Tryptophan, kynurenine, kynurenic acid concentrations and indoleamine 2,3‐dioxygenase activity in serum and milk of dairy cows with subclinical mastitis caused by coagulase‐negative staphylococci

Abstract

The aim of the study was to investigate serum and milk concentrations of tryptophan (TRP), kynurenine (KYN), kynurenic acid (KYNA), and indoleamine 2,3-dioxygenase (IDO) activity in cows suffering from subclinical mastitis caused by coagulase-negative staphylococci (MSCNS). TRP and kynurenines were determined by high-performance liquid chromatography (HPLC), and IDO activity was calculated as the KYN/TRP ratio. The blood and milk samples were collected from 40 midlactation Holstein-Fresian cows from two herds in the Lublin region in Poland. In the milk samples from 20 cows with subclinical mastitis, coagulase-negative staphylococci were isolated and in the milk obtained from healthy cows growth of microorganisms was not detected. TRP, KYN and KYNA concentrations were significantly lower in milk of cows with MSCNS compared to control animals (4.47 vs. 7.24 µM, 0.14 vs. 0.21 µM, 1.58 vs. 2.18 nM, respectively). There was no statistically significant difference in TRP and KYNA concentrations in serum between the studied animal groups (32.97 vs. 39.29 µM, 31.3 vs. 26.5 nM, respectively). In turn, the level of KYN was lower in the serum (0.81 vs. 1.13 µM) of cows with mastitis compared to healthy ones. No statistically significant differences in IDO activity, both in serum and in milk (25.24 and 27.55, 28.56 and 27.17, respectively) was revealed between the studied groups. These findings may have potential implications for diagnosis of mastitis in cows because reduction of these parameters in milk might be a marker predicting the occurrence of the disease.

Effects of Energy Supply from Roughage and Concentrates and the Occurrence of Subclinical Ketosis on Blood Chemistry and Liver Health in Lactating Dairy Cows during Early Lactation

“…This indicates that ketotic conditions may not necessarily influence the activity of the enzyme indoleamine 2,3-dioxygenase. This result is corroborated by studies in which peripartal inflammatory diseases like mastitis and metritis were not affecting the kynurenine-to-tryptophan ratio [39,40].…”

UVB Radiation and Selected Tryptophan-Derived AhR Ligands—Potential Biological Interactions in Melanoma Cells

“…Moreover, selected tryptophan metabolites were also found in human sweat [ 25 ]. Bearing in mind the exogenous sources of KYN and KYNA in the human body, it should be noted that these tryptophan metabolites might be absorbed from the gastrointestinal tract and distributed to the periphery as they are found in various beverages and food products [ 18 , 19 , 21 , 22 , 26 , 27 , 28 , 29 , 30 ]. Interestingly, previous studies revealed that KYNA is also present in plants, including herbs, and in bee products used in cosmetics and skin care treatments.…”

Acute-phase inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4) levels in serum and milk of cows with subclinical mastitis caused by Streptococcus species and coagulase-negative Staphylococcus species

“…The presence of microorganisms in bacteriological analysis was recorded in 124 quarters 541 milk samples from 97 cows (74 cows: 1 quarter; 19 cows: 2 quarters; and 4 cows: 3 quarters) with SCC >200,000 cells/mL. Collection of blood and quarter milk samples was described in a previous study (Bochniarz et al, 2018). Inclusively, in 22 quarter milk samples with SCC >200,000 cells/mL obtained from 14 cows, growth of microorganisms was not detected.…”