Next Article in Journal
Dietary Supplementation of Chestnut Tannins in Prepartum Dairy Cows Improves Antioxidant Defense Mechanisms Interacting with Thyroid Status
Next Article in Special Issue
Effect of Supplementation of Lambs with Whole Cottonseed: Impact on Serum Biomarkers and Infection by Gastrointestinal Parasites under Field Conditions
Previous Article in Journal
Incorporation of Plant-Based Diet Surpasses Current Standards in Therapeutic Outcomes in Inflammatory Bowel Disease
Previous Article in Special Issue
Different Types of Glucocorticoids to Evaluate Stress and Welfare in Animals and Humans: General Concepts and Examples of Combined Use
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Metabolites
Volume 13
Issue 3
10.3390/metabo13030333
metabolites-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Association between Tryptophan Metabolism and Inflammatory Biomarkers in Dairy Cows with Ketosis

by
Zhengzhong Luo
1,†,
Kang Yong
2,†,
Zhenlong Du
1,3,
Yixin Huang
1,
Tao Zhou
1,
Li Ma
1,
Xueping Yao
1,
Liuhong Shen
1,
Shumin Yu
1,
Zuoting Yan
3 and
Suizhong Cao
1,*
1
Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
2
Department of Animal Science and Technology, Chongqing Three Gorges Vocational College, Chongqing 404100, China
3
Lanzhou Institute of Animal Husbandry and Veterinary Pharmaceutical, Chinese Academy of Agricultural Sciences, Lanzhou 730050, China
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Metabolites 2023, 13(3), 333; https://doi.org/10.3390/metabo13030333
Submission received: 10 January 2023 / Revised: 20 February 2023 / Accepted: 21 February 2023 / Published: 23 February 2023
(This article belongs to the Special Issue Metabolic and Endocrine Responses to Stress and Disease in Animal Production)
Browse Figures
Versions Notes

Abstract

:
Dairy cows with ketosis have high circulating beta-hydroxybutyric acid (BHBA) concentrations alongside which inflammation is concomitantly developed. Tryptophan (Trp) is an essential amino acid that participates in the regulation of the inflammatory response. However, the association between Trp metabolism and inflammation in dairy cows with ketosis remains unclear. Therefore, blood samples from healthy (n = 10) and ketotic (n = 10) primiparous dairy cows were collected at the calving date and the day of ketosis diagnosis (7 days in milk (7 DIM)). Serum levels of non-esterified fatty acids (NEFA), BHBA, haptoglobin (HP), serum amyloid A (SAA), lipopolysaccharide, and cortisol were analyzed. Tryptophan and its metabolites were quantified using liquid chromatography–tandem mass spectrometry. At 7 DIM, the concentrations of NEFA, BHBA, HP, and SAA were higher and the levels of Trp, kynurenine (KYN), indoleacetic acid, indole-3-lactic acid, and 3-indoxyl sulfate were lower in the dairy cows with ketosis compared with those in the healthy cows. However, the KYN/Trp and melatonin/Trp ratios increased in the cows with ketosis. At the calving date, the serum lipopolysaccharide levels did not differ between the healthy and ketotic cows, whereas the levels of NEFA, HP, and cortisol increased in the ketotic cows. Correlation analysis showed that Trp deficiency and elevated Trp metabolism in the dairy cows occurred during ketosis. Overall, our results suggest that abnormal Trp metabolism may contribute to the pathogenesis of ketosis.

Graphical Abstract

1. Introduction

Dairy cows experience a metabolic challenge during the transition period, especially after calving, characterized by an unbalanced energy status [1,2]. To adapt to this negative energy balance, dairy cows mobilize body fat, which is accompanied by elevated circulating concentrations of non-esterified fatty acids (NEFA) that are common in cows during the post-partum period [3,4]. Poor metabolic adaptation can result in a higher concentration of NEFA, which increases the risk of metabolic disease after calving [5,6]. Some researchers have suggested that NEFA contribute to the development of ketosis and displaced abomasum [5,7,8]. Traditionally, beta-hydroxybutyric acid (BHBA) is generated from the NEFA in the liver via partial oxidation and then released into certain organs, such as the heart and brain, as an alternate fuel source [9]. However, when NEFA produce excessive BHBA in response to poor metabolic adaptation, dairy cows’ blood BHBA concentration increases to more than 1.2 mmol/L and ketosis occurs [10,11]. During the early lactation period, particularly during the first week of lactation, 40–60% of dairy cows suffer from ketosis [11,12,13]. The prevalence of subclinical ketosis is higher than that of clinical ketosis in lactating dairy herds [14,15]. Evaluations of economic loss indicate that ketosis is not the main factor affecting milk production but it increases the risk of other diseases and culling [16,17]. Sordillo et al. [18] and Pascottini et al. [19] have reported significant negative effects caused by the inflammatory response to ketosis. The levels of inflammatory biomarkers, such as haptoglobin (HP), serum amyloid A (SAA), and lipopolysaccharide (LPS), increase in dairy cows with ketosis [20,21,22].
Tryptophan (Trp) is an essential aromatic amino acid whose metabolites participate in the regulation of inflammation and insulin resistance [23,24]. Tryptophan metabolism follows three major pathways: (1) Trp is converted into kynurenine (KYN) in the liver and immune tissue, which is mediated by the two rate-limiting enzymes tryptophan 2,3-dioxygenase (TDO) and indolamine-2,3-dioxygenase (IDO) [25]. (2) Serotonin or 5-hydroxytryptamine is generated from Trp in enterochromaffin cells via hydroxylation. The serotonin is acetylated to form N-acetylserotonin (NAS) in order to finally produce melatonin (MLT) [26]. Finally, (3) Trp is directly transformed into several molecules, such as indole-3-lactic acid (ILA), indoleacetic acid (IAA), and indole, by the gastrointestinal microbiota [27]. In cows, besides BHBA and NEFA, KYN was recently reported as a new indicator of negative energy balance [28]. The levels of Trp and KYN in blood samples are lower in dairy cows with ketosis than in healthy cows [29]. In addition, serotonin is involved in the regulation of metabolic homeostasis in dairy cows during transition periods [30]. However, changes in Trp metabolism in dairy cows from calving to lactation have rarely been studied, and the association between Trp metabolism and inflammation in ketosis events remains unclear.
Therefore, in this study, we aimed to determine the role of Trp metabolism in ketosis development. The concentrations of plasma Trp metabolites in dairy cows with ketosis were quantified using liquid chromatography–tandem mass spectrometry (LC-MS/MS). The levels of inflammatory biomarkers in the serum were concurrently analyzed on the calving date and the day when ketosis was diagnosed. Individual Trp metabolites and serum variables were integrated to assess the potential functional links between the different Trp metabolism pathways and inflammatory responses. Our findings provide novel information regarding the pathogenesis of ketosis in dairy cows.

