Metabolomic changes of uterine fluid of lactating cows with subclinical endometritis and treated with docosahexaenoic acid (DHA)

Postpartum uterine disease in dairy cows can cause important health problems in animals and economic losses to producers. An adequate management of animals around calving is crucial for maintaining animal health status and future lactation. Omega-3 fatty acids, such as docosahexaenoic acid (DHA), have been shown to have beneficial effects on the health of cows. In this pilot study, we analyzed the effect of intrauterine administration of DHA in cows with subclinical endometritis. Cows with subclinical endometritis at 26 ± 3 days in milk (DIM) were randomly assigned to receive an intrauterine infusion of: (i) DHA 0.16 % dissolved in saline solution (DHA group), or (ii) only the vehicle without DHA (control group). Uterine fluid was collected by non-surgical uterine flushing in all cows 24 h after treatment to analyze metabolomics using gas chromatography-mass spectrometry (GC-MS) and cytokine concentration by ELISA assay. Metabolites of the citric acid cycle (TCA cycle), linoleic acid metabolism, pantothenate and CoA biosynthesis, alanine, aspartate, and glutamate metabolism, and glyoxylate and dicarboxylate metabolism were reduced in the uterine fluid of the DHA group. Linoleic acid was reduced in the DHA group, which is relevant because of its role as a regulator of the innate immune function. In addition, a trend toward lower levels of IL-8 in the endometrial fluid was observed in cows in the DHA group. These findings suggest potential benefits of DHA on the uterine immune response in vivo, which could improve the health status of cows with subclinical endometritis.