Progres® in ruminants: More propionate with in-feed resin acids

Hannele Kettunen, R&D Manager 

Hankkija’s resin acid-based feed innovation Progres® was promoted at the International Symposium on Ruminant Physiology, ISRP 2019. This event, arranged every four years, is the major international, scientific conference on ruminant physiology. This year, the congress took place at the beautiful city of Leipzig in Germany on September 3-5. Hankkija Oy sponsored a coffee break for the meeting.

The extensive scientific program was divided into several oral presentation sessions and poster sessions. A total of 199 posters were presented at the event, 3 of which came from Hankkija. The posters got a lot of attention from the attendees.

Here below we present one of Hankkija’s posters, with the title “Resin acid composition increases propionate and butyrate production in a Rumen Simulation Technique (RUSITEC) model”, by Kettunen et al. This in vitro simulation study was conducted at the University of Veterinary Medicine Hanover by the research group of Dr. Prof. Gerhard Breves.

Rumen Simulation Technique (RUSITEC) model

In the RUSITEC model, the authentic ruminal microbiota from lactating dairy cows was allowed to digest a typical dairy cow diet, with or without Progres®, for a total of 16 days. The system included a total of six replicate RUSITEC vessels, each with a volume of 800 ml. By sampling the vessels in a time series, the effect of the feed supplement Progres® could be studied in detail. Read the poster below for details and results of this study!

Resin acid composition increases propionate and butyrate production in a Rumen Simulation Technique (RUSITEC) model

Increased ruminal propionate production has been linked to a higher capacity for milk production by lactating dairy cows. Tall oil fatty acid -based resin acid composition (TOFA; Progres®, Hankkija Ltd) is a known microbial modulator and performance enhancer in monogastric farm animals.

Our hypothesis was that TOFA would favorably modulate ruminal bacterial populations and enhance propionate production. We studied the effects of TOFA in a Rumen Simulation Technique (RUSITEC) experiment.


Trial outline

  • Six 750 ml RUSITEC fermentation vessels, loaded with fresh bovine rumen content (liquid and solid)
  • Daily substrate: 6 g hay + 4 g concentrate feed 
  • Equilibration phase of 7 days, control period of 1 day
  • Experimental period of 8 days, during which TOFA (330 μl) or control (ethanol 550 μl) was added to vessels during the daily exchange of the substrate bags. This amount of ethanol is known not to affect the fermentation. 


  • Days 8-16: redox potential, pH, NH3-N and, gas volume and percentages of CH4 and CO2
  • Days 9-11 and 13-15: organic matter degradation
  • Days 8, 12 and 16: liquid- and solid-associated microbes.

Microbial DNA was extracted and subjected to bacterial population analysis by Illumina MiSeq 16S rRNA amplicon sequencing (V34 region).


  • Increased by TOFA: Production rates and molar proportions of propionate and butyrate (p<0.01; Figures 1A and 1B) 
  • Decreased by TOFA: Molar proportion of acetate (p<0.05; Figure 1C), production rate and molar proportion of isovalerate (p<0.01; data not shown)
  • Not affected by TOFA: pH, redox values, organic matter digestibility, total production rates of short chain fatty acids, NH3-N, gas volume, percentages of CH4 and CO2, relative abundances of microbial phyla of the liquid or solid phase
  • Analysis for the operational taxonomic units revealed only a few transient changes as a response to TOFA.

Figure 1. Molar proportion of propionate (A), butyrate (B) and acetate (C) of all short chain fatty acids in fermentation vessels during the control period (CP; day 8) and the experimental period (Days 9-16). Treatments: Control (Con) and tall oil fatty acids (TOFA). Significance: * p<0.05; ** p<0.01; *** p<0.001.



As hypothesized, TOFA shifted the fermentation towards the production of propionate. However, TOFA did not have other major impacts on fermentation in this model. Studies with lactating dairy cows are needed to evaluate the effects of TOFA on milk production.