2. Materials and Methods

2.1. Animals and Study Design

The experimental protocol was approved by the Institutional Animal Care and Use Committee of Sichuan Agricultural University (NO. DYY-2018203039). The study was conducted at a modern dairy farm in Sichuan Province, China. In this study, 90 primiparous, pregnant dairy cows of similar age and number of days into gestation were selected and housed in cow barns. The prepartum dairy cows were fed twice daily with a total mixed ration consisting of 29.04% corn silage, 32.67% oat hay, 7.26% wheat straw hay, 29.14% complete feed (Hengfeng Feed Co. LTD, Sichuan, Meishan, China), 1.45% soybean meal, and 0.44% choline on a dry matter basis. Dairy cows were transferred to fresh barns after calving and were fed three times daily with a total mixed ration consisting of 18.80% corn silage, 17.27% alfalfa hay, 4.32% oat hay, 32.61% complete feed (Sichuan Hengfeng Feed Co. LTD, Meishan, China), 6.47% cottonseed, 6.48% beet pulp, 12.95% steam-flaked corn, and 1.10% molasses on a dry matter basis. The cows had free access to fresh water. The dry matter intake of the cows was recorded daily. Lactating cows were milked daily at 06:30, 14:00, and 21:30 in a 60-point rotary milking parlor (Afimilk, Kibbutz Afikim, Israel). Dairy cows’ health was monitored by vets. The evaluation criteria regarding health status, including clinical signs, rumen fill scores, body condition scores, and fluctuations in milk yield, were described as reported previously [31]. In addition, the evaluation criteria for diseases, such as milk fever, mastitis, metritis, retained placenta, abomasal displacement, clinical ketosis (BHBA ≥ 3.0 mmol/L), and diarrhea, were described in our previous report [32]. A blood BHBA concentration of ≥1.2 mmol/L in the first week post-calving was classified as ketosis, and subclinical ketosis was defined as 1.2 mmol/L ≤ BHBA < 3.0 mmol/L [10,11]. Before the morning feeding, blood samples were collected from all cows via the caudal vein at 1 day in milk (DIM; calving occurred within 6 h after the colostrum was released) and 7 DIM. Blood BHBA concentration was determined at 1 and 7 DIM using a Blood Ketone Meter (WD1621, Nova Bio Vet, Waltham, MA, USA). Serum and plasma (using heparin sodium as an anticoagulant) samples were collected, centrifuged at 1500× g for 10 min at 25 °C, and subsequently stored at −80 °C.
In this study, 20 healthy cows were monitored (mean ± standard error of the mean (SEM); BHBA = 0.64 ± 0.02 mmol/L at 1 DIM and BHBA = 0.91 ± 0.04 mmol/L at 7 DIM). Cows with diseases had said ailments diagnosed. There were 15 cows with only sub-clinical ketosis (BHBA = 0.69 ± 0.03 mmol/L at 1 DIM and BHBA = 2.29 ± 0.07 mmol/L at 7 DIM), while there were 55 with signs of other diseases, including 5 with milk fever, 4 with mastitis, 11 with metritis, 10 with retained placenta, 5 with abomasal displacement, 6 with clinical ketosis, 2 with diarrhea, and 12 with more than two diseases or others. Ten cows that were diagnosed with only sub-clinical ketosis were of a similar age and had similar female calf weights, body condition scores, calving ease scores, and actual days of pregnancy at last parity (Table 1). For comparison with the former animals, 10 healthy cows in similar condition as mentioned above were randomly selected to form a control group.

2.2. Serum Markers Analyses

Serum NEFA, HP, SAA, LPS, and cortisol levels were determined using commercially available test kits from Nanjing Jiancheng Bioengineering Institute, China. The levels of serum HP, SAA, LPS, and cortisol were analyzed using a competitive enzyme-linked immunosorbent assay (inter-assay coefficients of variability (CV) < 12% and intra-assay CV < 10%). NEFA concentration was determined using a coupled enzymatic reaction system (acyl CoA Synthetase-acyl CoA oxidase method, inter-assay CV < 8%, and intra-assay CV < 10%).

2.3. Quantification of Tryptophan and Its Metabolites

The deuterated internal standards MLT-d4 and creatinine-d3 (Sigma-Aldrich, Merck, St. Louis, MO, USA) were added to 200 μL aliquots of plasma samples and mixed with 800 μL of acetonitrile-methanol (1:1, v/v). Plasma samples were pretreated as reported previously [33]. In brief, all mixtures were sonicated in an ice water bath and incubated at −20 °C for 60 mi; thereafter, they were centrifuged at 14,000× g for 20 min at 4 °C. The supernatant was collected and vacuum-dried. A total of 100 μL acetonitrile:water (1:1, v/v) was added and mixed. The supernatant was collected by centrifugation at 14,000× g for 15 min at 4 °C. Subsequently, the supernatant was analyzed for Trp and its metabolites using liquid chromatography– (LC; 1290 Infinity II, Agilent Technologies, Santa Clara, CA, USA) tandem mass spectrometry (MS/MS; QTRAP 6500, AB SCIEX, Framingham, MA, USA). In LC analysis, the mobile phase consisted of A (5 mM ammonium acetate and 0.2% ammonium hydroxide in water) and B (acetonitrile with 0.5% ammonium hydroxide). The gradient elution procedure was as follows: 0–5 min, 5% to 60% B; 5–11 min, 60% to 100% B; 11–13 min, 100% B; 13–13.1 min, 100% to 5% B; and 13.1–16 min, 5% B. The MS was equipped with an electrospray ionization source and operated alternately in positive-ion mode with +4.5 kV and negative-ion mode with −4.5 kV ion spray voltage. The source temperature was maintained at 580 °C, and the curtain gas was supplied at 35 psi. Ion source gas 1 and gas 2 were provided at 45 psi and 60 psi, respectively. MS/MS data were collected with a multiple reaction monitor, and the peak area was acquired using the MultiQuant software (v3.0.2; AB SCIEX, Framingham, MA, USA). Tryptophan (CAS#73-22-3), KYN (CAS#2922-83-0), serotonin (CAS#50-67-9), NAS (CAS#1210-83-9), MLT (CAS#73-31-4), IAA (CAS#87-51-4), ILA (CAS#1821-52-9), and 3-indoxyl sulfate (IS; CAS#487-94-5) (Sigma-Aldrich, Merck, MO, USA) were used as internal standards for the quantification of targeted metabolites in the plasma. The calibration curve and corresponding regression coefficients were obtained based on the concentration gradient of the standard, and the targeted metabolite concentrations were subsequently calculated.

