Good intestinal health for pigs is critical for both performance and profitability. Worldwide trends in raw material availability and quality, production potential of pigs and legislation make a good gut health even more critical. Weaned piglets are especially more vulnerable as litter sizes continue to grow. Drinking water can provide solutions to control gut health in pigs.
Intestinal health is the most determining factor for pig health in general, herd performance and eventually farm profitability. Harmful bacteria like E.coli may colonise in the gastrointestinal tract, resulting in clinical and sub-clinical diseases. Reduced feed intake and daily gain, inactivity and decreased social interactions are all observed in animals with bacterial infections.
Worldwide, there are several trends that draw attention to intestinal health which nowadays is more critical. The first trend relates to raw materials used for animal feed production. In an era of increasing volatility in raw material prices and availability, being able to secure sufficient raw materials of acceptable quality is becoming one of the main challenges for the livestock industry.
In an effort to reduce feed costs and to obtain sufficient feed raw materials, livestock producers are often forced to make use of unconventional protein and carbohydrate sources or materials of lower quality. Furthermore, changing climate conditions, such as extremes in temperature and precipitation or drought have their impact on quality parameters like bacteria counts, yeast and mould prevalence. This means that pigs need to be able to deal with continuously changing diet compositions and qualities which is a risk factor for their health.
Production potential The second trend is seen in the production potential of pigs, which continues to increase due to genetic, management and nutritional improvements. To reach peak performance, pigs need an optimal support.
One of the most important gains observed in recent years is the increase in litter size. Over the last ten years, average litter size increased in total with about three piglets per litter. At the same time, birth weight decreased and the number of small piglets increased which resulted in a negative development for piglet mortality. These trends resulted in more lightweight and vulnerable piglets at weaning. For such piglets control of gut health is more critical. Legislation and society are related to the third trend. Food safety issues like Salmonella are rising on the agenda and use of antibiotics and zinc oxide is increasingly being restricted. The latter means that alternatives are increasingly needed to support gut health and food safety.
Drinking water application Sub-optimal intestinal health may result in sickness behaviour of pigs. During a period of disease, pigs will drop their feed intake; they will, however, maintain their water intake. This makes strategies to control antibacterial issues and to support gut health via drinking water highly interesting. Dosing flexibility is a second important feature of drinking water treatments as dosing may be adjusted at any given moment. In case of healthy animals and stable production, a basic dosage will be sufficient which can easily be increased when gut health is at risk or during periods of stress like weaning, change of diet, vaccinations and mixing of animals.
Where common water treatment products, like chlorine and hydrogen peroxide may offer good water sanitising properties, they do not act inside the animal where gut health support is needed. Organic acids have the ability to clean drinking water in combination with supporting gut health in the animal by improving digestion (reduce pH in the stomach) and having antibacterial effects in the small intestine through buffered acids. After the ban on antibiotics in the EU, organic acids were used as one of the main replacements. Especially blends of free and buffered organic acids fit for an effective antibacterial (E. coli) control in water, stomach and small intestine, see Figure 1.
Characteristics of acids blends Each organic acid has its own physical and chemical characteristics, leading to a specific anti-microbial effect. Combining organic acids in a synergistic blend controls enterobacteria in a broad-spectrum way. Organic acids may also be buffered thereby forming salts in the product. These buffered acids, including ammonium formate, effectively control enterobacteria in the small intestine by the proton-donation properties of ammonium under continuously formation of formic acid. This brings the antibacterial properties into the small intestine of pigs as buffered acids are released with increasing pH.
By combining free and buffered organic acids in a synergistic blend, as done in Selko-pH, it controls microbiota in a broad-spectrum way leading to more effective control at a lower dosage than single acids as reflected in Table 1. In addition, the buffering of acids also changes the behaviour of an acid blend as reflected in Figure 2. Adding free acids like formic or lactic to the drinking water causes a sharp decrease of the water pH. This is limiting the inclusion level as drinking water pH should stay above 3.6 in order to avoid taste deviations and reduced water intakes. By partially buffering an acid blend, the pH decrease in drinking water is less sharp and remains at a higher level. The latter means that products containing buffered acids may be dosed at a higher level, providing pigs with a stronger gut health support.
Pig trials The effect of a synergistic combination of free and buffered organic acids on technical performance of pigs was tested in several studies with piglets, growing pigs and growing/finishing pigs. Figure 3 shows the results for piglets during the first four weeks post weaning which is the most vulnerable period for piglets. Due to higher feed intake as well as a more efficient utilisation piglets receiving the acid blend grew faster. The incidence of diarrhoea was decreased compared to the control, expressing an improved gut health. Benefits were also found during the first weeks in the growing phase (Figure 4) which is another stressful period due to many changes. Pigs receiving the acid blend grew more efficient and faster (Hungarian trial). Organic acids may also be used to control Salmonella. In a large field study on this topic, coordinated by the Dutch Product Boards for Livestock, Meat and Eggs, pigs were followed during the complete growing and finishing phase (40,000 animals). The focus was to reduce Salmonella prevalence at pig farms. At the start all farms had a status 3 reflecting a heavy Salmonella prevalence (level of Salmonella antibodies was measured in blood by an indirect ELISA using optical densities). During the trial period Salmonella prevalence was significantly reduced for the farms bringing the status to score 1 which reflects a low or no infection. In this trial technical performance was improved reflected in both daily gain and feed conversion ratio (FCR), see also Figure 4.
Water applications Worldwide trends in raw material availability and quality, production potential of pigs and legislation make a good gut health more critical. Especially weaned piglets are nowadays more vulnerable. Water application offers an effective route to support intestinal health as pigs maintain their water intake during periods of disease and dosing could be adjusted at any moment. The studies presented demonstrate that a synergistic combination of free and buffered organic acids offer a strong contribution to support gut health and animal performance in piglets, growing and finishing pigs.
By: Jaco Eissen and Evelien van Donselaar, Selko Feed Additives, Tilburg, the Netherlands (firstname.lastname@example.org)