Dietary sodium diformate and glycerine monolaurate affects fecal pathogen load in lactating sows

摘要

Compound feed is not only an effective way of delivering nutrients to animals, but it has long been utilised as a delivery strategy for non-nutritive additives used to promote health. To this end, the industry relied heavily on the use of antibioticsas growth promoters in the feed for decades, until it became clear that the development of bacterial resistance against these compounds could jeopardise their future in the fight against bacterial disease, not onlv in animals, but also in human health care. The search for alternatives became critical around 15 years ago, beginning in Europe, where it led to a ban of antibiotic growth promoters in feed in 2006. It is generally agteed that good gut health is effective against intestinal pathogens, a strategy that has only been made possible through the removal of antibiotic growth promoters in feed. Creating and maintaining a healthy intestinal environment has become essential to productivity and food safety programmes alike. Maintaining a healthy gut requires up to 25% of the daily protein and 20% of the dietary energy supplied with the feed. This strategy should be carefully planned into the dietary programme, to avoid wasting resources. Acidifiers have a long history of safe and effective use in diets for pigs, especially in Europe where their application was pioneered. Meanwhile, experience has shown that acidifiers are the most reliable product group of the non-antibiotic growth promotets available in Europe and can also be used safely and effectively with other additives. Papatsiros and Billinis stated in this regard "...Dictarv acidifiers can actually become the most common andefficacious alternative solution co antibiotics, in order to improve health status and performance in pigs".' In pig diets, organic acids and their salts take effect in the gastrointestinal tract, mainly in the proximal tract - the stomach and small intestine. While pH reduction can inhibit pathogen growth and optimise pepsin activity, it cannot alone account for the numerous benefits reported when organic acids are included in diets for pigs. Supplementing diets with organic acids reduces the pH in the stomach, especially in weaning pigs, where it stimulates the activation of pepsinogen to pepsin and thus may improve protein digestibility and decrease the rate of gastric emptying; further improving protein digestion by increasing the rate of proteolysis of large protein molecules. The bacteriostatic and bactericidal effects of organic acid anions also take effect in the proximal gastrointestinal tract. Here, the differential inhibition of Gram-negative pathogens (e.g. E coli, Salmonella) compared to beneficial bacteria such as lactobacilli and bifidobacteria improve the microbial load (eubiosis) in the tract, preventing post-weaning diarrhea. Several studies have shown that the bactericidal effect of organic acids can still be strong in the absence of a significant decrease in pH. They arc therefore also useful in combating bacterial pathogens in grower-finisher pigs and sows.4 While the antimicrobial impact of organic acids and their salts, including diformates, is mainly directed against Gram-negative bacteria, medium chain fatty acids (C6 to CI2) have been shown to have also an antibacterial impact against various Gram-positive bacteria.' This is especially true for lauric acid and its monoglyceride ester monolaurate.6 Streptococcus suis, a Gram-positive bacterium, is one of the most common harmful bacteria in pig production. It also proliferates in the digestive tract. Most piglets contract the bacteria from the sow during parturition. Thus, decontamination of the sow feces may help in reducing infection. However, data on the combined impact of these additives on gut health in sows under commercial conditions had not yet been generated. This formed the impetus of this trial.