Biomarkers of inflammation and gut permeability in dairy cows with or without dietary resin acids

The 71^st annual meeting of the European Federation of Animal Science (EAAP) took place as a virtual meeting, due to the global travel restrictions during this year. Hankkija FFI’s poster with the title “Biomarkers of inflammation and gut permeability in dairy cows with or without dietary resin acids” was presented as a pre-recorded three-minute introductory video, like all other posters of the event. The abstract presented the main results of the post doc work of Dr. Nanbing Qin from the Department of Veterinary Biosciences, University of Helsinki, and it was presented by Dr. Hannele Kettunen from Hankkija FFI.

During the periparturient period and early lactation, dairy cows are prone to low-grade systemic inflammation which decreases their productive capacity and which often leads to clinical illnesses. In dairy cattle, up to 75% of all clinical cases of illness are associated with the periparturient period.

Inflammation, disturbed microbiota and impaired intestinal barrier functions are often interlinked. Inflammatory processes impair intestinal barrier functions and lead to increased gut permeability which leads to the so-called “leaky gut syndrome” and a vicious circle of inflammation. Feed materials and additives which alleviate the inflammation, improve intestinal integrity or balance the microbiota might help the cows through the periparturient period with less health issues.

Here we investigated the effects of two dietary coniferous resin acid supplements on biomarkers of intestinal permeability and systemic inflammation in dairy cows during the first 10 weeks of lactation.

Thirty-six Nordic Red cows were assigned to a control diet, resin acid concentrate -supplemented diet (RAC), and a tall oil fatty acid -supplemented diet (Progres®) by a randomized block design from three weeks prior to the predicted parturition until ten weeks postpartum. In both treatments, the daily dose of resin acids was adjusted to 0.65 g per cow. The cows were sampled for blood from the tail vein at weeks 2, 3, 6, and 10 postpartum.

The following parameters were analysed from blood plasma using commercial ELISA kits: interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), tumor necrosis factor alpha (TNF-α), intestinal fatty acid-binding protein (I-FABP), lipopolysaccharide-binding protein (LBP), and serum amyloid A (SAA). The log-2 transformed data were analysed with repeated-measures ANOVA.

The studied biomarkers of inflammation first increased and then started to decline towards week 10 of the time series. The effect of time was statistically significant for all studied parameters, likely reflecting natural changes in systemic inflammation in dairy cows during the first weeks after calving.

The gastrointestinal barrier function biomarker I-FABP tended to be decreased by RAC (p < 0.1), compared with the control treatment. This finding suggests that pure resin acids may improve gastrointestinal barrier functions in adult ruminants. Previous research from monogastrics has shown such effects for in-feed resin acids. It is worth noting that the veterinary record of the present experiment showed reduced incidence of udder infections in the RAC group.

Cytokines IL-6 and IL-8 and IL-10 were slightly elevated by Progres® (p < 0.05) but they were not affected by RAC. Of these three biomarkers, IL-10 is an anti-inflammatory cytokine, IL-6 has both pro- and anti-inflammatory functions, and IL-8 is a neutrophil-specific chemoattractant with proinflammatory effects. Neither of the resin acid treatments showed significant effects on IL-1β, TNF-α, LBP, or SAA.

The results suggest that the resin acid treatments had positive effects on the immunological status and gut barrier functions of dairy cows during early lactation.

Reference: Biomarkers of inflammation and gut permeability in dairy cows with or without dietary resin acids Qin N.¹, Niku M.¹, Junnikkala S.¹, Vuorenmaa, J.², and Kettunen H.² Abstract no 21.29 in: European Federation of Animal Science (EAAP) virtual meeting 1-4 December 2020. ¹Department of Veterinary Biosciences, University of Helsinki, 00014 Helsinki, Finland, ²Hankkija Oy, FI-05800 Hyvinkää, Finland