One of the PIGgest challenges: PWD

Farmers are getting worried; the legal restrictions on using the antibiotic agent Colistin are becoming more of a reality – and not only in the EU. In 2016, China banned Colistin in livestock production, where it was used as a feed additive to improve growth and to prevent GI-tract issues like post-weaning diarrhoea (PWD). There is now a fear of increasing losses and rising medication costs. This fear is warranted as in the EU, almost every fourth piglet is estimated to be affected by PWD.

Colistin, which was used as feed additive to improve growth and to prevent GI-tract issues like post-weaning diarrhoea (PWD) was banned in China in 2016. In addition to the use of Colistin, adding zinc oxide (ZnO) to the diets used to be a common practice for counteracting PWD. ZnO is licensed for treatment and control of PWD for the doses of 2.5 g/kg feed for 14 days post-weaning. Although ZnO used at pharmacological levels reduces PWD, there is evidence for a stimulation of antibiotic resistance as well as environmental concerns due to high levels of excreted ZnO. However, as ZnO will be banned in the EU by 2022, alternative methods for protecting the animals from PWD are required.

Concurrently, animal welfare is gaining attention. Both consumers and producers have a strong demand for healthy animals to obtain safe, natural and high-quality products. To achieve these goals, the intestinal tract is the premier site which needs to be influenced. It is the most exposed surface within the body and sensitive for disruption during the initial post-weaning period and other stress periods. The gut mucosa as a selective barrier acts as first line of defence against pathogenic agents responsible for PWD, e.g. toxin producing E. coli. Therefore, a healthy gut is an effective digestive and defensive organ, supplying the animal with nutrients and protection against enteric diseases. Solutions to enhance gut health are necessary to support piglets in their early life.

Solutions to enhance gut health are necessary to support piglets in their early life. Photo: Werner Dedl

Protect piglets from weaning challenges

During weaning and the 10-14 days after, piglets face major challenges. It’s a race against time: the piglet is separated from its mother, put into a new environment with new pen mates and less digestible feed. At the same time, its digestive tract and immune system are not sufficiently developed yet to cope with all these stressors. The intestinal mucosa is prone to damage, the feed intake decreases and the growth rate drops, while present pathogens threaten to induce infections, with PWD being most important during this critical time. PWD is characterised by watery diarrhoea, dehydration, loss of body weight and high mortality. Loss in growth performance and requirement for (antibiotic) medication are resulting in a loss of profit for the farmer. Although there is no full replacement for antibiotics and ZnO available yet, several strategies are utilised to support piglets during weaning. These include optimisation of diets according to the animals’ requirements (e.g. high digestible raw materials for young animals) and to supplement feed additives.

A promising approach to counter weaning-associated problems, especially PWD, is the supplementation of specific phytogenic feed additives (PFA). Plant-based, natural feed additives are in high demand and comprise various active ingredients. These active ingredients have a wide range of modes of action to support piglet health in a natural way: by stimulating immune functions, improving the intestinal barrier or reducing the adherence factors of pathogens.

Natural solution on different levels

As weaning challenges are complex, strengthening only a single factor of the animals’ health is not enough to prevent PWD and support piglets during weaning. In other words, the piglet needs protection from different angles: the sensitive intestinal wall must be protected from adherence of pathogens and bacterial overgrowth, excessive oxidative and inflammatory processes must be prevented, and the animal defence should be strengthened from inside out.

Designing a PFA to support gut integrity, reduce microbial pathogenicity, and stabilise the intestinal microbiota in post-weaning piglets requires a careful selection of several phytogenic compounds such as flavonoids, essential oils and mucilages. To face the multitude of problems, the PFA supports the animal on three different levels: On the first level, the gut mucosa is protected by a fine film of phytogenic mucilages, preventing adhesion of pathogens like E. coli. On the second level, a specific synergistic effect of the ingredients reduces pathogenicity of intestinal bacteria via Quorum Sensing Inhibition (QSI). QSI is the disruption of bacterial communication pathways, leading to a lower concentration of pathogenic virulence factors, e.g. reduced expression of fimbriae (= reduced adhesion of E. coli to mucosal cells) and suppression of bacterial toxin production. On the third level, the ingredients provide strong anti-oxidative and anti-inflammatory effects, mediated via upregulation of anti-oxidative and anti-inflammatory enzymes as well as direct scavenging of reactive oxygen species. Thus, in addition, the integrity of the intestinal mucosa is strengthened by reduced cell turnover. A high performance is supported from different angles, as a healthy intestinal wall increases nutrient uptake.

Figure 1 – Effect of a phytogenic feed additive on the incidence of diarrhoea and medication in post-weaning piglets.

Healthy animal – better performance

A field trial was conducted on a commercial farm in Germany with a permanent occurrence of E. coli-associated PWD. 800 post-weaning barrows and gilts (Danbreed x Piétrain) were allocated randomly to 32 identical pens with 25 weaners per pen (16 repetitions per treatment group), receiving either an unsupplemented feed (control) or the same basal feed supplemented with a specific PFA (Fresta Protect). Addition of the PFA reduced the incidence of PWD by 31% and usage of medication by 45% compared to the control group (Figure 1), therefore representing substantial savings on medical expenses for the farmer. A summary of three trials indicates an increased performance in post-weaning piglets (Figure 2).

Figure 2 – Effect of a phytogenic feed additive on growth performance of post-weaning piglets.

References available upon request

Author: Anne Oberdorf Technical Communications, Delacon Biotechnik, Austria