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Quantitative determination of conjugated linoleic acid and polyunsaturated fatty acids in milk with C17:0 as internal marker - Evaluation of different methylation procedures.

ABSTRACT: Fatty acids are commonly analysed by gas chromatography as their corresponding fatty acid (FA) methyl esters (FAME). For quantitative determination of individual FA an internal standard like C17:0 is necessary. Conjugated FA and polyunsaturated fatty acid (PUFA) represents a challenge in the methylation steps, as they are sensitive to pH changes and oxidation. The present study was carried out to determine the efficiency of different methylation procedures on quantitative determination of conjugated linoleic acid (CLA), PUFA and response of internal standard. The highest response of internal standard was observed for boron trifluoride (BF₃)/methanol and methanolic HCl followed by NaOCH₃, while cis-9, trans-11 CLA, total CLA and PUFA was higher with methanolic HCl followed by NaOCH₃ compared with the BF₃ method. These data can be useful for quantitating of milk FA.

SUBMITTER: Lashkari S

PROVIDER: S-EPMC5614719 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

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Quantitative determination of conjugated linoleic acid and polyunsaturated fatty acids in milk with C17:0 as internal marker - Evaluation of different methylation procedures.

Lashkari S S Jensen S K SK

Data in brief 20170915

Fatty acids are commonly analysed by gas chromatography as their corresponding fatty acid (FA) methyl esters (FAME). For quantitative determination of individual FA an internal standard like C17:0 is necessary. Conjugated FA and polyunsaturated fatty acid (PUFA) represents a challenge in the methylation steps, as they are sensitive to pH changes and oxidation. The present study was carried out to determine the efficiency of different methylation procedures on quantitative determination of conjug ...[more]

PMID: 28971129

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Project description:The objective of this study was to determine whether adding phytoncide oil (PO) and soybean oil (SBO) to the dairy cow diet could increase milk conjugated linoleic acid (CLA) and depress methane (CH4) emissions in Holstein dairy cows. Rumen fermentation was conducted at four levels of SBO (0, 1, 2, and 4%, on DM basis) and two levels of PO (0 and 0.1%, on DM basis) with in vitro experiment. To evaluate blood parameters, fecal microbe population, milk yield and fatty acid compositions, and CH4 production, in vivo experiment was conducted using 38 Holstein dairy cows divided into two groups of control (fed TMR) and treatment (fed TMR with 0.1% PO and 2% SBO as DM basis). In the in vitro study (Experiment 1), PO or SBO did not affect rumen pH. However, SBO tended to decrease ruminal ammonia-N (p = 0.099). Additionally, PO or SBO significantly decreased total gas production (p = 0.041 and p = 0.034, respectively). Both PO and SBO significantly decreased CH4 production (p < 0.05). In addition, PO significantly increased both CLA isomers (c9, t11 and t10, c12 CLA) (p < 0.001). Collectively, 0.1% PO and 2% SBO were selected resulting in most effectively improved CLA and decreased CH4 production. In the in vivo study (Experiment 2), 0.1% PO with 2% SBO (PSO) did not affect complete blood count. However, it decreased blood urea nitrogen and magnesium levels in blood (p = 0.021 and p = 0.01, respectively). PSO treatment decreased pathogenic microbes (p < 0.05). It increased milk yield (p = 0.017) but decreased percentage of milk fat (p = 0.013) and MUN level (p < 0.01). In addition, PSO treatment increased both the concentration of CLA and PUFA in milk fat (p < 0.01). Finally, it decreased CH4 emissions from dairy cows. These results provide compelling evidence that a diet supplemented with PSO can simultaneously increase CLA concentration and decrease CH4 production with no influence on the amount of milk fat (kg/day) in Holstein dairy cows.