2.4. Statistical Analysis

The chemical structures of the targeted metabolites were generated using the ChemDraw 20.0 software (PerkinElmer Informatics, Waltham, MA, USA). To compare the variables between the healthy and ketotic groups, a two-tailed Student’s t-test was performed using the SPSS software (v21.0, IBM, Armonk, NY, USA). Repeated measures ANOVA was also performed. The DIM scores were defined as fixed effects in the model, and each cow was defined as a random effect. The threshold of significance was set at p < 0.05, and trends toward significance were declared at 0.05 ≤ p < 0.10. Graphics were generated using the GraphPad Prism software (v9.0, GraphPad, San Diego, CA, USA). Data are expressed as mean ± SEM. The associations between Trp metabolism and clinical parameters were determined using Spearman’s rank correlation in the R platform (v4.2, https://www.r-project.org, accessed on 15 December 2022). Correlation thresholds were set to Spearman’s r > 0.4 or r < –0.4 and p < 0.05.

3. Results

3.1. Alteration of Milk Yield, Dry Matter Intake, and Serum Markers in the Healthy and Ketotic Cows

There was no significant difference regarding the dry matter intake and milk yield in the dairy cows between the healthy and ketotic groups at 1 DIM and 7 DIM (Figure 1). At 7 DIM, the mean milk yields in the healthy and ketotic cows were 25.45 kg and 28.26 kg, respectively. At 7 DIM, the blood NEFA concentrations in the ketotic cows were significantly higher (p < 0.01) than those in the healthy cows. Noticeably, at 1 DIM, the NEFA concentration in the ketotic cows was significantly higher (p < 0.01) than that in the healthy cows. Compared with those in the healthy cows at 1 DIM, the serum HP and cortisol levels increased (p < 0.1) in ketotic cows. However, SAA and LPS levels did not differ between the healthy and ketotic cows at 1 DIM. At 7 DIM, the SAA and HP levels increased (p < 0.1) during the ketosis event. Serum SAA and LPS levels in the dairy cows increased significantly (PDIM < 0.05) from 1 to 7 DIM.

3.2. Alteration in Tryptophan Metabolism

Tryptophan metabolism consists of KYN, serotonin, and microbiota pathways, which were altered during the ketosis event (Figure 2A). The plasma Trp and IS concentrations were significantly lower (p < 0.05) in the ketotic group than those in the healthy group at 7 DIM (Figure 2B). In contrast to those in the healthy cows, the concentrations of KYN, ILA, and IAA showed a decreasing trend (0.05 < p < 0.1) in the ketotic cows. The levels of eight metabolites in the Trp metabolic pathway, namely, Trp, KYN, serotonin, NAS, MLT, IAA, ILA, and IS, did not differ between the healthy and ketotic groups at 1 DIM. However, the ILA/Trp, IAA/Trp, and IS/Trp ratios were higher (p < 0.1) in the ketotic group than those in the healthy group at 1 DIM (Figure 3). Additionally, the KYN/Trp, NAS/Trp, and MLT/Trp ratios were higher (p < 0.1) in the ketotic group than those in the healthy group at 7 DIM.

3.3. Association between Tryptophan Metabolism and Inflammatory Biomarkers during Ketosis Events

To explain the associations between Trp metabolism and inflammatory challenges during the ketosis events, Trp-related metabolites were integrated with serum biomarkers based on Spearman’s correlation analysis (Figure 4). The decrease in Trp concentration was negatively correlated with increased levels of NEFA (r = −0.71, p < 0.001), SAA (r = −0.54, p = 0.015), and BHBA (r = −0.60, p = 0.006) levels. During the ketosis events, an increased KYN/Trp ratio was positively correlated with the increased NEFA (r = 0.62, p = 0.004), BHBA (r = 0.55, p = 0.012), and SAA (r = 0.53, p = 0.018) levels. In addition, the IS/Trp ratio was positively correlated with the SAA level (r = 0.57, p = 0.01) during ketosis events. Notably, the SAA level was positively correlated with the NAS/Trp (r = 0.49, p = 0.029) and MLT/Trp (r = 0.58, p = 0.008) ratios. The circulating NEFA level was positively correlated with the MLT/Trp ratio (r = 0.54, p = 0.012).

