Metabolomics of Four Biofluids from Dairy Cows: Potential Biomarkers for Milk Production and Quality

Abstract

The fundamental understanding of the mechanisms regulating milk protein synthesis is limited. This study aimed to elucidate the metabolic mechanisms of milk production affected by forage quality through studying metabolites from four biofluids (rumen fluid, milk, serum, and urine) collected from 16 lactating cows fed alfalfa hay (AH, high-quality, n = 8) and corn stover (CS, low-quality, n = 8) using gas chromatography-time-of-flight/mass spectrometry. The cows fed AH exhibited higher milk yield (P < 0.01), milk protein yield (P = 0.04), and milk efficiency (P < 0.01) than those fed CS. A total of 165, 195, 218, and 156 metabolites were identified in the rumen fluid, milk, serum, and urine, respectively, while 29 metabolites were found in all four biofluids. In addition 55, 8, 28, and 31 metabolites in each biofluid were significantly different (VIP > 1 and P < 0.05) between the AH- and CS-fed animals. These metabolites were involved in glycine, serine, and threonine metabolism; tyrosine metabolism; and phenylalanine metabolism. Further integrated key metabolic pathway analysis showed that the AH-fed cows may have more comprehensive amino acid metabolisms, suggesting that these metabolite-associated pathways may serve as biomarkers for higher milk yield and better milk protein quality.

049 Physiological and molecular mechanisms associated with performance, immunometabolic status, and liver function in transition dairy cows fed rumen-protected methionine or choline

“…In terms of dairy cows, results from both our group and others have confirmed the alterations on the transcriptome level (Ji et al, 2012, Osorio et al, 2014a, Li et al, 2016 as well as metabolome (Sun et al, 2015) level in response to nutritional interventions. For instance, microarray analysis from our group revealed a greater overall subclinical inflammatory-like condition in feed-restricted cows compared with overfed cows (Shahzad et al, 2014).…”

“…Metabolomics profiling of rumen fluid, milk, serum, and urine from lactating cows fed high-vs. low-quality diets suggest higher N loss and low N utilization efficiency in response to low quality diet (Sun et al, 2015).…”

Doses Lactobacillus reuteri depend on adhesive ability to modulate the intestinal immune response and metabolism in mice challenged with lipopolysaccharide

“…GC-TOF-MS is a widely used approach in metabolomics for its high resolution and sensitivity1328. Metabolomic studies evaluating the effects of Lactobacilli on the intestines of the host are limited.…”

Biomarker and pathway analyses of urine metabolomics in dairy cows when corn stover replaces alfalfa hay

“…Sixteen multiparous (3.6 ± 1.8 parity) Holstein cows were randomly assigned to 2 groups according to BW and milk yield as described by Sun et al [6]. Both groups were offered consisting of 55 % concentrate mixture and 15 % corn silage with different forages (Additional file 1: Table S1): (1) alfalfa (AH), containing 23 % alfalfa hay and 7 % Chinese wild rye hay, and (2) corn stover (CS), containing 30 % corn stover instead of alfalfa hay and Chinese wild rye hay.…”

“…In previous work, we characterized certain results for common metabolites in four biofluids (rumen fluid, milk, serum, and urine) [6]. We concluded that a deep analysis of metabolites from a single representative biofluid should be used to generate specific biomarkers and pathways to distinguish the metabolic profiles of dairy cows fed different diets.…”