from the feed and replaced by the fermented rapeseed protein.  

Mette O. Nielsen, Professor at Aarhus University, expected growth to be reduced when replacing ZnO with fermented rapeseed; “We were counting on a small loss in the average daily growth due to a high concentration of fiber in the rapeseed products, but instead we reported a higher growth rate”. 

Fermented rapeseed improved the growth by 600 grams compared to the zinc-diet and 2,4 kilos compared to the SPC-diet alone. 

Gut health development

A healthy gut equals good overall health. Gut health is measured by the gut’s ability to absorb and utilize feed. It’s also a prerequisite to have a diverse composition of gut bacteria without domination of pathogenic bacteria.

The zinc diet and the fermented rapeseed diet both improved the guts’ ability to absorb nutrients (measured on the length of the gut villi and crypt depths) compared to SPC. The very same diets positively affected the diversity of the gut bacterial flora of the piglets compared to SPC. 

Read about the Danish multiplier, who phased out zinc oxide several years ago. 

Gut inflammation detected in ZnO-pigs

Another critical parameter when evaluation piglet health is the density of the gut barrier (mucosa) The barriers most crucial task is to protect the piglet from bacteria entering the bloodstream and a thick and dense one, leaves the piglet more protected. A vital health measure as the condition of the gut barrier is decisive for how well the immune system works. The experiment also measured the development of the piglets’ immune system across the three diets (measured on GALT-structure in the gut).    

The trial showed that piglets feed with fermented rapeseed had an increase of density and thickness of the gut barrier and an 8-fold increase in the development of the immune system compared to both ZnO-piglets and SPC-piglets. The scientists concluded that the ZnO-piglets had no development of the immune system whatsoever.

On a scale from normal to severe gut inflammation, both the ZnO-piglets (SPC+2.500 ppm zinc) and SPC-piglets (SPC) had slight to moderate gut inflammation (measured on the presence of SL-infiltration). In contrast, piglets fed with fermented rapeseed were diagnosed as normal. 

“Most of our customers are surprised that medicinal zinc in high doses harms the development of a functional immune system and even causes gut inflammation. Production-wise it means that there are unexploited possibilities to improve gut health and well-being when producing zinc-free pigs. An advantage resulting in more resilient piglet with higher growth for many of our customers”, says Jens Legarth, CEO of European Protein.

Download table here

Table: Comparison of effects when using medicinal zink or fermented rapeseed (EP100i)

Source: Gizaw D. Satessa et al., Impact of Dietary Supplementation of Lactic Acid Bacteria Fermented Rapeseed with or without Macroalgae on Performance and Health of Piglets Following Omission of Medicinal Zinc from Weaner, Animals, 2020, 10(1),137′


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A new Danish EU-funded sow trial will determine why sows fed lacto-fermented seaweed become more healthy and productive. Read all about the trial here.


European Protein is a Danish family-owned protein producer. We work to promote health and productivity for animals through functional and sustainable plant proteins. The company was founded in 2011 and has protein factories in Denmark, Ukraine and the US.

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