4. Discussion

Dairy cows with ketosis present with metabolic stress, which is characterized by excessive lipid mobilization and inflammatory dysfunction [18,20]. The dietary supplementation of dairy cows with tryptophan has been recommended to relieve stress and improve production during the lactation period [34]. Via a metabolomics approach, Trp metabolites have been found to participate in the development of ketosis [28,29]. However, the mechanisms underlying Trp metabolism and ketosis remain unclear. In this study, we used a targeted metabolomics method to analyze the levels of Trp and its metabolites in dairy cows on the calving date and the day on which ketosis was diagnosed and concurrently integrated them with inflammatory biomarkers. Our results demonstrate that inflammatory biomarker levels increased and Trp metabolism was enhanced in the dairy cows with ketosis. Notably, the ratio of Trp metabolites was altered in the ketotic cows during calving, indicating that abnormal Trp metabolism may be associated with inflammation before ketosis is confirmed. Our findings provide novel mechanistic insights into the pathogenesis of ketosis.
Dairy cows experience excessive lipid mobilization even before the confirmation of ketosis [35,36]. In the present study, we found that the circulating NEFA concentration was markedly higher in the ketotic cows, but the BHBA levels did not differ on the calving date, which is consistent with the results of Ha et al. [37] and Turk et al. [38]. In general, NEFA metabolism has two harmful pathways: (1) abundant NEFA reassemble to produce triglyceride (TG) in the hepatocellular endoplasmic reticulum, which further causes TG accumulation in the liver; and (2) carnitine palmitoyltransferase 1 transports NEFA to the mitochondria, where ketone bodies are subsequently generated from NEFA metabolism through incomplete oxidation [2,4]. TG storage likely precedes BHBA synthesis in dairy cows after calving [39,40]. Notably, NEFA play an important role in the development of inflammatory responses in periparturient dairy cows [41]. Palmitic acid, a Toll-like receptor-4 agonist, is a major component of NEFA and induces a pro-inflammatory response by activating the NF-κB pathway [42]. Dairy cows with hyperketonemia exhibited higher palmitic acid levels [29,32]. Acute-phase proteins, including HP and SAA, are regarded as biomarkers for evaluating the inflammation statuses of dairy cows [43]. NEFA concentration was strongly positively correlated with HP and SAA levels in dairy cows during the transition period [44]. In line with our findings, few studies have reported that the HP and SAA levels increased during ketosis events [20,22]. Furthermore, cortisol and LPS are important induction factors that promote the expression of acute-phase proteins in hepatocytes [45]. In the present study, LPS levels did not differ between the healthy and ketotic cows from the calving date to 7 DIM, but the serum cortisol concentration increased at 1 DIM. Abuajamieh et al. [20] found that the circulating LPS level in ketotic dairy cows did not alter post-calving, whereas ketotic cows suffered from the challenge of a high concentration of LPS before the prepartum period. Pascottini et al. [19] also suggested that metabolic stress and systemic inflammation in dairy cows during the prepartum period may result in the development of ketosis after calving. Therefore, the dysregulation of inflammation is an important contributor to the development of ketosis, but the factors that lead to differences in systemic inflammation warrant further investigation.
Tryptophan is an essential amino acid produced in the diet and plays a crucial role in the regulation of immune function [46]. Notably, Trp deficiency occurs in dairy cows with hyperketonemia [29,42,47]. In addition, the Trp levels in dairy cows decreased during the ketosis event, and the levels of partial metabolites, including KYN, ILA, IAA, and IS, also decreased in the present study. However, a decrease in Trp levels may lead to lower concentrations of the downstream metabolites. Therefore, the ratio of individual downstream metabolites to Trp was analyzed to explain the changes in Trp metabolism during the ketosis events. In the present study, KYN and serotonin pathways were enhanced in the ketotic dairy cows on the day of diagnosis. The KYN pathway is a major route of Trp metabolism and is regulated by IDO and TDO [25,48]. The expression of IDO and TDO is induced by proinflammatory cytokines [49,50] and corticosteroids [51], respectively. Larsson et al. [52] demonstrated that the plasma Trp level decreased and KYN/Trp ratio increased following LPS treatment. Furthermore, the KYN/Trp ratio was positively correlated with cortisol levels with respect to the cows’ inflammatory statuses [53]. Importantly, KYN is metabolized by enzymatic oxidation and non-enzymatic cyclization to quinolinic acid and further to nicotinamide adenine dinucleotide (NAD+) via the Preiss–Handler pathway [54]. KYN-derived NAD+ regulates the programming of the inflammatory response by modulating the level of succinate (a tricarboxylic acid cycle metabolite) and maintaining redox homeostasis [55].
In contrast, serotonin is converted into NAS by arylalkylamine N-acetyltransferase and further metabolized to MLT by hydroxyindole-O-methyl transferase [56]. MLT relieves palmitic acid-induced cytotoxicity by attenuating oxidative and endoplasmic reticulum stress [57]. In addition, MLT lowers the expression of acute-phase proteins, including SAA, HP, and C-reactive protein, in bovine mammary epithelial cells stimulated with LPS and plays a key role in anti-inflammation [58]. However, Horst et al. [59] suggested that circulating serotonin was not correlated with NEFA and BHBA levels in ketotic dairy cows, which is consistent with the results of the present study. Furthermore, microbial Trp catabolites participate in inflammatory regulation and the development of metabolic disease [60,61,62]. For example, Bifidobacterium adolescentis, Bacteroides fragilis, Bacteroides thetaiotaomicron, and Eubacterium cylindroides in the intestine convert Trp into ILA and IAA [27,63]. Krishnan et al. [60] and Ehrlich et al. [64] reported that IAA and ILA attenuate pro-inflammatory cytokine expression via the activation of the aryl hydrocarbon receptor. Unexpectedly, Trp-derived indole is transferred into the liver and further converted to IS by cytochrome P450 2E1 and sulfotransferases [65]. IS is cytotoxic at high concentrations and enhances the expression of interleukin-6 and SAA [66]. Likewise, we found that the IS/Trp ratio was positively correlated with SAA levels during the ketosis events. Our study also found that IAA/Trp, ILA/Trp, and IS/Trp ratios increased in the ketotic group cows at their respective calving dates. Thus, Trp metabolism may participate in the progression of inflammation in dairy cows with ketosis through feedback regulation, which requires further research.

5. Conclusions

Dairy cows experience excessive lipid mobilization and inflammation before a diagnosis of ketosis is made. We found that the Trp catabolism of gastrointestinal microbiota in the ketotic dairy cows was enhanced on their respective calving dates. Despite the circulating Trp deficit in cows during ketosis events, Trp metabolism was elevated and closely correlated with inflammatory biomarkers. This study suggests that elevated tryptophan metabolism may be a consequence of ketosis. Future studies are required to analyze the regulatory enzymes involved in Trp metabolism and the downstream metabolites of KYN, which may provide new therapeutic and preventative options.

Author Contributions

Conceptualization, Z.L., K.Y., Z.D., Y.H., T.Z., L.M., X.Y., L.S., S.Y., Z.Y. and S.C.; methodology, Z.L., K.Y., Z.D., T.Z., Z.Y. and S.C.; software, Z.L; validation, Z.L., Z.Y. and S.C.; formal analysis, Z.L., K.Y. and Z.D.; investigation, Z.L., Z.D. and T.Z.; resources, Z.Y. and S.C.; data curation, Z.L. and S.C.; writing—original draft preparation, Z.L., K.Y., Z.D., Y.H., T.Z., L.M., X.Y., L.S., S.Y., Z.Y. and S.C.; writing—review and editing, Z.L., K.Y., Z.D., Y.H., T.Z., L.M., X.Y., L.S., S.Y., Z.Y. and S.C.; visualization, Z.L. and Z.D.; supervision, S.C.; project administration, Z.L. and S.C; funding acquisition, K.Y., Z.Y. and S.C. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Natural Science Foundation of Sichuan, China (No. 2023NSFSC0234), Natural Science Foundation of Chongqing, China (No. CSTB2022NSCQ-MSX1602) and Key R&D Program Supported by the Department of Science and Technology of Gansu Province (No. 20YF8NA029).

Institutional Review Board Statement

The animal study protocol was approved by the Institutional Animal Care and Use Committee of Sichuan Agricultural University (No. DYY-2018203039).

Informed Consent Statement

Not applicable.

Data Availability Statement

Data is not publicly available due to privacy or ethical restrictions.

