Organic acids are also preservatives with antimicrobial activity. In addition, it helps the digestibility of the feed by maintaining the microbiota balance in a positive way and supports intestinal health. Organic acids are widely used in livestock to maintain animal welfare by promoting the prevention of excessive bacterial growth; and quality assurance of raw materials, feed and drinking water.
Focus on challenges
Especially in post-weaning diets, the main goal is to focus on challenges. During weaning, piglets cannot produce enough endogenous hydrochloric acid to maintain a low stomach pH. This low stomach pH is necessary for 2 important reasons. The first is the creation of a natural barrier against bacteria entering the gastrointestinal tract. The second is the pre-digestion of protein by activating the enzyme pepsin, which takes place only at a low pH.
These difficulties are created by environmental changes (which cause stress) when the piglet is separated from the sow and regrouped with different offspring, and the physiological change from weaning to a solid, less digestible diet.
In the past, antibiotics were used as the main strategy to overcome the post-weaning stage. Recently, with the increasing interest in the use of antibiotics, alternative solutions have started to attract more attention.
Organic acids as alternative solution
Organic acids can play a role as part of these alternative solutions to antibiotic use. They can do this in the gut in 2 different ways. First, certain organic acids are known to lower the stomach pH of piglets, facilitating an easier passage during weaning, leading to conditions unfavorable for the growth of potentially harmful bacteria and favorable for beneficial bacteria such as lactobacilli and bifidobacteria.
Secondly, the bacteriostatic and bactericidal effects of organic acids play an important role in supporting animal welfare. The correct inclusion and combination of the acid mixture will play an important role in its effectiveness. For example, combining short chain fatty acids (SCFA) with medium chain fatty acids (MCFA) targets different bacteria in the gastrointestinal tract.
Pathogenic gram negative bacteria
SCFA can affect pathogenic gram negative bacteria like Escherichia coli, salmonella, klebsiella and Enterobacteriaceae passing through the bacterial cell membrane in the undissociated or neutrally charged state. Once inside the bacterium, they decompose in an alkaline environment. This leads to increased osmotic stress and activation of proton pumps that will eventually deplete the bacteria.
Pathogenic gram positive bacteria
in terms of pathogenic gram positive bacterialike clostridium, staphylococci and streptococci, MCFA penetrates the bacterial cell membrane, causing it to break down and also reduces the bacteria’s energy production.
Experiment with a mixture of 2 acids
Wisium, ADM’s premix and service brand, has created a complete portfolio of organic acid solutions called Acidulik. Under this portfolio, a series of solutions called Acidu’fit have been formulated to help maintain a balanced microflora that can be used in water or feed at different stages of animal production.
In a trial conducted in the Netherlands (cf. table 1), the performance of 2 batches from the second stage of weaning (20-40 kg) was compared with these acid mixtures. The control group was given a control diet consisting of formic and lactic acids. The treated group received a combination of organic acids and an SCFA consisting of 90% lauric acid and glycerol monolaurate (GML).
As you can see table 1The group treated with organic acid plus SCFA had a numerical improvement in mean daily gain and feed conversion ratio. The mixture of lauric acids and GML inhibits the pathogenic microbial flora. This results in more nutrients being available for animal growth. Although GML is rapidly hydrolyzed by bacteria, lauric acid is metabolized slowly. Therefore, it resides in the gastrointestinal tract for a longer period of time.
In summary, by combining different organic acids using SCFA and MCFA, it is possible to streamline the process to achieve a more complete pH lowering and improve feed digestion, avoid pathogenic bacteria and provide a safe start for piglets.
References on request.