Development of antibiotic resistance and options to replace antimicrobials in animal diets

Abstract

, fax +45 89 99 13 78, email KnudErik. BachKnudsen@agrsci.dk As there is a risk of developing antibiotic resistance, a number of commonly-used antimicrobial growth promoters have been banned in the EU member states. This decision has put new emphasis on using the diet to control enteric bacterial infections of pigs. Dietary carbohydrates constitute a major proportion of diets for pigs, and the carbohydrate fraction has a diverse composition, with different properties in the gastrointestinal tract, some of which are of importance to gut health. Findings from different studies indicate that dietary carbohydrate composition influences the expression of swine dysentery and infection with nematode worms after experimental challenge with Brachyspira hyodesenteriae and Oesophagostumum dentatum respectively. In both cases the type, amount and physico-chemical properties of the carbohydrates entering the large intestine played an important role in the infection, and emerging data suggest a synergism between different porcine pathogens. There is also increasing evidence that the feed structure, which relates to the type of plant material in the diet and the way it is processed, can be used to reduce Salmonella prevalence at the herd level. However, it should be stressed that using the diet to manage gut health is not straightforward, since the expression of a pathogen in many cases requires the presence of other components of the commensal biota.

Antimicrobial use in swine production and its effect on the swine gut microbiota and antimicrobial resistance

“…All bacteria found in the swine intestinal tract, however, are potentially affected upon consumption of an antimicrobial agent. Antimicrobial growth promoters in particular, tend not to be well absorbed in the gut and can act directly on the microbiota, mainly on Gram-positive bacteria (Erik and Knudsen 2001).…”

Community composition and development of the post-weaning piglet gut microbiome

“…Both practices increase the risk of infections with pathogenic organisms, and thereby the need for antimicrobial strategies, which has included the common use of antibiotics. [2][3][4][5][6][7][8][9][10][11][12] Although antibiotics may kill some pathogens, the surviving bacteria can develop antimicrobial resistance (AMR) against the class of antibiotic used [13][14][15][16][17][18][19][20] , as well as against other antibiotic classes [21][22][23][24][25][26][27][28][29][30][31] . A retrospective U.S. livestock study found evidence of multidrug resistance (resistance to >3 antimicrobial drug classes) in Escherichia coli that increased from 7.2% to 63.6% between the 1950s and the 2000s 32 .…”

Short-chain fructo-oligosaccharides enhances intestinal barrier function by attenuating mucosa inflammation and altering colonic microbiota composition of weaning piglets

“…The growth-promoting effect of antibiotics and zinc oxide likely benefits from the improvement of gut functions and the adjustment of gut microbiota (Smith et al 2002;Xu et al 2018). However, the overuse of antibiotics and zinc oxide has caused severe antibiotic resistance problem and environmental contamination (Erik and Knudsen 2001;Vahjen et al 2015). Therefore, consistent efforts have been made to seek natural substituents of antibiotics and zinc oxide to improve the growth performance of weaning piglets.…”