Acknowledgments

We thank Shanghai Applied Protein Technology Co., Ltd. (Shanghai, China) for LC-MRM/MS analysis.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Bell, A.W. Regulation of organic nutrient metabolism during transition from late pregnancy to early lactation. J. Anim. Sci. 1995, 73, 2804–2819. [Google Scholar] [CrossRef]
  2. Drackley, J.K. Biology of Dairy Cows During the Transition Period: The Final Frontier? J. Dairy Sci. 1999, 82, 2259–2273. [Google Scholar] [CrossRef]
  3. McCarthy, M.M.; Mann, S.; Nydam, D.V.; Overton, T.R.; McArt, J.A. Short communication: Concentrations of nonesterified fatty acids and beta-hydroxybutyrate in dairy cows are not well correlated during the transition period. J. Dairy Sci. 2015, 98, 6284–6290. [Google Scholar] [CrossRef] [Green Version]
  4. Adewuyi, A.A.; Gruys, E.; van Eerdenburg, F.J. Non esterified fatty acids (NEFA) in dairy cattle. A review. Vet. Q. 2005, 27, 117–126. [Google Scholar] [CrossRef] [Green Version]
  5. LeBlanc, S. Monitoring metabolic health of dairy cattle in the transition period. J. Reprod. Dev. 2010, 56, S29–S35. [Google Scholar] [CrossRef] [Green Version]
  6. McArt, J.A.; Nydam, D.V.; Oetzel, G.R.; Overton, T.R.; Ospina, P.A. Elevated non-esterified fatty acids and beta-hydroxybutyrate and their association with transition dairy cow performance. Vet. J. 2013, 198, 560–570. [Google Scholar] [CrossRef]
  7. Li, Y.; Ding, H.Y.; Wang, X.C.; Feng, S.B.; Li, X.B.; Wang, Z.; Liu, G.W.; Li, X.W. An association between the level of oxidative stress and the concentrations of NEFA and BHBA in the plasma of ketotic dairy cows. J. Anim. Physiol. Anim. Nutr. 2016, 100, 844–851. [Google Scholar] [CrossRef]
  8. Tremblay, M.; Kammer, M.; Lange, H.; Plattner, S.; Baumgartner, C.; Stegeman, J.A.; Duda, J.; Mansfeld, R.; Dopfer, D. Identifying poor metabolic adaptation during early lactation in dairy cows using cluster analysis. J. Dairy Sci. 2018, 101, 7311–7321. [Google Scholar] [CrossRef] [Green Version]
  9. Newman, J.C.; Verdin, E. Ketone bodies as signaling metabolites. Trends Endocrinol. Metab. 2014, 25, 42–52. [Google Scholar] [CrossRef] [Green Version]
  10. Duffield, T.F.; Lissemore, K.D.; McBride, B.W.; Leslie, K.E. Impact of hyperketonemia in early lactation dairy cows on health and production. J. Dairy Sci. 2009, 92, 571–580. [Google Scholar] [CrossRef] [Green Version]
  11. McArt, J.; Nydam, D.; Oetzel, G. Epidemiology of subclinical ketosis in early lactation dairy cattle. J. Dairy Sci. 2012, 95, 5056–5066. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  12. Serrenho, R.C.; Williamson, M.; Berke, O.; LeBlanc, S.J.; DeVries, T.J.; McBride, B.W.; Duffield, T.F. An investigation of blood, milk, and urine test patterns for the diagnosis of ketosis in dairy cows in early lactation. J. Dairy Sci. 2022, 105, 7719–7727. [Google Scholar] [CrossRef] [PubMed]
  13. Cascone, G.; Licitra, F.; Stamilla, A.; Amore, S.; Dipasquale, M.; Salonia, R.; Antoci, F.; Zecconi, A. Subclinical Ketosis in Dairy Herds: Impact of Early Diagnosis and Treatment. Front. Vet. Sci. 2022, 9, 895468. [Google Scholar] [CrossRef]
  14. Berge, A.C.; Vertenten, G. A field study to determine the prevalence, dairy herd management systems, and fresh cow clinical conditions associated with ketosis in western European dairy herds. J. Dairy Sci. 2014, 97, 2145–2154. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  15. Steeneveld, W.; Amuta, P.; van Soest, F.J.S.; Jorritsma, R.; Hogeveen, H. Estimating the combined costs of clinical and subclinical ketosis in dairy cows. PLoS ONE 2020, 15, e0230448. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  16. Cainzos, J.M.; Andreu-Vazquez, C.; Guadagnini, M.; Rijpert-Duvivier, A.; Duffield, T. A systematic review of the cost of ketosis in dairy cattle. J. Dairy Sci. 2022, 105, 6175–6195. [Google Scholar] [CrossRef]
  17. Raboisson, D.; Mounie, M.; Khenifar, E.; Maigne, E. The economic impact of subclinical ketosis at the farm level: Tackling the challenge of over-estimation due to multiple interactions. Prev. Vet. Med. 2015, 122, 417–425. [Google Scholar] [CrossRef] [PubMed]
  18. Sordillo, L.M.; Raphael, W. Significance of metabolic stress, lipid mobilization, and inflammation on transition cow disorders. Vet. Clin. N. Am. Food Anim. Pract. 2013, 29, 267–278. [Google Scholar] [CrossRef]
  19. Pascottini, O.B.; Leroy, J.; Opsomer, G. Metabolic Stress in the Transition Period of Dairy Cows: Focusing on the Prepartum Period. Animals 2020, 10, 1419. [Google Scholar] [CrossRef]
  20. Abuajamieh, M.; Kvidera, S.K.; Fernandez, M.V.; Nayeri, A.; Upah, N.C.; Nolan, E.A.; Lei, S.M.; DeFrain, J.M.; Green, H.B.; Schoenberg, K.M.; et al. Inflammatory biomarkers are associated with ketosis in periparturient Holstein cows. Res. Vet. Sci. 2016, 109, 81–85. [Google Scholar] [CrossRef]
  21. Shen, L.; Zhu, Y.; Xiao, J.; Qian, B.; You, L.; Zhang, Y.; Yu, S.; Zong, X.; Cao, S. Serum adipokines play different roles in type I and II ketosis. Asian-Australas. J. Anim. Sci. 2020, 33, 1930–1939. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  22. Brodzki, P.; Marczuk, J.; Lisiecka, U.; Szczubial, M.; Brodzki, A.; Gorzkos, H.; Kulpa, K. Comparative evaluation of cytokine and acute-phase protein concentrations in sera of dairy cows with subclinical and clinical ketosis as a different view of the causes of the disease. Vet. World 2021, 14, 1572–1578. [Google Scholar] [CrossRef] [PubMed]
