#17-049

Complete

Date Full Report Received

06/11/2018

Date Abstract Report Received

06/11/2018

Research has demonstrated that medium chain fatty acids (MCFA) can serve as reduction strategies for bacterial and viral pathogens in animal feed and ingredients. However, it is unknown how the type or level of MCFA impact bacteria growth. Furthermore, it is not known if MCFA can serve as an antibiotic alternative to therapeutic doses of antibiotic used in the swine industry. The objective of this study was to assess the role of medium chain fatty acids as an alternative to medically important antibiotics by 1) evaluating fatty acid concentrations of commercially-available or based MCFA products and evaluation of bactericidal activity through the development of a low-cost benchtop model and 2) compare the efficacy of MCFA vs. therapeutic chlortetracycline supplementation in feed for disease-challenged pigs.

From the first objective, it was determined that the MIC of MCFA varied among bacteria species. The lowest MIC of the MCFA was 0.43% of a 1:1:1 blend of C6:0, C8:0, and C10:0 for Campylobacter coli, 0.25% C12:0 for Clostridium perfringens, 0.60% 1:1:1 blend for generic Escherichia coli, 0.53% C6:0 for ETEC, and 0.40% C6:0 for Salmonella Typhimurium. It was also noted that the commercially based product containing higher concentrations of C6:0 or C8:0 had lower MIC in gram negative bacteria.

For the second objective, 100 entire male pigs (initially 14.1 ± 1.6 lb BW and weaned at 22 days of age) were used in a 29-day disease challenge study. Pigs were allowed 5 acclimation days, followed by 2 days of disease challenge with enterotoxigenic β-hemolytic Escherichia. coli, serotype O149:K91: K88 (ETEC). After the challenge, pigs were allotted to a diet with 1 of 5 treatments: 1) Control with no additives, 2) 400 g/ton CTC (Chlortet 200G, Eco Animal Health, London, United Kingdom), 3) 1.08% of a 1:1:1 blend of C6:0, C8:0, and C10:0 (Nuscience Group, Drongen, Belgium), 4) 3.93% developmental Product A (Nuscience Group, Drongen, Belgium), and 5) 1.04% developmental Product B (Kemin Industries, Des Moines, IA). Treatments 3, 4, and 5 were included at rates to derive a 1% MCFA concentration in finished feed. Pigs were fed treatment diets for 14 days following the disease challenge to mimic a therapeutic dose of CTC and fed a common diet from d 14 to 21. There was no effect of dietary treatment on growth performance form d 0 to 7 or d 14 to 21. From d 7 to 14, pigs fed diets supplemented with CTC, 1:1:1 blend, or Product B had improved F:G compared to those fed the control diet.
Pigs fed diets with CTC had increased fecal shedding of ETEC from d 7 to 14, while those fed diets with Product B having less fecal ETEC shedding on d 1 compared to d 14. While other disease markers, such as fecal score, plasma urea nitrogen, and haptoglobin, decreased with time, they were not affected by dietary treatment.

Overall, the inhibitory efficacy of MCFA varies among bacteria species. This suggest that MCFA mixtures may provide a wider spectrum of bacterial control. It was also noted that supplementing ETEC-challenged nursery pigs with MCFA-based dietary treatments led to similar growth performance as a therapeutic dose of 400 g/ton of CTC. As commercial products containing MCFA become available for livestock, it is important to consider the interaction between MCFA chain length and concentration on the potential to effectively mitigate various feed-based bacteria.