TY - JOUR
T1 - In vitro susceptibility of swine pathogens to feed additives and active ingredients with potential as antibiotic replacements
AU - Neath, Charlotte
AU - Portocarero, Naheeda
AU - Jones, Cerith
N1 - This article is protected by copyright. All rights reserved.
PY - 2021/12/16
Y1 - 2021/12/16
N2 - Aims: The rise in antibiotic resistance requires the reduction of antibiotic use in all sectors. In animal production, many commercial alternatives to antibiotics have been developed for incorporation into feeds, but a lack of evidence on their antibacterial activity limits confidence in their application. We aim to compare the antibacterial activity of feed additives and active ingredients to better understand their usefulness. Methods and Results: The antibacterial activity of 34 active ingredients and feed additives, including medium- and short-chain organic acids and essential oils, was tested against pure cultures of five bacterial swine pathogens. Antibacterial activity was observed using an agar plug diffusion method and quantified via broth microdilution. A diverse range of antibacterial activities were observed. The highest inhibitory activity against Staphylococcus aureus and Streptococcus suis was exhibited by the C12 monoglyceride (0.49 mg ml
−1). The monoglyceride of C12 was more effective than C12:0 against Strep. suis, but neither C12:0 nor its monoglyceride showed efficacy against the gram-negative micro-organisms tested. The most active against Escherichia coli were the C6:0 medium-chain organic acids and potassium diformate (1.95 mg ml
−1). For Salmonella Typhimurium, potassium diformate, sodium diformate, and a blend of C8:0/C10:0 (each 1.96 mg ml
−1), and for Actinobacillus pleuropneumoniae, eugenol (0.49 mg ml
−1) showed the most promising activity. Conclusions: We identified broad-spectrum antibacterial activity, such as the C6:0 MCOA, and those with interesting narrow-spectrum activity, notably the killing of Strep. suis by C12 monoglyceride. We have identified additives that show the most promising bioactivity against specific pathogens. Significance and Impact of the study: We broadly compare a large collection of feed additives and active ingredients for their antibacterial activity against a diverse panel of bacterial swine pathogens. This provides a solid base of evidence which can drive the development of feed supplementation strategies with the aim of reducing dependency on antibiotic use in swine production.
AB - Aims: The rise in antibiotic resistance requires the reduction of antibiotic use in all sectors. In animal production, many commercial alternatives to antibiotics have been developed for incorporation into feeds, but a lack of evidence on their antibacterial activity limits confidence in their application. We aim to compare the antibacterial activity of feed additives and active ingredients to better understand their usefulness. Methods and Results: The antibacterial activity of 34 active ingredients and feed additives, including medium- and short-chain organic acids and essential oils, was tested against pure cultures of five bacterial swine pathogens. Antibacterial activity was observed using an agar plug diffusion method and quantified via broth microdilution. A diverse range of antibacterial activities were observed. The highest inhibitory activity against Staphylococcus aureus and Streptococcus suis was exhibited by the C12 monoglyceride (0.49 mg ml
−1). The monoglyceride of C12 was more effective than C12:0 against Strep. suis, but neither C12:0 nor its monoglyceride showed efficacy against the gram-negative micro-organisms tested. The most active against Escherichia coli were the C6:0 medium-chain organic acids and potassium diformate (1.95 mg ml
−1). For Salmonella Typhimurium, potassium diformate, sodium diformate, and a blend of C8:0/C10:0 (each 1.96 mg ml
−1), and for Actinobacillus pleuropneumoniae, eugenol (0.49 mg ml
−1) showed the most promising activity. Conclusions: We identified broad-spectrum antibacterial activity, such as the C6:0 MCOA, and those with interesting narrow-spectrum activity, notably the killing of Strep. suis by C12 monoglyceride. We have identified additives that show the most promising bioactivity against specific pathogens. Significance and Impact of the study: We broadly compare a large collection of feed additives and active ingredients for their antibacterial activity against a diverse panel of bacterial swine pathogens. This provides a solid base of evidence which can drive the development of feed supplementation strategies with the aim of reducing dependency on antibiotic use in swine production.
KW - Swine pathogens
KW - Pigs
KW - Antimicrobial Feed additives
KW - Streptococcus suis
KW - Escherichia coli
KW - Salmonella Typhimurium
KW - Staphylococcus aureus
KW - Actinobacillus pleuropneumoniae
U2 - 10.1111/jam.15318
DO - 10.1111/jam.15318
M3 - Article
C2 - 34608714
VL - 132
SP - 1713
EP - 1723
JO - Journal of Applied Microbiology
JF - Journal of Applied Microbiology
SN - 1364-5072
IS - 3
M1 - 15318
ER -