  23. Cervenka, I.; Agudelo, L.Z.; Ruas, J.L. Kynurenines: Tryptophan’s metabolites in exercise, inflammation, and mental health. Science 2017, 357, eaaf9794. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  24. Oxenkrug, G. Insulin resistance and dysregulation of tryptophan-kynurenine and kynurenine-nicotinamide adenine dinucleotide metabolic pathways. Mol. Neurobiol. 2013, 48, 294–301. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  25. Bender, D.A. Biochemistry of tryptophan in health and disease. Mol. Asp. Med. 1983, 6, 101–197. [Google Scholar] [CrossRef] [PubMed]
  26. Lesurtel, M.; Soll, C.; Graf, R.; Clavien, P.A. Role of serotonin in the hepato-gastroIntestinal tract: An old molecule for new perspectives. Cell Mol. Life Sci. 2008, 65, 940–952. [Google Scholar] [CrossRef]
  27. Roager, H.M.; Licht, T.R. Microbial tryptophan catabolites in health and disease. Nat. Commun. 2018, 9, 3294. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  28. Xu, W.; Vervoort, J.; Saccenti, E.; Kemp, B.; van Hoeij, R.J.; van Knegsel, A.T.M. Relationship between energy balance and metabolic profiles in plasma and milk of dairy cows in early lactation. J. Dairy Sci. 2020, 103, 4795–4805. [Google Scholar] [CrossRef]
  29. Li, Y.; Xu, C.; Xia, C.; Zhang, H.; Sun, L.; Gao, Y. Plasma metabolic profiling of dairy cows affected with clinical ketosis using LC/MS technology. Vet. Q. 2014, 34, 152–158. [Google Scholar] [CrossRef] [Green Version]
  30. Laporta, J.; Moore, S.A.; Peters, M.W.; Peters, T.L.; Hernandez, L.L. Short communication: Circulating serotonin (5-HT) concentrations on day 1 of lactation as a potential predictor of transition-related disorders. J. Dairy Sci. 2013, 96, 5146–5150. [Google Scholar] [CrossRef] [Green Version]
  31. Yong, K.; Luo, Z.Z.; Luo, Q.; Yang, Q.W.; Huang, Y.X.; Zhao, X.X.; Zhang, Y.; Cao, S.Z. Plasma metabolome alteration in dairy cows with left displaced abomasum before and after surgical correction. J. Dairy Sci. 2021, 104, 8177–8187. [Google Scholar] [CrossRef] [PubMed]
  32. Luo, Z.Z.; Yong, K.; Huang, Y.X.; Zhang, C.S.; Shen, L.H.; Jiang, H.; Yang, X.; Zhang, Y.; Cao, S.Z. Effects of replacement of corn silage and distillers’ grain diets with hay during prepartum on the health and production performance of dairy heifers postpartum. J. Anim. Physiol. Anim. Nutr. 2022, 106, 682–689. [Google Scholar] [CrossRef] [PubMed]
  33. Luo, Z.Z.; Shen, L.H.; Jiang, J.; Huang, Y.X.; Bai, L.P.; Yu, S.M.; Yao, X.P.; Ren, Z.H.; Yang, Y.X.; Cao, S.Z. Plasma metabolite changes in dairy cows during parturition identified using untargeted metabolomics. J. Dairy Sci. 2019, 102, 4639–4650. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  34. Choi, W.T.; Ghassemi Nejad, J.; Moon, J.O.; Lee, H.G. Dietary supplementation of acetate-conjugated tryptophan alters feed intake, milk yield and composition, blood profile, physiological variables, and heat shock protein gene expression in heat-stressed dairy cows. J. Therm. Biol. 2021, 98, 102949. [Google Scholar] [CrossRef]
  35. Wankhade, P.R.; Manimaran, A.; Kumaresan, A.; Jeyakumar, S.; Ramesha, K.P.; Sejian, V.; Rajendran, D.; Varghese, M.R. Metabolic and immunological changes in transition dairy cows: A review. Vet. World 2017, 10, 1367–1377. [Google Scholar] [CrossRef]
  36. Loor, J.J.; Everts, R.E.; Bionaz, M.; Dann, H.M.; Morin, D.E.; Oliveira, R.; Rodriguez-Zas, S.L.; Drackley, J.K.; Lewin, H.A. Nutrition-induced ketosis alters metabolic and signaling gene networks in liver of periparturient dairy cows. Physiol. Genom. 2007, 32, 105–116. [Google Scholar] [CrossRef] [Green Version]
  37. Ha, S.; Kang, S.; Han, M.; Lee, J.; Chung, H.; Oh, S.I.; Kim, S.; Park, J. Predicting ketosis during the transition period in Holstein Friesian cows using hematological and serum biochemical parameters on the calving date. Sci. Rep. 2022, 12, 853. [Google Scholar] [CrossRef]
  38. Turk, R.; Podpečan, O.; Mrkun, J.; Flegar-Meštrić, Z.; Perkov, S.; Zrimšek, P. The Effect of Seasonal Thermal Stress on Lipid Mobilisation, Antioxidant Status and Reproductive Performance in Dairy Cows. Reprod. Domest. Anim. 2015, 50, 595–603. [Google Scholar] [CrossRef]
  39. Vailati-Riboni, M.; Palombo, V.; Loor, J.J. The omics side of fatty liver: A holistic approach for a commonly occurring peripartal disease. In Periparturient Diseases of Dairy Cows: A Systems Biology Approach; Ametaj, B.N., Ed.; Springer International Publishing: Cham, Switzerland, 2017; pp. 223–246. [Google Scholar]
  40. Grummer, R.R. Etiology of lipid-related metabolic disorders in periparturient dairy cows. J. Dairy Sci. 1993, 76, 3882–3896. [Google Scholar] [CrossRef]
  41. Mezzetti, M.; Bionaz, M.; Trevisi, E. Interaction between inflammation and metabolism in periparturient dairy cows. J. Anim. Sci. 2020, 98, S155–S174. [Google Scholar] [CrossRef]
  42. Palomer, X.; Pizarro-Delgado, J.; Barroso, E.; Vazquez-Carrera, M. Palmitic and Oleic Acid: The Yin and Yang of Fatty Acids in Type 2 Diabetes Mellitus. Trends Endocrinol. Metab. 2018, 29, 178–190. [Google Scholar] [CrossRef]
  43. Tóthová, C.; Nagy, O.; Kováč, G. Acute phase proteins and their use in the diagnosis of diseases in ruminants: A review. J. Vet. Med. 2018, 59, 163–180. [Google Scholar]
