BLOGS > UNIVERSITY RESEARCH: ANTIBACTERIAL EFFECTS OF OLUS®C12

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UNIVERSITY RESEARCH: ANTIBACTERIAL EFFECTS OF OLUS®C12

20/10/2025 Pigs Poultry

Glycerol monolaurin is a monoglyceride with strong antibacterial effects, mainly against Gram positive bacteria like Staphylococcus spp., Enterococcus faecalis, and Clostridium perfringens, while being less effective against Gram negative bacteria like E. coli and Salmonella spp.

Glycerol monolaurin is the active ingredient of Olus®C12, which is used to improve intestinal health by controlling the growth of potential pathogens in the small intestine of monogastric animals. In this in vitro experiment, the minimal inhibitory concentration of Olus®C12 was determined at NPChemBio Co., Ltd. in South Korea.

Materials & methods

  • Olus®C12 90% was dissolved in 99.9% ethanol prior to use.
  • Each of three bacteria (Streptococcus pneumoniae, Staphylococcus aureus and Clostridium perfringens) were inoculated onto a tryptic soy agar plate and incubated for 24h at 37°C. Single colonies were harvested and inoculated into a tryptic soy broth and incubated for 24h at 37°C. Bacterial growth was assessed by measuring the optical density (OD) at 600 nm using a spectrophotometer. A bacterial suspension was prepared by adjusting the culture to approx. 5×105 CFU/mL.
  • The test sample with Olus®C12 was serially two-fold diluted. 96 μL broth and 4 μL of the diluted sample were mixed and added to the wells of a 96-well microtiter plate. Streptomycin (10 μg/mL) was used as positive control, and 4 μL ethanol (without the test material) as negative control. Wells with only broth without bacteria or test material were used as blanks for OD correction. The microtiter plates were incubated for 24h at 37°C. After incubation, the contents of each well were thoroughly mixed to resuspend the bacteria, and the OD was measured at 600 nm. Finally, the OD values were corrected for the blank, and used to calculate bacterial growth inhibition. The minimum inhibitory concentration (MIC) is defined as the lowest concentration that achieves 100% growth inhibition.

In vitro results showing the effect of Elan®C12 on three bacterial species: Streptococcus pneumoniae, Staphylococcus aureus, and Clostridium perfringens.

* Product name updated from Elan® to Olus®.

In each bar graph, the positive control is given in green. Bacterial growth inhibition is shown, starting with the highest concentration of Olus®C12 at the right hand side of the bar graph, whereas the concentration is halved with each bar moving to the left. The lowest concentration that achieves full growth inhibition is the MIC value.

 

Results

Each test revealed a clear inhibition curve: the higher the concentration, the stronger the effect.

  • Clostridium perfringens: 99% inhibition at 35 µg/mL.
  • Streptococcus pneumoniae: 99% inhibition at 8.75 µg/mL.
  • Staphylococcus aureus: 99% inhibition at 20 µg/mL.

These MIC values are referring to the Olus®C12 product (90% GML concentration) that was used as the test substance. No MIC values could be determined for Salmonella gallinarum, Salmonella typhymurium and E.coli, up to the highest concentration tested of 70 μg/mL, 70 μg/mL and 1.48 mg/mL. Therefore, no results are reported on these Gram negative bacteria.

 

Practical relevance

Based on these MIC values, it can be calculated that a dietary dose level of Olus®C12 60% of 500 g/ton feed (i.e. 300 μg GML/mL) is adequate to limit growth of these Gram positive bacteria in the intestinal tract (assuming a water to feed ratio of 2:1).

 

Conclusion

A dietary dose level of Olus®C12 60% of 500 g/ton feed is adequate to limit growth of Streptococcus pneumoniae, Staphylococcus aureus and Clostridium perfringens in the intestinal tract, whereas no MIC against Gram negative bacteria could be determined.

Learn more about how Olus®C12 can support performance — contact our team today.

 

Professor Jan Dirk van der Klis, man met krullend haar en ronde bril die een zwarte Olus blouse draagt voor een natuurlijke groene wand.About the author

Prof. Jan Dirk van der Klis – Consultant Animal Nutrition

Jan Dirk van der Klis is a renowned poultry consultant with a PhD in Animal Nutrition from Wageningen University. Throughout his career, Jan Dirk has made noteworthy contributions to the industry. With his extensive expertise, he is offering valuable nutritional guidance to enhance the health and productivity of poultry. Jan Dirk’s profound knowledge and experience are pivotal in meeting the specific nutritional requirements of poultry and devising effective feeding strategies to yield optimal results. Since 2019, Jan Dirk has been working with Olus.

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