Feed additives

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Replacing antibiotics and ZnO in weaning piglets

Recent reports are highlighting the effect on resistance to ZnO and the ecological impact zinc can cause next to the fact that zinc is contributing to antibiotic resistance. Good animal health right from the beginning will be more important than ever and will need a multifactorial approach.

Since the EU-ban on the use of antibiotics as growth promotor, other continents are following this example. China has recently banned colistin and the US Food and Drug Administration presented new federal rules in which all 31 antibiotics for growth promotion would completely be withdrawn.

As a consequence the use of antibiotics in animal rearing is under a lot of pressure, fearing for the economic profitability of the business. On top of that the EU recently decided to ban the use of medicinal zinc oxide as a control measure for weaning diarrhoea. A transition period of 5 years has been foreseen. All EU member states can decide for themselves when to ban ZnO, which might speed up the process as countries will not want to be seen as last to eliminate ZnO in the public opinion.

Studies confirm that the gut barrier function is rapidly affected within 24 hours after weaning. Photo: Henk Riswick
Studies confirm that the gut barrier function is rapidly affected within 24 hours after weaning. Photo: Henk Riswick

Weaning stressors

Postma et al., recently highlighted the importance of good managing practices on the farm, improved biosecurity, optimised vaccination and clever use of antimicrobials, resulting in a significant reduction of 52% antimicrobials from birth to slaughter. Weaning is one of the most stressful situations in a pig’s life with not only environmental stressors such as a change in temperature and stable environment and psychological stressors such as new littermates and a new to be established hierarchy. Also nutritional stressors such as reduced sow-milk and the change to a vegetable diet with exposure to antinutritional factors are important.

All these stressors play a key role in an altered immune system including a reduced gut barrier, clearing the path for pathogens such as Escherichia Coli to provoke diarrhoea. Where piglets in nature are weaned around 10-12 weeks, the current commercial weaning is done at one third of that time. At that moment, the passive immunity originating from the sow is reduced rapidly and building up active immunity is a long-term process. Moreover, increasing litter sizes due to genetic improvement with related problems such as lower birthweight and lower colostrum intake per piglet and are making the challenge even bigger.

Intestinal integrity under pressure

Studies confirm that the gut barrier function is rapidly affected within 24 hours after weaning. It will take several weeks before it is partially restored, because the systems regulating the intestinal barrier are altered for a longer period then just post-weaning. 2 important measures for the intestinal barrier function or barrier integrity are the trans layer specific electrical resistance measurement (TER/TEER) and apparent paracellular permeability coefficient (APP). The higher the electrical resistance (TER) of the barrier, the better its integrity and functionality.

The paracellular permeability is measured by the transport of fluorescein isothiocyanate (FITC) dextrans. The higher the APP value, the lower the paracellular permeability and thus the higher the resistance of the intestinal barrier. As stress factors are present, for example around weaning, the intestinal barrier is lowered and permeability is increased. Table 1 illustrates the effect of induced heat stress on the TER and APP in growing pigs. As a higher intestinal permeability or ‘leaky gut’ is associated with inflammation and increased susceptibility to enteric pathogens, problems such as diarrhoea, streptococcus and oedema disease, are more frequently seen. As the obvious aids such as antibiotics and/or zinc oxide are leaving the shelf at a fast rate due to legislation and public opinion, new approaches in young animal nutrition are inevitable

Start early

Low birth weights and low initial average daily gains induce slow growth in later stages resulting in economic losses. Overall, Lopez Vergé et al. concluded that the lactation and weaning period are most critical toward growth retardation in the pigs life. Getting the piglets to take up colostrum and eat in an early stage limit this effect, as high colostrum intake has a stimulating effect on growth before and after weaning.

A well balanced creep feed, will lead to better adaptation to solid feed intake, as the piglets are stimulated to develop the acid secretion capacity in the stomach and have a better intestinal development to digest vegetable proteins and carbohydrates after weaning, resulting in lower risk of post weaning diarrhoea and higher post-weaning performance.

Getting the piglet to eat early requires special attention to the feed. It is combining highly palatable ingredients, flavourings and taste enhancers as well as incorporating highly digestible ingredients. Next to that appropriate farm management such as correct stable temperature, clean feeders, unlimited access to clean water, etc, are essential to get the maximum out of the provided feed. It is obvious that there is a need for a smooth transition between pre-and post-weaning diets, as this avoids extra stress in an already very critical period.

Total concept needed

As antibiotics are often supplied by water, an underestimated advantage of early feed intake is that at weaning, piglets can take up health supporting additives without problems. It is clear that carefully selected feed formulation does not stand alone. Health supporting additives and good management must be part of the total concept in order to succeed without antibiotics.

Nuscience developed a multifactorial approach to tackle these challenges. The creep feed reference Babito ensures an early feed intake. As every 50g of feed intake before weaning results in 10% higher villus height, the piglet is given a head start. The new prestarter Babi-range offers 3 new feeding lines for modern pig husbandry requiring solutions for different genetics, health status and weaning ages. Babi Delicious is focusing on promoting feed intake, while Babi Robust is focusing on health challenged pigs. The Babi Dynamic lines meets both challenges half way.

Zero-approach

To give an answer to new challenges such as the ban on ZnO at weaning age, Nuscience developed Vitazero, i.e. an exogenous defence shield for weaned piglets. Trials have shown that this concept can replace the use of ZnO and Colistin in the weaning feed.

The concept combines nutritional optimisation with a 5 way exogenous defence shield for early piglet health without antibiotics nor ZnO:

  1. Killing bacteria entering the stomach,
  2. Improving overall immunity,
  3. Maintaining gut barrier function,
  4. Capturing bacteria and toxins,
  5. Blocking endotoxins from binding on intestinal receptors.

A specific combination of short and medium chain fatty acids (MCFAs) kills pathogenic bacteria and regulates the intestinal flora. Purified medium chain fatty acids (Aromabiotic) have proven positive effects like a high antimicrobial activity, increased villus/crypt ratio and improved overall immunity. A synergistic mixture of natural anti-oxidants will lower the intestinal permeability and maintain the gut barrier (Figure 1).

A unique sophisticated fibre concept with multiple modes of action is included in Vitazero. Gram- bacteria can remain toxic even after kill off, as their outer cell membrane consists to a great extent out of lipopolysaccharides or LPS. Vitazero will protect the receptors on the intestinal wall (Figure 2). In that way, redundant immune response reactions are being avoided. This unique fibre concept also binds pathogens in the intestine to create a wash out effect. Bacteria are being agglutinated and excreted lowering the infection pressure in the intestine.

In general, it can be concluded that replacing antimicrobials and ZnO demands a multifactorial approach. Managerial excellence one the farm remains one of the key aspects together with nutritional expertise to be able to encounter the new challenges on our path.

References available on request

Author: Bart Matton, product manager pigs N4U, Nuscience

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