  44. Kováč, G.; Tóthová, C.; Nagy, O.; Seidel, H.; Konvičná, J. Acute phase proteins and their relation to energy metabolites in dairy cows during the pre-and postpartal period. J. Acta Vet. Brno 2009, 78, 441–447. [Google Scholar] [CrossRef] [Green Version]
  45. Jain, S.; Gautam, V.; Naseem, S. Acute-phase proteins: As diagnostic tool. J. Pharm. Bioallied. Sci. 2011, 3, 118–127. [Google Scholar] [CrossRef] [PubMed]
  46. Le Floc’h, N.; Otten, W.; Merlot, E. Tryptophan metabolism, from nutrition to potential therapeutic applications. Amino Acids 2011, 41, 1195–1205. [Google Scholar] [CrossRef]
  47. Guo, Y.S.; Tao, J.Z.; Xu, L.H.; Wei, F.H.; He, S.H. Identification of disordered metabolic networks in postpartum dairy cows with left displacement of the abomasum through integrated metabolomics and pathway analyses. J. Vet. Med. Sci. 2020, 82, 115–124. [Google Scholar] [CrossRef] [Green Version]
  48. Hayaishi, O. Properties and function of indoleamine 2,3-dioxygenase. J. Biochem. 1976, 79, 13–21. [Google Scholar] [CrossRef]
  49. Savitz, J. The kynurenine pathway: A finger in every pie. Mol. Psychiatry 2020, 25, 131–147. [Google Scholar] [CrossRef]
  50. Connor, T.J.; Starr, N.; O’Sullivan, J.B.; Harkin, A. Induction of indolamine 2,3-dioxygenase and kynurenine 3-monooxygenase in rat brain following a systemic inflammatory challenge: A role for IFN-gamma? Neurosci. Lett. 2008, 441, 29–34. [Google Scholar] [CrossRef]
  51. Walker, A.K.; Budac, D.P.; Bisulco, S.; Lee, A.W.; Smith, R.A.; Beenders, B.; Kelley, K.W.; Dantzer, R. NMDA receptor blockade by ketamine abrogates lipopolysaccharide-induced depressive-like behavior in C57BL/6J mice. Neuropsychopharmacology 2013, 38, 1609–1616. [Google Scholar] [CrossRef]
  52. Larsson, M.K.; Faka, A.; Bhat, M.; Imbeault, S.; Goiny, M.; Orhan, F.; Oliveros, A.; Stahl, S.; Liu, X.C.; Choi, D.S.; et al. Repeated LPS Injection Induces Distinct Changes in the Kynurenine Pathway in Mice. Neurochem. Res. 2016, 41, 2243–2255. [Google Scholar] [CrossRef] [PubMed]
  53. Millischer, V.; Heinzl, M.; Faka, A.; Resl, M.; Trepci, A.; Klammer, C.; Egger, M.; Dieplinger, B.; Clodi, M.; Schwieler, L. Intravenous administration of LPS activates the kynurenine pathway in healthy male human subjects: A prospective placebo-controlled cross-over trial. J. Neuroinflam. 2021, 18, 158. [Google Scholar] [CrossRef] [PubMed]
  54. Vecsei, L.; Szalardy, L.; Fulop, F.; Toldi, J. Kynurenines in the CNS: Recent advances and new questions. Nat. Rev. Drug Discov. 2013, 12, 64–82. [Google Scholar] [CrossRef] [PubMed]
  55. Xie, N.; Zhang, L.; Gao, W.; Huang, C.; Huber, P.E.; Zhou, X.; Li, C.; Shen, G.; Zou, B. NAD(+) metabolism: Pathophysiologic mechanisms and therapeutic potential. Signal Transduct. Target Ther. 2020, 5, 227. [Google Scholar] [CrossRef] [PubMed]
  56. Yabut, J.M.; Crane, J.D.; Green, A.E.; Keating, D.J.; Khan, W.I.; Steinberg, G.R. Emerging Roles for Serotonin in Regulating Metabolism: New Implications for an Ancient Molecule. Endocr. Rev. 2019, 40, 1092–1107. [Google Scholar] [CrossRef]
  57. Xu, D.; Liu, L.; Zhao, Y.; Yang, L.; Cheng, J.; Hua, R.; Zhang, Z.; Li, Q. Melatonin protects mouse testes from palmitic acid-induced lipotoxicity by attenuating oxidative stress and DNA damage in a SIRT1-dependent manner. J. Pineal Res. 2020, 69, e12690. [Google Scholar] [CrossRef] [PubMed]
  58. Yu, G.M.; Kubota, H.; Okita, M.; Maeda, T. The anti-inflammatory and antioxidant effects of melatonin on LPS-stimulated bovine mammary epithelial cells. PLoS ONE 2017, 12, e0178525. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  59. Horst, E.A.; Kvidera, S.K.; Abuajamieh, M.; Mayorga, E.J.; Al-Qaisi, M.; Baumgard, L.H. Short communication: Ketosis, feed restriction, and an endotoxin challenge do not affect circulating serotonin in lactating dairy cows. J. Dairy Sci. 2019, 102, 11736–11743. [Google Scholar] [CrossRef]
  60. Krishnan, S.; Ding, Y.; Saedi, N.; Choi, M.; Sridharan, G.V.; Sherr, D.H.; Yarmush, M.L.; Alaniz, R.C.; Jayaraman, A.; Lee, K. Gut Microbiota-Derived Tryptophan Metabolites Modulate Inflammatory Response in Hepatocytes and Macrophages. Cell Rep. 2018, 23, 1099–1111. [Google Scholar] [CrossRef]
  61. Agus, A.; Planchais, J.; Sokol, H. Gut Microbiota Regulation of Tryptophan Metabolism in Health and Disease. Cell Host Microbe 2018, 23, 716–724. [Google Scholar] [CrossRef] [Green Version]
  62. Zhao, C.; Bao, L.; Qiu, M.; Feng, L.; Chen, L.; Liu, Z.; Duan, S.; Zhao, Y.; Wu, K.; Zhang, N.; et al. Dietary Tryptophan-Mediated Aryl Hydrocarbon Receptor Activation by the Gut Microbiota Alleviates Escherichia coli-Induced Endometritis in Mice. Microbiol. Spectr. 2022, 10, e0081122. [Google Scholar] [CrossRef] [PubMed]
  63. Smith, E.A.; Macfarlane, G.T. Enumeration of human colonic bacteria producing phenolic and indolic compounds: Effects of pH, carbohydrate availability and retention time on dissimilatory aromatic amino acid metabolism. J. Appl. Bacteriol. 1996, 81, 288–302. [Google Scholar] [CrossRef] [PubMed]
  64. Ehrlich, A.M.; Pacheco, A.R.; Henrick, B.M.; Taft, D.; Xu, G.; Huda, M.N.; Mishchuk, D.; Goodson, M.L.; Slupsky, C.; Barile, D.; et al. Indole-3-lactic acid associated with Bifidobacterium-dominated microbiota significantly decreases inflammation in intestinal epithelial cells. BMC Microbiol. 2020, 20, 357. [Google Scholar] [CrossRef] [PubMed]
