Key issues in designing feed for antibiotic-free pork

The threat of growing antibiotic resistance in bacteria, combined with increased demand for meat showing ‘healthy’ attributes, has meant a significant impetus for antibiotic-free pork production. It moved from being rare to becoming a significant niche market. To give an example, the French animal nutrition company Sanders, produced 105,000 finisher pigs for dedicated antibiotic-free markets in 2016, and the plan for 2017 is to increase to 155,000 and even 200,000 in 2018.

Adequate nutrition represents only a part of the success in such a project; breeding stock quality, buildings and equipment, farm management, health control and development of human resources need to be associated into an improved feeding programme in order to develop robust antibiotic-free production system.

Current practical experiences point out 2 key issues in practice:

• health issues for young animals remain the number one cause of failure to comply with antibiotic-free specifications; and,
• in order to prevent health disorders in the pig, everything starts with the dam

Immunity transfer to offspring

Immunity transfer from sows to offspring is well-known and well documented. Adequate vaccination schedules and sow feed design will improve the transfer of immunoglobulins to the piglet through improved colostrum composition and milk production. It is, however, difficult to assess sow health status on farm. Before becoming ill, sows usually don’t show any obvious signals of discomfort or difficulties in adapting to immune challenges.

Therefore, there are still many question marks in understanding how sow health improvement affects offspring health and performance. Through the example of solving acute neonatal diarrhoea, the role of sow health has slowly become a bit clearer. Most neonatal diarrhoea outbreaks involve known pathogens (e.g. E. coli, C. perfringens, C. difficile, porcine rotavirus). They are more frequent in litters from young sows.

In many farms, despite increased efforts in hygiene management and vaccination, recurrent diarrhoea persists for a long time. In these situations, changes in feed design and sow feeding management, especially in the days around farrowing, often reduce the severity of diarrhoea in the litter to a third when measured in duration. In addition, these approaches prevent nearly all recurrence. This is related to changes in the microbial profile of sow faeces, with less excretion of pathogens and endotoxins in the farrowing crate and with appeased inflammatory status of the dam, associated to improved nursing quality (nursing behaviour and milk production).

Piglets with fewer days of diarrhoea exhibit higher growth rate until weaning. Upgrading sow feed is one key factor of success in antibiotic-free pork production. More research, however, is needed to help decision makers be confident in such an investment.

Antibiotics and weaning piglets

The weaning piglet has long attracted the attention when antibiotic usage is the subject. In order to reduce digestive disorders, it is common sense nowadays to consider that the piglet should recover its nutrient intake as fast as possible after weaning.

Diets with a high nutrient density, however, fail at maximising this goal. In order to stimulate eating behaviour, it is essential to allow the gut to function and the easiest way to do it is to have the gut filled with feed material. Ingredients improving the feed structure and selected source of plant fibre can help achieve this goal.

In order to compensate for the inclusion of fibre-rich products, selecting palatable ingredients and adapting the nutrient profile of the feed are critical to reach adequate amounts of digestible nutrient intakes. In addition, in order to improve feed structure to stimulate eating behaviour, combining coarse mash and pellets in the feed provided to the piglet around weaning, has proven to be successful. When offered to the piglet around the weaning period, feed efficiency is not degraded as improved gut function compensates for the mash form of half the diet (see Table 1).

Following basic rules

Of course, following the basic rules of piglet diet design remains crucial: to start with a careful selection of raw materials. In addition to this, crude protein levels have to be maintained as low as possible in order to prevent protein fermentation in the gut, and functional additives and ingredients to help controlling pathogens in the gut are mandatory to support gut health.

A veterinary prescription of registered pharma-grade zinc oxide (ZnO) is possible these days; its future opportunities may be rather limited, as ZnO has been associated with increased antibiotic resistance transfer in bacteria. All of this points in the direction of a smart selection of raw materials and a combination of organic acids.

It is useful to stabilise gut microflora with probiotics, and to support the gut barrier with antioxidant activities and ingredient modulating the inflammatory response. This can be achieved through an intensive selection process of ingredients, involving research trials in controlled clean and challenged conditions and large-scale field comparisons. Considering the consequences of combining the additives and ingredient is crucial for controlling the feed cost.

Vectorising key additives

Researchers at Mixscience found opportunities to ‘vectorise’ key additives: this means taking opportunities of existing synergies between ingredients, carriers and coaters, combining formulation and proprietary technology to produce the Vstar range of products included in feed solutions. When applied to organic acids or zinc oxide, for example, more potent forms of the active ingredients can be incorporated into the piglet feed.

Not relying on therapeuticals in pig production implies strengthening disease prevention and being fast and accurate at detecting challenges to counteract disease evolution. Progress is expected from Precision Livestock Farming applied to raising antibiotic-free pigs in the future.

Continuous collection of information from the barn, and adequate real-time data analysis, should be connected to the feeding equipment, in order to deliver the best feed to the pigs based on their status. Which are the relevant information pieces to capture? How fast can this information be processed and summarised? What could be the consequences on production cost? Plenty of practical questions remain to be addressed in future research projects.