Project description:Conjugated linoleic acids (CLAs) and conjugated linolenic acids (CLNAs) have gained significant attention due to their anticarcinogenic and lipid/energy metabolism-modulatory effects. However, their concentration in foodstuffs is insufficient for any therapeutic application to be implemented. From a biotechnological standpoint, microbial production of these conjugated fatty acids (CFAs) has been explored as an alternative, and strains of the genera Propionibacterium, Lactobacillus, and Bifidobacterium have shown promising producing capacities. Current screening research works are generally based on direct analytical determination of production capacity (e.g., trial and error), representing an important bottleneck in these studies. This review aims to summarize the available information regarding identified genes and proteins involved in CLA/CLNA production by these groups of bacteria and, consequently, the possible enzymatic reactions behind such metabolic processes. Linoleate isomerase (LAI) was the first enzyme to be described to be involved in the microbiological transformation of linoleic acids (LAs) and linolenic acids (LNAs) into CFA isomers. Thus, the availability of lai gene sequences has allowed the development of genetic screening tools. Nevertheless, several studies have reported that LAIs have significant homology with myosin-cross-reactive antigen (MCRA) proteins, which are involved in the synthesis of hydroxy fatty acids, as shown by hydratase activity. Furthermore, it has been suggested that CLA and/or CLNA production results from a stress response performed by the activation of more than one gene in a multiple-step reaction. Studies on CFA biochemical pathways are essential to understand and characterize the metabolic mechanism behind this process, unraveling all the gene products that may be involved. As some of these bacteria have shown modulation of lipid metabolism in vivo, further research to be focused on this topic may help us to understand the role of the gut microbiota in human health.

Project description:Background:Starch is an important substance that supplies energy to ruminants. To provide sufficient energy for high-yielding dairy ruminants, they are typically fed starch-enriched diets. However, starch-enriched diets have been proven to increase the risk of milk fat depression (MFD) in dairy cows. The starch present in ruminant diets could be divided into rumen-degradable starch (RDS) and rumen escaped starch (RES) according to their different degradation sites (rumen or intestine). Goats and cows have different sensitivities to MFD. Data regarding the potential roles of RDS in milk fat synthesis in the mammary tissue of dairy goats and in regulating the occurrence of MFD are limited. Results:Eighteen Guanzhong dairy goats (day in milk?=?185?±?12 d) with similar parity, weight, and milk yield were selected and randomly assigned to one of three groups (n?=?6), which were fed an LRDS diet (Low RDS?=?20.52%), MRDS diet (Medium RDS?=?22.15%), or HRDS diet (High RDS?=?24.88%) for 5?weeks. Compared with that of the LRDS group, the milk fat contents in the MRDS and HRDS groups significantly decreased. The yields of short-, medium- and long-chain fatty acids decreased in the HRDS group. Furthermore, increased RDS significantly decreased ruminal B. fibrisolvens and Pseudobutyrivibrio abundances and increased the trans-10, cis-12 conjugated linoleic acid (CLA) and trans-10 C18:1 contents in the rumen fluid.A multiomics study revealed that the HRDS diet affected mammary lipid metabolism down-regulation of ACSS2, MVD, AGPS, SCD5, FADS2, CERCAM, SC5D, HSD17B7, HSD17B12, ATM, TP53RK, GDF1 and LOC102177400. Remarkably, the significant decrease of INSIG1, whose expression was depressed by trans-10, cis-12 CLA, could reduce the activity of SREBP and, consequently, downregulate the downstream gene expression of SREBF1. Conclusions:HRDS-induced goat MFD resulted from the downregulation of genes involved in lipogenesis, particularly, INSIG1. Specifically, even though the total starch content and the concentrate-to-fiber ratio were the same as those of the high-RDS diet, the low and medium RDS diets did not cause MFD in lactating goats.

Dataset Information

Quantitative determination of conjugated linoleic acid and polyunsaturated fatty acids in milk with C17:0 as internal marker - Evaluation of different methylation procedures.

Publications

Quantitative determination of conjugated linoleic acid and polyunsaturated fatty acids in milk with C17:0 as internal marker - Evaluation of different methylation procedures.

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