  65. Yacoub, R.; Wyatt, C.M. Manipulating the gut microbiome to decrease uremic toxins. Kidney Int. 2017, 91, 521–523. [Google Scholar] [CrossRef] [PubMed]
  66. Schroeder, J.C.; Dinatale, B.C.; Murray, I.A.; Flaveny, C.A.; Liu, Q.; Laurenzana, E.M.; Lin, J.M.; Strom, S.C.; Omiecinski, C.J.; Amin, S.; et al. The uremic toxin 3-indoxyl sulfate is a potent endogenous agonist for the human aryl hydrocarbon receptor. Biochemistry 2010, 49, 393–400. [Google Scholar] [CrossRef] [Green Version]
Metabolites 13 00333 g001 550
Figure 1. Bar plot indicating the changes in dry matter intake, milk yield, non-esterified fatty acids (NEFA), haptoglobin (HP), serum amyloid A (SAA), lipopolysaccharide (LPS), and cortisol between the healthy and ketotic cows at 1 and 7 days in milk (DIM). 0.05 ≤ # p < 0.1, * p < 0.05, and ** p < 0.01.
Figure 1. Bar plot indicating the changes in dry matter intake, milk yield, non-esterified fatty acids (NEFA), haptoglobin (HP), serum amyloid A (SAA), lipopolysaccharide (LPS), and cortisol between the healthy and ketotic cows at 1 and 7 days in milk (DIM). 0.05 ≤ # p < 0.1, * p < 0.05, and ** p < 0.01.
Metabolites 13 00333 g001
Metabolites 13 00333 g002 550
Figure 2. Tryptophan (Trp) metabolism in dairy cows during the ketosis event. (A) Diagram of Trp metabolism pathway, including kynurenine, serotonin, and microbiota pathways. (B) Levels of Trp and its main metabolites between the healthy and ketotic groups at 1 and 7 days in milk (DIM). 0.05 ≤ # p < 0.1, * p < 0.05, and ** p < 0.01.
Figure 2. Tryptophan (Trp) metabolism in dairy cows during the ketosis event. (A) Diagram of Trp metabolism pathway, including kynurenine, serotonin, and microbiota pathways. (B) Levels of Trp and its main metabolites between the healthy and ketotic groups at 1 and 7 days in milk (DIM). 0.05 ≤ # p < 0.1, * p < 0.05, and ** p < 0.01.
Metabolites 13 00333 g002
Metabolites 13 00333 g003 550
Figure 3. Ratios of individual metabolites to Trp between the healthy and ketotic dairy cows. Trp, tryptophan; KYN, kynurenine; SRT, serotonin; NAS, N-acetylserotonin; MLT, melatonin; ILA, indole-3-lactic acid; IAA, indoleacetic acid; IS, 3-indoxyl sulfate. 0.05 ≤ # p < 0.1, * p < 0.05.
Figure 3. Ratios of individual metabolites to Trp between the healthy and ketotic dairy cows. Trp, tryptophan; KYN, kynurenine; SRT, serotonin; NAS, N-acetylserotonin; MLT, melatonin; ILA, indole-3-lactic acid; IAA, indoleacetic acid; IS, 3-indoxyl sulfate. 0.05 ≤ # p < 0.1, * p < 0.05.
Metabolites 13 00333 g003
Metabolites 13 00333 g004 550
Figure 4. Tryptophan and its metabolites associated with clinical phenotypes during the ketosis events. NEFA, non-esterified fatty acids; BHBA, beta-hydroxybutyric acid; SAA, serum amyloid A; HP, haptoglobin; LPS, lipopolysaccharide; COT, cortisol; Trp, tryptophan; KYN, kynurenine; SRT, serotonin; NAS, N-acetylserotonin; MLT, melatonin; ILA, indole-3-lactic acid; IAA, indoleacetic acid; IS, 3-indoxyl sulfate. * p < 0.05, ** p < 0.01.
Figure 4. Tryptophan and its metabolites associated with clinical phenotypes during the ketosis events. NEFA, non-esterified fatty acids; BHBA, beta-hydroxybutyric acid; SAA, serum amyloid A; HP, haptoglobin; LPS, lipopolysaccharide; COT, cortisol; Trp, tryptophan; KYN, kynurenine; SRT, serotonin; NAS, N-acetylserotonin; MLT, melatonin; ILA, indole-3-lactic acid; IAA, indoleacetic acid; IS, 3-indoxyl sulfate. * p < 0.05, ** p < 0.01.
Metabolites 13 00333 g004
Table
Table 1. Calf weight, calving ease score, body condition score, age, actual days of pregnancy, and beta-hydroxybutyric acid level between the healthy and sub-clinical ketotic dairy cows.
Table 1. Calf weight, calving ease score, body condition score, age, actual days of pregnancy, and beta-hydroxybutyric acid level between the healthy and sub-clinical ketotic dairy cows.
ItemHealthy Cows
(n = 10)		Sub-Clinical Ketotic Cows
(n = 10)
Calf weight (kg), female37.90 ± 0.8438.20 ± 0.97
Calving ease score1.10 ± 0.091.20 ± 0.13
Age (month) 127.34 ± 1.0628.08 ± 0.94
Day of pregnancy (d)275.40 ± 1.06274.50 ± 0.47
Body condition score 23.50 ± 0.043.60 ± 0.06
BHBA concentration at 1 DIM0.63 ± 0.030.72 ± 0.04
BHBA concentration at 7 DIM0.89 ± 0.052.36 ± 0.09 **
1 The age of dairy cows on the seventh day after calving. 2 Body condition score was assessed on the seventh day before the due date. DIM = days in milk. Data are expressed as mean ± SEM. ** p < 0.01.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Luo, Z.; Yong, K.; Du, Z.; Huang, Y.; Zhou, T.; Ma, L.; Yao, X.; Shen, L.; Yu, S.; Yan, Z.; et al. Association between Tryptophan Metabolism and Inflammatory Biomarkers in Dairy Cows with Ketosis. Metabolites 2023, 13, 333. https://doi.org/10.3390/metabo13030333

AMA Style

Luo Z, Yong K, Du Z, Huang Y, Zhou T, Ma L, Yao X, Shen L, Yu S, Yan Z, et al. Association between Tryptophan Metabolism and Inflammatory Biomarkers in Dairy Cows with Ketosis. Metabolites. 2023; 13(3):333. https://doi.org/10.3390/metabo13030333

Chicago/Turabian Style

Luo, Zhengzhong, Kang Yong, Zhenlong Du, Yixin Huang, Tao Zhou, Li Ma, Xueping Yao, Liuhong Shen, Shumin Yu, Zuoting Yan, and et al. 2023. "Association between Tryptophan Metabolism and Inflammatory Biomarkers in Dairy Cows with Ketosis" Metabolites 13, no. 3: 333. https://doi.org/10.3390/metabo13030333

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop