Untargeted metabolomics and lipidomics to assess plasma metabolite changes in dairy goats with subclinical hyperketonemia

Impact of subclinically hypocalcemic stress on the plasma metabolomic profile of dairy goats

OBJECTIVE

This study aimed to explore novel aspects of disease prevention and control in Guanzhong dairy goats through the application of metabolomics and lipidomics.

METHODS

In this study, plasma samples were collected from 96 primiparous Guanzhong dairy goats with similar body condition scores (2.75±0.15, mean±standard deviation) on the day of calving. The aim was to identify key differences in metabolite expression between diseased and healthy animals using metabolomics and lipidomics.

RESULTS

Twenty-three differential metabolites and 30 differentially altered lipids were identified, which were associated with various metabolic pathways, including phenylalanine and tyrosine metabolism, aminoacyl-tRNA biosynthesis, and glycerophospholipid metabolism. Our research revealed significant differences in the regulation of calcium-related hormones and associated metabolites between subclinical hypocalcemic and healthy dairy goats. Specifically, parathyroid hormone and aspartate aminotransferase were positively correlated in the healthy group and negatively correlated in the subclinical hypocalcemic group.

CONCLUSION

The identification of phenylalanine and phosphatidylserine as potential biomarkers for subclinical hypocalcemia in dairy goats offers a novel approach to managing this condition, potentially transforming prevention and control strategies in the dairy goat industry.

Insights into the Regulatory Effect of Danggui Buxue Tang in Postpartum Dairy Cows Through an Integrated Analysis of Multi-Omics and Network Analysis

Postpartum dairy cows often face significant challenges due to metabolic disorders. Danggui Buxue Tang (DBT), a botanical drug composed of Astragali radix and Angelica sinensis radix in a 5:1 ratio, has been recognized for its potential to alleviate metabolic disorders. Its regulatory mechanisms on livestock metabolic health have remained unexplored. This study integrated the analyses of serum pharmacochemistry, network pharmacology, serum metabolomics, and fecal microbiota to investigate the regulatory effects of DBT on metabolic adaptation in postpartum dairy cows. Following the oral administration of DBT, levels of blood non-esterified fatty acids and beta-hydroxybutyrate were decreased in multiparous dairy cows one week after calving. Five absorbed prototype metabolites of DBT were identified, specifically formononetin and nicotinic acid, both of which play roles in the regulation of lipid metabolic homeostasis. Furthermore, DBT modified the composition of the gut microbial community and glycerophospholipid levels. Decreases in serum phosphatidylethanolamine and phosphatidylcholine levels were closely correlated with the relative abundance of Bacillus and the concentration of circulating beta-hydroxybutyrate. These findings suggest that DBT contributes positively to metabolic health in postpartum dairy cows by regulating the gut microbiota and glycerophospholipid metabolism, providing new insights into strategies for promoting metabolic adaptation in dairy cows.

Plasma and milk metabolomics profiles in dairy cows with subclinical and clinical ketosis

Ketosis, a commonly observed energy metabolism disorder in dairy cows during the peripartal period, is distinguished by increased concentrations of BHB in the blood. This condition has a negative impact on milk production and quality, causing financial losses. An untargeted metabolomics approach was performed on plasma samples from cows between 5 and 7 DIM diagnosed as controls (CON; BHB <1.2 mM, n = 30), subclinically ketotic (SCK; 1.2 < BHB <3.0 mM, n = 30), or clinically ketotic (CK; BHB >3.0 mM, n = 30). Cows were selected from a commercial farm of 214 Holstein cows (average 305-d yield in the previous lactation of 35.42 ± 7.23 kg/d; parity, 2.41 ± 1.12; BCS, 3.1 ± 0.45). All plasma and milk samples (n = 90) were subjected to liquid chromatography-MS-based metabolomic analysis. Statistical analyses were performed using GraphPad Prism 8.0, MetaboAnalyst 4.0, and R version 4.1.3. Compared with the CON group, both SCK and CK groups had greater milk fat, freezing point, and fat-to-protein ratio, as well as lower milk protein, lactose, solids-not-fat, and milk density. Within 21 d after calving, compared with CON, the SCK group experienced a reduction of 2.65 kg/d in milk yield, while the CK group experienced a decrease of 7.7 kg/d. Untargeted metabolomics analysis facilitated the annotation of a total of 5,259 and 8,423 metabolites in plasma and milk. Differentially affected metabolites were screened in CON versus SCK, CON versus CK, and SCK versus CK (unpaired t-test, false discovery rate <0.05; and absolute value of log(2)-fold change >1.5). A total of 1,544 and 1,888 differentially affected metabolites were detected in plasma and milk. In plasma, glycerophospholipid metabolism, pyrimidine metabolism, tryptophan metabolism, sphingolipid metabolism, amino sugar and nucleotide sugar metabolism, phenylalanine metabolism, and steroid hormone biosynthesis were identified as important pathways. Weighted gene co-expression network analysis (WGCNA) indicated that tryptophan metabolism is a key pathway associated with the occurrence and development of ketosis. Increases in 5-hydroxytryptophan and decreases in kynurenine and 3-indoleacetic acid in SCK and CK were suggestive of an impact at the gut level. The decrease of most glycerophospholipids indicated that ketosis is associated with disordered lipid metabolism. For milk, pyrimidine metabolism, purine metabolism, pantothenate and CoA biosynthesis, amino sugar and nucleotide sugar metabolism, nicotinate and nicotinamide metabolism, sphingolipid metabolism, and fatty acid degradation were identified as important pathways. The WGCNA indicated that purine and pyrimidine metabolism in plasma was highly correlated with milk yield during the peripartal period. Alterations in purine and pyrimidine metabolism characterized ketosis, with lower levels of these metabolites in both milk and blood underscoring reduced efficiency in nitrogen metabolism. Our results may help to establish a foundation for future research investigating mechanisms responsible for the occurrence and development of ketosis in peripartal cows.

Condensed tannins fed to dairy goats: Effects on digestibility, milk production, blood parameters, methane emission, and energy and nitrogen balances

Condensed tannins (CT) are plant polyphenols that can affect feed digestibility and are potentially able to reduce enteric CH4 emissions in ruminants. In this in vivo trial with 8 lactating goats, we investigated the effects of 4 levels of inclusion of a commercial CT extract from quebracho (0%, 2%, 4%, and 6% on dry matter basis; CON, Q2, Q4, and Q6, respectively). The experimental design was a repeated 4 × 4 Latin square with 28-d periods (24 d of diet adaptation and 4 d of sample collection) using metabolic cages and 4 open-circuit respiration chambers. The inclusion of CT in the diets did not affect the dry matter intake (DMI) but caused a linear decrease in diet digestibility, with reductions up to -11% for dry matter, -21% for crude protein (CP), -23% for α-amylase- and sodium sulfite-treated neutral detergent fiber corrected for insoluble ash (aNDFom), and -13% for gross energy, when comparing the Q6 and CON diets. However, ruminal total volatile fatty acids (VFA) concentration was not affected by CT, although there were changes in VFA proportions. Milk yield was highest for Q4 (3,371 g/d) and lowest for Q6 (3,066 g/d). In terms of milk composition, CT induced a linear reduction of fat and CP concentrations. The reduction in CP digestibility resulted in a linear reduction in the milk urea level, up to -37% with Q6. Positively, CT linearly reduced the somatic cells count expressed as linear score. The feed efficiency was linearly decreased by CT inclusion. Furthermore, a shift from urinary to fecal nitrogen excretion was observed with CT. The retained nitrogen was always negative (on average -1.93 g/d). The CH4 yield (on average 19.2 g of CH4/kg DMI) was linearly reduced by CT inclusion, up to -18% with Q6. Regarding the CH4 intensity, CT induced a linear reduction when expressed per kilogram of milk, but not per kilogram of fat and protein-corrected milk. Moreover, the CH4 production per kilogram of digestible aNDFom was linearly increased by CT. The metabolizable energy intake (MEI) was not affected by the treatments, but the metabolizability (q = MEI/gross energy intake) was reduced as CT inclusion increased. From the results of the present study, it turned out that CT have a negative impact on feed digestibility and feed use efficiency. Condensed tannins can lower CH4 emissions from ruminants; however, the main mechanism of action is likely the decrease in feed digestibility. Furthermore, CT did not improve the N use efficiency. According to these findings, the positive environmental impacts of CT are only related to the shift from urinary to fecal N excretion.